The inside of the tank can be cleaned and coated using a product made for gas tanks from POR15.  There are other products out there, but POR15 is the only one that I have never heard any complaints about.  They sell a kit that comes with an acid solution to wash the tank out with first, then coat according to the directions.  Please remove the petcock first unless you don't plan on ever using that one again.

My gas tank on my '58 Chevy was in pretty bad shape inside when I got it.  I took the tank off, dumped some MEK (Methyl-Ethyl-Ketone) in it and a three foot length of logging chain, then shook the piss out of it.  It cleaned it up enough that I am able to use it without coating the tank.

I've got a 5 gal dented Harley tank on the way that I'll have to  recondition & paint so I've been doing some research.

I've heard good reports about this stuff:

http://www.amazon.com/CYCLE-TANK-SEALER-KBS-Coatings/dp/B000IBDIX2

and another product called Kreem

http://reviews.ebay.com/How-to-use-the-KREEM-Gas-Tank-Sealer-Kit_W0QQugidZ100...

The bargain basement solution is pea gravel and muriatic acid. But then you have to neutralize it.

Good point about the filter! Would be critical to install an inline fuel filter after all the work is done to save the petcock and carb jets. Nomatter how clean you get it you'll still have little floaters for a few tanks at least, even with the coating products.

I got my ninety-nine cent tank cut in half, horizonally.  It is an older tank, had been dented and bondo'ed, and redented, and had some sort of tank sealant sloshed around inside.  It is FUGLY inside.  I'm going to clean it with the sand blaster!  Then put it back together two or three inches taller.

I used por15 on an old Honda Shadow. Works great.

Paladin,

When you put the tank back together are you welding it? Do you think some of the newer body panel epoxies would hold up to gas?

Is that a lap weld or but weld? I have a mig and replaced about nine panels in my old 79 ford but I'm not sure my welding would be up to a gas tank fix.

But its an intruiging possibility, custom upsize a stock tank.
Dang, another choice in the mix
Seviersavage

seviersavage wrote on 10/10/08 at 07:49:49:


I was thinking of flanging and soldering, or maybe brazing.  Then, just in case I leave a small unsealed spot, a inside coat of a gas tank sealer  (saw such on the web, will have to hunt for it again) that claimed to seal holes much larger than any I'd leave.

By modifying a stock tank I get to keep stock mounting and (rather important to me) the narrowness of the stock tank.  I don't think a two inch taller tank would be really noticeable unless you were near a stock Savage.  Two inches, plus losing the speedometer hole, should gain me 1 to 1.5 gallons, three inches should be 1.5 to 2 gallons increase.