Questions about lost wax casting

[Matt Smith]

Hello, I am intrested in possibly casting some parts for some knifes I will be making in the future and I have some questions regarding how to go about it. I have read alot about the lost wax process and I know in therory how to do it but I have a few questions concerning materials. First of all I do not have access to a kennel oven so I was wondering if there is a type of wax I can use to make my peices in which can easily be melted out of the mold using a regular home oven or even gently useing a torch to melt the wax out of the mold once set. I was considdering moldind some bars of common candle wax mixed with bees wax to use to carve my pieces out of...This way it should still be flexible enough for me to carve and still can be easily melted out of the mold. Would this work or is there a wax suttible for my needs out there. Also I was wondering about the mold material it self... I want something that will hold up to some heat but it doesnt have to be extremely high heat since I plan on useing pewter.. I have read that a mixture of silica flour and regualar plaster will make a strong heat resistiant mold... Any advice or input i would appreicate it THANKS

[dan_m]

Matt, if you read the post I wrote which is pinned at the top of the foundry/casting section, you'll find answers to most of your questions. A kitchen oven does not get nearly hot enough, and a torch will destroy your molds. You want coarse sand for the molds, not silica flour, the $2/bag stuff from home depot works fine. They need to be brought slowly up to 600 or so, then up to 1200-1250 for a sustained period of time so the temperature is even through to the middle. Get a pottery kiln for cheap off CL (<$100), it works fine though itneeds constant checking and adjusting. A kitchen oven will eventually melt out your wax, but will not vaporize the residue which will leave you with unusably porous casting. Plus it won't drive all the moisture out of the molds, so they will probably just blow apart anyway.

Edit your profile to show your location, someone nearby might be willing to help you out. If you're close to Philadelphia I'd be glad to show you my setup.

[Matt Smith]

Thanks for the advice I live In Evansville IN by the way

[Rio Bravo]

Matt,

I use commercial grade materials to construct thin shell ceramic molds. I melt/burn out the wax with a torch. It's quick and easy with the thin shell. Just make sure you have adequate exhaust (or do outside) as there will be much smoke.

Pick a wax based on how you will model and carve it; not on how it melts. You have to get the temperature up to a point that any wax will melt anyway.

[ThomasPowers]

Check to see if a local community college has a jewelry making class. Most do in my experience and you can get trained on lost wax casting through them!

[Bentiron1946]

Do NOT try to do a burn out in you home over, you'll be sorry as all get out and your wife will be a long time forgiving you, plus the fire department will be all aggravated with you too. To burn out most any wax it takes upwards of a 1,000 F+ to achieve a good clean burn out. I have done both regular investment and ceramic shell and if you don't have a really good burnout and leave any residual wax behind you can have either a total disaster for a casting or one that results in so much work you should have thrown it back in the pot for a remelt. Thomas has excellent advice on looking for a community college or perhaps a community arts program that has a jewelry program so you can learn lost wax casting. I just read a lot of books at first and started off with sand casting and later moved into lost wax but along the way I built all of my own equipment. It isn't rocket science as our ancient ancestor did it without all the modern hoopla and you can too. Best of luck with your projects.