Saturday, November 3, 2012

how to model water


Water is modelled in so many ways. Some methods work and others are disastrous. The worst way is to install a sheet of rippled glass! There are many products available on the market and a large number of them just will not cure so the surface remains sticky and will collect every thunder bug that visits your railway room! One in particular just requires heating to make it liquid. Sadly, probably due to 'Health and Safety', the damn stuff melts at such a low temperature that it too becomes sticky on a hot day!
Another problem for models is that dust will gradually land on the water and the effect is lost. If the surface is really hard, it is possible to clean this off with a soft brush, but in the end, a new thin gloss coating has to be applied to keep the whole affair looking wet.
Although very slightly light blue in colour, water changes its appearance mostly due to reflections on the surface. Rivers may also have a high particulate content and may be brown in colour. The River Platte in Colorado is described as being too thick to drink and too thin to plough. A river may be relatively clean, but an outfall from say, a factory or confluence with another stream may result in most interesting colour effects.
So let's look at some methods that work.
 
real water
All the experts say that this should never be used and I have to admit that it made sense. That is until I saw the East German RĂ¼gensche Kleinbahn 009 model railway. Railway ferries plied across the river being operated by turning a handle and the whole affair looked entirely convincing. It is a major crown puller in every exhibition it goes to. The whole affair depends upon clever colouring of the river bed and some good construction to ensure it is water tight. I would have to say I was excited about the model and if I needed a moving boat would do it myself. At the end of the show, the water is decanted into a container using a sump plug.

 
still water

A rarely seen view of the stagnant pond behind County Gate Station. This is the water supply for the locomotives
The first job is to model the bottom, painting it in browns and greens. I then model the banks add marginal plants such as reeds fallen branches, etc. I do not use the 'special products' available as they all take too long to cure (if at all). I prefer two part clear epoxy resin with a cure time of about an hour. This is available from suppliers of composite aircraft, and a pot last a very long time. Another alternative is epoxy varnish supplied such as is supplied by Interlux. It does take longer to cure though.
While the 'water' is workable it must be carefully brushed up to the required edges so that no meniscus shows. Several coats are required to ensure a feeling of depth. Care is needed to prevent bubbles and no coat should be more than one mm.
This is also the method I used for modelling the dirty harbour water at Glenthorne Harbour. The description below also explains how I built the harbour walls.
 
Glenthorne Harbour Dock
The harbour wall were made using Wills sheets expoxied to the timber framing. The wall near the cliff is random stone and represents the original small fishing dock which existed prior to the expansion into Glenthorne Harbour. The brickwork of the dock is very weathered as this is where coal is continually offloaded. The top to the Wills sheets is level with the rail head. The brickwork was extended onto the plaster by the use of a scribe in order to create a 9" edge brick capping. The tide line has been added at this stage but seaweed and mussels will wit until the timber groins are added.
A useful tip, if you ever want really worn and distressed model wood, soak the parts in an enzyme called 'lignase'. This eats away lignin. Remove and wash when the erosion is to taste. If using balsa wood, the enzyme 'cellulase' will first remove the more 'pithy' element. The enzymes are not too hard to get from a scientific supplier. Deeply fissured timber can be modelled in this way. I also use a steel wire brush in a Dremel to distress end grain, as in the tops of the timber piles.
The timber is first painted in matt black and then the surface colours are dry brushed. Wood is rarely brown in colour, unless it has just been creosoted. The nail holes on the horizontal rubbing strakes are added once the structure is assembled using a dental pick and rust colour added. One strake has become detached and the nails remain in the pile, represented by fuse wire with a tiny blob of epoxy at the end to represent the head.
The seaweed has been added. A thin line of green Ulva at the edge between sea and air and bladder wrack (Fucus vesiculosus) and Chondrus crispus below. The nails can just be seen that attach the rubbing strakes. Seaweed is rarely modelled correctly on dock sides. The brown algae begin about a foot to 18 ins below high water as it is more efficient in photosynthesising below water.

the sea wall at Whitby
I first paint a line of PVA for the green algae. I guide the level by resting the brush horizontal on the edge of a piece of wood the correct height. A few small squiggles are just fine! The baseboard is then placed on its side and Woodland Scenics 'blended turf' is sprinkled on.  This is just the right colour. Once this has dried, I then painted the rest of the wall down to the bottom with a liberal coat of PVA. This is sprinkled with grey fine chopped foam. The baseboard is the put back to the horizontal the the PVA/grey foam mix is very lightly brushed downwards with a soft, wet sable brush. In a few places, the wall will again be exposed, which is how it ought to be. Once this has dried, excess is removed using a dental pick and the surface wet brushed with the correct reddish brown paint. Some of the grey colour shows behind which is also correct. The brown colour is allowed to spill onto the 'sea bed'.
If you are modelling mussels, these can be made from very small round seed and painted semi mat black and added where needed. I felt Glenthorne was probably a bit too hostile for mussels!
The rest of the sea bed was painted while this was still wet using browns and greens, 'well mottled'. If there is to be a transparent sea finish, don't forget that some ships will ground a bit now and then at low water and leave marks. Some will be thin and well defined, where the end of the keel or rudder has scraped. Where the keel has touched along its length there will be thicker dark lines, represented in the photo below by horizontal brown splodges!

 the coal wharf walls finished with a rather uncomfortable reminder of the 'Black Shirts' of that era. The lines under water will represent keel scrapes once the water has been built up. At this point, only one coat of 'water' has been added.
The water starts off using West two part penetrating epoxy. This cures rock hard in two hours and covers very well. I brush it up a little onto the seaweed to represent wetting. I will apply three coats of this, (each about 1mm thick). This is as far as I can go at this point until the ship is in place. The rippled surface can then be added, by working the surface with a brush while the epoxy is beginning to get a bit stiffer.
 
fast flowing rivers
Below, is a description how I built the East Lyn River.
The river bank in front of the viaduct is detailed. The East Lyn can be quite fast flowing during rainy periods and the banks are gradually eroded. This exposes tree roots and more boulders, which eventually fall into the river. In places, the bank will collapse. On the inside of bends, shingle can be deposited.
Firstly, the river is coated with PVA and Woodland Scenics talus scattered on the river bed and pushed into the glue.
After painting with the desired colours (browns with a few patches of green), the first layer of water is added. This is two part epoxy resin. (West epoxy). Shingle banks are carefully added while the epoxy is still wet.
The banks are modelled using Polyfilla, with talus pushed into the vertical surface and sea moss pushed in to represent tree and shrub roots.

here the banks are built up and detailed
Once this is completed and painted, the surface coating of the river itself was modelled to give the river the impression of movement.
We have tried water effects by Woodland Scenics but do not like the finish, which is not sufficiently glossy. In the end, a second coat of two part epoxy was applied, and just at the right moment when nearly cured, it was manipulated with a dental pick with touches of gloss white added to simulate foam and movement. An alternative is to use clear silicone sealant which can be easily moulded to your requirements.

A hard to take photo. The completed water effects: direction of flow to right
A faster moving river can be modelled by adding PVA with a little white water-based paint included and moulding it to represent foam down river of the rocks.

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