home made tanks
I prefer woven mat, but I think for making a tank, what I call "chopper mat" is a better way. resin, hardener, the cheapest throw away brushes you can find, plastic cups, elmer glue, toothpicks, cardboard, scotch tape.
make the shape you want with the foam board, ;you will melt the foam away later with acetone. figure 1/4 inch to 3/8 inch thick at all places. Use cardboard and scotch tape to make round fittings like the drain pipe. measure the stuff like fittings to figure out what outside diameter you are going to have to have in the end.
do not make "hot" resin mixes. the slower you can do the curing the better result you will have. many epoxies work very well but are more difficult to work with. My favorite is pre impregnated cloth. comes to me frozen, takes 12 to 30 hours to cure and is not cheap. Fiberglass will be the best all round choice for a project like this. read up on working with fiberglass and watch a weeks worth of videos before you attempt this... there is a video out there of a guy that made a motorcycle gas tank.... with a foam core.... find it and watch it. along with other videos. Takes time, but is not difficult. at least not to me. it is messy and the chemicals will cause nerve damage, do not use this **** in an enclosed space and do not use this with out the correct kind of face mask. This nerve/brain damage thing happens small amounts at a time but is very very real. One of the nicest guys I know is a painter and twenty five years of painting has now made him a slow thinking person now. He is a shadow of the man that started painting cars when he was 17.
and think about how a tank drains. build a mini version out of card board put a layer of fiberglass on the bottom and sides and fill with some water and see how it works, that will let you make changes if you need to..... baffles will help reduce internal stresses from fluid pounding around on the insides. If you know anything about water hammer, you will get an idea. Many dont think about the force of the fluids on the inside when stopping. starting and turning. the result is a broken tank. if the tank is biggish 40 gallons or more and the bus a cutaway van kind of thing, you can feel the liquid sloshing around. this comes more in to play when things go wrong, like a blow out on a turn in the rain......... shifting loads poor driving skills and all hell breaking loose at once compounds problems. also have to make strong enough to handle loads going over bumps, pot holes, curbs and road hazards. Imagine this tank anywhere near a tire that looses a tread. that flap of tread will really beat the hell out of stuff. consider putting a 14 or 12 gage steel on the side and bottom that is exposed to road hazards. beats a smashed tank that is unusable from damage.
it is a satisfying thing to me to be able to make custom stuff, but it is often cheaper in the long haul if I spend time to find stuff that is premade ... I can spend 40 to 80 hours looking at tanks to be able to get an idea of who makes what an what is expensive and what is inexpensive and what is cheap junk. The last black tank I made, had 1/2 thick walls, carried 100 gallons, had built in rinse sprays, was sloped and curved in such a way that **** did not get stuck in the tank, baffled, fit a very irregular shape, formed part of the bottom of an undertray for the aerodynamics on a truck, think semi sized truck an took three mini models to make and final tank took two weeks working about four hours a day.