Braze on top of braze?

Kmot · Dec 14, 2010

Quick question needing an answer:

I want to go around once more on an item I brazed, so that I can make a more aesthetically pleasing fillet.

Do I:

1) Brush on flux first, then heat and apply braze rod

2) Just heat and apply brazing rod on top of the old braze

Thanks!

arnoldb · Dec 14, 2010

Kmot, it would be option 1 - flux up the area well again and then go around.
If you don't flux it, the additional brazing won't flow properly. You'll also find that the new brazing will start to flow before the old brazing actually melts again.

Regards, Arnold

steamer · Dec 14, 2010

What Arnold said... ;D

Troutsqueezer · Dec 14, 2010

Could be I'm a bit nit-picky on this one: I'm not sure I would follow the exact order of steps listed in number one. Generally, I apply flux then I shape and place the brazing rod on the joint and then heat the whole area at once. You mentioned you would heat first and then add rod but I suspect you already know the best way to do it.

Kmot · Dec 14, 2010

Thanks fella's!

Ned Ludd · Dec 14, 2010

It's been a long time since I brazed anything but I used to braze on braze without extra flux. Generally the flux is to clean/protect the base metal but if that is already covered, and therefore protected from oxidation, with braze there should be no problem.

Having said that, how is your skill at brazing?
For fun I used to make belt buckles out of brazing rod by just fusing rod to more rod, you have to be careful or the whole lot just melts away. Not bragging you understand, anyone with a minimum of skill could do it. Oh, and I did not use any flux at all.

Rereading you post before pressing the "post" button, could it be that you did not have the job hot enough the first time round? If you have lumps of braze or an uneven fillet on the job it sounds like that might be the case. By the way, is this proper braze with brass/spelter rods or is it silver braze?
Ned