brazing

[kozu]

this is my first post, as a new member,here goes.I was forging 304 1/4 inch ss. rod today, finished the forging part, then i wanted to braze two pieces together, normaly i have no problem, i am gas brazing, oxygen dial on 8 act.on 4 i use a 3/32 bronz coated rod, i had a difficult time brazing the two together, did i change the ss, by forging. Yes i did get then to stick but it was hard. Any help will be apprieciated. thanks sean.

[Randy]

I just "brazed" some stainless to brass. At the welding supply company they suggested a silver solder instead of braze rod. The chart had a stainless steel listing of 50% silver. I got a 1 ounce roll for $27, but it worked great.

[MattBower]

The oxides that form on stainless at high temperature are really tough and will prevent filler metal from wetting the steel. You probably formed a thick oxide layer during forging. Did you sand/grind it off before you brazed? What sort of flux did you use?

[Dodge]

FWIW, I think your gas pressures are a little low. I generally run the Ox at 10 - 12 and the Acet at at least 7 or 8 unless I'm cutting at which case the Ox would need to be increased. This may not seem like a big change but I'm not so sure even the best gauges are very accurate below 5 psi. The gasses may not be mixing properly or giving you a hot enough flame. I understand its not that big of material, but you could use higher pressure to insure accurate readings and still turn the flame lower to accommodate the smaller material. You don't have to run the torch at WOT. Hope this helps :)

[John B]

In practice, I find a carburizing flame on the oxy/acet set up works best for brazing or silver soldering, equal oxy and acet, then back off to a small nosed double cone rather than a defined tapered oxy heavy cone.

Works for me.

[ThomasPowers]

Special fluxes for brazing stainless---were you using them?

[kozu]

thanks everyone for the great tips, thanks dodge, i kicked up the act. and oxy. this worked, i cleane everything up well, got better penetration, i better leave that word alone, thanks again. Sean.