Interesting gas tank repair

[UberXY]

My 86 R65 has been weeping a small amount of gas over the last few months. I assumed the welds around the petcock bungholes were compromised, and given that the bike needs painted anyway, I took the tank to the local radiator shop, a place that has been around for a long time.

Turns out that a little water had collected in the wells just fore of the bungs. The normal and reserve intake tubes stick above the level of water so I never had a carb problem, but it rusted the tank from the inside enough to create some porosity.

The guy fixed it by cutting back to good metal, and the soldering in copper patches on both sides. Very nice work, won't rust again, and reasonably priced.

I've never heard of this kind of repair before. How have you guys repaired tanks?


All the body work is now in the paint shop for the winter...

http://lh3.ggpht.com/_LrrHrU8m-Bk/Swgb_JvqB5I/AAAAAAAACgA/ToTfQwYNxos/s800/DSCN1299.JPG

[sgborgstrom]

I'm no expert, though I have done a fair amount of sheet metal work restoring a few old cars over the years. One of my references indicated that repairs using dissimilar metals will eventually fail along the braze line as the two materials react with each other.

Since I use a small MIG welder it's one of those tidbits I filed away in one corner of my brain. I know they braze bicycle frames together, and there are a couple of brazed joints on the window frame of the 42 year old truck I'm working on that look ok so who knows what kind of time frame we're looking at.

[Yarddog]

For decades, it was common for bodymen to braze sheet metal together, however, we didn't use copper...and actually, the proper term is 'brass welding'... but hey, brazing rolls off the tongue better...I suspect the radiator shop used copper because that was what was available.

In your case, the dissimilar metal issue will probably rear it's ugly head well after your lifetime!!! It might be a good time to lay in another spare tank in the meantime, just for ducks, since it's possible for this to happen again in another area...and you might not always be able to source another tank as easily as you can right now...

[UberXY]

It might be a good time to lay in another spare tank in the meantime, just for ducks, since it's possible for this to happen again in another area...and you might not always be able to source another tank as easily as you can right now...

Thanks for the tip. I've been casually searching for a R65/80/100 tank, but most of the ones I have found were worse than mine. :( However, some day I will come across a brand new one somewhere...

[mmmalmberg]

I've heard of soldering (not brazing) copper for tank repairs on cars. A friend who worked in a service station back in the 70's said a standard cheap fix (with fuel in the tank!) was to heat up a penny real hot with solder on it and stick it onto the prepped spot. Now I can imagine that didn't last forever but who knows....

[swall]

Older bikes, like Harleys and Indians prior to 1950 had gas tanks that were soldered together. Common restoration practice these days is to fix rusted out areas with soldered patches. Terne plated steel works, as does brass sheet and brass screen (with solder to fill the grid) . I don't see a problem in using copper sheet. With any of these repairs, it is beneficical to put a sealer in the tank afterwards. My preference is for epoxy, thinned with acetone.

[kgadley01]

theres a process that's done to seal the inside of any kind of fuel tank. the name of the product escapes me at this moment, but what if you did the repair then resealed the tank?

[krpreston]

theres a process that's done to seal the inside of any kind of fuel tank. the name of the product escapes me at this moment, but what if you did the repair then resealed the tank?

I suspect the product you are thinking of is called "Kreem".

Re "bazing", the correct term is actually "bronze welding".

[20774]

I suspect the product you are thinking of is called "Kreem".

POR-15 is also another common product. Never had the chance to use either.

[jforgo]

I used POR15 on my leaking R65 gas tank. Very good stuff - but an all day project. Single petcock tanks like the R65 tend to collect water on the blind side.

[Bill Burke]

I used POR15 on my leaking R65 gas tank. Very good stuff - but an all day project.
I think jforgo meant an "all week" project. The recommended drying/curing time alone is three or four days. I did it last Spring. Good stuff.

[kgadley01]

POR-15 is also another common product. Never had the chance to use either.

You are the correct one. it was Por-15 I was thinking of.