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I have to install a new aluminum gas tank and have read that it should be placed over plastic strips. Is it a certain kind of plastic and where does everyone get it from?
In Honolulu I would think that you should be able to find plastic wholesalers/retailers in the yellow pages?
I wouldn't think that there would be anything special with the type of plastic that would be used. Cripes, I would think that you could use plexiglass.
Let us know if there is no plastic wholesalers/retailers on the island.
Hi Sevenx, I went through an earlier discussion about the whole aluminum vs. plastic debate. I settled on aluminum because I could get a custom 80-gal tank built to fit, whereas plastic tanks only come in set sizes. The closest that would fit would be about 40 gal. According to many, aluminum is great if you install it properly. I plan to coat it with coal tar epoxy, which should make it close to corrosion proof.
Yo Brandin,
Went through the same decision process bout 3 yrs. ago. Had aluminum originally with tar coating. Bought boat used, (built '78) but original owner never used boat very much. None the less, tank sprung a leak in an area where salt water was able to make contact with tank. Guess can't complain much if tank lasted 20 plus years but just wanted to suggest you make sure there is no way standing salt water can be in contact with tank and that tank will not rub against anything which will expose aluminum. That's the problem I had, eventually sprung another leak. Decided to have a custom fiberglass tank built which has not had a problem yet...keeping the fingers crossed!
I think everyone got away from you orginal question, when you install the Al gas tank the supports need to have a non water absorbing material between the support and the tank (you'll get corrosion at the wet spot), you can use many things, neoprene strips, starboard plastic, rubber etc. Usually ther are wooden blocks or spacers to secure the tank or strapping-all should have some sort of material betweent he tank and the support.
I hope this answers you question.
I don't think it is poreous, maybe you're right, I'm not a diver. But something should go between the supports. When I change the tank in my grady there was some sort of rubber between the blocks and the tank. I reused what was there, no corrosion at those spots, just where the saltwater collected on the bottom because the plug was left in the drain hole of the wooden chamber the tank was surrounded by.
Dave M has it right. Mcmastercarr. I bought a 4' square sheet of 1/4" frp, bunch of money in shipping, as I recall. I have over half of it left, e-mail me if you want the balance. It also went thru my carbide cir. saw blade pretty quick. It does take to 5200 real well, just roughen it up with some 80 grit first. I actually 5200 my tank, using the strips to the hull directly. stuck just fine. ndwinfree@earthlink.net
I just used the strips, with 5200 on both sides. 2" wide strips, every 24". Glued to the tank first, let cure, then apply to the exposed strips. I have a 200 gal AL tank that exactly follows the "V" of the hull. I imagine this will work only for "constant deadrise" hulls, like mine, that are thick and rigid. There is about 6" of "free space" at the very bottom of the tank at the bilge to allow water to pass. Also, I irridited the tank and sprayed 3M undercoating on the bottom 1/3.
I ordered the high density polyethylene from McMasters. Thanks for the lead. It sure is a lot of work to install the tank properly, but hopefully this is the first and last time I'll have to do it.
brad; note that HDPE doesn't take adhesive well. This is why FRP is used. It would be OK as a spacer, but you will need to secure the tank some other way.
Great thread. i am about to put a new tank in my boat as well. When i pulled the old tank, it was held in by foaming it in and then nailing two 2x4 over the top (seriously, must have been a redo as the factory could not have been that lax). Anyway, in the belly of the tank are two longitudinal (going with the length of the boat) wood strips that are totally glassed in. i presume that they were factory placed to keep the tank just above the bilge. Both strips are delam'd (with worm dirt inside) and need to be replaced. With that done, i was then planning to run a length of neoprene along the strips and place the tank on that, then hold the tank down with straps or L-brackets. Does this sound like a decent plan? i think that there is a pic of my tank bed in a previous post ("pulling cockpit sole") if i've confused anyone. AND hopefully someone has answered Bradin's question. Thanks.
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Plastic strip for gas tank 
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