I would like advice on what type of epoxy, fabric and how many layers I need to build a water tank about 60” long x 20” wide x 10” high. I removed the rear seats from my F350 Supercab and want to build a roughly 40 gallon water tank that will conform to the floor. I will pump the water into my slide-in camper when the water there runs low. Being in the Styrofoam business we can make a perfect male mold in expanded polystyrene foam, fiberglass around it and then cut the tank in half to remove the mold. I assume we can bond the two halves back together. How many layers of what type of fabric do we need? For the large horizontal surfaces I plan to bond ¼” birch plywood to stiffen the flat surfaces but everywhere else we need adequate strength in the glass matrix.

 

I didn't think glass resin would even stick to styrofoam- the one time I tried it melted the foam..

You might want to get a tank roughly the size you want, and then make a pad under it, rather than cut the tank and have to worry about the join.

Alternatively - a female mold with a large enough hole (maybe where the fill point is) to get a small chop gun into it might do the trick without having to.... "HALVE" the project later.

It would give you a removable plate with all your fittings on it that can be modded later if anything comes up. Rubber gaskets can be made out of many things.

If it was me, I'd poke around RV dealers and see if they have a tank left over from a warrantee job. Call that inside info - having worked for the big three RV dealers around town, I know for a fact they have PILES of leftover stuff that they are happy to sell off any way they can, or even GIVE away. I used to know where I could lay my hands on a hundred gallon diesel tank brand new that was for a class A diesel pusher, it was ordered for a job that was never done

~That happens a lot.

The dealers/Service Managers then have a choice, what to do with the stuff they got (often free) for a coach that either drove on by, or just never showed up

Perfect example: The mattress I sleep on was for a coach. A good queen size, out of a Prowler I think - it stood in the corner of the service office at D&N Campers for a long time. They had cut the tag off of it, and sent the tag back to whoever makes Prowler coaches as proof that it was used. Since the coach never came to have the job done, or whatever happened, they were going to toss it in a dumpster

Since you want it to work WITH an RV, I think that would be a great way to cut some miles off of your project

If you give the service area guys any idea that you like to fab stuff - they will danged near ADOPT you!

Every RV service area also has at least one guy that does nothing but glass, and gel sides. They usually drink in their offtime too - so a "FOUNT of WISDOM" may be open to you for the price of a sixpack


(Yeah - I'm the nefarious type. If the front door is locked - let's see if they have a smoking area)