# Firebox Insulation Questions



## Colorado0321 (Mar 18, 2021)

Hey all, I'm working on the design for my reverse flow smoker (construction will start mid May) and decided that being in northern Colorado where good smoking wood is costly, I'd better insulate the firebox to increase efficiency.  With that in mind, I've a couple of questions that I thought of while working on the CAD model:

1) How important is the thickness of the outer layer of steel?  I'm planning on 1/4" for the inside walls, but was wondering if 3/16 or 1/8 would be fine for the outer walls so that I may save some weight and material cost?

2) Is it worthwhile to install actual insulation, or will a 1-2" air gap suffice?  Also, if worth it to wrap in insulation, what is the best source for buying some?

Thanks!


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## civilsmoker (Mar 18, 2021)

It all depends on what "you" want but a 1/8 skin should be fine.  This is just me, but if you are going to spend the time to double skin the fire box I would put insulation in it.

8 lb ceramic would be the best, but its spendy and you SHOULD use a respiratory when working with it.  I use this stuff in my forge, it is excellent stuff.

For a BBQ, the easiest stuff would be some rockwool safe and sound.  Its good to 2100 ish, its cheep (like 50-60 bills at the hardware store) and easy to get.  

Take a look at this build.  It is one of the best examples of an effective low effort/cost fire box insulation application that I have seen.

https://www.smokingmeatforums.com/threads/25-gal-perfect-patio-reverse-flow-smoker.159699/


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