DAP Fireblock foam

[noodlestsc]

Well I did it. If you look a few posts back I went and picked up a Century FW240007.

Tomorrow after work I will be fabbing up my block off plate to do the install. The way I am doing the install is there will be a block off plate with my 6" pipe running through it and up about 18" into my exist masonry chimney. My question is this. I would like to put some insulating factor behind my block off plate so as to help with the cold when I am not using the stove. I have a few cans of DAP fireblock foam already and want to know if anyone else has used it up against the stove pipe before. It is ASTM and UL tested but I can't find anyplace that shows me to what temperature it is good to (I could give a call to DAP but I figured I'd ask here first.)

Has anyone ever used this stuff before? I don't want to hear a bunch of answers on logistics and "other" firesafe insulation, because I know I can always just go get firestopping mineral wool if I have to. I am just looking to see if anyone has info on this product alone.

 

[webbie]

OK, let me do a quick address of these "fire" products caulk and the hearth industry. In general, there is little or no use of all these fire block compounds with most hearth product installations. Reason: These products are designed for installation and use at regular temperatures. Their only "fire" function is to stop the spread of fire from one room to another (similar to fire rated sheet rock, etc.).

The products I have seen with these names are designed for enclosing around wires and pipes and other large holes which might be through walls and floors that are "fire rated", meaning that a fire in that room takes a certain amount of time to spread to any adjoining room. As you can see, that has nothing to do with stoves, etc.

I am saying that the best products to use with stoves are, in general:

1. Silicone, for lower temp uses such as where the plate hits the fireplace wall - also hi-temp silicone for pellet and gas vent and for storm collars on metal chimney.
2. Furnace cement (usually silicate based) for up against the pipe - Rutland Black is a popular brand of this.
3. Refractory cement for patching larger holes and firebricks.

The whole "rumor" that started a long time ago on this site about using these products was, IMHO, based on mis-information and misunderstanding.

Here is one example:
http://www.rectorseal.com/index.php?site_id=1&product_id=205
(fire block, UL ASTM caulk)
from the spec sheet:
-----------------------
INSTALLATION
7. Limitations
RS 136 cannot be used in areas where
there is continuous vibration on the open-
ing, where wet conditions exist or may
occur or where there are continuous
temperatures above 120 F
136 is not suitable for exterior or wet area
============================

OK, so there is one fire block that can't be used at even 120, let alone 500 plus......another example is a wall made of thick wood. This might have a fireblock rating (take a while for fire to get through it) but obviously does not have a high temp rating (get the difference?)

So do it the old fashioned way, with furnace cement and other compounds rated for high temp use, NOT FIREBLOCK.

 

[noodlestsc]

Got it, thanks for the info. FIREBLOCK FOAM = BAD IN MY SITUATION

 

[webbie]

Better yet, most cases need no insulation on top of the plate - if you are going to insulate it, many mineral wools, kaowools, fiberfrax and even fiberglass (with no paper, and certain are made with less bindings and in thinner pieces) can be used. You can often get stuff like this, even mixable stuff, at plumbing and heating supply houses. Good Luck!

 

[webbie]

OK, made a little wiki article out of this info and more - just for future reference:
https://www.hearth.com/econtent/index.php/wiki/Adhesives_for_the_Hearth/