Try using a buttering pass of brass on the A-36 around the perimeter where the 3/8 brass will go, the braze. Still preheat. Make sure all mill scale is removed prior. What type of filler material are you using?



Hope this helps.


Brian Maas

It's likely that the brass has a lower melting point than the brazing rod. You could get an idea by taking two similar sized small pieces (one of the brass one of the rod) and heating them evenly until one melts. An oven would be perfect but a torch is probably good enough. If the brass melts first you need different filler. Try the silver brazing alloys used by refrigeration people (some of them contain no or very little silver and thus are not too costly. If that 2.5" is the thickness of the plate its going to take a lot of heat to get the surface of the plate up to the melting point of the brazing filler. Hard to do without melting everything else in sight. Perhaps more preheat will help. I understand bronze mig wire is available. Tig brazing has been mentioned here and is a possibility.
Good luck
Bill

Hi Chuck

If the copper alloy is a Cu-Zn brass, then it is possible that you could have a corrosion mechanism at work called de-zinctification. This tends to make the material "spongy" and then it has very eratic behaviour when heated.

Obviously this would not be an issue if the Cu alloy was new stuff. If however it has been in service for some time, then this is a possibility.

Regards
Niekie Jooste
Fabristruct Solutions