Page 1 of 1

Welding pinholes in petrol tank

Posted: Mon May 01, 2023 12:06 am
by will_curry
Anybody had any experience of welding up pinholes in an Arrow petrol tank?

My tank has three small pits in the bottom directly under the filler cap. Elsewhere
looks fine with the camera - very little corrosion.

Rather than fill the tank with chemical sealant which I might regret later I had wondered
about the wisdom of drilling through these pits and then getting the resultant small
holes welded from the outside.

I've done much the same with 4-stroke tanks many years ago with gas and quite successfully -
I'm still using one of the tanks. I wondered if there was anything about the Arrow tank
which might cause problems. I'll have to get someone else to do the welding as I don't
have the bottles any more.

Re: Welding pinholes in petrol tank

Posted: Mon May 01, 2023 5:35 am
by ian williams
hi will ;
better to solder the tank with 3mm dia 60/40 solder , stick of body lead , and some solder paste flux , propane torch , gaz stove and a radiator iron [looks like a copper axe ] .
you can buy flux paste that has powdered lead in it , much like the old fryers flux paste , i think frost restoration sell the paste which is used for body filling with lead .

i did my NH tank this way on the bottom of it .

kept the iron hot on the gaz stove , i used a propane blowtorch and radiator iron for soldering but i used both in combination with eachother , maybe bit of flame on the tank and maybe the iron depending how much heat i needed etc .

obviously i had left the tank open to air for a week or two first and also filled with water and flushed out and then dried it out etc prior to putting any heat near it .
you brush the solder paste on first then heat it to tin the metal .
i also have bakers fluid as well i might use once ive got some solder onto the metal and want to spread it a bit more with the iron . ... 3AQAvD_BwE

this iron is like the type i use but is a gas powered one instead of heat it up on the gas type , you can lay "axe" down at a low angle and swirl the lead around . ... th=1&psc=1

i did an old fordson tractor tank a while ago and it was well peppered , on bottom of tank repairs you dont grind the solder back , just leave it proud .

this is all for repairing bottom of tanks really but you could also use body lead etc to repair top of tanks but that is a difficult job to do it right .

i used SLOSH to line my tank inside , although it was petrol tight i still wanted to line it inside .

normally the 2 stroker tanks dont rust out if they have oily fule in them , im still on my original 1958 tank in my 58 leader but it had fuel in it for the 30years it was sat in shed off the road .

hope you get it sorted out without much fuss , be carefull though .


Re: Welding pinholes in petrol tank

Posted: Mon May 01, 2023 2:59 pm
by will_curry
Thanks Ian for a wonderfully detailed reply.

I'd not considered solder as a possibility before.

Re: Welding pinholes in petrol tank

Posted: Tue May 02, 2023 2:58 pm
by cbranni
I can second the use of solder, just need to be very clean, good luck


Re: Welding pinholes in petrol tank

Posted: Tue May 02, 2023 7:23 pm
by john.mitchell
I seem to remember an artilcle about using thin metal rods, part of a dentist's armoury... I believe they were sharp and could be pushed into the holes. Can't find it though.

Re: Welding pinholes in petrol tank

Posted: Thu May 04, 2023 10:01 pm
by Vincent.vanGinneke
long ago. a Dutch dentist, I think his name was Charles Qua.