Fuel Tanks Part Deux

[harbormaster]

I pulled the tank out of the ******, and cleaned it out. I have removed the foam from the tank and have noticed the start of corrosion in spots on the outside of the tank.

First question: What can I do to neutralize the corrosion and coat the the tank with?

2nd Question: If I can find something good to coat the tank I will use foam. If not i would like to mount it another way. Suggestions?

Tell me how you would do it and why. There is more that one way to do this so do not be afraid to state a diiferent viewpoint. (let the games begin...)

[mattyboy]

tank, foam corrosion???
surely you Jest :wavey:

Matty

[harbormaster]

Son, When wus the las time you was bitch slapped! :biggrin:

[mattyboy]

I'm from NU york,
I get HO slapped all the time :) :jestera:



Matty ;)

[MOP]

Scot without seeing the tank that is a hard question! Have you tried to look inside the tank through the sender hole, that is "best" done in low light with a bore scope or if not available use one of those little flex neck mini bulb lights not real good but should still give you a decent idea. If no whitish debris is present IE: indication of aluminum corrosion or pitting then maybe nothing is going on inside. Now on the out side look at the data tag it will state the thickness. If the deterioration is to half I would dump it for new, however if it is not that bad it can be lightly blasted with PUMICE. Use a regular small sand blaster the one that look like a 5 gallon pale, leave the big sand tip on the end. You want to clean not blast the pitted areas until bright. It is a good idea to lightly blast the entire exterior, this will aide in getting a good coating bond. The 31 Bertram article in the other tank post does a very nice job of explaining how to do the coating. Foaming it in is still the best as far as I can see for securing in the boats we drive. Just make sure you have water and air passages.

Phil

[penbroke]

I am certainly no expert on the subject but you asked.

Assuming the tank is aluminum. Aluminum is self protecting in that it forms a thin layer of oxide on the surface that will prevent further corrosion. Halting the present corrosion should be as simple as scraping off any loose material and letting it dry well. One of the links in the other thread mentioned coal tar epoxy or something like that as a coating.

If the tank was originally foamed in it may not have any provisions for mechanical fastening (ears, tabs etc.) and you may be stuck with foam or welding some type of mounts to it. I know people have welded on old gas tanks before but it doesn't seem like a good idea if it can be avoided.

The key is not to let water stay in constant contact with the aluminum. Anything that touches the surface has to be completely sealed to it with no voids. The rest of the surface needs room for airflow to dry.

FWIW: The old Bayliner I scrapped out last spring had an aluminum tank just laying in the bilge. No foam, no fastening at all. It was resting on the hull between the stringers with bulkheads fore and aft and the floor above it. (I had to cut the floor out with a sawzall to remove it.) It was completely enclosed within 1 inch or less on all sides with NO ventilation at all sitting in bilge water. The boat was from the early eighties and the tank is in excellent condition.

Frank

[Rootsy]

now i have not done this to an aluminum tank but EVERY tractor that i go through that doesn't ahve a galvanized tank gets coated. you can buy this kit and do it yourself or have it done. the tank gets boiled or what not to get cleaned... then an epoxy type substance is placed inside and agitated to coat the tank. that's for corrosion resistance on the inside... now if we are worried about the outside there are a few things you can do to protect it after you get it CLEAN.

#1 anodize

#2 Powdercoat... of which method i would be more likely to go with due to cost. just seal the tank up.. sandblast the outside and send her to the powdercoater... 50 bucks or so should get it done in any color you want... and well since it is a baked on plastic it won't let water through and well you have to literally beat on a surface just to get it to chip or crack...

they don't heat the surface hot enough to hurt welds or what not either...

just a couple of my hairbrained ideas...

JR

[doug hess]

To clean my tank I used a $20 Taiwan sand blasting kit from a discount store an and beach sand.

For coating the tank use a good industrial grade 2 part epoxy ply mastic paint without thinning.

When reinstalling the tank it is not necessary to fill the area 100 percent with foam. Leave plenty of breathing space and allow the area to ventilate.