Clay / Refractory crucible

Grog = a refractory material that is in a solid state and does not bind together when water is added to it. Already fired fireclay can be used as grog, after being ground to the right size

Category:

Howto & Style

Tags:

• crucible
• melting
• tiegel
• schmelztiegel
• metal
• foundry
• furnace
• backyard
• kiln
• aluminum
• bronze
• brass
• copper
• silver
• gold
• casting
• green
• sand
• lost
• wax

[Robkat3751]

Here is a ram press operation done in a commercial factory. The process is the refined version of what you see done on this video. Notice the bubbling at the mold just before the part releases, this is air injected into the plaster die which causes the water to help in releasing the part. For a small part this can be done with an arbor press or by hand if you are only making one part.

If you would like to see this process on youtube search "rampressing"

[fedaikn]

@Robkat3751 thank you for the information, unfortunately i have not found the video you refere to.

could you post the link to it?

[fly2000jtb]

what were the amounts again on the sand fire clay firebrick etc...? ccooolllllll video tooooooo!! we are making a few crucilbes now well as soon as we get the rifgt amounts thankas again joseph t fly2000jtb

[fedaikn]

@fly2000jtb the amount is variable but a good mixture is 40% fireclay and 60% crushed firebrick. use crushed firebrick, do not use sand as it will melt at about 1000 deg celsius and compromise the crucible.

i have used one of these crucibles for more than 7 bronze pours. it got a bit vitreous on the inside because of the borax used as flux for the bronze.

if you need help write me. good luck and be careful with it !

[panzuman]

yery good tutorial i will be buying a fire brick soon to make the grog and i have a propane blast furnace will this get to hot to fast for this kind of crucible?

also is 20 dollers for an ounce of silver good?

[fedaikn]

@panzuman i found the silver price to be about 18 USD per ounce, of course that goes only for fine silver or 99,9% pure silver. to make jewelry you need 925 silver and that should be a bit cheaper. go to silverprice . org

my crucible is really small, i guess it can hold about 200g of silver. because it is so small it is less subjected to fail because of uneven heating. no idea if your propane furnace heats it to quick, just try and see what happens.

[softservejazz]

This dude rules.

[halfmumi]

Fantastic video.Thanx a lot.

[itscorcor]

@fedaikn thats great news, it gives me hope in using your recipe, however i do hope of finding a more powerful heat resistant home made crucible, but thx for awesome tutorial

[Robkat3751]

The male part of the die, or mold and the outer part as you call it can be made from casting plaster. Use a store purchased crucible as a master.  When the plaster is completely dry it is ready. Before you use the ram die soak it in water until it stops bubbling then it is ready. the clay will release easily but remove it immediately.. You can buy grog from any ceramic supply company as well as any grade of fireclay. Lincoln fireclay or lincoln 4-6 come to mind.

[itscorcor]

very in depth, thank you

[carr60ick]

Well done, giving me lots of ideas to recover scrap silver.

Max Keiser reckons silver will reach $500/ozt, so this DIY set up looks a good investment.

Thanks again for all your help :)

[hobomnky]

great video

[commandZ3R0]

HA wikipedia