Buttplate casting cracked

[bob in the woods]

I was annealing a buttplate casting prior to working on it. Heated it up to a dull red in the wood stove, then cooled it in a pot of hot water . Now there are a couple of cracks in the casting. Any ideas as to why ?

[jsb30]

Because it was quenched in water

[Stophel]

It is S.O.P. to anneal brass and quench it in water.

I would guess that the cracks were flaws in the casting and were there to begin with.  You just opened them up where you could see them.  They would have shown themselves at some point anyway.

[Bill Raby]

It cracked from the quenching. The brass used in castings is usually a different alloy than brass sheet or bar stock. You have to air cool cast brass parts when annealing.

[bob in the woods]

It cracked from the quenching. The brass used in castings is usually a different alloy than brass sheet or bar stock. You have to air cool cast brass parts when annealing.

I've not had that problem before when using sand castings.  This is/was a very high quality wax casting.  Live and learn !   

[flinchrocket]

I have silver soldered small cracks in brass. I didn't want to ,but it was a cheap fix and don't show to bad now. Nobody else has ever mentioned it.

[smylee grouch]

I don't know the why of the cracks but I'm sure I read it on this forum that there is a brass colored solder that you could fill inn the cracks  with when you get to that point.

[rich pierce]

Rio Grande sells a brass colored silver solder. Expensive and thin. Hi f possible I’d start over with a new casting instead. If the casting was a bronze alloy I’d not want to work with it.

[bob in the woods]

No, not a bronze casting.  I hate those !!   More work to clean up, and they never ever look "right"
I'm going to file this one out and see how it plays out. Perhaps a little peening and a solder job will do it's magic. 

[Mike Brooks]

Never had that happen in 40 years. I always quench in water. I would guess it's the alloy. I'd soft solder  it up and go on.

[Scota4570]

When ordering "brass" parts what should one specify, or look out for, to be sure they are getting soft brass and avoiding those hard, brittle, odd colored bronze castings?

Is there a particular supplier or foundry who uses  the wrong material?  Aren't  they aware that they are making a substandard part? 

[oldiemkr]

I agree with Mike. Soft solder it. Won't even see it unless it's real wide.
I never quench anything. I usually put the hot metal on a heat sink , usually a bandsaw table and let it cool.
Quenching will find any crack or impurities.

[jerrywh]

I would guess you got it too hot before quenching it.  Buy a new one.

[flehto]

Have annealed many brass parts and never quenched  in water....just let them air cool. Really don't know why they should be quenched in water. ....they cool down fairly fast.....Fred

[jerrywh]

Book says quench at about 1350 or about there but From experience, it seems that brass gets pretty soft whether you quench it or not. Personally, I can't tell any difference one way or the other.
 Now with sterling silver, you are supposed to let it cool down to a black heat or 800° F. and then quench or it may crack.

[bob in the woods]

Thanks to all . I really appreciate the advice .  I figured I'd try the solder, [ what did I have to lose ? ]
and now that everything is filed up, you would never notice it. 

[Stophel]

I think quenching brass is purely so that you can handle it again right away.

I have quenched brass with no problems for a long time.  I've also sometimes just heated it, then let it sit and cool off on its own.  Doesn't seem to matter, just takes longer.