How hard is it to braze brass to aluminum? Can you use an alum brazing rod?

-- Joe

 

not sure it can be done, i'd try sil-flos if i were doing it

 

Ede,

need to weld a brass hose barb to an alum blower discharge. Gonna see 10-14psi boost. bad idea?

-- Joe

 

actually i thought about it some more and you can't. you might get a zinc rod to work but not sure of the quality. i'd weld a bung on the aluminum and tap it for a pipe thread and get a barb to fit it.

 

Ede,

Can you braze cast iron, or steel bov flange to alum? If so what would you use for a rod, zinc?

-- Joe

 

You cannot braze to aluminium. You need argon gas to tig or mig weld aluminium. Only aluminium can be welded to aluminium.

 

danger that's not 100% true i've welded steel to aluminum, but there's a trick to it that i'm not telling. great way to win a bet or two.

 

Why do they sell alum brazing rods for brazing aluminum then? Is it a scam?

So whats the answer? No you can't braze iron or steel to alum, or yes you can mig it with argon/co2 or ?

-- Joe

 

for your purpose it can't be done, for mine it can

 

isnt there enough meat to drill and tap for the fitting?

 

you can braze Steel/Aluminum and Copper/Aluminum, dont see why you could not do Brass/Aluminum... just make sure you get both metals hot enough. Or just Silver Solder it...

 

lee you can't braze to aluminum. only reason i can think of is the melting point of aluminum is below that of brass/bronze. ok another reason i can think of is bronze or silver solder wouldn't stick to aluminum.

 

Silver solder will stick to aluminum. I do alot of custom phase change setups and sometimes i use aluminum transmission coolers for Condensors and Evaporators.

These things run at 350psi+ and dont leak.

And you dont need to melt the brass, you only need to have the metal hot enough to melt the filler. Hell, Copper filler will probably braze Brass/Alum, its a pretty good all around filler.

 

I know you can braze aluminum to aluminum. I have rods and detailed instructions on how to do it. Heat both parts to 1080f, and then apply the rod.

The issue is I have an alum BOV, but the flange for some reason is steel. I can prolly make a new flange out of alum, but we're talking all day at the machine shop vs welding..

 

lee if you're brazing you have to melt the brass. how else is the brass going to go anywhere?
edit:
ok i guess i was using a bit of slang defination for brazing thinking it had to be dome with a brass rod. after looking in the aws terms book they classify several things as brazing not using a brass rod.

 

thinking about it you might be able to tig brass to aluminum with aluminum bronze filler metal. i have a little bit, might give it a try and see what happens.

 

Yeah, with brazing you do not need to melt the base metal. The base metal just needs to be hot enought to melt the filler. (brazing rod)

A brazing rod normally has a lower melting point than the base metal, or else your whole project would start melting away.