Insulating the firebox

cemiddle · Post by **cemiddle** » April 15th, 2013, 3:55 pm

I'm starting to put together a list of supplies i will need to build my cooker. I'm thinking of insulating my firebox. It's 24"X 24" square. What is the best way to go about doing this? I've considered using fire bricks then welding another wall around the interior but wasnt sure if that would be the most effective method. Any input would be appreciated.

The Czar · Post by **The Czar** » April 15th, 2013, 6:50 pm

It depends on how thick of metal you're going to use if you're going to use 1/4 inch plate ......insulation is probably not necessary...

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SmokinFF · Post by **SmokinFF** » April 15th, 2013, 6:51 pm

Fire brick will add a bunch of weight. You can wrap it with a fireproof batt insulation and add a skin on the outside. I'm no fancy builder tho.

YouTube · Post by **Frank_Cox** » April 15th, 2013, 9:22 pm

SmokinFF brings up a good point that is not usually talked about when this question is asked..... Fire Brick is heavy lolol
I always insulate and wrap with lighter gauge when I need an insulated firebox.

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cemiddle · Post by **cemiddle** » April 15th, 2013, 9:32 pm

Thanks for the input guys. How much difference in fuel consumption and keeping steady heat will insulating actually make. I plan on using 1/4 inch plate, and I know it probably doesn't need insulation but I've read where it helps in these areas. I only plan on building this thing once and if it will make a big difference I might as well do it now.

Smokeone · Post by **Smokeone** » April 16th, 2013, 6:11 am

I'm not sure how much it will save. It depends a lot on the air temp. I don't know where you are located,but if it is not really cold, I would just do the 1/4" box.

alleyrat58 · Post by **alleyrat58** » April 16th, 2013, 7:01 am

I insulated mine mostly because I didn't want my toddler to get 3rd degree burns if he touched it. I used 1/4" inside and 16 GA out. I am less than satisfied with the results. I framed it out with 2x2 tubing then insulated between the inner and outer skins. I'm not sure how much the insulation helps vs just having the firebox the correct size which is why I rebuilt in the first place.

I'm not saying don't but plan out some practical things first, like how to attach it in place. Also, have Frank give you the name of the insulation we buy for out cabinets, that stuff is awesome.

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goodwla · Post by **goodwla** » April 16th, 2013, 7:04 am

Are you guys saying that depending on the thickness of the FB plates, you may/may not have to insulate?

Please explain more.

AustinKnight · Post by **AustinKnight** » April 16th, 2013, 10:17 pm

I've always read a insulated firebox helps fuel consumption,faster recovery and easier temp control. I have only seen one reverse flow here in Austin,Tx but the guy said the same thing I just spoke of. I kinda want to insulate my box when I finally build, is it really not necessary using 1/4 plate cause I could save a few hundred bucks and have a nice big bbq with the money saved from the plate cost.

??

Here are some pics I gathered from another site for build help later when I get going...The guy who built this box said he would've gone with ceramic instead of what he used I can't remember why. Sorry I don't have the end pic's but you get the picture

AustinKnight · Post by **AustinKnight** » April 16th, 2013, 10:17 pm

Double post

alleyrat58 · Post by **alleyrat58** » April 20th, 2013, 10:07 pm

The ceramic has a much higher temp rating. Frank used mineral wool in the last insulated build for SmokerBuilder's gravity-feed model and I couldn't be happier with that.

goodwla wrote:Are you guys saying that depending on the thickness of the FB plates, you may/may not have to insulate?

Please explain more.

You really need to use 1/4" no matter what. The heat is just too much for anything less than that. I have personally warped 1/4" with a hot fire more than once. My RF runs roughly the same with the insulated firebox as it did without it. I think it is a situation of diminishing returns. Insulating the firebox in my experience is really better to keep you from burning yourself than to improve the function of the smoker, overall.

cemiddle · Post by **cemiddle** » April 22nd, 2013, 12:37 pm

Thanks for all the info. I've decided to not insulate and spend the money elsewhere it doesn't sound like the extra money for insulating is worth it when I can use it elsewhere on my cooker.

YouTube · Post by **Frank_Cox** » April 22nd, 2013, 6:22 pm

sounds great!

goodwla · Post by **goodwla** » April 22nd, 2013, 9:23 pm

alleyrat58 wrote:The ceramic has a much higher temp rating. Frank used mineral wool in the last insulated build for SmokerBuilder's gravity-feed model and I couldn't be happier with that.

You really need to use 1/4" no matter what. The heat is just too much for anything less than that. I have personally warped 1/4" with a hot fire more than once. My RF runs roughly the same with the insulated firebox as it did without it. I think it is a situation of diminishing returns. Insulating the firebox in my experience is really better to keep you from burning yourself than to improve the function of the smoker, overall.

My FB is mostly 1/2 inch with the exception of the face that is 5/8 and the bottom that is 3/4. I have considered putting some insulation on the outside and wrapping it with 1/8 skin. Is there a pro/con to this?

Smokeone · Post by **Smokeone** » April 23rd, 2013, 7:03 am

Oh my, that is one heck of a fb! I don't think insulation will make a difference. So my answer is no, don't do if.

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The Czar · Post by **The Czar** » April 23rd, 2013, 7:13 am

Holy crap… Are you building a tank…to Withstand armor piercing bullets?… I'm going to have to say I agree don't do it… Man I think that thing is probably heavy as a tank isn't it?

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goodwla · Post by **goodwla** » April 24th, 2013, 9:40 am

well, it was cheaper than buying new steel. I went to the local scrap yard and they had a lot of 1/2, 5/8, 3/4 plate there that was 19 cents per pound vs the 80ish cents for new.

I will not have to worry about it rusting out anytime soon.

Last night had a disaster happen also, when moving the smoker back into the barn to mount it to the trailer, it dropped off the fork lift. landed right on its back. Good news is the FB did not bend at all. bad news is it hit directly on one of the counter weights and bent the door.

The Czar · Post by **The Czar** » April 24th, 2013, 11:21 am

Doh!

Hope you got a Ford to pull that beast with...

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