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nhoman

Ceramic Blanket

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This is the first time I ever worked with this stuff. Just a few questions - am I supposed to just pack it lightly or was I right in compacting it, squashing into corners in order to get a tight fit?

Second question - despite my best efforts, I now have fibers all over my arms and probably down into my unmentionables. Any secret cures for getting rid of the itch?

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You don't want it compressed, but you do want it tight. I think you did good.

Wash your hands and arms first. Take a cold shower, wash, then turn up the heat and wash again. You may be itching for a few days though...If you think NEW ceramic wool is bad, wait till you reline! Used stuff is 10x worse! Wear breathing protection, rubber gloves, sleeves, and an apron next time.

Do you plan to coat the blanket with something? The coating will stabilize the wool, make it resist damage better, prevent air born dust, and possibly reflect heat better (depending on the product).

Phil

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Wear breathing protection, rubber gloves, sleeves, and an apron next time.

Do you plan to coat the blanket with something?


I wore a long sleeved overall, rubber gloves with elastic on the wrists, a dust mask... That stuff is microfine and just gets in EVERYWHERE :). I think next time I'll just get me a Hazmat suit :rolleyes:

Yes I will be covering it with a refractory paint but that'll have to wait till morning. The burner is probably about 90% complete so if all goes well I should be able to fire her up by tomorrow night. Sometime later I will get some firebricks for the floor but for now the excitement is just too much... Burn baby Burn.

Still to do:
Support and adjuster for the burner assembly.
Feet
Handle
Door(s)
Paint (Maybe)

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Next time you have to mess with the stuff try keeping a spray bottle of water with you. Mist the area you are working, specifically the sides you cut. i found this to help alot. Nick.

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Thanks - I tried the water tip before applying the paint and it worked like a charm.

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I was going to suggest getting it wet, no need to mist it, water won't hurt it a bit and it sure cuts down on the dust.

I like ITC-100 as a coat, it reflects heat well and is pretty resistant to fluxes. Plain kaolin clay at a thin slip consistency makes a good coating and it's cheap. Fluxes are caustic at welding temps and silicates are soluble in caustics so a little molten borax will go through uncoated ceramic blanket like hot water through cotton candy. Kaolin clay (porcelain when fired) is a very high alumina clay and darned resistant to caustics. The first time I tried coating Kaowool I just submerged it in kaolin slip and pumped it like a sponge. I wasn't happy with the results but that was before I knew much about the stuff and it lasted well in the forge so maybe it was fine.

Frosty The Lucky.

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Frosty, I looked into ITC100 but to get it here would have been a killer. Exchange rate of about 7:1 and the weight of the stuff would have been prohibitively expensive for me. Instead I got something locally - the supplier calls it electric paint. Came in a fine white powder. I added water, mixed it well and painted it on. I didn't wait for it to dry - instead I fired up the forge and panicked a little when some of the stuff started dripping and running down the walls. Soon after there was a bit of steam as the water got cooked off and I left it running for about another 5 minutes. Then I turned off the gas and plugged up the openings with some leftover blanket and left it to stand overnight. This served two purposes - I stuck the blanket down with mastic (looks like cement in a tube but sticky beyond belief). Leaving this mastic out in the air to dry will probably take a month. After baking it for a bit, it turned hard like cement.

The paint has certainly firmed up the fibers but it is not very strong. It flakes off if you knock it a bit hard and it probably won't take much weight before it starts to crumble either.

On the up side though, this stuff glows bright yellow and holds the heat beautifully. I think I will follow MacBruce's example and get some broken firebricks for the floor. At the moment I have some old paving bricks in there and I'll see how they hold up. Perhaps I'll just stick with them.

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I am using a home-made mix that I have not had opportunity to compare to commercial mixes. Very simple, 70% zircopax (zircon flour) 30% kaolin, by weight. Mix well dry, then mix with water to form a thin "milkshake" slip and paint it on. Let it dry for a bit then fire. The zircon is a very effective grog, and the materials can be had from anyplace that sells pottery supplies.

Slide a high temperature firebrick or a piece of kiln shelf in the bottom of the forge to support work. My coating suffers from the same delicate nature, so don't poke it.

Phil

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I just broke out the coating and pulled the kaowool from my forge and relined it. The stuff was cracking and chipping badly. Im thinking I did not apply the hard coating properly. I used insulating cement from the place I got my kkowool from. It looks like insulation mixed with a little motor and hardens but still has some give to it.

My question is how thick should that layer be? I smeared it on by hand to coat the wool fairly well and I think I might have 1/4 inch layer but probably not much more consistently. Should I apply more? Once it dries, I will paint it with Plistix that I bought as a substitute for ITC-100

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The thicker it is the more likely it will be to check from the thermal cycling. The Kaowool is all the insulation you're likely to need, a little more isn't worth the hassle. Even a third inch of Kaowool isn't worth the trouble.

I don't know anything about Plistix so I'm not going to comment. Phil's home brew on the other hand is sound though I can't comment on the ratio in the commercial mix. It's the zirconia that makes the nearly indestructible coating, we're talking a shade below diamond hard and WAY more heat resistant.

Frosty The Lucky.

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I used what they call rigidizer, a clear liquid you brush on. It has worked well. I used 1/2" brick on the floor to prevent flux from eating thru.
I have the leftovers, I built another forge, but the rigidizer has dried up in the jug(turned to crystals) not sure if I can re-constitute it ? If not I'll buy more

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