3/11/2011
-- I am in the middle of rewriting this with the latest, improved
techniques. The big changes (already added below) are new mold-lining
techniques to replace spray paint: a fast tape-lining method and a
resin-lining method. I will eventually add additional and improved
images, and review the whole mess to prune out the numerous false
starts.
Here are the latest and greatest:
Here are some examples of index-cardstock molds and their castings
This octahedron is about 3/4" tall:
The mold is masking-taped closed and taped to a base for stability.
This
bar is 1.5" long -- the mold that it was cast in is flipped upside-down
to show it better (note masking tape to removibly secure the corners).
To the right is the taped-together mold, taped to a stability base,
with a cross-bar buttress to hold the sides in against the outward
pressure of the liquid resin (if I were making a batch of these, I would
line molds side-by-side so as to only need to buttress the outermost
sides):
One-use glued-together mold
(this was not the best way to mold something this intricate -- see later suggestions):
Assembled bars and cross-bits:
The
cross elements above are a complex, challenging, fragile shape,
requiring a fancy one-use mold -- you can see it didn't come out
perfectly (the rods were thicker than their sockets so the bottom brace
broke during assembly), but the rod bits did (trust me
)
Nice hex chip (1.2" side to side)
Printed-out index-card pattern for hex chip mold:
Pencil-rubbing embosses the letters from a quarter on the mold:
The cardstock mold... embossed, scored, folded and embellished with a hole-punched dot of craft foam and a star decal:
Taped
and buttressed by an anti-skew skirt (a mold pattern with the center
cut out outside the lines to accommodate the thickness of the walls and
tape... masking tape tape still needed to seal corners):
Face-on
view of cast resin chip, showing socket and embossments: star indent
and barely legible letters (the excessively wavy texture is due to
applying inadequately mixed/smeared release agent):
I
reused the same cardstock hex chip mold six months later (without the
dot) but with smoother grease so less texture and quite legible embossed
lettering:
Side view of first hex chip from cardstock mold (all major flaws are due to incompetent resin mixing/pouring):
Reverse
side of first hex casting (blank top side of mold) note less wavy
texture from better smeared greasing (the seeming underfill void at
lower right is actually due to an insufficiently weighted lid which
allowed the self-repulsive resin to push up and the frozen bubbles are
from not waiting for it to gas-out):
Characteristic
self-repulsion void of fresh resin added atop old (solid, yet not fully
cured) resin -- note how the right side of the lid was actually pushed
up off the side wall so that a void could form:
Edge view of 2nd, better-poured, chip:
Edge view of newest, almost-perfect chip:
This
is a cute trick for casting (and prototyping) simple game bits (like
dice) without the hassle, expense, and time of making a latex/silicone
mold (which is an art in itself!). A nice way to "jump into" resin
casting without needing anything but the resin (plus catalyst) and also
an easy way of creating geometrically regular, precision-designed
originals that are (ironically) hard to sculpt! Also, you can share the
patterns physically or over the internet, which is cool. A game could
come with printed molds for the pieces for DIY'ers. At their simplest,
these are flat-sided objects -- I will give tips on how to produce
indentations with these molds, e.g., pips on dice... simply curved
surfaces should also be possible. Originals made this way can also be
incrementally modified to add fancier details. With a fixative and some
care, the molds can be reused at least a few times. I've only tried
this with slower-curing "small-jug" clear acrylic, so I can't be sure
that fast-curing "big-jug" resin wouldn't bond to the cardstock despite
the release agent (fast-curing binary epoxy did this when I tried it,
but my technique wasn't as good then -- it still works but I had to soak
and scrub off the soggy mold, so it isn't at all reusable).
Why:
I
came up with this technique for three reasons: first, I'm cheap (I
already spent the 12$ for a starter mix kit at Micheal's crafts and was
hesitant to invest another $15 in mold-builder glop when I already have
too many un-used craft supplies cluttering my shelves!), second, I'm
impatient (slow curing resin already consumes up to a day to cure, and
when I bought the vile-smelling latex mold-builder, I found that it
takes days to cure, although my technique is underdeveloped), and third,
I was trying to make geometrically regular, symmetric, precision-shaped
bits, rather than detail-sculpted miniature figures, so it occured to
me that if I printed them out, they'd be regular, precise, and have flat
surfaces. (In ten years, 3D "printers" may be available, but until
then, we'll have to make do.)
addendum: I used the clear
resin because it's readily available in small/cheap quantities. For
anyone new to resin casting, it can be purchased in all sorts of solid
colors, including various faux stone types.
http://hirstarts.com/
is a great knowledge resource.) Here is a great resin-casting
tutorial, and funny (she's using a store-bought plastic mold with
indented gem shapes):
http://www.youtube.com/watch?v=0pnr21sjV2g
As she explains, there are two kinds of casting plastic: one is a
type of binary epoxy and the other is a catalyzed resin -- the latter is
a really noxious, smelly chemical (like model cement x 100) that cures
faster. I think all the solid colors are the latter variety. The
binary kit is a cheaper, more pleasant start, but the resin is cheaper
in bulk. Here are both types (plus the not-so-noxious yet still
vile-smelling latex mold builder -- if you ever want mold builder, get
the silicon variety if at all possible!)
