Framebuilders - stainless lug silver braising question.. flux?

hey guys,

the silver flux im using doesent seem to be performing to my satisfaction. brazing stainless lugs isnt fun. im using gasflux type u, in addition to the gasflux in the flame. i hope to learn of some better flux on steroids.

I've never used Gasflux U, but I believe that's a white paste, right? I have better luck brazing SS with Safty-Silv black paste. I think Gasflux makes a black paste. (Note that I use Gas-flux in-line fluxer).

What silver braze alloy are you using?

Brazing SS lugs is fun if everything is super clean with the right flux and wire.

I have had fine success with Gasflux U. Heat control is absolutely critical, though, as overheated stainless makes a quick and nasty mess. Get it red hot and you might as well stop right there, let it cool down, re-clean and prep, and try again. In my experience, anyway.

I have had fine success with Gasflux U. Heat control is absolutely critical, though, as overheated stainless makes a quick and nasty mess. Get it red hot and you might as well stop right there, let it cool down, re-clean and prep, and try again. In my experience, anyway.
+1

Bob Brown uses Gasflux U on 953 frames with stainless lugs and says both cleanliness (absence of any contaminents) and heat control are paramount. Read what he has to say HERE (http://bobbrowncycles.blogspot.com/2006_10_01_archive.html) on his blog (scroll down to October 19 blog entry).

I've never used Gasflux U, but I believe that's a white paste, right? I have better luck brazing SS with Safty-Silv black paste. I think Gasflux makes a black paste. (Note that I use Gas-flux in-line fluxer).

What silver braze alloy are you using?

Brazing SS lugs is fun if everything is super clean with the right flux and wire.

thanks for all yr quick replies, we have an account w/ safty-silv, so i'll try that stuff.. thanks also for the bob brown blog link, looks interesting..

I've never used Gasflux U, but I believe that's a white paste, right? I have better luck brazing SS with Safty-Silv black paste. I think Gasflux makes a black paste. (Note that I use Gas-flux in-line fluxer).

What silver braze alloy are you using?

Brazing SS lugs is fun if everything is super clean with the right flux and wire.

Thanks for the tip, Steve. Taking a look at Harris' site (http://www.harrisproductsgroup.com/consumables/fluxes.asp), they recommend the black for stainless, thick parts, higher heat applications. It has a 200 degree higher temp range (1800 vs. 1600).

I have been doing stainless small parts with the Stay Silv white with no problems, but it looks like the black would be useful for things like bottom brackets.

I have been building frames for 30+years and love gas fluxers but never had much luck using them with silver solder. They work great with brass brazing but not so hot with silver. I would go with straight oxy-act and paste flux.

Mike Howard