K Fac-19

[dbhansen]

Re: K Fac-19

It seems that there are several types of insulating boards that are not intended for weight-bearing applications in an industrial setting, but that can bear plenty of weight for backyard oven use. Insblok-19 and KFAC-19 probably fall into that category. SuperIsol is a slightly better insulator that can bear more weight (compressive strength = 300 psi), so I think that's why some have suggested it might be better. With other materials, there's a trade-off between strength and insulating ability. Marinite, for example, is much denser and has a compressive strength of 1000-3000 psi, but the thermal conductivity numbers are quite high. You also have to watch for how they react to water, to make sure they don't compress when wet (search for "Kaowool" in this forum to find out why!).

[tdibratt]

Re: K Fac-19

Thanks Jim, yes it is Elvis at Alhpatherm. He helped me out when I built my last oven. Since then the art has matured and advanced over the last 3 years into using new products so just want to be sure I do my research before I go out and spend the money.

Yes he suggested the KFAC-19. I have been doing some more reading on this forum and I think I cam across a post by you that suggested that KFAC-19 does not possess the strength that insblock-19 has and I interpreted it to mean it may not be good to use.

Thx

[CanuckJim]

Re: K Fac-19

TDI,

Don't know who your supplier is, but I'm also in the Toronto area, so here's a knowledgeable source: Alphatherm Inc., 8201 Keele Street, Unit 4, Concord, Ontario L4K 1Z4; 905-738-6732. Talk to Elvis there.

Jim

[dbhansen]

Re: K Fac-19

You shouldn't have a problem with it assuming it is similar to Insblok-19, which many folks here have used successfully. Here is a spec sheet for KFAC-19, which indicates a compressive strength of 33 psi, which should be more than enough for a standard oven.

I'd explain your intended use to the supplier and ask if it will work.

[tdibratt]

Re: K Fac-19

A lot of good discussion here about KFAC-19. I also just source a local supplier who carries this product and am wondering whether or not it is a good thing to use? If it cannot sustain the weight of the firebrick hearth floor plus all the weight of the firebrick dome and thermal mass, then I should be leary, right?

Thx

[bolex16mm]

Re: K Fac-19

Jim,
Thanks for your quick reply. I was afraid that was the answer. Knowledge about Bolex cameras and insul board, what an amazing forum.
Tony

[CanuckJim]

Re: K Fac-19

Cameraman,

I've used both K-Fac 19 and SuperIsol type board. K-Fac is not intended for weight bearing applications, while SuperIsol is.

Jim

[bolex16mm]

Re: K Fac-19

Since the K Fac-19 boards are not as expensive as the Super-isol,calcium-silicate or cal-sil boards, I can put down 4" of insulation instead of 2" for the same amount of money. Is it overkill to put down two layers of K Fac-19, or will 2" be plenty?
Tony

[jpar]

Re: K Fac-19

According to my understanding, Insblock 19 is relabeled K Fac 19. In industrial kilns and furnaces, these products are almost never used in areas where structural strength is needed. They are typically used in sidewalls and arches. If they are used in hearths, boards are put between firebrick piers.

[beaglestorm]

Re: K Fac-19

Well using the most rudimentary of calculations.

150 dome bricks + mortar weigh about 1200 pounds.

51" diameter total area including dome and floor = 2043 sq/in
42" floor area = 1385 sq/in

Subtracting floor area from total area (not accounting for the door opening) gives a total of about 657 square inches of area underneath the weight of the dome.

so...

1200 lbs / 657 sq/in = 1.8 PSI way way below the 38 listed in the specifications.

This seems way too low. Can you check my math? What am I missing? Even if it is 50% off, either product should hold up fine.

[dmun]

Re: K Fac-19

Its organic binder gives INSBLOK-19 excellent cold strength but will dissipate above 475?F.

That's interesting, since it's primary use, when I researched it, was for the exterior of ceramic kilns, outside the insulating firebrick layer. Ceramic kilns are fired to red heat repeatedly, and their floors are weighted down with pots and heavy kiln furniture. (Think about a stack of five or six pizza stones held apart with ceramic pillars, each layer with a load of heavy pottery.) You'd think it would hold up to oven conditions (800f, and the weight of a pizza or two.)

In my case it seems to have, although I'm not going to tear it apart to measure it.

[beaglestorm]

Re: K Fac-19

I am also going to be using Insblock 19. For comparison it looks like the KFac has 4800 PSF of compression strength vs 5472 PSF for the Insblock 19. The Modulus of Rupture is 95 PSI for Kfac vs. 115 PSI. And both of these are lower than the Super-isol specifications. I had both available here locally as well, I only chose Insblock because of the good reviews it got here on the forums. Good luck.

Oh and the insblock has a simillar disclaimer on their spec sheet here:

http://www.hwr.com/products/datasheetsv1/INSBLOK-19.pdf

INSBLOK-19 is a 1900?F maximum service temperature lightweight mineral wool block insulation. INSBLOK-19 exhibits very low thermal conductivity, good moisture resistance, easy handling, and easy cutting. Its organic binder gives INSBLOK-19 excellent cold strength but will dissipate above 475?F. INSBLOK-19 meets the ASTM C612 Class 5 specification. Its principal application is as a backup lining to lower furnace shell temperatures.

[bolex16mm]

Re: K Fac-19

I am considering using K Fac-19 mainly because I can get it locally. The shipping costs for the FB board are nearly one half of the cost of the boards. However, I don't want to do something foolish because I can save some money. How long of a period of time are we talking about for the K Fac-19 product to break down. Thanks in advance for the info on the insulation boards.
Tony

[Les]

Re: K Fac-19

I see the hight temp mortar as a plus. In regard to your concerns of the oven getting to hot - I don't know if that would be possible, and if it is, just add less wood.

Les...

[jpar]

Re: K Fac-19

Kfac boards, along with conventional ceramic fiber boards, are fibrous products. As they see temperature, the binders burn out and these products loose strength. Super Isol and similar cal-sil boards have much higher compressive strength, and will not compress under the weight of the oven and hearth.