Coatings over ceramic fiber insulators serve either the purpose of keeping ceramic fibers from being released and flying around, which eventually will find their way into your lungs.....not a good thing, or they add a degree of heat reflection/insulation to the insulation..... some coatings do both.

Personally, I'm a fan of ITC-100. It's expensive, but works the best of any "coating" I've tried. The thing to remember about any of these type of coatings is that they are applied LIGHTLY. Thicker IS NOT better....in fact it's just wasting the product. I'll use ITC-100 as an example..... it comes in a very thick paste form. Put a few tablespoons into a plastic container, and add a TINY amount of water and mix. Keep doing this until the coating is the consistency of latex paint. Spritz the ceramic fiber it's being applied to with water (this allows it to adhere without tearing the insulation). The use a cheap paint brush and "paint" the coating onto the ceramic fiber. No more than a light coat brushed on (as if you were painting a wall). The last step is the most important...LET IT CURE NATURALLY! IF YOU TRY TO RUSH THE CURING BY FIRING THE FORGE, THE COATING WITH CRACK AND FALL OFF! Meaning you just wasted the product and your efforts. At most place a 100 watt light bulb inside the forge that has been coated. Even then, expect it to take a week or more for it to cure, depending on the environment where you live.

Generally with ITC-100 applied to a forge, it will pull approx. 500F more than an uncoated version, assuming everything else is correct.

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Coatings over ceramic fiber insulators serve either the purpose of keeping ceramic fibers from being released and flying around, which eventually will find their way into your lungs.....not a good thing, or they add a degree of heat reflection/insulation to the insulation..... some coatings do both.

Personally, I'm a fan of ITC-100. It's expensive, but works the best of any "coating" I've tried. The thing to remember about any of these type of coatings is that they are applied LIGHTLY. Thicker IS NOT better....in fact it's just wasting the product. I'll use ITC-100 as an example..... it comes in a very thick paste form. Put a few tablespoons into a plastic container, and add a TINY amount of water and mix. Keep doing this until the coating is the consistency of latex paint. Spritz the ceramic fiber it's being applied to with water (this allows it to adhere without tearing the insulation). The use a cheap paint brush and "paint" the coating onto the ceramic fiber. No more than a light coat brushed on (as if you were painting a wall). The last step is the most important...LET IT CURE NATURALLY! IF YOU TRY TO RUSH THE CURING BY FIRING THE FORGE, THE COATING WITH CRACK AND FALL OFF! Meaning you just wasted the product and your efforts. At most place a 100 watt light bulb inside the forge that has been coated. Even then, expect it to take a week or more for it to cure, depending on the environment where you live.

Generally with ITC-100 applied to a forge, it will pull approx. 500F more than an uncoated version, assuming everything else is correct.

Thanks Ed, Wayne Coe recommended the Matrikote. It does the same as ITC-100. I just need to know if I need to put refractory mortar over the Matrikote once cured, or if I am just wasting materials. I personally don't think the mortar or cement is needed over the Matrikote, but would like others thoughts.

Not to belittle the product, but I've tried the Matrikote...... it doesn't hold a candle to ITC-100 in any aspect. Whatever coating you decide on, it should be the "top coat", covering it with anything negates any advantages it might offer. If you're just looking for a cheap way to seal ceramic fiber insulation, you can use refractory mortar, and thin it down like I mentioned previously, and then allow it to fully cure.....they you're good to go.

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Not to belittle the product, but I've tried the Matrikote...... it doesn't hold a candle to ITC-100 in any aspect. Whatever coating you decide on, it should be the "top coat", covering it with anything negates any advantages it might offer. If you're just looking for a cheap way to seal ceramic fiber insulation, you can use refractory mortar, and thin it down like I mentioned previously, and then allow it to fully cure.....they you're good to go.

Thanks again Ed. I already have the Matrikote, so I will just use it over the ceramic board. I did a little more research and your advice is spot on about it being the topcoat. Being a hobbyist right now, I'll see how the Matrikote holds up and when it is gone, I will give the ITC-100 a go. Thank you for your response.

Aaron