I wanted to make objective markers and scenery incorporating fuel barrels. GW makes some lovely ones in their battlefield acccessories pack, but at 15$ it can get rather expensive if you want to make a fuel depot...
Then I took a look at internet for other solutions. Not a whole lot of cheaper alternatives and, to my suprise, no castable barrels. So, I decided to try and make my own mold... that didn't come out so great. Next step was to try and scratchbuild my own.
Wooden 5/8'' dowels, thin string and carpenter's glue. First cut 6x pieces of dowel 7/8'' long. Mark where the "bumps" should be. Pre-cut lengths of string, enough to wrap once or twice, according to the diametre. Dab some glue to the end and wrap string. I used an old crafting knife to help work the string in it's proper place. Do the same to the next dowel, by the time you have glued the first "bump" to your six barrels, the first will be dry enough to wrap the second. Go through your barrels again and then again with the next "bump" and so forth... I'm sure you get the idea.
The end result might not be high quality, but it does the job at a minimal cost and time. Took me an hour to do the six barrels. Mixed in with the real GW stuff, it comes out ok.
Oh! If you're wondering, the palets are WFB monster bases with the sides cut.