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Burn out on a budget

Hi all.
I am a UK based hobbyist on a budget and want to get into lost wax casting now that I have gone about as far as I can with cuttlefish, soapstone and Delft clay. I’ve got some excellent professional casters in London who do contract stuff for me occasionally but that is not the same.
Any advice for doing this on the cheap (short of moving to the US where tools seem to be much more abundant and less expensive)? Melting the metal is easy, my problem seems to be how to get bubble free flasks, burn them out and then get a good pour.
I look at the work done historically and they can’t have had vac pumps and PID controllers, so this must be possible even if it does take a bit longer. Realistically I have about £300 to blow on this before I have to have stern words with myself.
Really appreciate your help, and happy new year.
CP

There are plans online to build a burnout oven or kiln. You can add your own controller. Take a look at https://www.auberins.com for various types of manual controllers. I don’t do lost wax casting, but needed an oven for annealing and heat hardening. I bought a simple Auber controller and retrofitted it to my very old, very manual kiln and it works great. I am not sure what you will find in the UK, but good luck…Rob

Awesome, thanks for the tip, I’ll go check them out.

Ah, budget burnout… The first time after leaving college that I needed to cast, I had little to no casting equipment beyond my Smith silversmiths torch. I invested using the vibration of a saber saw (sans blade) to debubblize the investment. Then I found an old red clay standard flower pot, lined the inside with about 3 layers of asbestos furnace tape (It was still made of asbestos in the '70s) and then a double layer of aluminum foil. Poked a pencil through the drain hole. My kitchen stove was electric, (gas would have been better) but I turned on one if the small burners, put a bit of aluminum foil down on it, then the flask, and then covered with the flower pot. Turned on kitchen fan. Went to bed. In the morning, a nicely burned out flask was ready for casting via steam casting. My “casting machine” was a length of dowel with a jar lid screwed to the end, its open cavity lined with a thick layer of wet paper towels. Worked perfectly. It was actually the first time I’d tried steam casting, so I was quite happy that it worked as easily and well as it did. Cheap though the flower pot was, though, soon after I found plans in a lapidary nagazine to build an actual burnout furnace from some sheet metal and fire brick… The burnout furnace I have now is bigger, and cost a boatload more money, but its intrinsically the same design as that home built one…

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Yup. Most anything can/will work as a hammer *(a rock or a $200 plus dollar fancy hammer), just depends on your pocketbook!!! Good story/info. Thanks,

JD

“I look at the work done historically and they can’t have had vac pumps and PID controllers, so this must be possible even if it does take a bit longer. Realistically I have about £300 to blow on this before I have to have stern words with myself.”

The modern technique of lost-wax casting that most jewelers use only dates back to the beginning of the 20th century. Before that, investing was mostly done with clay mixed with cattle dung, a method still used in India and Africa. It apparently works well, but if you don’t want to try recreating that technique you can use plaster and silica to make your own investment. If you don’t have a vacuum pump you can apply the first coat of plaster-based investment with a small soft brush before putting the wax model in the flask and pouring in the rest. I’ve heard of people using charcoal grills and ceramic vessels to approximate burnout kilns (much like in Peter Rowe’s story above) but haven’t tried that myself. If you do this, be sure to do it outside - the fumes can be deadly. Kitchen ovens won’t work; the temperature must get over 1000F to eliminate wax residues - 1200F is usually recommended, and some materials need more heat to burn away entirely.

when I was thinking about building a kiln found a useful book “Electric Kiln Construction For Potters” by Robert Fournier was the most useful in calculating the electric coil requirements
That said you might want to look for a used kiln, would think that 300 Pounds would be enough to find used