MIG brazing

[JayRS4]

Afternoon all, and merry christmas eve (just to show i`m not a completely miserable git)

I have a little project in mind that i`d like to do in copper, theres going to be quite a lot of joins on it, so gas brazing would probably be out, and I dont have an oxy setup to get more localised heating.

Has anyone tried mig brazing with a conventional machine (ie not a fancy lorch, no disrespect meant). What does it turn out like, does it flow as well as when using gas?

Pics to accompany your replies would be good if possible. I remember Matt did post some a while ago, but i think there lost in one of the machine threads, and they had been ground flush in the photos.

Cheers all

 

[Omniata]

If doing in copper could you TIG with copper rods???

 

[Iain Westland]

Matts are in his album I think. in the new year my 3phase goes in, then I can try it out for myself

iain

 

[gordon stephenson]

There was a post a while ago by TechnicAL, stating that the welding characteristics of the Lincoln SP-170 was suited to brazing but I don't know about any other welding sets.

 

[JayRS4]

Om, TIG would be my preffered option, but I just sold it. Depends on when I have a play with this idea, i might have a replacement by then

Iain and Gordon, cheers, will have a look in the album and look for Al`s thread.

I`m led to believe that brazing is usually done with a very low current, hence the 15 amp setting as an option on the Portamigs, mine can match that so should be interesting.

Matt, if you are reading, when I said not Lorch, it was only because i thought it used some of it`s electrical whizzbangery to aid the process, which obviously i don`t have, if it doesnt then I stand corrected and appreciate any input.

Thanks guys

 

[matt1978]

Hi Jay,

You should be able to Mig Braze with your conventional mig, so long as its got a good quality Transformer and Choke.

The Braze wont flow like it does when you use the Gas method. That encourages caperilary action which sucks the metal into spaces.



Mig Brazing is very simerla in aperance to conventional Mig welding, with the exception that the welds are a golden/Yellow color.

If you are going to attempt it, use a 0.8mm wire and either a 98% Ar 2% Co2 or a straight 100% Ar sheilding gas.

 

[TechnicAl]

The other consideration is the voltage. MIG Brazing needs lower volts than MIG. If your set wont go down low enough use a bigger wire. 0.8mm wants about 12-15V but 1.0mm will be about 18-20 V. Some sets will probably want different settings, like Matt says it depends on the build quality.