Is brazing harder or easier than I think

Date 11-03-2003 21:29

I am a metal sculptor trying to extend my materials range from mild steel to stainless by using brazing (i.e. I can't afford tig!). My results are real inconsistent - solid beautiful joins or the thing just falls apart - and I can't figure out why.

I am using an oxyacetelyne torch with a #0 welding tip; usually joining 20 gauge SS (up to 16 guage); and doing flat joints where there is 1/8" to 1/4" flat overlap between the two pieces. Also using silver rods - real expensive but my welding supply store says that's what I need for stainless.

Any thoughts would be appreciated.

By jwright650 (*****)

Date 11-03-2003 21:47

What % of silver is in your rods?
just curious,
John Wright

By gangel99 (*)

Date 11-04-2003 01:04

The spec is 56% silver - melting point of 1145F. This seems a bit on the low side so maybe the issue is overheat.

By aircraft (**)

Date 11-03-2003 22:55

I'm having better luck with alot smaller torch than #0. I'm no expert I have thown into the mix of having to do alot of silver brazing of SS. My problem was getting the metal too hot which is why I have migrated to smaller and smaller torches. Smith has a large selection of brazing tips, much more than any other brand.

By bzzzzzzzzzz (**)

Date 11-04-2003 04:13

stainless is tricky to braze because it has high thermal expansion and low conductivity. heat it as evenly as possible.

By RonG

Date 11-04-2003 17:17

The Cappillary action requires lots of heat in SS because most SS's resist heat flow. So I guess more heat would help.

Also bare in mind SS corrode instantly making cleaning a big issue. We clean and soak parts in Denatured Alcohol most of the time.

We use the a black paste flux on the high temp Solder That you described. You never mentioned flux.

Unless your Sculptors are going to be exposed to high temps I would use the less expensive Silver Solder. It is a lot easer to work with and the flux is not near as nasty.

By gangel99 (*)

Date 11-04-2003 18:51

Thanks for your reply. I am using the correct flux (according to mfg specs). You are correct that it is pretty nasty - I use a mask with fume cartridge filters.

Unless it is a public sculpture where kids might play on it then metal scuplture just has to hang together and structural integrity is not much an issue.

The reason I want to work in stainless is to do outdoor pieces that won't rust.