Bending Brass Castings

[Paul R]

I recall posts sometime in the past re. the bending of brass castings. Trigger guard in this case.
IIRC, there was some difference between sand cast & wax cast as far as bendability is concerned.
Unfortunately, my computer skills were inadequate in the last hour to locate related posts in the archives.
Can anyone help me out?

Paul

 

[crockett]

Brass is the opposite of steel. To harden steel you quench. To soften steel you bury in sand and let cool very slowly. On brass- to soften, quench. Some folks recommend quenching every time you bend brass but I think that is too much. In any event a sand or wax cast part probably cooled slowly. This might make it brittle so heat it up cherry red and quench. This softens the metal. Those who reload ammunition have to deal with the mouths of cases getting brittle and they will place the cases in a pan of water and heat the necks cherry red and tip them into the water to quench and soften.
The big difference between sand cast and wax cast-to me- is the sand cast often has more air holes and it is not as good a casting. According to the theory sand cast should be void free but I think the sand crabs pour too quickly.
I've only done this a few times and I heated to cherry red and kept it there about 30 seconds and then quenched- that seemed to work.
Wait a bit for some more replies- it may be better to hold the red color longer- I'm not sure. As I said, that's the way I did it and never had a brass part snap.

 

[LRB]

Heat brass to a low red heat. Too much heat and the zinc will start to separate from the copper. As soon as it is a dull red, you can stop heating. There is no need to quench. The job is done from the heat, not the quench, but there is no harm in quenching if you don't want to wait for the piece to cool. There should be no difference in the brass as to how it was cast, BUT, many wax castings are more a bronze rather than yellow brass. That would be the difference in malleability

 

[Flash Pan Dan]

Wick is correct. I’ve annealed thousands of brass cartridges and never quenched a one. I would heat them up to a low red, drop them in a container, and go on to the next. I would do that every 5th time I reloaded the batch. They would last from 15 to 30 reloads before I would start getting split necks then I would throw away the hold batch. Without annealing a batch would only last from 6 to 8 reloads maximum.

 

[Flintfan69]

It's true that quenching the brass after it's been heated doesn't actually do the annealing. But it also doesn't hurt anything, unlike steel where it will be hard after a quench.

You quench brass after annealing so you don't have to wait around for 20 minutes for it to cool before you can handle it and start working on it.

 

[crockett]

Well, it looks like by quenching as soon as I got a red color I was- by pure luck- doing it the right way. I'll still quench just to be able to handle right away but I did not know it would soften either way.
In catalogs, such as Track of the Wolf, there is usually a big difference in the cost of sand cast and wax cast. For example a trigger guard that is sand cast may cost $9.95 and the wax cast $29.95. I thought the main diffference is quality- the sand cast may have more air holes and also there is a lot of scab on the exterior that has to be filed off. Are there other differences between wax cast and sand cast?

 

[LRB]

No, not other than many wax casting are a bronze. I may not spell this name right, but Reaves Goering? has a good rep for quality wax cast yellow brass. I think he supplies the fittings to Jim Chambers. Not sure, but I think so.

 

[rich pierce]

Some of the wax cast stuff cannot be annealed in my experience.

 

[jerrywh]

If you quench brass after heating while still red hot it will be softer but the difference will probably not be noticeable as it is very small.
Wax casting is a lot more expensive but much more precise. The end finish is much better making for less work when polishing. I started sand casting years ago but switched to wax casting because of the quality. Both processes will produce castings of the equal hardness and ductility if the same brass is used to cast with. If you get a brass casting that will not bend without breaking it is the brass used not the process used to cast it. Some here will argue the point but they are not professional casters.
It is possible to make brittle castings with good brass by some fault in the casting process. Most brittle brass castings people get are actually not brass but silicon bronze. Silicone will not anneal and is brittle but looks like brass.

 

[matt denison]

Jerry said:
" Most brittle brass castings people get are actually not brass but silicon bronze. Silicone will not anneal and is brittle but looks like brass"

I wax cast and use "best yellow brass" for all of my hardware. It makes life easier for the end builder as it can be annealed and worked much easier than the bronze brassish "stuff" used by many others. I am astounded when I see some prices in catalogs advertising prices for trigger guards and butt plates that cost less than what it costs me using my own waxes and molds. Then I read on this and other forums about parts cracking and breaking when being bent.

Always remember and never forget: ya' gets what ya's pays for.

 

[jerrywh]

"Always remember and never forget: ya' gets what ya's pays for."
AMEN. Well most of the time anyway.

 

[nilo52]

Thanks Crockett,

I learned something new today :hatsoff:

Nilo

 

[MJMarkey]

It's not so much the way it was cast but the brass aloy mix. Soft yellow brass will bend somewhat without heat But Bronze (Pink Brass) tends to be hard and doesn't bend easily or at all. Be very carefull when trying to bend castings like trigger guards and butt plates. Bend at your peril.

 

[jerrywh]

Bronze is a alloy of copper and tin. Brass is an alloy of copper and zink. Red brass simply has more copper in it than yellow brass. There are many brass alloys. Some contain a small amount of lead. The best brass for gun castings is called 360 alloy and is about 31% zink and the rest copper. Some suppliers call a lot of stuff bronze that is accually brass. you need to specify the alloy to get the correct stuff. Most brass fittings are good stuff but stuff like faucets are not.
Check out this site for specs on brass. Note the elongation specs. http://www.onlinemetals.com/brassguide.cfm

 

[Paul R]

The stock I am presently working on is a fantasy build with a thumbhole, giving it a semi-pistol grip. I know, I know, I would never try to call it any kind of a HC school, but it is a flinter and from the lock forward it has the 'look' of a HC rifle but again, does not match any classification. I think it's better then anything TC built.
Any way, I was able to bend the Track Vincent, wax-cast triggerguard to a good fit.
Thanks to all who replied.

Paul