"Quick" Process Summary:
-Design a form on you computer;
-Print
it on medium thickness index card stock (or other cardstock -- textured
stock will produce textured castings; I don't think that the thinnest
index card stock, e.g., Oxford 3x5", is stiff enough to be of much use
-- Mead brand 3x5's are suitably thick);
--Line the mold to keep the release agent from infiltrating and softening the mold:
--Either:
-(For
a fast, one-use mold) Apply mailing/package tape to the inside face of
the card (this is usually the back side). This will seal it so the
resin doesn’t adhere to the card -- you will usually also need an
unprinted "lid" card that is similarly prepared;
--Or
-(For a reusable mold)
(Spray
both sides with a fixative (like spray paint) to make the stock firmer,
more durable, less permeable to the release agent, and score more
cleanly -- you will usually also need an unprinted "lid" card that is
similarly prepared (I happen to have clear spray paint, but since you
will usually be spraying the reverse of the printed side, it shouldn't
matter what color it is); I believe that the spray paint I used
to use as a fixative produced the many bubbles and yellowing seen in
the above bits -- it's quick but dirty. Instead, seal the cardstock
with the casting resin for a longer-lasting, more cleanly removing mold
-- you will usually also need an unprinted "lid" card that is similarly
prepared. This is very messy! I usually treat several molds at a time
since it’s a big production.
On a disposable work surface, such
as a plastic garbage bag taped onto a table, with lots of ventilation,
rubber gloves, lots of paper towels, and skin lotion ready to remove
stray resin from yourself, mix a small amount of resin and apply it to
the inner-mold surface of the printed index card (this is usually the
back side -- it’s a good idea to also treat the outside face). A folded
index card, taped over with packing tape, makes a nice disposable
spatula: spread the resin back and forth so that it penetrates and
permeates the entire printed area of the card, then scrape off the
excess (it can be re-used on the other side), flip the card, then treat
the reverse side. Scrape off the excess and wipe each side "dry" with a
piece of paper towel (it may take several flips and moves to dry areas
on the work surface to completely "dry" the card). Set aside to dry for
24+ hours with the "bad" (outside) face, downwards, on something
stick-proof, like wax paper or a disposable plastic plate.
--[REDO
FOR TAPE LINING METHOD!] Cut out the form and score the fold lines with
an X-acto knife (for crisp corners) then fold it (the printed side will
be the outside) into a (most easily) open-top form and tape together
with masking tape (scotch tape gets unstuck by the resin);
-(Optionally) glue or masking tape it onto a cardstock base strip for stability and as a handle;
-If
necessary, buttress the sides to keep them from skewing or bowing out
under the pressure of the resin inside -- anything removable that will
hold the sides in place will do, e.g., taping a little block in place...
one idea, shown above and below, is an anti-skew skirt/cuff made from
another card with the form printed on it, but only the form cross
section cut out (outside the lines to allow for the thickness of the
walls and maybe notches for the masking tape at the corners). Cover the
buttress/skirt with masking tape, which resin doesn't stick to well;
-Add
an narrow removable collar of masking tape around the top of the
taped-up mold to raise the lip by 1/8 or so to draw the resin meniscus
(which will be concave) up so that the center level is about where we
want the final surface to be with one pour. (The extra resin on the
collar will be removed when the top is placed.);-If you
are not using a tape-lined mold, you will need to add a release agent
to keep the resin from sticking to it; if you are using a tape lining,
you don't need a release agent, and if you use one, brush marks will be
visible on the casting (which could add grain/texture, if so desired).
Grease the inside and lip with a release agent (see below), allow it to
"dry" fully (it should leave a noticeable greasy residue!) Do this with
the skirt and lid (inner and outer surfaces) too. Release agent (I'll
call this "grease" when I get lazy) can be bought where resin is sold or
you can make your own of a
thoroughly blended/smeared 1:3
solution of petroleum jelly and paint thinner/naptha/gasoline -- the
idea is to dilute the jelly into an emulsion(?) so that when the solvent
evaporates, a thin, even layer of grease is left behind. The easiest
way of getting the jelly thoroughly emulsified is to mix it in with a
Q-Tip, mashing it against the walls of your mixing container to
repeatedly soak up and squeeze out the mix (you could similarly rub the
jelly into a piece of paper towel or cotton ball that you then place in
your solvent reservoir, then repeatedly soak up and squeeze out the mix.
More coats of greater dilution should work best -- for a smooth
texture, you want well-mixed release agent that is smeared: a Q-tip is a
good applicator, although a small brush will help get it into the
corners and crevices. To add a wavy or mottled texture, mix a smaller
ratio of jelly into the solvent (and apply it to the mold) with a paint
brush so there will be suspended globs of jelly that aren't smeared
flat. (Skin lotion is good at removing any sticky resin you get on your
hands, tools, etc. -- smear some on a strip of paper towel to keep
handy while you work.) I am legally required to tell you that you
should wear rubber gloves and eye protection at all times when working
with casting fluids, and work only in a well-ventilated area;
-Pour
your resin. Always mix more resin than you'll need, as multiple mixes
(or even pours) will produce visible boundary layers, as on the hex bit
shown above (if you're using a solid color resin or you're going to
paint the bit, that's less important). Clear resin may be tinted with
the dyes sold for this purpose or (less successfully) with inkjet
printer dye -- this resulted in a particulate appearance when I tried
it... for a "marbled/seamed" look, separate a portion of the mixed resin
to dye and then stir it into the clear resin poured in the mold --
you'll probably want to leave room to pour a clear layer at the top so
that it doesn't streak when you level it off. (Acrylic paint also works
for coloring/marbling resin, but I can't say for sure how this would
affect the bit's structural integrity and durability);
-Wait for the resin to gel up a bit and de-gas (bubble out) -- for warmed Clear Cast Epoxy, 1-3 hours --
then peel off the temporary collar (never mind any excess resin that comes off with it).
