How would I cast small parts in brass or bronze?

[Locksmith]

Someone brought a very old lockset in to the shop a few days ago. One of the bronze parts inside the mechanism was broken and and we couldn't fix it. The thought occured to me that I might be able to cast small parts like this, similar to what Dave Gingery did in his 1st book on casting, just on a smaller scale. Since the broken parts are usually in the lock case and aren't lost, I could conceivably glue them together long enough to have a template.
Any thoughts on this would be greatly appreciated.
What would i need to do this?

[Herm Williams]

I would suggest lost wax process. Check the library or a night class at a local college. go to google there is more than you will ever need to get started. Basic process is simple but it can get complicated.
re

[skeeter]

I have worked with jewelry and cast gold and silver. I never worked with brass or bronze.

You will need to read up on lost wax casting and see how to work with this as it will allow you to make parts from various metals and plastic.

In a nut shell you take the part and make a model out of wax. The wax model has to be made slightly larger. The metal casting will shrink a small amount.
You then place the wax model into vestment. (something like plaster of paris) The wax model inside is melted out in an oven. Then the molten metal is poured into the cavity. Lots of other things to consider while this is being done.

You will need an oven to cure and melt out the wax, a vacuum pump to get the air out of the vestment. You can use a O/A torch to melt the metal, using a crucible.

You can get lots of information at your local library and doing a search on Google.

I hope this is clear enough to help you understand what is needed to cast.

Good luck.

[CCWKen]

You can use a O/A torch to melt the metal, using a crucible.

Yep. Don't try it in a cast iron ladle. I shouldn't mention how I know. Brass and bronze will melt at a lower temp but I was using pure copper and trying to rush the melt. Before I knew it, I had a hole in my ladle and a blob of cupperous ferrite on the bench.

[Locksmith]

I knew you guys would know the score.
Here's a big issue, or maybe not. How hot do I need to get to melt brass and bronze? Most likely, these things would be bronze.
As an aside, I have a kit called The "Clam", which is used to cast copies of keys. I very rarely use it, but it has been a great help when I did. Basically, it is a hinged plastic device, which is filled with clay. The clay is flattened out flush with the top of each side of the clam and then dusted with baby powder. The key is inserted, the clam is squeezed close and then the key is open and removed. A sfunnel is made on the top of the clay and small reliefs are carved off the impression of the key. The clam is closed and and Woods Metal is melted and poured.
It appears that this method is similar to sand casting without the sand.

[PTSideshow]

lock, depending on the the type of bronze 1920'F to 1945'f. And if it its alpha or beta brass from 1630'F naval (roman) brass 1935'F for Gilding metal. these figures are the melting point. http://www.backyardmetalcasting.com/forums/index.php
Good source for all things cast. Just remember the zinc fumes from the heated metal. Ammen C W has a book called Casting brass from 1985 ISBN 0-8306-0810-9 you probably get it from the amazon used. it was put out by tab books. The US navy foundry book is another good one. McGraw-Hill bought tab books and the foundry book is being reprinted.
http://www.lindsaybks.com/
http://www.nbbooks.com/
http://www.gesswein.com/catalog
http://www.ofrei.com/
for supplies for lost wax casting and books ect.

[mike petree]

I think bronze melts at appx 1850 deg f. I've had no problems melting it in my small propane fired crucible furnace. O/A would be neccessary if you don't melt it in a furnace environment. Lost wax would be the way to go as the others have stated.
Good luck with your project,
Mike

[BobWarfield]

Yuo can do some pretty cool work with lost wax casting. Here is a one fellow's locomotive stack:



He made the molds for the wax from acrylic:



Details at bottom of this page:

http://www.thewarfields.com/MT/CCBlogJune2006.htm

Best,

BW