brazing rods..?

[jontera]

Has anyone had any experience of using them?

if so what are they like to use (easy or hard?) and are they any good for light stuff? (exhaust patch / minor body panel kind of stuff....not runcorn / forth bridge repairs)

could you give us some easy to follow tips or tricks, along with what i need to be looking out for.

also can someone solve an arguement, sorry heated discusssion I was having with the father in law...

which is hotter...Butane or Propane? sould be which produces the most heat?

cheers in advance...

(bet Gregster's fingers are twitching right now, seems to be something that would fall into his area of expertise)

[ghosthunter]

Hi I use to use brazing rods all the time in the good ole days before mig's became affordable. Very easy to use brazing rods, especially the fluxed ones. Used carbon torch with the arc welder and very pleased with the result. After all most early bicycles were brazed with no problem, but with technology improving alot are welded now.
Do not braze structural members as MOT will fail now. Didnt matter in the old days and I never had a brazed joint fail!. The metal always tore first. Just remember to clean all the flux off when your done as its corrosive.
As for butane versus propane. Butane has a higher calorific value than propane. So for the SAME VOLUME of gas BUTANE is hotter as it has a higher energy content. The confusion arrises because propane regulators release gas at a higher rate to compensate. Propane performs much better at lower temps than butane. I think butane stops gassing off at -10 and propane is something like -40, but dont quote me on that. So propane is the main choice nowadays.
Despite all the science to the layman propane does apperar to be hotter.

[jmc]

I use rods which have flux inside them but I find its better to use brazing flux as well.
Also get all the metal you want to braze really clean.
The powder flux is mixed with some water to make a paste which I put on (only where you want the braze to go) with a small brush or anything small like the end of a brazing rod.
Take your time and get everything set up well and weigh or clamp the job down to stop it moving when heated.
Wear sunglasses or dark goggles .
Heat the whole job up evenly as you can ( preferably some where where its a bit dark) with the flame and when the job is bright red heat( the powder flux paste will look all black and funny by now ) introduce the end of the rod into the flame and just above the work.It should melt, drop onto the job and flow quickly around where the flux paste was put.
It is possible to build up a bit more braze on top if you need to while its hot.
If you are doing an exhaust pipe its a bit trickier because its round and the braze will tend to run around to the underneath and gather in a blob.There should be enough left on the top to work.
Braze will also follow where the hottest part of the job is.This can work to your advantage so keep the top of the pipe slightly hotter.
Clean up the job afterwards and get any flux off, I've always filed the shiny glassy flux off and then scrubbed mine under running water.
If you look up welding suppliers you should get good advice and they may split a packet of fluxed rods for you.
If not then you may be able to buy a rod or two and flux off a local fabricator.
Do a test braze first on some scrap steel.
Good luck.

[jontera]

Cheers chaps, sounds easy enough (famous last words) will give it a try on some scrap first. it was something that got into my head at work today and kind of got stuck (and expanded a little)

had a read through google and watched a few vids on the tube of u, and it seems that heat is key.

if i can sort of master it then that's another "trick" in the toolbox....never know could come in useful somewhere..