Any surface bubbles can be popped with a pin or needle, or pulled out
with a toothpick. Manually flatten the resin surface by pressing on
your greased top cover with a flat presser: excess resin will be forced
out the sides (if you way over-filled it, you might first need to dip
in a toothpick to pluck out some resin to keep the sides from bowing
out). Use a greased blade (e.g., X-acto knife) to scrape away any stray
resin on the top, then flip the mold, so the top is now at the bottom,
and scrape away the excess resin that was forced out on the lid and
sides of the mold. Check that the adjacent sides are still flat: if
they're bulging, press them with the blade to push some more resin out
the loose lid. Any resin on the outside of a crack will draw resin out
from the inside, leaving voids! We flip the mold not merely to easy
scraping away the excess resin but to reverse the motion of any hidden
bubbles that were rising to the lid, so they hopefully get trapped in
the middle of of the resin, rather than on any face surface;
-You
need to place a flat weight on top of the mold as the resin cures (the
weight needs to be significant: tape will not be adequate, as the resin
repels itself so strongly that it can rapidly force the lid up to open a
void inside!). A coffee mug is about the right weight: you might tape
the mold down just to make it a stable base, then place a piece of wax
paper on top to protect the bottom of the weight, and tape-tether the
mug so it stays balanced on top (or place other objects around the mug
so it can't lean or fall to any side);
-When the resin has become
basically solid -- for Easy Cast Epoxy, this takes 8-12 hours, although
it will actually stay flexible for days -- peel/cut the tape away from
the sides of the mold so you can pull/peel them free of the bit (a
little petroleum jelly on you fingers will help keep the resin from
sticking to you; avoid touching the sticky casting itself -- you may
want to allow the resin to cure further before you peel it off the
bottom of the mold so that it won't get finger prints, etc., on it in
the process. If you wait too long to start peeling off the mold, it may
stick permanently -- solvent/release compound can help with stubborn
areas.) Pick/peel/scrape residual resin from mold if it is to be reused
(an X-acto knife is good for all of these steps). Snip/slice off any
flash (places where the resin may have oozed out of the mold);
-Finishing:
matte/foggy surfaces on translucent bits can be clarified/smoothed
with a little resin catalyst, a layer of fresh resin mix, water-diluted
acrylic floor "wax", e.g., Future brand, or (probably) clear spray
paint. If you're going to paint the bit, so transparency isn't an
issue, small hollows can be filled in with more resin (remember to
weight any top or the resin will push it up and leave a cavity!) or
Future wax (you can build up significant thickness with this stuff).
Bits can be painted (presumably, acrylic paint would be best, and might
stick better to slightly sticky resin). When resin is fully cured,
surfaces can be smoothed with (pricey) 800+ grit automotive sand paper
(give it two days at least! -- even if it seems fully hardened, it can
still soften and smear due to the heat of friction). A swipe of
lower-grit sandpaper could be used to add a faux wood-grain;
Drafting the pattern:
We
could simply draw a form diagram on cardstock with a printed grid
pattern, but that's tedious, unreproducable, and requires that the grid
be accurate. I simply use MS Word to design forms: it has proper
rulers, an adjustable grid/snap function, and allows you to group and
resize figures (not including text boxes). Following Pelni's advice
(see reply below), I finally downloaded Inkscape (you want the
"Installer") and it is indeed awesome for this, once you figure out the
myriad options. Here, we want a simple hexagon with rectangular sides
that fold up (I won't bother with a top). Snap to Grid/Objects modes
can alternatingly be a help or a hindrance to align the shapes (for this
project, the shapes won't snap together). I choose hexagon from Quick
Shapes, then hold the shift key down to draw it equilateral. (In
Inkscape, you'll want "Snap-to-everything.") I can always resize the
whole form pattern later, but to properly coordinate the side heights
versus lateral dimensions, I should try to get them correct from the
start, so let's say that I lay out the hexagon to a definite size (we
can adjust this with the Format command, although I want the the
height/width ratio of the hexagon stay constant). Then I'll draw a side
rectangle along a horizontal edge to match the edge length as closely
as I need (I will set the shapes to be transparent (no fill) and
overlap the edge lines to help align them. I can then format the box
(hence, bit) height to a specific measurement. Now I copy and paste it
into the other five side positions, rotating by +/-60 degrees with
Format to align them and copying the opposite sides to save effort (I
find they sides crowd at the corners so I have to go back to resize and
recopy the original rectangle for a better fit). I want to add an
embellishment to the center of the bottom, so I draw cross-hairs to mark
it. Then I draw a circle around it to center the coin I want to emboss
inside. I then select the whole pattern and Group it to make it one
object.
One won't normally want to add an attached lid to the
form, as it serves no purpose and complicates pouring the resin, but it
might be needed if both top and bottom had embellishments that had to be
centered and aligned, as on the die below:
In the form below, I attach a duplicate cap hexagon and sides:
While
the sides on the bottom half are taped together to form the sides of
the mold, the top ones are simply folded down as flaps so that the lid
will close into a relatively fixed alignment. You can see this in the
cube mold below (as well as a buttressing anti-skew skirt):
This mold on the right is taped together, taped down, buttressed, and ready to pour.
Depending
on how large my pattern and cardstock are, I may arrange duplicates of
the pattern on the same page for printing. For a complicated
object/pattern, it can be useful to print the pattern on the cardstock
base to help align things (like the arms of the cross elements in the
fancy assembly above): if you find yourself needing this, you might
want to re-consider the use of this technique or your pattern... If I
try making this cross-bar element again, I might glue together an
original out of separately cast reusable elements to pour a conventional
mold around, or fill the card mold with hot glue or something to make
it rigid, then pour a layer of resin around it to make a negative "pour
and pop through" mold.
