Scuttle fuel tank repairer request.

[JonE]

what wattage is "very large" out of interest?

[Howard Wright]

Hi Peter

If you are going to have a go at soldering.  Clean the tank out thoroughly.  There must be absolutely no trace of petrol around at all. (Sorry if this is teaching Granny to suck eggs ).

I have used solder paint recently as a flux.  Works very well. Funnily enough I’ve not had much success with Bakers!  

Cheers

Howard

[Biddlecombe]

If I use a copper head, no flame soldering iron will the tank still need thoroughly cleaning or will just empty and allow to vaporize for a day or two be OK?

[A G Wood]

JonE-200W or better.
Proper sheet metal workers will rightfully roll their eyes, but a good alternative patch material is common brass shim stock. .
As others have said, don't risk an open flame without de-gassing the tank. My preference for this sort of repair was to first thoroughly wash out the tank with hot soapy water and then refill it positioning the tank so only the area of the repair was above water.
Biddlecombe- I've done it in the past on other makes with a sizzling hot soldering copper. Making sure the heating is done a safe distance away, and the flame is extinguished before the heat is applied to the tank. Tin your affected area and the patch first, and hold the patch in position while you sweat it on with something like a scriber, that won't act as a heat sink.

[Biddlecombe]

Thanks for that. I have just found this in the garage. Not sure about the flux? The flat solder stick has GPO No. 8 stamped on it!
   
   

[Stuart Giles]

The GPO solder looks like the stuff used on "wiped" lead joints.  The other stuff looks like Tinmans solder so should be OK. Difficult to get an idea of the actual size of those irons, but the bigger one would be the best bet. The Laco flux is OK on steel, but in my experience the work needs to be immaculately clean before you tin steel with the iron, if the solder doesn't take first time, clean the steel again before having another go. 

I usually use this flux for soft soldering steel:https://soldersandfluxes.co.uk/p1324/S26...-Flux.html
Which seems to work very well even though the blurb says it's for Stainless (for which it is truly excellent) the fumes are hideous, so if you do use it, make sure there's good ventilation where you're working.

[A G Wood]

I agree with Stuart, the GPO branded stuff looks like wiping lead most likely used by the cable jointers. In my brief and ignominious career with the NZ equivalent of the GPO, the electrical [60/40] stuff was always flux cored wire. I'd go with the stick too, which could be 50/50 and should be fine, but try a test run and see how you go...

[Robert Foreman]

Peter, 
    If you need assistance you can always bring it over as you aren't a million miles away. 
  PM me if you need to.

[Biddlecombe]

I'd love to thank you. I'll be in touch after I've finished the wife's instruction in gardening.?

[Chris KC]

After my last failed soldering project I looked up shelf-life of soldering flux and concluded that might have been a factor - like yourself I was using (or attempting to use) an old tin of my dad's that had been sitting around for 30 years.

In the past when needy of small scraps of copper sheet I've used central heating pipe - slit lengthwise and batter it flat. Annealing copper is a doddle - hold it in a flame (kitchen stove) until it glows a uniform cherry red then quench it in cold water.

I've read in the past of people using old-fashioned flat irons as a makeshift high-capacity soldering iron in such cases. They will soak up a lot of heat.

Finally, on safety, I'm not sure there's any real way of eliminating all traces of petrol vapour from a fuel tank; at least any task which relies on this should probably be left to a pro. Looking at those pinholes put me in mind of the coke-can bazooka I made as a student, the ignitor hole was just about the size of a pin. We used lighter fuel as a propellant and a tennis ball as the projectile. After several disappointing poots indoors we took it out to the uni playing fields, with a bit more air circulating the resulting explosion threw the ball clean across the cricket pitch (there was a game in progress) and into the trees beyond. I lost all feeling in the tip of one finger for a couple of years. My ears rang for about a week. After that we turned to safer entertainments like letting off outdoor fireworks indoors...