My Fuel Tank Fun...
Howdy, Kevin -
I posted on here about replacing my E38 fuel tank a couple of years ago, but curiously can't find the thread now.
I strongly recommend replacing the tank instead of patching. A new tank will buy you 25+ years of usage. If you patch, it could spring another pinhole leak any time.....
I second Loren's recommendation for Berry Sheet Metal. Mr. Berry built the original tank for my boat and is still in business in Costa Mesa.
Here is a pic of my old tank. It would not fit through the companionway. The tanks were built into place before the decks was laid on during building. I had to cut the smallest (forward, port) corner off to get it out.
After draining, airing and thoroughly wiping the tank, I put a chunks of dry ice inside to allegedly chase out all the fuel fumes. This also neatly balled up the fuel gunk that was adhered to the tank interior and made it much easier to clean.
I used a vibrating multi-tool with metal cutting blade to cut the corner off.....took a while...! Since the bottom of the hull curves up under that corner, the tank is not very thick at that part and I only lost 2-3 gallons of capacity.
Here is a pic of the new tank Mr. Berry made with the missing corner. It fit into place perfectly...!! I had him make it out of slightly thicker aluminum to hopefully provide even longer life.
Berry told me 25 years is pretty typical life for a fuel tank. They simply develop pinhole leaks due to temperature-swing condensation over the years.
He was reluctant to put an access port in the tank, but I insisted. Tank has been great for two years now.
Good luck with your project and hit me up with any questions...!!
Curt