Metal Casting Zone

They have wax injection pots for casting jewlry. look at youtube vides for investment casting and wax injection.

the sprue will vary according to the part you are making, johncast can help you out here

the investment mold will be broken apart to get your treasures. some people save the used investment and grind it up mix with new and reuse it.

most of the time when you cast jewlry like you arethey use a cintrifical machine, and they dont have a vent when they cast it this way, sometimes it is called spin casting as well....

you can probably sprue up 100 at a time for casting, might be easier for someone to cast them for you due to cost of the equipment, or just try and pour a casting and see how it goes

try this
www.contenti.com/products/casting.html

Thanks everyone!

With lost wax/investment casting, do people ever use a method for filling the mold with the molten metal other than spinning it in a centrifuge?

I will post more questions if I have them.

Clayton

yes but the smaller the casting the harder it is to get the mold to fill properly.

Some use vacuum casting. You place the mold in a vacuum chamber with the sprue exposed, pull a vacuum and pour the metal in. The investment allows air through so it draws the metal into the mold.
There was a video on steam casting. Heat the investment and the metal, pour metal into sprue and quickly put a can with a damp rag in it on top. The heat from the investment and the metal makes steam and pushes the metal into the mold. I think this is for small single castings. It would be about the cheapest. Here's a video, not the one I wanted.

steam casting

you beat me to the steam casting bit!!! on tv here a couple of weeks ago they featured the making of metal charms. i took note of course. it was a round machine with a crucible in the middle. it had silicone molds . the crucible was filled with zinc and switched on. as it spun it flung the metal out into the molds.they made it look so easy. the silicone molds have to be renewed every few casts!silver melts at a much higher temp so silicone wont do for a mold. the high cost of silver may prohibit conventional sprue and runners unless you have a couple of kilos spare in the scrap heap! id would love to pour some of my models in silver and gold!!(i wish!!!!!)

Hi Clayton 707
Very interesting project Clayton, XL was correct in mentioning my years in the jewellery trade, We cast items similar to what you are wanting to make.
Firstly would like to see those 1/50 cannons. I have often woundered if it would be a wise move to put some 1/87 cannons in my range of models here in Australia.
Any how back to the lost wax casting , This is surly the only way to produce a good piece of jewellery with some fine detail. Yes Clayton you are correct in what you say regard the wax patterns they have to be made over and over again, but with a good mould made correctly with good sprues to feed the wax models and later the flow of metal, making the waxes is not too hard. Waxes can be made by gravity casting by just dropping the wax into the mould ,but if the pattern is detailed as most are ,a wax injector is required.
These simple machines are a wax pot which can be sealed of and a small compressure or pump mounted on the top of the pot like mine, increases the pressure ontop of the wax in the pot, Not unlike a garden spray we use for weeds in our garden .The rubber mould is held between two metal plates and held together firmly and is placed againist the nozel of the wax injestor and the mould is pushed firmly onto the nozel which opens the wax pot ,with the wax under pressure the wax is injectered into the rubber mould. With a few moulds many waxes can be made in an hour. If you are wanting to produce 100s of these cannon pendents two moulds rotated on a wax machine can produce waxes very quickly. The process is time consuming and has many steps, which all have to be followed very,very carefully, compared to other forms of casting,one has to except this,but the results are well worth the wait,if all goes well. Look at some of the videos on the web there great I've enjoyed many of them, and you can get a good idea of the process. Keep us all posted and ask more questions if you have problems,hope this helps Johncast Aust

Hello John,

Thanks for writing. I have looked at some youtube videos, and with that and the explanations here, I am really getting to understand the process and equipment required quite well. Looks like an initial investment but it is probably worth it. I can carve in wood, as you can see, and I am thinking I could come up with many jewelry designs to cast and sell.

I see you can also inject hot wax into a silicone mold with a syringe. Probably the low cost way...

I just bought a vacuum pump for pulling bubbles out of molds and am going to buy tools as the wife allows.

I did post a picture of the cannons in this thread. I also have pictures of them on my website in the section for my Vasa model.

Cheers!
Clayton

Hi Clayton
Great to see the cannons all in different scales,Im sure that most of the cannons could also cast very well in pewter spin casting,they look great.
You are right in what you say ,there is quite a lot of equipment required to the process of lost wax casting,keep a constant lookout on ebay for pre loved equipment,sometimes under jewellery tools. I was very lucky back in 04,to buy a hole complete outfit for lost wax casting, I picked it up for a very good price,so you can be lucky.
Good to read that you have a vacume, These are very important for the process of making a RTV rubber moulds,to do the moulds perfectly you have to have this piece of equiptment. Just be carefull if you vacume the mould after pouring, if the master is a solid item all is ok, but if the item is of a laminated item air inside the laminated pieces can destroy the surface of the master. I vacumed a master years ago that was two pieces of styrene glued back to back quite well ,when item was placed in the vacume the small amount of air between the two laminated surfaces forced it way out by spliting the two styrene pieces apart ,I didn't find out till the mould was opened . The mould was ruined. So I only vacume the rubber when I mix then pour but don't vacume again. Also you will need the vacume when you invest the flasks for lost wax casting,there is an alternative by placing the flasks into a vibrating table or something similar but vacume is much better. Johncast

Yes I am happy to have a vaccum now. The molds that I made for the cannons were not made with a vaccum and so had some more clean up work to do after casting than was probably tolerable for production casting.

The cannons are actually not different scales. They are all the same scale, 1:50, but are of many different calibers and sizes. Vasa carried 7 different types of guns and all are represented there.

Thanks for all your help, and I will ask more questions if I have them.

Clayton