Help with Refractory Lining

B

Beran73

New Member
Hi,

I am brand new to knife making. I have begun to work on building a gas forge from old fire extinguishers. Ive done research on refractory lining made from multiple different mixtures (Plaster of paris and sand, portland cement and peralite, firebrick grog and plaster, etc...). Im not really sure what would be best, and what a good mixture ratio is.

Would anyone have a good idea, or pass along some good resources?

Thanks!
 
I'd just get some ITC-100 and be done with it. Mix it up with water and brush it on.

You can get it from Bailey Ceramics/Pottery I think.

It's excellent at reflecting heat and goes on easy and doesn't shrink and crack.
 
Check out my web-site at the Forge Supplies page.
ITC-100 is an Infrared Reflective product. It is a very good product but terribly expensive. It has no strength and will get broken almost every time you touch it with a piece of metal. It will contain the airborne fibers as long as it doesn't have holes in it exposing the ceramic blanket.


On my web-site I have two tutorials, one that I wrote about how I like to build a forge and on by John Emmerling on building a Ribbon Burner.


If you will cast the interior of the forge, over the ceramic blanket, about 1/2" thick you will get a good, strong, efficient, long lasting forge, then paint over that with either Plistix or Metrikote. Plistix and Metrikote, like ITC-100 are Infrared Reflective products but much cheaper than ITC-100. Kast-0-Lite is a light weight, insolating castable refractory.

Let me know if I can help you.
 
There are basically three types of refractory (insulation) that are used in forges. 1- Castable Refractory: Comes in bags or pails, is mixed with water (similar to portlan cement). 2- Ceramic fiber blanket, names include Kawool, insulwool, etc. This is the easiest to work with/install, but produces airborne hazards...so a respirator should be worn. 3- Insulboard: This is rigid format material that comes is various size sheets....it's generally the most expensive and fragile of the lot.

My advice is to not waste your time with all the homemade things you find on the net.... most of them don't work at best.....and many of them are just plain dangerous. Personally, I use a combination of castable and 1" thick, #8 density kawool for my forges. I also use ITC-100 as a "slurry" coat on the interiors.
 
Thanks Ed,

I found a place to sell Kaowool here in Fairbanks AK, what would be your recommendation for a cast able to apply after the insulation?
 
Forge Lining

I built my forge about 3 years ago. I used two layers of 1" Kaowool. coated with Metricote. It is not in use continuously, but has taken me through a few knife projects and some forge welding. It has held up well, but has needed a little re-coating in some spots. One time was due to changing the size of rear opening/exhaust. The welding process can be hard on the lining, as the flux falls onto the bottom. I laid firebrick (of proper heat rating) on the bottom to protect the lining a little better. I'm glad I did. It's worked very well for me-but I have to say thanks to all the more experienced people who shared their ideas through forums like this. I gleamed a lot and surely saved myself a lot of grief by listening to the ones who not only know, but will take the time to share what they know. :1:
Wayne Coe was very helpful, and that's where I got my Metrikote- and probably my Kaowool, and maybe the firebrick?- I don't remember for sure on that. I do recall tho that he gave great service. I'd say buy a little extra Metrikote (or whatever you choose to coat with, for future repairs or recoating). Makes sense when you figure the shipping anyway.
That's just what I did, on the advice of others, and have had good results with occasional use so far. I'm sure there are other approaches and some here would have a more rigorous test of those approaches.
But, I'm pretty sure all here would agree: Don't skip the liner-coating, as airborne fibers can cause long-term heath problems- worse than say regular fiberglass. The coating also adds to the efficiency of the forge and (I think) helps with IR emissions.
 
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