Fancy stuff:
I'm just going to
throw some extra stuff out here, since I've been working on this this
post for months and I'm really sick of it now. Embossing: Emboss after
spraying on the fixative; temporarily affix the item to the card so it
stays put as you rotate it to make the rubbing. BGG's "Lindelos" had
the idea of copying the fine interlocking ridges that allow poker chips
to stack onto self-made pieces for his "Compass" prototype: this can
certainly be done with conventional molding (remember the mini
sculpter's motto: "Why sculpt a shape when you can copy it from
something you have lying around?"); this might just work with this
cardstock technique by firmly pencil-rub embossing the fine ridges on
the outside surface of the mold, as I did the (much larger) lettering
from the coin in the hexagon chip above (these ridges might be too fine
to emboss -- I tried this, running the point of the pencil radially to
accent the ridges and it seems borderline for molding). (Incidentally,
this stacking only looks perfect for circular chips (or bits with a
definite top and bottom), as geometry dictates that the bits can't
always sit on each other in perfect rotational alignment if any are
flipped.)
If one were making a bunch of identical/corresponding
bits, arranging the molds in an array will reduce wasted resin and
eliminate the need for side buttresses except at the outside border:
bars could be laid side by side, hexagons in a hex grid, etc..
One
might experiment with different orientations of the same shape, for
example, turning a hex on its side and filling from one skinny side.
Since the top side tends to have a different texture and otherwise be
problematic, this could mean a smaller, less noticeable problem area.
It might make frozen-in bubbles less (or more!) of a problem.
Here's a little primer on "Undercuts:"
One
might use the same techniques to make a cardstock prototype original
that might be filled with hot glue to be rigid, then place a wide lid
over and flip to pour mold builder over. For simple Meeple-type bits,
one could probably make a rigid pop-through mold (removable top, adhered
bottom) with casting resin itself: here, the mold needn't be flexible
because the bit can be pushed right out.
For a one-use (or
pop-through) mold that won't need to be peeled apart, hot-glue makes a
good sealer/damming/buttressing material.
Related:
A
variety of materials can be used as unorthodox resin molds, most
obviously, rubber baking/ice-cube forms (silicon or otherwise).
Anything rubbery is a potential candidate: hot glue, foam craft
sheeting, oven-bake clay, and, as a liner in a cardtock mold, vinyl
contact paper/shelf liner, duct and masking tape -- these last two add
interesting, more organic textures to the bit. Below are a bit cast in a
masking tape-lined mold (left) and craft sheeting (right):
I
have been told that people have used latex caulk as a mold builder, but
I couldn't get mine to cure fast enough to bother. One should bear in
mind that larger castings (and/or faster-curing "big-jug" resin) can get
quite hot, which might warp or melt something like hot glue (binary
epoxy is basically the same thing as fast-casting resin (you can indeed
cast bits with it), and gets hot enough to be a fire hazard). Ideally, a
mold should be reusable, which requires that the cast bit can be
removed non-destructively -- this either requires a flexible mold or a
mold form that can be unfolded and peeled off the sticky bit inside.
Cardstock falls in the latter category. Less-flexible elements like
hot-glue, etc., can then be affixed to emboss the inner faces of the
cardstock to leave indentations in the cast resin when the form/mold is
peeled away, e.g., pips or numbers on a die. In the hex chip shown
above, a simple star sticker and stick-backed craft-foam dot produce
tidy indentations -- cardstock cut-outs could be used to emboss just as
well, as might be hot glue, regular glue, or possibly even a volumetric
pen (not the correct name for those pens that draw puffy lettering on
fabric) or a thick paint (the release agent kept the sticker from
grabbing the resin instead of the cardstock, so this should work too).
Craft foam sheeting with holes in it (affixed to an outer surface) could
also be used as a basing instead of an embossment, so that one gets a
projecting bas-relief in the casting, rather than an indented one... one
might make ones own LEGO-type pieces with corresponding plugs and
sockets (this might or might not be as easy as punching a hole and using
the removed dot as the corresponding negative). Something like this:
You
can cast a cylinder in a suitably-greased section of drinking straw...
(if you wait several days for it to fully cure then roll it in the straw
a bit, there should be less resistance). Any tall pop-through mold
might adhere to the large side surface area too strongly to pop through.
Gorno
-
-
-
-
Very cool stuff.
Resin will not stick to two things. Wax
and silicone. And I've had great success using Future Floor Finish as a
release agent. You can a also buy a silicone spray. Both work well.
Any
ink without water as an ingredient can be used to tint the resin. Look
for lacquer based ink at a art/drafting supply shop. You use very
little and for very small batches it enough to simply dip and tooth pick
into the ink and use it to stir the resin.
In Canada you can get
a bar top finish called Nu-Lustre-55 (Available at Rona) that works
great and is cheaper and can be had in larger quantities than the water
effects stuff at Michaels.
I also vibrate the resin in the mold
and it seems to help with any bubbles but I have only used silicone
molds so far. I'll definitely have to give this a try.
-
-
-
-
MK-Ultra71 wrote:
Resin
will not stick to two things. Wax and silicone. And I've had great
success using Future Floor Finish as a release agent. You can a also
buy a silicone spray. Both work well.
I'm very surprised about the
(presumably water-diluted?) acrylic Future "wax" (I think we're talking
about the same product), since it sure seems to stick to solid resin.
Maybe there's some sort of odd reaction with the (also-acrylic) liquid
resin? Hmmm -- I don't recall if I ever tried household items
ScotchGuard (which has silicon) and Resolve carpet spray (which has
Teflon)... addendum: I did try these -- since they're water-based,
they make the cardstock soggy and leave it warped and weakened, also
ScotchGuard comes out as a foam.I tried cooking spray, but it was
too thick and bubbly (I like to inch my way into a DIY technique with
stuff I already have, especially as I usually lose interest once I've
convinced myself that I could do it if wanted to.)
They say that
binary casting epoxy and acrylic resin aren't compatible... I wonder
what would happen if one tried to layer them? Mix them? Mate them?
BWA-HA-HA! addendum:"... binary casting epoxy fluid can be
safely applied to cured polyester casting resin BUT polyester casting
fluid applied to cured binary epoxy resin will attack and soften it."
