Installing aluminum fuel tanks, need help!

[grady]

I only respond to this post because I think I might have a couple of hints that may save you some grief down the road.

I'm by no means an expert, but I tend to over think everything and research till me fingers bleed

I am currently in the middle of a complete refit, which just happens to enclude replacing the single 96 gal alum tank with a new 96 gal main and a new 56 gal aux. Both made from the original equip manufactuer.

In my research I've came across a couple of does and don'ts

DOES:

1, coat the tank with a high performance epoxy ( devoe has one that out performs coal tar) one that's meant for underground tank installs, impreious to chems and salt water. http://www.duspec.com/datasheet/data...t=Get+Document

2, use a closed cell rubber strip on the bottom of the tank to support it's weight on the bilge/hull bottom ( just placed not glued ) approx 1/2" X 2" X the tank width, placed every 12"- 14" or so

3, block the fore and aft and side to side movement with wedges ( let's say you use a 3/4" X 3" block (X2) to keep the tank off the aft bulkhead then use a wedge placed on the fore bulkhead to firmly press the tank against the aft block. ( use a strip of the closed cell rubber between all blocks and the tank)

4, then use a 2X4 or something to block the movement of the tank upwards toward the sky ( away from the bottom ) again using the strips of close cell rubber between the tank and the blocks ( the rubber can be held in place with staples to the blocks, if it were me those staples would be monel and on the sides of the blocks not facing the tank.



DON'TS:

1, glue to, bond to, or foam in, any alum tank

2, never allow the tank to come into contact with hard surfaces.

3, allow as little movement as possible (none)



hope this helps

[piperca]

Thanks for the information!

[Ike]

I was looking at an web page yesterday that talks about installing tanks in aluminum boats. The guy said 5200 has to be allowed to set up for a while before it will stick to aluminum. He didn't say how long.

Seems to me that you are dealing with the oxide issue. Aluminum has a natural oxide coating, invisible to the eye that protects it from corrosion. It also does not allow paint and other compounds to stick. You would need to clean the oxide off. Acetone would probably work. But even water and a good cleanser would probably get enough off to allow 5200 to stick.

[piperca]

Ike, I used half a gallon of acetone on the tank bottom before I started the project of glueing the starboard.

I am leaning towards coal tar epoxy then, I know you don't want to hear it, but, foaming in the tank. My research has shown that if the tank is treated properly before foaming, the foam will not affect the tank in any way. I'm still in the consideration stage, so I'll let you know.

[Ike]

Before you go ahead and foam that tank in you might want to read this. http://marinesurvey.com/yacht/fueltank.htm. David Pascoe is pretty knowledgeable and he gives a great explanation of how to install an aluminum tank.

[Ike]

I almost forgot. Almost exactly the same discussion has been going on on the Metal Boat Society Forum. Here's a link http://metalboatsociety.org/phpbb2/v...403&highlight=

[pasty63]

What about using thickened epoxy (with cut fibers) instead of 5200 to glue the starboard to the tank? It seems a complete coating on the back of the starboard pieces would keep the moisture out as well as 5200.

[piperca]

Originally Posted by pasty63

What about using thickened epoxy (with cut fibers) instead of 5200 to glue the starboard to the tank? It seems a complete coating on the back of the starboard pieces would keep the moisture out as well as 5200.

This is an interesting idea; how would I do this? (materials, prep, etc.)

Yes, you are reading correctly, I still haven't installed the tanks or engines. Luckily I didn't, since I'm going to install diesel engines now, which means I need to have the tank guy burn in a return line.