AJS & Matchless Owners Club

When I've done weld or braze repairs to tanks I've run the garden hose continuously through the thing, fuel taps out, for an hour. Then I've used washing-up liquid and left the tank full of water and soapy bubbles for a few hours. Then I've swilled it through with the hose for another good long time. It seems to work. No noticeable petrol fumes afterwards anyway and I'm still in one piece.

Most likely you are suffering from Petseal breaking down due to the ethanol in petrol, it may have been added to the tank to cure the leak you now have.

At some stage you are going to have to remove it all, but certainly before any welding.

Use 98 petrol to reduce the deterioration of the liner further (there is conjecture if this will work due to variability of supply from the refinery).

Araldite may work as a temporary repair, I would err to JB Weld, however for certainty use a fuel tank epoxy this may have to go on a little thick though.

Hi

I'd shy away from epoxy repairs in this case - go for a flexible silicon or polysulfide fuel resistant product, it will seal better and last longer. It will probably be easier to remove when it comes to the professional repair too.

Regards Mick

After a while Araldite went soft and leaked when I tried it.

on one of the forums I read of an american product which is apparently the dogs danglies but for the life of me I cannot find it now, regarding the petseal or similar, I have got most of it out, havn't tried today been laying path edgings that certainly takes it out of me at my age now. kind regards

les ward wrote:After a while Araldite went soft and leaked when I tried it.

I can confirm that is what happens and brake fluid has the same effect!

Pumping exhaust gas into a tank before welding is an old dodge but I am not sure that modern emission free exhaust fumes would be any good. I once tried welding a lawn mower tank, poked the 'oxy' flame into the filler and there was a 'whoosh' so I thought that now it would be safe to weld. Oh no! as the metal got up to brazing heat the round tank exploded and unrolled itself into a flat sheet. The customer was not impressed but at least all I got was singed eyebrows and a telling off from the boss(my Dad).My Norman two stroke (not my Nippy, Mr. Goldstar,the other one) had a leak and Petseal did not work so I used a Plastic Padding product called Leak-Fix which seems to be working.Paul

Hi Paul, gotta fin d the bloody seepage first still eluding me! you gonna be at Sittingbourne anytime this coming week? kind regards

pkr87 wrote:Pumping exhaust gas into a tank before welding is an old dodge but I am not sure that modern emission free exhaust fumes would be any good. I once tried welding a lawn mower tank, poked the 'oxy' flame into the filler and there was a 'whoosh' so I thought that now it would be safe to weld. Oh no! as the metal got up to brazing heat the round tank exploded and unrolled itself into a flat sheet. The customer was not impressed but at least all I got was singed eyebrows and a telling off from the boss(my Dad).My Norman two stroke (not my Nippy, Mr. Goldstar,the other one) had a leak and Petseal did not work so I used a Plastic Padding product called Leak-Fix which seems to be working.Paul

It's the lack of oxygen in the exhaust gas that works the wonder.

so far, got the damn great lump out at last, perfectly formed to the fron lower part but adhering to diddly squat, tried the air method and a commercial leak detector loaned by my chum, nothing whatsoever can I find, looking at the inner part I'm not surprised and there is no rust or indication externally, will fill with fuel and see what happens, overall it looks like I could assist by just using a good sealant and using it correctly with all the cleaning agents etc, I have POR15 in some tanks but SLOSH seems to make good claims anyone used it? kind regards