Maybe this incompatibility, in a beneficial effect, is what allows you
to use Future wax as a release agent?
MK-Ultra71 wrote:
Any ink without water as an ingredient can be used to tint the resin.
That's
why it's surprising the ink-jet ink worked at all! It dissipates into
tiny bubbles, and had no discernible effect on the mechanical properties
of the resulting bit... (It's probably not a great idea, but it works
and I had it already!)
MK-Ultra71 wrote:
Look
for lacquer based ink at a art/drafting supply shop. You use very
little and for very small batches it enough to simply dip a tooth pick
into the ink and use it to stir the resin.
In Canada you can
get a bar top finish called Nu-Lustre-55 (Available at Rona) that works
great and is cheaper and can be had in larger quantities than the water
effects stuff at Michaels.
I'm not familiar with either, are they
tints for clear resin? (I used the clear kind because it's readily
available in small/cheap quantities. For anyone new to resin casting,
it can be purchased in all sorts of solid colors, including various faux
stone types. http://hirstarts.com/ is a great knowledge resource.)
Gorno
-
-
-
-
Really cool and inspiring.
Inkscape is a free application that is good for drawings like those.
-
-
-
-
Great post.
This is a good and cheap method for making
small molds, and the great thing about it is that it's very accessible
to everyone. One of my hobbies before boardgame design was building
papercraft models. So while I was reading your post, the possibilities
seemed endless! You could make simple characters, towers, doorways,
walls, and all sorts of objects using this method. Since cardstock
molds are generally one-use deals, if you need to make anything in bulk
you could always use a RTV molding agent to cast your original object,
assuming it came out well enough that you'd like many copies of it.
-
-
-
-
Wow. 5 GG to you. Great post.
-
-
-
-
This is a great resin-casting tutorial, and funny... (quoting from another thread):
xeromist wrote:
Gorno
-
-
-
-
I forgot to mention in my original post that patterns can be
shared physically or over the internet, which is cool. A game could
come with printed molds for the pieces for DIY'ers.
I have to
confess that my paper-casting technique isn't as perfected as I thought:
I have gotten some perfect results with closed-top molds, but I haven't
gotten it down to the science I thought I had -- I will keep updating
my original post as I continue to refine my technique. Resin is a very
oddly behaved substance: it's very self-repulsive so loves to climb
walls and overflow, even forcing off a loose lid to make room to form an
edge void, but seems to contract in its final curing phase, producing a
(smaller) corner void if the lid is tight! This combination is a big
challenge to fully closed, self-finishing molds like what I'm trying to
do, but I hope I can discover a reliable procedure as I keep
experimenting. It needs to be open to de-gas, then held closed to avoid
voiding, and then we have to worry about contraction! If one doesn't
mind sanding off one surface (or accepting frozen bubbles there), it's
fine.
My latest idea Edit: sucked is to add an
extra removable collar around the top of the taped-up mold (either wax
paper or just masking tape) to draw the resin meniscus up so that the
center level is where we want the final surface to be: once the resin
de-gasses and gels, I'll pull off the collar (never mind the excess
resin) to close and weight the lid. My next idea is to leave one corner
unweighted and curled up slightly so there's extra resin there to be
drawn in as it contracts.
I definitely recommend the
clear casting (binary mix) epoxy to start with: the low odor and more
predictable mixing are worth the slow curing process, especially now
that's it's too cold up North to be properly ventilated! Micheal's
Crafts Stores sells these (hiding on the bottom shelf in the adhesive
section at my local store): if you can get a weekly circular, there's
always a "40% off one item" coupon.
Gorno
-
-
-
-
"Good news, everybody!"
I've figured out how to get very nice results on all sides: my trick
is to do all but a top face first (under-fill), then over-fill the top
after the initial pour cures (then cover, flip, and weight it after the
top fill gels). I've also come up with a much simpler, albeit one-use,
alternative technique with minimal mold preparation that further
produces smooth-faced bits like those above: I revisited my original
thought of backing the pattern with mailing tape (thus, lining the
inside of the mold) and creasing along the folds -- I now score the
cardstock into panels for sharp, uniform folds/edges, and it turns out
to be surprisingly easy to do so without scoring the tape in the
process!) I'll eventually get around rewriting my original post to
reflect what I've learned, and I'll shortly start to post a series of
instructional projects of increasing difficulty.
Gorno
-
-
-
-
John, thank you for this great post. 5 geek gold to you sir! Your
concept is explained in such thorough detail here, and I really
appreciate it, as I am about to make my entry into the resin-casting
world. I have carefully read through your instructions several times,
and have even taken notes, so I think I am ready to try soon!
But,
I did then read this final post you left here, and I am just slightly
confused about your new-found alterations and techniques. Could you
possibly explain them a little more thoroughly? To clarify:
1) I
am under the impression that you now fill in the bottom 3/4 of a mold,
let it cure (8-12 hours?), then fill in the top section? Doesn't that
leave a visible seam line in your mold? I only ask because in your
initial instructions you said to mix more resin than you might need, as
second mixings/batches leave seams.
2) Are you saying that you
no longer coat the paper with the release agent, but rather now use
packing or cellophane tape to coat the inside of the mold? What do you
mean exactly when you say, "...and creasing along the folds -- I now
score the cardstock into panels for sharp, uniform folds/edges, and it
turns out to be surprisingly easy to do so without scoring the tape in
the process."?
I am so eager and excited to make nice, clean,
clear shapes like you have shown in your last picture there! They look
very cool, and I'm in love with your paper-mold technique. I have
always been very intimidated by the whole mold-making aspect, and since I
am pretty skilled at the computer, this is perfect for me!
Thank you again for such a great contribution to the gaming community!
-
-
-
-
rcpete22 wrote:
John, thank you for this great post. 5 geek gold to you sir!
