replicating fuel tanks

Well, I hate to tell you, but....... Hey, I blew the $30 for a new resin-casting kit, (previously I used latex to cast the mold and who knows what to cast the parts), so far the only thing I've use the new kit for is casting some tiny antenna mounts which would have been next to impossible to scratch build. I don't know of any other method to accurately reproduce a part, and I'm not exactly the new kid on the block.

If you work very carefully, you can make a two piece mold (one for each side) from modeling clay. Lay out two rectangles of clay about 3/4" longer and wider than your tank and about 1/2" thicker than 1/2 the tank. Sprinkle talcum powder on the surface (keeps the clay from sticking when you remove the male mold). Then carefully push one side of you tank straight down into the clay (watch out for any side movement). Once the tank half is fully into the clay, remove the male mold by pulling it straight up. Do the same for the second half. Now you can use your choice of resins to make your tank halves. I use fibreglass resin that I get at the local automotive supply store (Wal-Mart carries it too). Mix it according to the instructions (don't stir to rapidly or hard - makes bubbles in the mixture) and gently pour it into your molds. If you spot any bubbles in the resin after it's poured, you can try to remove them by sticking a toothpick into the resin and very gently poking the bubble. (or you can leave it and fill it with putty after you remove the tank from the mold). Let the resin set up over night and then remove the tank halves from the clay molds and wash them with warm soapy water.
Now all you have to do is sand the mating surfaces until they match and then glue them together using CA or epoxy. Check for bubbles, fill any found with putty, sand and primer. Takes some practice (especially pushing your male mold into the clay and removing it without distorting the female mold). But it's a whole lot cheaper than buying the Dow Corning and Lumilite. Hope this helps a little.

PS - You'll find that it's easier if you still have the tank in two pieces.

thanks for the info guys.

I just had an idea: take thick plaster of paris, make a mold with the kit parts, and then seal it with something(will Future work?). and then pour thin plaster of paris into the mold, let it set and remove. it may sound crazy because the idea just popped into my head.

Jason

Think the plaster of paris mold would probably work great. But am unsure as to using plaster of paris to make the part with - going to be awfully brittle. Give it a try and let us know what you find out.

I will give it a try. But it'll be a while(like a few weeks) before i can try it, because i'm moving into a new home, and i'll have no time for modeling. but stay tuned to this topic; I WILL try it and post the results.

thanks.