# What is "Mil Pac" sealant?



## tubbster (Nov 2, 2008)

My new gas stove says I need it to seal the exhaust to the flue collar. Will the high temp red work?


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## thechimneysweep (Nov 2, 2008)

Mil Pac is used in coaxial gas pipe installations to ensure that the exaust doesn't leak out of the inner layer and blend with the incoming combustion air.  It is black, has the consistency of peanut butter, and never hardens, so the pipe can be taken apart if need be.  Hi-temp silicone might perform the same sealing function, but you've got to be FAST and RIGHT, as once the silicone sets up, you'll never get those pipe sections apart again.


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## tubbster (Nov 2, 2008)

How do you feel about Rutland stove cement in its place?

Thanks!


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## webbie (Nov 2, 2008)

Stove cement is not air tight at all. I'd rather see you use the red or hi-temp black RTV.


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## tubbster (Nov 2, 2008)

Webmaster said:
			
		

> Stove cement is not air tight at all. I'd rather see you use the red or hi-temp black RTV.



Well shucks. What's the worst that can happen here?
It would be a very small leak if at all, the inner flex pipe fit fairly good, and I slopped it up nice. I can not think that it would screw it up that bad? It is venting straight out through about 18" of pipe to the side of the house.


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## PaulRicklefs (Nov 3, 2008)

tubbster said:
			
		

> My new gas stove says I need it to seal the exhaust to the flue collar. Will the high temp red work?



Yes Red high temp will work.  In fact in my province I'm REQUIRED to put red high temp on any vent connections that require screws, plus I need to use high temp silver tape on top of that.


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## tubbster (Nov 3, 2008)

This thing is TOGETHER. I.E., it will not come apart so easy now. The external part of the coaxial pipe is all red rtv'd. I can not see how it would vent into the living space. The only issue as I see it would be a slight leak from exhaust to the intake side of things. I have yet to hook up the gas. 

If it does not work right, major surgery ahead....


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## R&D Guy (Nov 5, 2008)

You'll be fine.  Unless your pipe is really screwed up, the leakage between the flue and combustion air will be negligible.  I have 3 gas fireplaces in my house, the one downstairs is the highest BTU and is the only one with a horizontal run/horizontal termination.  It's 36K BTU's and I used red silicon to seal the outer pipe only then went over the joins with metal tape.  So long as the pipe doesn't leak inside the house (which sounds like you've covered) and it's a listed vent configuration your safe.


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## tubbster (Nov 5, 2008)

R&D;, is that unit a commercially available one? 

The reason I picked the Napoleon was it was the only one I could find that was in the mid 20's for input that had a straight out vent that was documented, no snorkle or vertical rise needed. (Venting out about a foot below and centered on a window) If I knew of one that even more nuts, I would have considered it.

Come to think of it, I maybe should have asked here first. Oh well, it's a done deal now!


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