Thanks for the generous tip! 
Quote:
1)
I am under the impression that you now fill in the bottom 3/4 of a
mold, let it cure (8-12 hours?), then fill in the top section? Doesn't
that leave a visible seam line in your mold? I only ask because in your
initial instructions you said to mix more resin than you might need, as
second mixings/batches leave seams.
Quite so! I am contradicting
that instruction... (one might possibly set aside the spare mix and
refrigerate it (in an air-tight, child-proof container!) in hopes of
slowing the reaction so that it could be used in the second step, but
even an identical mixture might not eliminate the boundary seam). You
fill the mold almost completely (>=95% of the volume) so that it
reaches the top edge on all sides (you may need to stir it to brush it
against them). Since the resin clings to surfaces, it will stay, while
leaving a slight hollow at the top. You let it cure fully before adding
the top layer and capping it, as fresh resin will melt almost-cured
resin (depending on the resin, up to 48 hours curing may be required).
If the resin is clear, the imperfect match of the layers will
leave a visible boundary layer, but only inside the bit and close to one
face... this is as close to perfection as I've been able to get -- I
decided that a uniform shape/surface took priority over a perfect
interior (much as with a supermodel!) (For the alternative
"overfill-then-sand" approach, I've found 800-grit automotive sandpaper
at Home Depot in sander-pad packs at a more reasonable price than
full-sheet packs.)
Quote:
2)
Are you saying that you no longer coat the paper with the release
agent, but rather now use packing or cellophane tape to coat the inside
of the mold? What do you mean exactly when you say, "...and creasing
along the folds -- I now score the cardstock into panels for sharp,
uniform folds/edges, and it turns out to be surprisingly easy to do so
without scoring the tape in the process."?
Correct: this is an
alternative approach in making one-use molds. In my first experiments, I
taped the back-side/inside of the card then folded the card/tape
composite into a mold -- unfortunately, this thick, two-layer composite
won't crease sharply, resulting in rounded edges, which might be
acceptable except that they wouldn't match the sharp edges where cut
seams met. My next thought was to cut apart the faces of the mold and
assemble them on the tape one by one, so that there would only be tape
at the seams, which could be folded crisply -- this is tedious and
imprecise. At the time, I discounted the idea of first taping the
card-back then cutting apart the panels on the tape (by slicing through just
the cardstock and leaving the tape intact), as I feared it would
irredeemably puncture the tape lining and let the resin pour out at the
bottom edge. When I finally revisited this idea I found that it
actually was possible to do this without ruining the tape layer
(heavy-duty mailing tape is thick enough to forgive the imprecision of
human slicing). Thus, we get the benefit of separate panels without as
much nuisance, while eliminating the need for a carefully administered
release agent. I haven't tried this with adhesive shelf liner, which is
even thicker but has a larger span than mailing tape -- it might not
crease sharply, on the other hand, it shouldn't separate into its
component layers the way mailing tape does, so should peel off more
easily (I often have to use an Xacto blade to start the corner of the
tape peeling off the finished bit).
I'm delighted that someone
wants to try this! It's still a finicky process, so expect to have
disappointments. I look forward to your feedback and recommendations on
improving the technique! And I will reapply myself to the re-write
effort with your clarifications in mind (I'll post a notification post
here when I finally re-do the main post).
By the way, the bubbles
and yellowing seen in many of the bit images I've posted seem to have
been a result of the spray paint I then used to coat the mold.
Gorno
-
-
-
-
Thanks for the clarification! Before going forward I will just
specify that I plan on using the EasyCast clear epoxy resin, as that
seems to be generally preferred.
Ok, to verify I have this all correct:
1. Create and print shapes on Word or Inkscape.
2. Apply
packing tape to shapes prior to cutting them. Two questions here: I
imagine you are using a clear mailing tape, rather than the yellowish
tape? I did some mock-up experiments with the clear packing tape and had
a very difficult time, if not near impossible, cutting only the card
stock without cutting the tape. I did do so once or twice, but it is
such a hit-or-miss procedure that it would not be reliably efficient.
Furthermore, I did not see any separation of two composite layers as you
were describing, so I'm pretty confident I am not using the tape you
are describing. In either case, I assume you're taping over the
unprinted side of the card stock, then folding it so the printed side is
on the outside of the mold.
3. After the shape is cut, you
are then folding it so the printed side of the card stock is to the
outside, and the tape forms a liner on the inside with a perfect seal
from the bottom to the side walls. Question: how do you seal the corners
(i.e. the vertical edges where the side walls meet)? In a simple
rectangle shape, the tape would of course have to be cut in order to
fold the walls up. Does putting a small piece of packing tape on the
outside of the corner sufficiently prevent leakage there?
4. Mix
the EasyCast, allow to sit 2-3 hours for it to gel/de-bubble (yes?),
then pour 95% of the mold, brushing it to the top edge of the mold (per
your instructions).
5. Allow resin to cure (12 hours for EasyCast?). For this step, is a weighted top cap necessary, since the mold is not filled?
6.
Mix new resin (or remix old resin if refrigerated - if this is the
case, does it need to sit for a couple of hours again, or is it already
ready to go after remixing?), then pour into small remaining cavity at
top of mold.
7. Place card stock top cap on top of mold, then
weight it with coffee mug-type weight. You had mentioned
inverting/flipping the mold at some point in your original
instructions... should this be done here, or is just putting the cap on
with weight sufficient?
8. Once resin cures, work shape out of mold, and mold is discarded.
When
I purchased the EasyCast I had also purchased the release agent by the
same company. Do you still suggest the above practice over the use of
the manufactured release agent, or were you just preferring the above
over the process of making your own release agent, as you had described?
Also, if using the new, tape-based technique, I take it it is no longer
necessary to use clear spray paint on the paper before proceeding?
