Lost wax casting questions

[Nick martin]

Hi everyone,

Some of my designs that I've made are too delicate to be successfully cast with delft clay or cuttlefish so I wish to start having a dabble with lost wax casting, but before I do I've got a few questions that hopefully someone can help me out with.

I fully understand the process involved with lost wax casting, but here's my questions.

1. Can anyone recommend a good supplier for a vacuum table, investment powder and different sized casting flasks?

2. As I don't yet have a kiln, is it possible to burn out a small flask using a blowtorch such as a large sievert?

I also don't have a centrifugal casting machine but as far as I can work out I should be able to cast into a small flask using a normal torch and scorifier setup.

As I'm experimenting in this area I don't want to spend a fortune so any recommendations for cheap suppliers would be really helpful!

Many thanks,

Nick

[josef1]

HI Nick you will need a kiln to heat the investment this can take around 12 hours for a traditional burn out not really practical with a torch .casting flasks can be made from stainless steel tube from ebay car exhaust is good but make sure it's of a diameter you can get a rubber base for.investment can be bought from the main sellers it goes off so don't buy lots to meet a min order for example. If you need a vac table you may as well use a vac casting plate instead of a centrifugal machine .you need the vac/centrifugal force to make the cast dense and fill the mould just pouring it into the investment mould won't produce good results also the flask needs to be at the correct temp when casting silver for example around 550 deg c depending on your process I suppose

[Nick martin]

Thanks Josef. Looks like I'll need to spend some dosh on a kiln then.

As for the vacuum casting plate, where do you buy these from as I can't seem to find a supplier?

Cheers,

Nick

[josef1]

cant find a uk version but this type of thing https://www.riogrande.com/Product/rio-vacuum-table-for-mold-making-investing-and-casting/705012

[Nick martin]

Does everyone on here who uses the lost wax casting method outsource the work, or has anyone got an in-house setup?

I'm more interested in doing it at home myself, but trying to source a vacuum table and a centrifugal casting machine are proving impossible. Unless I go down the route of buying some Chinese rubbish off eBay.

Nick

[enigma]

I thought you could get away with just a vacuum table?
Could be wrong though, Im certainly no expert!

[Dennis]

While you are sorting out some equipment, you could also approach one of the casters in the link I gave to Lynn, Nick: http://www.thegoldsmiths.co.uk/library/technical-library/technical-portal/ Choose 'Trade Services'. Dennis.

[josef1]

8805880288018804

I do my own casting, this is my setup when it was newish its not quite as shiny now ! I decided I needed to cast myself as I was learning about CAD and need to see if my models would work in a real life situation. To be honest Its not really a cost effective way of doing it but I have found it very rewarding. I will try to describe the process a bit. The blue machine has a vacuum side and a casting side,I usually only use the vacuum side with the perspex dome to remove the air bubbles from the investment (similar to plaster of paris but with silica made for casting) then its allowed to set for around 90 mins its then placed into the kiln this cooks the investment for around 12 hours this makes it hard like pottery with a hollow area where the wax model once was, hence the term lost wax. The controller on the front of the kiln lets you set the burnout cycle the wax is melted out at first at around 150 deg c then it ramps up over a couple of hours to the temp required to fire the investment this is held for several hours then the temperature drops to the required temp for casting the metal, this varies but for example silver is around 550 degc . This temp is held until you remove the flask from the kiln . The Flask then goes into the red machine, this has an electrically heated part (the red glowey picture) that melts the metal, when the metal is liquid the flask is placed in the silver tubular compartment and vacuum is added to pull the metal into the flask once it is released from the melting crucible. The flask is left to stand and cool for 15 mins then dunked in cold water to break the investment away from the metal. and were nearly done just needs cutting off the main sprue and polishing setting etc

[mizgeorge]

serious tool envy coming from here.....

[ps_bond]

To be honest Its not really a cost effective way of doing it but I have found it very rewarding.

That was - grudgingly - my conclusion too. I'll cast one or two bits in Delft clay if the shape & detail are right, but everything else gets sent out.
If I had more space I might be more inclined to (and I still need to try out yuwake to use up some of my scrap copper).

[Nick martin]

Thats really helpful Josef, thank you very much.

Fair old investment in equipment then judging by your setup, although as I'd be casting relatively small items then I'm not sure Id need the furnace machine that you have.

I'm also producing stuff via CAD / 3D printer and thats precisely my reason for wanting to go down this route albeit with full control over the whole casting process in order to experiment and see how things work out.

Nick

[josef1]

Your correct you do not need the red machine, just electromelt or torch melt the metal, one of the things about the electromelt is that you can dial in the same temperature every time, with a tourch this is harder without lots of practice. There was a bit of method in my madness, I wanted to make sure I had a good success rate with casting as the models were time consuming to make as I started out by milling them from blocks of wax some models could take over 6 hours to make.I wasnt a nice prospect a flask full of them didnt work. So I tried to make everything as repeatable as possible it was a big investment but I think its well on its way to be paid off for me. I just hope when I die the Mrs doesn't sell them for what I told her they cost !

[Nick martin]

So did you end up buying the vacuum / casting machine combo from Rio Grande is the states?

Also what kind of kiln are you using Josef?

Cheers,

Nick

[josef1]

The kiln is a Neycraft vulcan 3-550. I did get them from the states I specified 240 volts at the time the exchange rate was a lot more favorable not sure if it would be as worth doing now though