Did you see the video of me dipping shell into hot water? It was a quick experiment to see if the shell will tolerate it. It does work. Now if you have to soak it for an hour, I'd say forget it. But I did repeated dips in 190degree water to melt wax and the shell survived. (yes it had not been fired yet)
I would try it. What have you got to lose right? With the R&R shell stuff, I would do first dip, slurry only. Let dry a day, then dip and use your smallest silica on the wet slurry. Cat box method of sprinkling the sand. Try to keep it even. Wait a day. Dip and move to the next larger silica. Wait a day. Repeat that last one 4 more times. I waited a day between coats, some say you can speed the last 4 layers with a fan, but I didnt risk it. Final coat should be slurry only, it helps seal in the loose sands.
That cat looks simple, Add a hollow wax sprue and pouring cup to his ass on the bottom. He might need one little sprue plumbed from the back of his head up to the pouring cup. See this for the hollow sprue>>>http://www.alloyavenue.com/vb/showth...t=hollow+sprue
I cant tell the actual size of your kitty, but be sure your pouring cup is much bigger than the cat. The bigger areas will solidify last and you want the cat as it hardens to pull material from the cup/sprue. This way you cat wont be deformed. Hope some of this helps, I'm just passing on what was taught to me here and has worked great so far.
Thanks Fredo for the pouring cup idea! Ingenious!
JagBoy, thanks, good to know that it resists immersion. Definitely worth to try, with 5 gals I'll have worth than enough for quite some tests!
I'll make the printed pattern and sprues hollow so I can put some water inside the model and dissolve the PVA without having the shell completely immersed or for too long.
So far I have to test with : PLA, PVA, moldlay, ABS, and the new Polymaker Polycast that will be availible next month in Europe!
All some good testing and data gathering about 3d printing and ceramic shell!
Next step is the burnout/firing oven, I haven't seen any interesting second hand furnaces around here... So I'll have to make one (too expansive to buy especially for electric furnaces...)
I think I'll try the steel bucket and ceramic blanket at first, maybe FishbonzWVa version with a refractory lining.
What would you recommend ?
What I can't see for now is : if I make a hole in the bucket base for wax/plastic to get out, how do I put a steel grid inside the furnace for the shell to stand on ? At the base ?
If so doesn't the direct flame from the burner damage the shell ? Or do I have to put the steel grid above the burner flame to avoid this ?
Direct flame wont hurt the shell at all. Fire away. It just needs to get to a complete orange heat and the vitrification process is done. In jewelry casting, collecting the wax doesnt happen with the pieces fully invested. The wax burns out and vanishes completely. I did this in a two step process. Dewax outside in the breeze on a grate and then into a closed furnace for the real heat. The goal is to keep the wax from flaming like crazy inside a nice furnace.
A little 3 legged stand with a ring on top with the piece sitting on it inverted should work for ya. See this thread for additional info.
Huh, I'll have to test the different options.
Thanks for the link, I found your shell in boiling water and shell firing with weed burner video again!
Will start finding all the stuff for the furnace. Even for refractory I'll have to find a shop, the one in hardware supplies store here just look like crap (really only good for a small bbq grills...). Hopefully I've a few adresses already listed!
I'll post back when I've more news (or questions!).
Found this electric kiln : http://www.anibis.ch/fr/bricolage-~-...po&so=d&fcid=0
Do you think it's a good piece ?
Max temp : 1260 C / 2300 f
Inner size : 15 x 15 x 17 inches
Around 400 $
Quite old but it could work if I do the burnout / dewax outside with a weed burner.
Hesitating it's around the same price it would cost to make a gas furnace but larger inner size and electric!
That could work for you if the size is big enough. I think the price is a bit high seeing I paid 25bucks for this old girl and it works! TWICE the size of the one you found.
You know the saying.... Quality, speed and money... PICK 2. If you need it now, cough up the dough AFTER you see the seller run it. Be sure you have the electrical service to hook it up to. In your part of the world, things like upgrading service can get stupid expensive, FAST! I noticed that thing said 380vt?
Yeah, you're right. And the place I will put it doesn't have the correct electric plugs and voltage...
I'm not that much in a hurry so I'll keep looking!
I was wondering about making a furnace in several pieces, like the Kwik Kiln (http://www.gpkcompany.com/Deluxe-KK-12-Kit_p_125.html) but a bit larger.
That would allow me to have one version with a hole in the bottom in case I need/want to dewax in it, or to have a solid bottom for firing/melting.
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