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Brazing Brass

ctwo

ctwo

Merely Rhetorical
Joined
Feb 5, 2015
Location
auf der motobahn
Moto(s)
motato
Name
Heyou
Can anyone around SF and south braze brass?

This part is for an all girls catholic school and I was going to give it a try, but I ran out of gas and oxygen and my tanks are no good.

Anyone willing to help out? I've straightened and prepped it and already started near the edge...

After brazing the top, I was going to braze the bottom and fill it in a bit since it's buckled a little, then mill the back side flat again. We just need the basic brazing done.
 

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If you're brazing brass, with brass, isnt that welding?

I cant help, other than with minutiae and semantics
 
auntiebling said:
If you're brazing brass, with brass, isnt that welding?

I cant help, other than with minutiae and semantics
Click to expand...

Well, the guy at Madco said it looked like brass, so he gave me low fuming bronze brazing rod. Bronze has a slightly higher melting temp, I suspect. Perhaps one would braze that brass bracket onto the bronze rods?

OK, or weld brass...

Another suggestion was silver solder, but I think that's not strong enough, and expensive!
 
that's gonna need another layer of metal for a stiffener, I don't think just braise/welding it back together will be strong enough

what is the part ?
 
ctwo said:
Well, the guy at Madco said it looked like brass, so he gave me low fuming bronze brazing rod. Bronze has a slightly higher melting temp, I suspect. Perhaps one would braze that brass bracket onto the bronze rods?

OK, or weld brass...

Another suggestion was silver solder, but I think that's not strong enough, and expensive!
Click to expand...
Brazing (or soldering) is when you use a filler that's significantly different than the base material - such as using brass or bronze on steel. Low temperature is soldering, high temperature is brazing (AWS says 840F is the cutoff).

Welding is when use use a filler that's the same type of material as the base metal.

In this case, as the base metal is brass and so is the filler, it sounds like it's welding. Using the same rod on steel would be brazing.

This is mostly just semantics.
 
Welding requires you to also melt the base material. Not sure what the base alloy is, but if it does not melt, it's still brazing.

It looks like a sand cast part and may not really be weldable. Also, not really sure if a butt "weld" like that with brazing rod is really going to be very strong. You need a lot of surface area for the bond to have much strength.

I would probably just drill four holes and back it up with a piece of sheet steel and use that for strength.
 
aminalmutha said:
Welding requires you to also melt the base material. Not sure what the base alloy is, but if it does not melt, it's still brazing.

It looks like a sand cast part and may not really be weldable. Also, not really sure if a butt "weld" like that with brazing rod is really going to be very strong. You need a lot of surface area for the bond to have much strength.

I would probably just drill four holes and back it up with a piece of sheet steel and use that for strength.
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If the base metal and filler are the same material, I don't know how you'd avoid melting the base metal. Maybe brass brazing rod has a particularly low melting point vs other brass, I don't know.
 
Junkie said:
If the base metal and filler are the same material, I don't know how you'd avoid melting the base metal. Maybe brass brazing rod has a particularly low melting point vs other brass, I don't know.
Click to expand...

True, but they could be different alloys.
 
If flange thickness is not critical, I would fab up a steel backing plate out of 1/4" thick material and drill a few new holes in the broken bracket. Tap your backing plate to match and you might be able to get away with just bolting it all together.
 
Yes, I could do it the hard way. It looks like 15 minutes for a competent welder, mostly just getting the part hot enough to start.

Actually, the initial request was to fab a replacement out of steel as there may be more... I could do it that hard way too. At least I can mig steel.
 
Mike95060 said:
If flange thickness is not critical, I would fab up a steel backing plate out of 1/4" thick material and drill a few new holes in the broken bracket. Tap your backing plate to match and you might be able to get away with just bolting it all together.
Click to expand...

I'd do something like this from the side we can see, betting the back side has to remain coplanar with adjacent brackets. U shaped doubler plate to hold it all together. Flathead screws from the back to hold it together. Then braze. Take doubler plate off and reassemble with epoxy in the joint.

No proffit sadly, it's a fiddly solution.
 
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