Epoxy coating fuel tanks?

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cnbirrell

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Joined
Aug 27, 2011
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Anybody have any thoughts on epoxy coating the inside of steel diesel tanks? I don't have any experience with it, but am in need of options for mine, an aging set on a 1971 GB36. Also, do you know of places in Puget Sound that do it?
 
Why? EXample, leaking?
 
Most metal tanks rust thru from the outside in.

You can paint the outside easily , use multiple coats at all welds , thats where the cracks or rust will show firsty
 
Anybody have any thoughts on epoxy coating the inside of steel diesel tanks? I don't have any experience with it, but am in need of options for mine, an aging set on a 1971 GB36. Also, do you know of places in Puget Sound that do it?

To coat the tanks properly they need to be removed from the boat. If you're going to remove the tanks, why not replace them with tanks with sumps, built out of Al and then epoxy coated.

If the rust is only on the top as a result of the fill spout or bad decks, you can coat the tops with a product such as POR-15. It's not a complete fix but may be good enough with out having to replace the tanks, assuming they aren't rusted thru.
 
I would be concerned that it would chip or flake off at some point and clog up the system.
For those who have done this, is it a real concern?
 
I would be concerned that it would chip or flake off at some point and clog up the system.
For those who have done this, is it a real concern?

We did the same thing Kieth did in the post referenced previously. I did the work myself and there have been no issues. Our insides were sludge and I was concerned about pitting/crevice corrosion along the bottom, the lowest corner and the associated seams. I did it as PM only, since we had no leaks. After cleaning the forward chamber, multiple wipe downs with acetone, I applied Flamemaster 3204. A bit of a PIA since the whole operation is done through a 9" inspection port.

http://flamemaster.com/wp-content/uploads/2014/07/CS3204-rev-01-07.pdf
 

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Did the inside of two tanks on our sailboat. AL tanks sitting in foam started to develop small pits. Had to cut three access openings, there were two baffles. Got instructions from West Systems for cleaning, treating and etching the AL before applying West System Epoxy and fiberglass cloth. No problem for the four years we owned the boat after that.

Bob
 
We did the same thing Kieth did in the post referenced previously. I did the work myself and there have been no issues. Our insides were sludge and I was concerned about pitting/crevice corrosion along the bottom, the lowest corner and the associated seams. I did it as PM only, since we had no leaks. After cleaning the forward chamber, multiple wipe downs with acetone, I applied Flamemaster 3204. A bit of a PIA since the whole operation is done through a 9" inspection port.

http://flamemaster.com/wp-content/uploads/2014/07/CS3204-rev-01-07.pdf

Larry, beautiful work. I'm thinking of doing the same thing as PM. Do your tanks not have baffles? Or is there access through the baffles?
 
Larry, beautiful work. I'm thinking of doing the same thing as PM. Do your tanks not have baffles? Or is there access through the baffles?

2-350 gallon tanks with 3 baffles per tank. I was able to see with an endoscope and also a flashlight/mirror into the other chambers. They slope significantly up from the low end where the inspection port is. After the fuel was pumped out they looked good. All the sludge had pretty much collected in the low end. After talking to other Krogen owners, the weak link on the 42's tanks, seems to be at the low end and leaks from the inside out.
 
I suppose it's possible to butch-up a repair of a leaking fuel tank by slobbering the interior with some kind of goo, or an epoxy of some sort on the exterior, or other band aide measures. They may well work for the remaining time that particular owner owns the boat. Or not-your mileage may vary.

Enthusiastic references have been made on this forum to tank coatings used in the aviation industry. No mention of the FAA-mandated routine inspection of such coated tanks, FAA-mandated removal and replacements of such coatings to retain aircraft certifications, no mention of the cost associated with the apparent success of such coatings in aviation use, etc.

I've also read on this forum an advocate of opening his tanks, crawling inside, and having a welder repair leak points from the inside. Seriously? I made a similar inquiry, for the same reasons, a couple of years ago in the Everett, WA area. I was met with absolute refusal by EVERY welder I could find to weld inside a tank previously filled with ANY hydrocarbon (ie-diesel), inside a flammable boat. Can you spell explosion, asphyxiation, or fire?They thought I was crazy, and no one would risk it. I'd love to meet that guy's welder. I expect he is a few bricks short of a full load.

Should you be fortunate enough to access all areas of either actual or suspected leaks, via inspection ports or man-sized access ports, then gooping them up may well work for you. It may well work for many years. But do the next owner a favor and disclose this fix to the potential next owner and his surveyor prior to sale. I'm betting they run for the hills. I certainly would.

All rants above are my personal opinion, of course. They are, however, backed with solid, direct experience in diagnosing and repairing leaks in water and fuel tanks aboard pleasure boats, and other professional experience in related subjects. So, for what it's worth, my conclusions for all leaking fuel AND water tanks aboard pleasure boats is remove and replace. Sounds harsh ($$), and it is. My safety and piece of mind is worth the money, and my conscience is clear when I pass on my boats to others.

Regards,

Pete
 
Agree with jungpeter on this one. I went thru the same dilemma with our 71 Grand Banks 36 and came to the conclusion that cutting the old tanks out and starting over was the best route to go. It's a dirty, stinky nasty job but once the old tanks were out, I was able to scrub the area underneath and give it a fresh coat of bilge paint. New tanks were made from 3/16 Aluminum with measurement to allow bringing them in thru the aft cabin. We lost a bit of capacity but it's a small trade-off for the piece of mind of all new tanks and no more diesel smell. Total cost was under $2,000 for the new tanks and I did all the rest of the work myself. Good luck with your project.
Stan
 
IF someone is going to spring for wrecking the interior to replace the tanks , why do it multiple times?

MONEL , is the answer EZ to work with tho a bit pricy.
 
Had fuel leaks in the tank were the angle had collected the tar, water,etc, over 15 years. Had the tank degased and welded twice,third time said screw it. Replaced the tanks and have been happy since. Did the refitting myself and friends who I gave fuel to for labor. Went very well and am happy with the replacement.
 
As many repairs here...there are several possibilities.....

The on the road, cruisin' repair designed to get us home or to a repair facility.

Sometimes they last and are forgotten for way too long. Sometimes the next owner finds them unfortunately but not all the time a cover up.

The next level is the repair that fits the current budget. Sometimes it's the perfect and final one...sometimes it is the 5 year plan or so.

Then there's the one we would all love to see everytime....but not always in the cards.

Almost every suggestion on TF can fit these criteria....so evaluate each one for what it is.
 
My black iron tank began a small leak. Ospho, cleaning and painting the outside with rustoleum, I had a fuel tank expert come in and do a fuel proof coating on the inside of the tank (his suggestion). He used the same 3M material that they use on aircraft fuel tanks.
4 years later, not a drop was leaking. Worked great. Not sure how "permanent" the solution was, but was a lot cheaper than the alternatives.
 
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