ceramic shell for forge lining?

[jawno]

I was talking to a foundry owner about buying some kaowool from him the other day. I mentioned that I was going to coat the kaowool with some ITC-100 to seal it after laying it in place. He mentioned that I could use some ceramic shell that he has for the same thing. I'm wondering if anyone has tried this? If so, how did it work. It seems to me that it might be too brittle but I've never used a forge before either and don't know what the consistency of ITC-100 would be either. Personally I'm more inclined to use the traditional material but I can get the ceramic shell for free. For those unfamiliar with ceramic shell, it is a plastery glue type liquid that drys as hard as a ceramic material and is used in high end foundry casting. I would appreciate any advise you are able to give me.

Thanks.

[Bentiron1946]

I'm somewhat familiar with ceramic shell casting and once the shell is fire is rather  fragile in nature. After repeated heating and cooling cycles it tends to come apart in small pieces. You can give it a try since it's free. At the iron pour one year we tried using  the  wool and ceramic shell in our pouring buckets but the shell just didn't hold up all that well in my estimation but then again molten iron is pretty hot compared to the inside of a forge.

[onetreeforge]

I do bronze casting for a living. did this to my kiln Kawool lining, it crackes and flakes off, anything that hits it will brake it,  I used liquid sodium silicate and molochite powder to hold the wool togeather, it worked well enough for me.

 

if you mixed liquid sodium silicate and a bit of water and sprayed it on would keep dangerous fibers from braking lose and make it more ridgid

[jawno]

This is what I suspected but I wanted to check with those who have more experience than me before committing to another path. Thank you both for your input. I will use a more traditional material like htc-100.

[Dodge]

I have never used ITC 100 (I know, I know; "Then why are you posting about it?" :rolleyes: ) That being said, from what I have read about it, rigidity is only a secondary (or even side affect) purpose of this product. Its primary purpose is heat reflection. As it is pure white, it reflects more heat than refractory mortars which usually cure to a gray color. Personally, on the two gassers I've built using wool, I have coated with a mortar that dries concrete hard. Ideally, the next step would be to coat the gray mortar with ITC or equivalent. If used by itself, its my understanding that the coated walls of the forge are still quite fragile I'm just a hobby smith and don't depend on my forge for income so I have never found it in my budget to use the reflective coating and I can weld in my blown gasser with no problem. Do I use more gas to do this? Maybe, but more importantly, (in my mind any way) is durability, I have yet to poke a hole through the mortar coating (which is probably about 1/4" thick) To get a build up of ITC or such that thick would be cost prohibitive for even my more successful smithing friends. For the price of 1/2 pint of HTC-100, which it about enough to coat one forge by it self and maybe two over mortar, you could coat several of forges with Greenpatch 421 (what I use)   YMMV

[jawno]

Thanks for the tip Dodge. I'll look at that product. Sealing the kaowool is my main goal rather than just heat reflection so a mortar may work better for me. I'll follow that link and see what it says about it.

[Pault17]

Dodge, I will have to look into that 421 stuff.  I have a small homemade gas forge that is about 6 years old without ever re-lighing or needing to.  Mind you, it is not a daily use thing and probably has less that 5-600 hours use.  That being said, I use kaowool coated in satanite to about between 1/16 and 1/8 inch (3 coats), then coated that with itc-100.  I have had no problems unless someone else uses the forge and tries to be the harlem globe-trottin blacksmith in it.

[jcornell]

Ceramic fiber really benefits from rigidizer (sodium silicate) that's subsequently coated with something like ITC (which reflects heat, increasing the efficiency of the forge) with an optional underlayer of a protective refractory like Satanite.

 

My little forge is coated with a home-made mix of kaolin and zircopax (I call it zircon frosting) which is close to ITC in performance.  It's somewhat delicate stuff and cracks and flakes, but it sure increases the efficiency of the forge, and provides some protection to the ceramic fiber.