Finally,
due to the 3-dimensional complexity of some of the shapes I'm looking
to make, I will be making a couple of different components in their
individual molds, then somehow gluing them together into the final
shape. What's the best way to glue two pieces of epoxy resin together?
More resin, regular epoxy glue, super glue, or something else?
Ok,
I think I have covered all my thoughts for now. I am excited to
experiment with all this! Thank you again for all your help and for
creating this innovative idea!
-Pete
-
-
-
-
rcpete22 wrote:
Thanks
for the clarification! Before going forward I will just specify that I
plan on using the EasyCast clear epoxy resin, as that seems to be
generally preferred.
I seriously need to get around to that
rewrite (it's been almost-done for months, and needs more, and
corrected, illustrations). I've just added the new lining methods (but
not the cutting and follow-up instructions) to the original post. I
will try to be as complete as possible here, but I don't have my notes
so I'll surely leave some stuff out.
My metal jug of the other
stuff (catalyzed polyester) gelled up sitting on the shelf, and it was
stinky anyway, so I haven't tested the new techniques with that,
although they should work.
I'll reorder your questions to present the answers more effectively:
Quote:
When
I purchased the EasyCast I had also purchased the release agent by the
same company. Do you still suggest the above practice over the use of
the manufactured release agent, or were you just preferring the above
over the process of making your own release agent, as you had described?
Also, if using the new, tape-based technique, I take it it is no longer
necessary to use clear spray paint on the paper before proceeding?
With
tape-lining, no release agent is necessary, in fact, petroleum jelly
will make the surfaces irregular (the imperceptible smear pattern in the
mold will be perceptible on the cast bit!) The store-bought release
agent would probably do no harm, since the tape may prevent it from
warping the cardstock, and might make the tape easier to peel off --
give it a shot and tell me how it works (remember to shake it up first
to get the full teflon goodness).
Quote:
In
either case, I assume you're taping over the unprinted side of the card
stock, then folding it so the printed side is on the outside of the
mold.
3. After the shape is cut, you are then folding it so
the printed side of the card stock is to the outside, and the tape forms
a liner on the inside with a perfect seal from the bottom to the side
walls. Question: how do you seal the corners (i.e. the vertical edges
where the side walls meet)? In a simple rectangle shape, the tape would
of course have to be cut in order to fold the walls up. Does putting a small piece of packing tape on the outside of the corner sufficiently prevent leakage there?
Your
assumptions are correct. Since the adhesive on plastic tapes is
dissolved by liquid resin (see next paragraph), the seams where side
edges meet need to be taped together with masking tape on the outside...
use standard masking tape, as I'm not sure if the low-tack, easy-peel
kind is sufficiently sticky to resist the solvent effect of the resin. I
use a tweezers to squeeze the tape and mold together in the
hard-to-reach corners. There will always be some leakage, it's OK.
Since
masking tape doesn't stick well to itself, make sure that the tape is
directly on the cardstock on either side of each seam, rather than
overlapping superfluous tape.
DO:
Seam tape DON'T!! -- masking tape trying to tape onto masking tape at seam! This will leak when exposed to resin! DON'T!!:
Quote:
I
did not see any separation of two composite layers as you were
describing, so I'm pretty confident I am not using the tape you are
describing.
Maybe I created a confusion between the unsharp-crease
issue and the layer separation. The separation happens to the tape as
it's being peeled off the cured bit: while fluid, the resin slips
around the seams and temporarily dissolves the adhesive layer -- the
plastic backer layer then adheres to the epoxy as it hardens... thus, it
actually separates from the adhesive as the cardstock is peeled off,
remaining as a cloudy skin on the bit, which then takes extra effort to
remove, revealing the shiny resin underneath.
Quote:
2. Apply
packing tape to shapes prior to cutting them. Two questions here: I
imagine you are using a clear mailing tape, rather than the yellowish
tape? I did some mock-up experiments with the clear packing tape and had
a very difficult time, if not near impossible, cutting only the card
stock without cutting the tape. I did do so once or twice, but it is
such a hit-or-miss procedure that it would not be reliably efficient.
Hmmm.
Puzzling. It doesn't have to be perfect: it's OK to nick the tape in
places, just so the resin only seeps, rather than flowing and I think
you tape it over with masking tape after the side seams are similarly
sealed (I don't have my notes here to check). Are you using the
thicker, classic sort of index card, like the Mead brand, or something
thin, like Oxford? I'm using a new Xacto and it still takes several
medium-pressure swipes to slice through the cardstock... If you can
hand-fold a card into a sharp crease without scoring it first, it's
probably too thin. (If a taped card creases sharply, without buckling
inside, something's definitely too thin!) I use clear tape, but it isn't
the thickest (it's just Scotch brand storage and mailing tape... I
don't remember about yellow tape and I think the brown mailing tape
would be too thin). Masking tape works too! In lieu of a technical
thickness specification, if I fold my package tape over to stick to
itself, it's impossible to finger-squeeze the tunnel left at the crease
smaller than half a millimeter across.
Quote:
4. Mix the EasyCast, allow to sit 2-3 hours for it to gel/de-bubble (yes?),
I
no longer think that any pre-pour settling is needed; I'm sure I was
over-mixing my resin, introducing air into it: I was following the
instructions, but maybe they assume people will be lazy and they
overcompensate for it. (I also think the now-obsolete spray paint was
reacting with the resin to produce or sustain the abundant bubbles seen
in the images.) Since the first (primary) pour of resin will be left
un-capped until it cures fully, it has plenty of time to de-gas in the
mold (and leak out a bit, and contract). The second pour should be left
uncovered a couple of hours after pouring to de-gas (we want it to
still be soft enough to press out the excess resin as we apply the lid).
