Question about working with brass

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kvolle

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Jan 24, 2008
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I have been forging knives and swords for 22 years and have always had my best friends dad make the fittings for me. He passed away not to long ago and I started making my own fittings. I started with copper which I found very easy to manipulate into any shape I wanted. I melted down old pennies (1983 and earlier) and made a mokume billet in which I was able to mill out to the shape I needed. I have tried just about everything with at least passable results. The question is how do you guys work with brass. I have round rod that I use to pin my handles and a couple of old brass plates from doors. I tried to heat them up and forge them to the shapes I needed which was an utter disaster. The first time I hit the rod it broke (no shattered) into pieces. And the plates got so brittle that they did the same. I tried melting it down like the pennies. No such luck. What am I missing here. I figured that if i got the brass to the right temperature I could manipulate it to what ever shape I wanted or at least melt it into a billet I could mill out. What is the trick to working with brass? Am I doomed to using other materials for every blade I make from here on out? Or is there something I'm missing? :mad:
Man I wish I would have taken advantage of the knowledge i had at my disposal for so many years. Please help.
 
Brass ? Which one ?? Door plates are usually cast and that's an alloy developed for casting not forging .It may be hot short or have other problems. Some wrought and cast alloys are free machining grades with lead in them which can cause forging problems. Brasses are copper with from about 5% to 40 % zinc.5-10% are called gilding metal .30% is cartridge brass which obviously is what they make cartridges with. It is used for that because it is the most ductile of the brasses. 40% is yellow brass. Unless you're interested in color I think the best would be cartridge brass....Similar is bronze and the best is probably silicon bronze....Some alloys like silicon bronze are best formed by cold hammer /anneal cycles rather than hot forging. www.copper.org
 
You cannot hot work brass easily, it's usually has to be cold worked, Brass gets very brittle with heat, and to melt it you put it in a crucible, cover with zinc oxide and charcoal, and put the heat to it. With out the zinc you will do nothing but oxidize the crap out of it. The charcoal acts like a flux.

http://www.green-trust.org/junkyardprojects/FreeHomeWorkshopPlans/SmeltingFurnace.pdf

http://www.backyardmetalcasting.com/

http://www.abymc.com/tmoranwms/Casting_CharBrass.html

http://answers.google.com/answers/threadview?id=252500
 
kvolle, did you want to lost wax cast any of these fittings? if so, I will tell you how to get started.
 
mete said:
Brass ? Which one ?? Door plates are usually cast and that's an alloy developed for casting not forging .It may be hot short or have other problems. Some wrought and cast alloys are free machining grades with lead in them which can cause forging problems. Brasses are copper with from about 5% to 40 % zinc.5-10% are called gilding metal .30% is cartridge brass which obviously is what they make cartridges with. It is used for that because it is the most ductile of the brasses. 40% is yellow brass. Unless you're interested in color I think the best would be cartridge brass....Similar is bronze and the best is probably silicon bronze....Some alloys like silicon bronze are best formed by cold hammer /anneal cycles rather than hot forging. www.copper.org
Click to expand...

Thanks mete. I have alot of old cartridges that I planned to re-use but never got around to it. Now how do I go about it? Can I forge, cold forge, or cast?
 
J.S. Carter, yes I found that out the hard way. I tried using the brass rods i use for pinning handles and boy did that go wrong. I did try forming it with out heating it but i believe it has been too hardened to work with. the same result as before. the rod just crumbled. as mete mention i am probably using the wrong material and i just don't have the same knowlege i have of steel. I will try your method but i am a little worried about the zinc. is that safe indoors? i have a really good ventilation system but not sure it would protect from fumes. I forge in my basement because i live in a neighborhood that i can't forge in my back yard.
 
Original, yes I would appreciate any help you can give me. I have a little knowledge of casting but certainly not enough to even pass as adiquate. I really appreciate you guys helping. Since I joined I read the replies and the advice and thought I'd give it a shot. I'm glad I did. you guys are great. Thank you.
 
