I have a leak at a weld on an aluminum diesel tank. I would like to repair using an epoxy or some type of glue. Any sugestions?

 

Better weld or aluminum solder

 

Once it has diesel on it, it is extremely hard to get properly cleaned and epoxied. Napa carries an epoxy that you can use but be warned that biodiesel or veggie oil will break down a lot of these epoxies.

Leaking stainless and aluminum tanks is very common in marine applications. The common fixes are to replace the tank, reweld the seam, or to glass the inside of the tank. Replacing the tank makes sense if there are starting to be a lot of pinholes in the welds. Over time, pinholes develop and all of the welds generally need renewing which involves a ridiculous amount of grinding. Grinding and rewelding does make sense if you are sure it is a localized problem or if the tank is a fancy custom tank that would be hard to replicate. When people glass the inside of their tank, they tend to drain all of the fuel, cut an access hole in the top, clean the tank very carefuly, tape the seams, and glass it.

Good luck.

 

Devcon Zip patch.
It will work .

 

mad,

Coal Tar epoxy is designed for marine tanks and is resistant to fuels. A buddy of mine repaired his fuel tank, about a year ago, that was built with steel plate. His tank was rusted through in places! I'ts a common problem with older boats built overseas. No external corrosion inhibitor on mild steel tanks! Sheesh, what were they thinking? Coal Tar epoxy is a common fix for tank leaks on boats.

It should work even better on your aluminum tank with only a small pin hole, but cleaning the aluminum surface is sometimes difficult. Getting all the oil removed and also preventing any corrosion until you apply the material is the hardest part. If you drain the tank and degrease the area to be fixed with ether or trichlor or something it's pretty good. To clean the surface, sand or bead blast the area. Then apply some epoxy and "wet" sand with the epoxy while it's still liquid. This prevents any surface oxidation as you scratch into the clean metal, and gets the cleanest surface possible for adhesion. I'm assuming you don't have a structural problem, just a pin hole or porous weld. If so, you won't need any fiberglass cloth, just a thick enough coating to stop the leak.

Of course, welding would be nice. But sometimes the logistics of tank removal, cleaning, and filling it with an inert gas first is just too difficult. Unless it's a structural problem like a stress crack or split seam from flexing.

 

Speaking from experience this stuff works:

http://store.hamiltonmarine.com/brow...2/4,24075.html

It's not cheap and as far as I know that is the smallest size you can buy.
I had a aluminum fuel tank , diesel, in a boat that leaked at the coupling that was welded low on the tank. Threads were corroded away from different metals . It got me through the season until I had time to cut up the deck and install new tanks.
Clean it as best you can and gob a whole bunch on there.
You mix it by hand, wearing gloves, have a bucket of water handy, open both cans,, with your right hand grab a handfull of the black, with left hand grab the same amount of the yellow, dip both hands in the bucket for a second then mix, knead together, keep dipping in the water if it gets too sticky. It will turn green when it is mixed well, only takes a few minutes.
Commercial fisherman use this stuff often for temporary repairs to get them back to town.

 

Is it too much trouble to heli-arc?

 

you do not need to clean the tank to weld. it is usually just as easy to weld the tank as to smear epoxy on it. if it is just a pin hole in the weld just put some epoxy on a sheet metal screw and screw it into the pin hole.