Quote:
then pour 95% of the mold, brushing it to the top edge of the mold (per your instructions).
5. Allow resin to cure (12 hours for EasyCast?). For this step, is a weighted top cap necessary, since the mold is not filled?
As
you say, no cap is needed. I have to check my notes -- I think I
allowed at least 24 hours for EasyCast, maybe 48! This may not be as
critical a factor as I fear, but the danger is (to repeat myself) that
even if the resin has seemingly hardened, it hasn't "frozen solid" --
it's still got un-reacted, un-connected polymer chains, and fresh resin
can re-liquefy the almost-cured resin it comes in contact with, and this
can cause it to force its way up and out and/or contract afterwards
(this "re-freshening" effect is probably why they recommend a brush of
fresh resin as a way of shining up dull/sanded casting surfaces). A
wise (or at least, impatient) approach would be to start several
castings at once, with variations on the technique, so that you won't
feel the time is wasted if some of them go badly.
Quote:
6.
Mix new resin (or remix old resin if refrigerated - if this is the
case, does it need to sit for a couple of hours again, or is it already
ready to go after remixing?),
Old resin won't need re-mixing. The
refrigeration method is highly speculative, and probably a bad idea --
there's a danger of accidental ingestion and/or poison vapors being
absorbed by beverage ice... If I were to try it, I would probably allow
a couple of hours for it to heat to room temperature (as soon as it
flows again, it should be good to go).
I'm exceedingly stingy
with resin, and that's a bad trait: it goes a pretty long way, and you
can always buy more! (I use excess resin mix to start a spare mold I
keep handy, to do odd experiments like making droplets on parchment
paper, or to pre-treat reusable molds, but that's another, very messy,
story.) You can always economize after you've mastered the technique.
Quote:
then pour into small remaining cavity at top of mold. 7.
Place card stock top cap on top of mold, then weight it with coffee
mug-type weight. You had mentioned inverting/flipping the mold at some
point in your original instructions... should this be done here, or is
just putting the cap on with weight sufficient?
You slightly
over-fill it with the new resin (about as high as it was shallow
before), then let it de-gas (the fancy phrase for de-bubbling) for a
couple of hours, then cap it with a tape-lined index card lid (tape
down), and weight it firmly (the hardened resin on the walls of the mold
will add to their bearing strength). The idea with flipping is that
any bubbles that remained after de-gassing would float upwards in the
flipped bit and get trapped inside its mass instead of forming pocks on
the upper surface surface... I don't know if I've bothering with this
lately, as bubbles are less of a problem.
Quote:
8. Once resin cures, work shape out of mold, and mold is discarded.
With
the tape lining, you peel off the top, then the sides of the mold peel
off/tear apart into panels. The cardstock layer peels off readily, but
the tape (sticky-side out) tends to stick to the epoxy. I use an X-acto
blade to pick at a top corner until the tape starts to peel, then use
the flat of the blade to peel it away, doing my best to keep the peel
going when I reach the fold at the bottom. I should try peeling a face
off, then slice it down the center so I can pull the halves off the
bottom in opposite directions and get the adjacent sides in the same
effort.
Quote:
Finally,
due to the 3-dimensional complexity of some of the shapes I'm looking
to make, I will be making a couple of different components in their
individual molds, then somehow gluing them together into the final
shape. What's the best way to glue two pieces of epoxy resin together?
More resin, regular epoxy glue, super glue, or something else?
I
would guess (for EasyCast) either more of the same epoxy resin or an
epoxy adhesive -- the former might leave the least visible seam, and
you've got it already! As they are like chemicals, they should soften
and meld the pieces together. It's possible to make reciprocal pegs and
sockets, but that's a higher degree of difficulty, and just showing
off!
Gorno
-
-
-
-
Thanks for all the info!
The cardstock I'm using is 110lb.
premium cardstock, so I'm pretty sure it's think enough. The problem I
was having was that it did indeed take me about 3 light passes with the
exacto knife to get through it, but sometimes it was one pass too many
for the tape. I'll keep playing with it; maybe I just need some more
practice and calibration.
I will definitely try applying the
release agent to the taped lining, as you make it sound as if the tape
gets pretty bonded to the resin and takes care to remove fully. Perhaps
the release agent will reduce that issue. I'll let you know!
I,
too, am exceedingly stingy with most materials I use for this type of
thing, so I will take your advice and try to adopt a more
learning/practice-style outlook for these first attempts. EasyCast isn't
overly expensive, so I'll use it without too much hesitation.
If
all goes to plan, I should be giving this a spin this weekend, so we'll
see what happens! Thanks again for all your extremely helpful
instruction, and I will certainly keep you posted on my progress and
maybe try to snap some photos as well.
-Pete
-
-
-
-
rcpete22 wrote:
The
cardstock I'm using is 110lb. premium cardstock, so I'm pretty sure
it's thick enough. The problem I was having was that it did indeed take
me about 3 light passes with the exacto knife to get through it, but
sometimes it was one pass too many for the tape. I'll keep playing with
it; maybe I just need some more practice and calibration.
I guess
the object isn't to cut visibly through the card, but to super-score it
so that it will snap apart when you fold it back. As long as the tape
can be folded and flattened to a sharp crease at the line, you've gotten
what you want. Besides, rounded bottom edges from un-sharp creases
aren't a disaster (it might be an interesting effect), I just set the
standard of perfection as the point where all the sides look and feel
the same.
Thanks for all the feedback: it's hard to know where
I've been unclear when I'm just talking to myself (one clue is if I take
a break and come back, then find myself asking, "What the hell does
that mean?!") I look forward to hearing (and seeing) your results.
Inks and washes tend to look better on it than normal colors. At the end I covered it with gloss varnish.
Anyway, it's really easy, no explanation will work better than trying it 
