[spud--1]

Hi im new to this forum and have been reading the excellent information, I am looking to cast some small replica medals from brass that have some fine detail but am a bit lost on where to start.

I have been told that lost casting would give the best details and have been reading up on this, from what i can gather i need a wax mold which is coated in some sort of plaster the melted out and the brass poured in.

What i am really struggling with is what i need to start this hobby, how do you make the initial mould for the wax and and what is it made from? Is this what a vulciniser does? Also after casting the wax do you coat it with something like this http://www.specialplasters.co.uk/ind...&productId=110 ?

I think i need an electric small furnace is there any uk suppliers of these? Also do i need a centrifugal or vacuum machine to get the best finish?

sorry for all the questions but there is so many different products available im a bit confused.

cheers

[Mitsui Seiki]

Take a look here. www.tpcab.se
Click,Production,Our method.
You might even see me in there in front of my Mitsui Seiki.
I worked there for 17 years before I moved to California.

[spud--1]

Hi thanks for that, what tempertaure does the brass have to be melted to? Is a centrifugal/vaccuum nescessary, does the wax have to be injected in the plastic mold or just melted and poured in?

regards

[blackbeard52]

http://www.buildyouridea.com/foundry.html

bob

[Mitsui Seiki]

Hi thanks for that, what tempertaure does the brass have to be melted to? Is a centrifugal/vaccuum nescessary, does the wax have to be injected in the plastic mold or just melted and poured in?

regards

Temps.
Admiralty Brass 1650 - 1720
Red Brass 1810 - 1880
Yellow Brass 1660 - 1710

The best way is injecting the wax(less air bubbles)but you can pour it.
You don't need a vaccuum/centrifugal.

Just a note. I worked as a CNC programmer.If you want more indepth casting info you should ask someone better qualified.

[spud--1]

ok thanks for the replys it all seems very expensive so far i think the followign list is what i need please correct me if im wrong.

1. an electric furness $450
2. A wax injection machine $400
3. A centrifugal casting machine $400
4. an electric burnout oven $1500
5. A vulcanizer and rubber molds $500
6. wax/plaster sprues etc $200

Is that about it and is there any way to reduce the costs? Is there any other way of melting the wax from the casts as this oven seems the most expensive bit?

cheers

[awerby]

would be more appropriate than the large-scale ceramic shell technique shown on that site. Brass is nasty to melt; it makes clouds of toxic white smoke. Try silicon bronze; it's much nicer to work with. It melts at about 1700 F; cast it about 100 degrees hotter. For large pours, you can just pour the metal in, but for small amounts of metal some extra help is needed to overcome surface tension, hence the vacuum and centrifugal casting apparatus. The initial mold is best made in rubber; I like 2-part silicone RTV best. Wax is poured into this, then the wax parts are encased in a plaster-silica mixture, heated to remove the wax, and cast.

To start with, I'd advise learning how to make duplicate parts in wax from rubber molds. These can be taken to places that specialize in jewelry casting which will do an excellent job for a reasonable price. Casting takes some specialized equipment and knowhow; it's a lot easier to blow it than do it right.

Andrew Werby
www.unitedartworks.com

Hi thanks for that, what tempertaure does the brass have to be melted to? Is a centrifugal/vaccuum nescessary, does the wax have to be injected in the plastic mold or just melted and poured in?

regards

[spud--1]

Does anyone know where you can buy metal from in small quantities in the u.k?

cheers

[Harryman]

Unless you really, really want to cast your own, have a lot of time and money, I'd suggest having a jeweler, or production jewery manufacturer do it for you. It's tough and expensive to buy/build all the equipment and make all the mistakes you'll make before you get good quality castings. Let alone learning to make decent molds, cast clean waxes etc. You should be able to find someone to cast in Silicon Bronze, it's easier and as Andrew said, far less nasty than brass.

I was in the business for 20 years and it takes a while to get the bugs worked out of a system and get what you want. There's lots of variables involved. It's easy to cast something like a structural part if you don't care what it looks like, it's difficult to cast something with lot's of fine detail like a medallion.

A jewelry style set up is definitely the way to go if your pieces are @ 3" or less in size, ceramic shell or foundry type casting is better for big stuff.

[Thinwater]

Harryman is right on. I cast a lot of aluminum and use all homemade equipment (foundry style). Small detailed parts take a lot of practice to make with a nice detailed finish like you need. Brass is hard to work with since the zinc burns out as it gets close to melting, it is very toxic. I have cast hundredss of parts and it still took me three tries to mold up and cast my ATM card.

[spud--1]

Does anyone know where is the cheapest place to buy metal prefarably in the uk?

regards