jdub

iTrader: (1)

Should you use the pourable foam to "lock" in the tank? Or should it be set on plastic stips and 5200 to a deck between the stringers? I've heard the foam causes corrosion on aluminum because it doesn't allow air to flow around the tank if it ever gets moisture. But just setting the tank on some strips with 5200 and not filling the voids on the sides sounds like the tank could shift. Any info or experiences? Also anybody know of a tank builder in the jersey area?

madbouyz

I'm not sure how often this subject comes up here , but over on the Donzi.net it's been hashed about a thousand times and it can get quite emotional sometimes.

How was the original tank installed ? Sometimes it is possible to remove a foamed in tank and install it in a way that concerns you less as far as corrosion goes.
The key is , that no matter how it's installed it must be epoxy barrier coated in some way. That's nine tenths of the problem beaten.

Tanks that are foamed in are MOST UNLIKELY to ever come loose and fly around .. they also are supported evenly all around.These are two critical issues. If the original was foamed in and it is possible to now install the new one in a different way , even support ,particularly on the bottom of the tank is very important. I'm not a big fan of tanks with 'tabs' on them bolted to stringers etc Fiberglass likes to flex , metal does'nt.

If you resort to foaming back in just make sure they tank is epoxy barriercoated (a guy over on the Donzi net did a websearch and found an excellent epoxy tar material) and use foam with a 4lb density.
Steve

jdub

iTrader: (1)

The original was foamed in but not coated. Moisture got in and never dried causing the aluminum to pit up. The tank does not leak but has some pretty bad pitting. I guess I could epoxy coat the tank and foam it back in but the pitting has me a little scared. If a get a new one made I will coat it and put a support under it and then foam it in.

KAAMASCARAB

I'm at the same point you are. The tank is .125 aluminum 150 gal., 7 1/2 feet long. My idea is to form four 1/4" thick 3" wide stainless steel strips to the same shape as the bottom of the tank, add 1/8" polypropolyene strips between the tank and the s/s strips, bond all of it together with 5200, and bolt the s/s strips to the stringers next to the tank. I don't see any good way of keeping foam from soaking up water over the years. I wonder if the hull needs the extra support of the foam and tank to keep that large area from flexing? I'd love to hear what you find out!!!!!

jdub

iTrader: (1)

KAAMA, after thinking about it I came up with getting the tank Rhino Lined (like a truck bed). I will then pour some foam and set the tank. Once the foam rises I will pour more down the sides and cut off any excess. I figure this way you get the best of both worlds, water tight because of the Rhino and solid because of the foam. I'm also going to Rhino Line my floor once I put it back in, maybe red or yellow

Catagory5

SP Sheetmetal in Toms River. They make great tanks and they are local. Follow thier instructions or take it to one of the shops they recommend. Like mine

jdub

iTrader: (1)

Catagory, thats who I had in mind.

Iggy

S & P Sheet Metal? They still in business, and still building fuel tanks?
They're located on RT 37 near Fisher Blvd. right?

My Dad's machine shop (in Toms River) used to do a lot of business with them back in the 70's. I made many trips to pick up formed parts.

Catagory5

One and the same. They have new owners since the 70's but they are still in the same place and still doing a nice job with fuel tanks. I use them exclusively.

madbouyz

I think you're on the right track here !

I picked up some good advice from an 'old timer' before I did mine and he strongly advised to do multiple small pours .
The foam has a lifting capability of (I think) 6lbs per sq inch when firing off , so weight the tank down very firmly and do a couple of small pours underneath from different sides one at a time. Once they've gone off you can do the sides with no worry.

After I trimmed the top of the excess foam I heavily coated it with a flexible epoxy coating to prevent water absorbtion from the top. Because of it's location it will be many many years before water affects the bottom part of the foam.