Exposing InsBlock 19 directly to oven interior

[kebwi]

The InsBlock 19 is perfectly flat and level so I'm not planning on applying a fireclay paste under the floor bricks (except for one that I put too much weight on and dented the InsBlock under it yielding a slightly tipsy brick, sigh.

I'm a little concerned that I shouldn't be exposing the InsBlock directly to a cooking oven via the cracks between the bricks. Is that a valid safety concern? Will it release any sort of vapor up through the cracks into the food?

I would strongly prefer not to remove the bricks and put down a layer of paste; I'm not sure I could ever get them perfectly placed again. I am considering squiggying fireclay paste (actually, I might as well use the copious firebrick mud from my saw) into the cracks without actually lifting the bricks out.

Is this necessary? Pointless? Noteably inadvisable for any reason?

Thoughts?

[Les]

Re: Exposing InsBlock 19 directly to oven interior

I'm a little concerned that I shouldn't be exposing the InsBlock directly to a cooking oven via the cracks between the bricks. Is that a valid safety concern? Will it release any sort of vapor up through the cracks into the food?

If that is the case, a lot of us are doomed. I don't think a vapor is an issue. The bad element of the block is the fibers/dust it emits when it is disturbed. I don't see how a thin bed of fire clay will protect you much more than the ash that will soon fill your gaps.

Just my opinion (and I respect it )

Les...

[RTflorida]

Re: Exposing InsBlock 19 directly to oven interior

As Les mentions, ash will soon fill all of the voids; Thats not to say there are no health concerns. But really, is there anything in our daily lives that does not pose some health problem to someone, somewhere? I say go for it and don't worry about it until a forum member mysteriously grows a third arm.

RT

[kebwi]

Re: Exposing InsBlock 19 directly to oven interior

That would be useful.

[dmun]

Re: Exposing InsBlock 19 directly to oven interior

Refractory insulations are designed to run at high heat. They are unlikely to produce any disagreeable outgassing like domestic insulations with their organic binders.

There would be nothing wrong with filling any cracks with firebrick powder, but as has been said, wood ash will do the same thing all by its self.

By the way, I have insblock19 under my oven floor, with no fireclay layer, and have never noticed any problem with it.

[jpar]

Re: Exposing InsBlock 19 directly to oven interior

Insblock 19 and other fiber based boards - (Kfac, FBX 19 board, kaowool board, most ceramic fiber boards) are manufactured with organic binders. These binders (starches, latex) will burn off at approx 450 deg F. The vapors are not toxic, but they do smell! Once the biders burn off, there will be no further outgassing. Boards do lose strngth after binders burn off.

[dmun]

Re: Exposing InsBlock 19 directly to oven interior

Here's a thread discussing this:

http://www.fornobravo.com/forum/f6/k-fac-19-a-3031.html

[Royal Ranger f16]

Re: Exposing InsBlock 19 directly to oven interior

I spoke to a Mr. Ward at Ward burner systems regarding the using of the Insblock 19 under the cooking floor brick. Ward burner systems is a place that sells the Insblock product. He did not want to sell it to me for this application because he said that if the hot gases from the fire could reach the product through a crack in the bricks it would "scorch and smell to high heaven". I am going to stay with the vermiculite /concrete base.

[kebwi]

Re: Exposing InsBlock 19 directly to oven interior

Whatever, it works perfectly fine for me. It wouldn't sweat it if I were you. Go with what works best.

Oh, but don't skimp on your floor insulation. It's where I and many other FBers lose our heat the fastest. Vermicrete has less insulating power than the various "insulating boards" so add an inch or so for good measure.

[dmun]

Re: Exposing InsBlock 19 directly to oven interior

He did not want to sell it to me for this application because he said that if the hot gases from the fire could reach the product through a crack in the bricks it would "scorch and smell to high heaven".

Mr. Ward is misinformed. The "19" in insblock19 indicates that it's made to withstand 1900 degrees f, which is unlikely to be reached in our application.

I have loose laid firebrick over insblock19, and I've never observed any outgassing. It's a widely used product here, and I've never heard a stink complaint.

[Royal Ranger f16]

Re: Exposing InsBlock 19 directly to oven interior

Whatever, it works perfectly fine for me. It wouldn't sweat it if I were you. Go with what works best.

Oh, but don't skimp on your floor insulation. It's where I and many other FBers lose our heat the fastest. Vermicrete has less insulating power than the various "insulating boards" so add an inch or so for good measure.

Thank you for the advice. I did the 5:1 vermicrete 4 inches thick. It seamed like the vermiculite was floating to the top or it looked like less portland on top anyway. Hopefully I didnt get to much water in it. When I poured it it was like thick oatmeal. Is there a 1 inch insulating board you would recommend?