Forge making advice

[Every_name_is_tak3n]

I have an order of kaowool, refractory lining, and some ITC 100 on its way to my house but I checked my order again and I only have enough of 1" kaowool to coat the forge size I am making once over, I must have been tired when I ordered it. Either way I was reading about people putting vermiculite in their clay lining mixtures and it does seem to have a high melting point of around a 1000C. Can I put a layer of vermiculite for say an inch think layer on the inside of an 8" pipe and then the kaowool inside of that? How would I hold it in place? Put a 6" stove pipe inside of the 8" pipe, fill it and seal the ends then fill the 6" with kaowool? Or should I just order more kaowool as 2" seems to be around the magic number. Thanks for all your advice!

 

[A.McPherson]

I'm no expert, but as so many folks say around here, buy quality and cry once. I'd just send of for more kaowool and do it right the first time.

 

[timgunn1962]

The extra Kaowool makes things easy and is the obvious way to do it. Buy enough to do one double wrap, rather than just enough to do a second layer.

Easy way to get it in an 8" pipe is to wrap a 4" pipe in polythene, wrap the Kaowool round it twice and rotate it as you push it all into the 8" pipe. Keep rotating the 4" pipe as you pull it out of the polythene, then peel out the polythene. It helps when wrapping if you've cut the ends of the Kaowool at about a 45-degree angle.

I gather ITC100 is best applied to a continuous serface, not direct onto the Kaowool.

Before I wrap the Kaowool, I stipple onto the inside surface, a runny mix of china clay powder (kaolin) and Zirconium Silicate (Zircopax) in either fiber rigidizer or Sodium Silicate solution.

ITC100 is hard to find and ridiculously expensive over here, hence the Zircopax; if I had ITC100 to hand, I would probably leave the Zircopax out.

The rigidizer soaks deep into the Kaowool, but the clay only tends to penetrate a short way, giving about 1/8" of hard crust on the rigidized Kaowool once fired. If you have no rigidizer, a runny mix of fire cement (fairly readily available) in water should give the crust, but will obviously not rigidize to depth.

Sodium Silicate solution seems to work just as well as the "proper" colloidal Silica rigidizer. Over here, it is much cheaper and can be bought at pottery suppliers. I use about 1 volume of 140-wt Sodium Silicate to about 4 volumes of tapwater; add the water slowly to the Silicate, mixing continuously.

 

[Stacy E. Apelt - Bladesmith]

Forget the vermiculite.

A 1" layer of kaowool will be fine for a general use forge. 2" is needed for a welding forge. If you don't want to order an additional blanket of kaowool, just use what you have.

The refractory layer on the wool should be 1/4" or more. This is usually satanite. Once that is installed and cured, the ITC-100 is applied over it and fired. Rigidizer is a nice thing, but isn't absolutely necessary. If using wool without rigidizer, just apply the satanite in several thin layers ( 1/8" or so). Make the first layer a bit on the wet side and let dry fully before napplying the second and third layer.

 

[Stacy E. Apelt - Bladesmith]

double post

 

[JMJones]

I have a two burner economy forge from Diamondback Ironwords, I have melted half inch steel in it and it has one inch of ceramic lining. The more insulated, the lower you can run the propane and save money. Ceramic wool and satinite are consumables that you should keep on hand anyway so when a problem arises, you are not without a forge while waiting for supplies.

John