How to repair leak at petrol tank seam?

[storkfoot]

Discovered today that I have a slight leak in the seam of my Vespa Rally tank. I haven't taken the tank out yet to check this 100% but I will.

The tank was rusty inside but was properly cleaned a couple of months ago. It was surface rust on the inside from standing many years. No indication that there are pin hole perforations in the tank.

I have no welding experience but on doing a few quick internet searches I can see that re-welding a seam on a petrol tank is not quite as straightforward as you may think. So, should I (i) drain, clean and dry the tank as best I can and take it to a good welder, or (ii) use something like:

http://www.frost.co.uk/por15-fuel-tank-sealers.html

As always, any tips or experience much appreciated

[CutdownSpence]

You will probably find the cost to get it welded would be more expensive than buying a decent 2nd one ! that's what I found anyway, (mine is stainless though)

[mr series 2]

I've used the Por 15 sealer & the sealer from tank care products I found the tank care products sealer far better

[carlos fandango]

Id get it welded and then maybe use a sealer such as the one mentioned previously por 15 , as i think this is resistant to ethanol, unlike petseal.

Before you get it welded drain the petrol out, then fill with water, this will get rid of the petrol vapour and should be ok to weld.
Russ

Nice Rally BTW

[storkfoot]

Thanks for the replies. I've got tank out and found one pin prick leak in the seam. I'm going to look at a weld and seal in case there are any other pin holes just about to surface.

Cheers, Russ. It is absolutely lovely to ride. All lammy owners should go for a spin on a Rally

[mr series 2]

The sealer from tank care products is 100% ethanol proof & I found it easier to use than POR 15 quicker drying & thicker coating
http://www.tankcareproducts.co.uk/index.htm

[goldeneye]

ive just got a 2nd hand RALLY 200 tank in a garage clearance, its a bit rusty on the top but solid enough, apart from the hinge on the cap flap,which is f@@ked. might be good to use as repair sections or do it up as a spare. you can have it for postage costs if you like. (its got the tap on as well.) just had a look at it, and its canny clean inside as well, would need minimal cleaning, and the hinge aint that bad either.

[storkfoot]

G/eye, thanks for the offer. Much appreciated. If you can leave it with me a couple of days I'll see what the welder says. I'll let you know by the end of the week if that's ok?

[goldeneye]

no probs S-foot! I"ll stick it in the corner with ya name on, if you need it just PM me .

[storkfoot]

The sealer from tank care products is 100% ethanol proof & I found it easier to use than POR 15 quicker drying & thicker coating
http://www.tankcareproducts.co.uk/index.htm

S2, I got this stuff and did it yesterday afternoon. Please reassure me that it will be fully cured by next Friday as I've got some serious miles to do on the Rally next weekend. I ask as, one day later, it's still very tacky AND the instructions say it should spend the next 5 days at 30 degrees

It never gets that warm up north