iwfabrication

New to forging, a couple detail questions

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Ive read and watched videos, but seems there is a lot of variation and advice. I am using a propane tank as my shell. I will line it with two 1" layers of ceramic wool. I have read to coat the first layer of wool and heat, then do the same for the second layer of wool. Yes or  no to this and why? Will be using KOL 30 for the coating at approx 3/8". If yes to coating both layers of wool, would I do a thinner coat on the first layer?

My other question is what to use for the floor. I am leaning towards kiln shelf/alumina. do I just sit this on top of my wool that has been coated in KOL 30, set it on top of the coated wool and then coat the kiln shelf, or set it on top of uncoated wool and coat the wool and kiln shelf together?

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Welcome to IFI! If you haven't yet, please READ THIS FIRST!!!

Your basic plan is good, with one detail: you're confusing rigidizing with a flame-face coating. Coating the layers with a solution of colloidal silica and firing them makes them stronger and less likely to shed ceramic fiber particles for you to breathe. The Kastolite coating then covers the inside of the chamber for durability and rigidity. A lot of folks will then a kiln wash such as ITC or Metrokote to improve the thermal performance. 

Kiln shelf is a good option. You can coat it with the kiln wash, but rigidizing or coating with hard refractory is unnecessary.

Please read over some of the older threads for more information.

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Welcome aboard, glad to have you. If you'll put your general location in the header you'll find out how many members live within visiting distance. An easier web handle would be nice too, your log in is a fumble fingered old guy's invite to amusing typos.

You have the basics of lining your forge about right and John's advice cleans it up nicely. The Kastolite 30 is a concrete hard 3,000 f. high alumina refractory and adequate flame face. It ONLY goes on the inside of the forge chamber where the flame lives. It's the last major armor against the: chemically highly active propane flame itself, mechanical abuse of placing and removing steel and the extremely caustic borax based welding fluxes. 

A final kiln wash is frosting on the liner, it's additional chemical and mechanical resistance plus being a poor thermal conductor it get and holds heat better than even KOL 30 so it re-radiates IR back into the forge and your work. I'm not a fan of using ITC-100 in propane forges, it isn't formulated for this purpose, it's designed as a release agent in ceramics kilns and some large furnaces to prevent products from becoming one with the kiln/furnace. 

A good floor is as easy as filling part of the bottom of the cylinder with rigidized ceramic blanket to your desired floor width. Just wet it to prevent fibers breaking loose and becoming airborne and thin it if desired and feather the edges to make a flat floor with a smooth transition on the sides. Rigidize and plaster with KOL 30. This makes a fine forge floor, I like about 1/2" of KOL on the floor but I have some new guys using mine so it takes more of a beating and gouging. If you're easy on things you can get away with less. 

Kiln shelf makes an excellent forge floor by just notching the blanket where it meets the kiln shelf's edges so it makes a smooth transition. No need to cover it with KOL but the final kiln wash isn't wasted on kiln shelf.

A recent post illustrated why you want to apply kiln wash in multiple thin layers with drying tie between rather than one thick layer. Thin layers is much less prone to flaking and shrink checking. Kiln washes like Plistex and Katrikote are ceramic products and dry and fire. KOL has an entirely different process that is laid out in the Forges 101 thread.

All your plan needs is a little fine tuning. You'll do  much better on Youtube, etc. once you know a little more about the craft so you can sift the wheat from the chaff. Youtube is mostly chaff and some dangerously bad.

Frosty The Lucky.

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It's not a make it or break it type of deal but try to get hydrophilic fumed silica. It's easier to mix with water.   Hydrophobic fumed silica mixes with water easier in combination with  a surfactant. A squirt of jet dri or shampoo will work to help it mix.  It becomes colloidal silica after you mix it with water.

Pnut

Edited by pnut

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