For old cartridges it's not worth the trouble IMO. You would have to melt them together. That of course will create Zn fumes which are toxic. ONLY do it outdoors and use respirator .
 
Mete, any other suggestions? Is there some place that I can buy brass that is forgeable/ castable? If not can you suggest where I can buy bar stock? I hate to waste material but if I plan out my pieces ahead of time I could just cut out and mill it to the shape I want with out wasting to much.
 
Ok, in order to cast brass, you will need a few simple tools and materials.
this is lost wax casting or you can sand cast, which may be easier for you.
The problem I see most have in casting bronze, is getting the casting temp. of the mold to a soaked 950f. (barely dull red in the shade)
The next important factor is getting the brass to a casting temp. What you are looking for is a small puff, NOT a pop of blue flame from the surface of the rolling molten brass, by using boric acid as flux, you will have some floating impurities, so when you see the little blue puff of flame, it is ready to pour into the mold and cast. One can steam cast, sling cast (centrifugal) or vacuum cast. You will need to study by search engine the method you will use.
There will be an average of 3% shrinkage of the cast fitting.
I cast my fittings, but I am a Jeweler and I have casted maybe 500lbs of bronze, lots of scrap, brazing rod, bearing races, all mixed, etc.
The advantage I see in casting, is that you can get great and fancy detail in intricate carving of the wax model, which with a wax bur or two for the dremel or foredom, you can quickly carve bolsters, gaurds, pommels, that you can cast and make injectable rubber molds that can be used over many times to make a series of parts for any amount of production runs you might make, big time saver. Do you see where I am going??

If you just want ingots to roll out, which may be the easiest for you, get an cast iron ingot mold the size you want to work with, beeswax it up, get the mold hot till the wax smokes and pour in the brass as soon as it puffs the blue flame, then anneal the ingot by getting it dull red and quenching in cool water, this will need to be done often. Get an small crock pot and fill half way with 50/50 battery acid and water from the auto parts store, this is good to knock the flux, (boric acid) off the ingot and annealing at the same time. The flux is best removed before rolling out, as it is hard stuff and will dent the bronze in the rolling proccess.

I hope this helps, I will try to answer any questions.:D
 
Original, thanks I will study up and tell you how it turned out. Is the Bronze the missing factor in the casts that i have already attempted? Does that somehow bond and change the structure to make it more ductile for working with? I was talking to a blacksmith I know and even though he had little knowledge of brass he had mentioned like mete did that it would have to be a mixture of different materials that determines how dense or maluable the brass is. Maybe I'm still off base but i will experiment with the advice that you have given so far and see where that takes me. Thanks for your help, i apreciate it.
 
kvolle, just like steel, you could use1/4in brazing rod so you know the type of brass is the same, but the real important point is the melting and the little puff of blue flame, if it pops to hard or too much the brass is overheated and will cause voids in the cast piece or if the overheated temp is held too long, you are burning out the zinc, which causes porosity. Wish I had the stuff to make a video for you guy's, seeing the proccess has a big ahh ha factor. So, once again, as soon as you see the little blue puff, and all the metal iin your melting crucible is moving as a red rolling ball, let her rip! pour immediately.
 
Original, I will be working on it this weekend. I appreciate the advice. I'll let you know what happens. Thanks again.
 
Original, Thanks for the advice. I tried you suggestion this week end and it turned out pretty good. I am not sure if I did this exactly right because I had a little slag like crust after the pour. I just made a square block from which I could mill the bolsters for the knife. The top of the square that was open to ambient formed a slag like film. This stuff was hard as all get out. I assume it happened because of oxidation. I did everything as you said and waited until I saw the little poof of blue flame and poured. Besides the slag the billet came out perfectly. I was able to finish my knife and it was a great feeling to accomplish something new. Thanks for all the help. I appreciate the assistance and guidance. Just goes to show an old dog can learn new tricks.
 
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