Tried to do this earlier today and failed, is it possible or anyone recommend an alternative method. I thought about using chemical metal but the bits i need to join are at the fuel tank. (never been any fuel in the tank)

When you say Solder, did you try doing it with a soldering iron? you need to braze them together with a torch

edit:^^^^^^
What he said is a much better idea.
Don't forget to flush the tank and then fill it with water and then be very careful. Oh yes, and afraid.

You need two things; enough heat and the right flux. After it's all clean as an operating theatre.
Killed spirits (no doubt some young jack-a-napes will come along and tell you the proper name of it, it's probably changed since I did alchemy in the middle ages) is what we used to use as a flux. DO NOT breath the fumes in.

[Edited on 28/8/07 by Confused but excited.]

Problem is either wrong flux or not enough heat. you need a good aggressive flux like Baker's Fluid and you need to get steel hot enough for the solder to melt on the steel not from the flame or soldering iron. Once you have a nice coat of solder flowing on the steel, do the same with the copper, bring the parts together when it is all fluid and add a bit more solder to fill any gaps.

make sure the steel is absolutely clean before you start and you should get a nice joint.

Caber

Silver solder will braze copper to s/s . The surfaces need to be very clean, and you need to use flux powder to get it to bond with the metal. I can't remember the flux I use, but its a white powder, I'm sure its acidic too.

You'll need a decent blow torch as the heat is conducted away quickly with copper, even stainless steel takes the heat away quick..!

Baker's Fluid.
See, told ya!

Flux thats where i went wrong, i am using a proper torch so no probs with heat had the steel red. but solder just balled and fell off.

Red is way too hot!

Just needs to be












smokin'.
Sorry, couldn't resist it.

Borax!!

Or is that for silver soldering? Oh well it had to be said

If you are using a "proper torch" that is capable of getting the steel to red hot, then braze it.
Halfords do little packs of half a dozen flux coated rods.
You will end up with a much stronger joint that will last for ever.

hth
Paul G

been meaning to ask and now I have opportunity ..... so what is difference betyween soldering and braxzing?

or what about welding a fitting to the tank and screwing the copper to it?