120 Gallon Propane tank with Insulated Fire Box

pr0wlunwoof · Post by **pr0wlunwoof** » March 14th, 2017, 8:42 am

Did a lot of research and decided on a reverse flow smoker with an insulated firebox as it seemed the best shot at temperature control and fuel efficiency.

Started with a 120 Gallon Propane tank:

pr0wlunwoof · Post by **pr0wlunwoof** » March 14th, 2017, 8:58 am

I had an old utility trailer that I don't use anymore as I upgraded last year. Figured it would work. Pictured is my brother in arms. He helped a ton in the beginning. Great machinist and all round swell guy.

After we mounted the tank we got to work on the firebox.

pr0wlunwoof · Post by **pr0wlunwoof** » March 14th, 2017, 9:13 am

Used this calculation to determine firebox size:

KingSmoke · Post by **KingSmoke** » March 14th, 2017, 9:20 am

Lookin good man. this is the same size tank I was looking for before I lucked into this furnace. What are your plans for the space on the other side of the trailer?

pr0wlunwoof · Post by **pr0wlunwoof** » March 14th, 2017, 9:48 am

The other side will be storage.

pr0wlunwoof · Post by **pr0wlunwoof** » March 14th, 2017, 11:41 am

KingSmoke wrote:Lookin good man. this is the same size tank I was looking for before I lucked into this furnace. What are your plans for the space on the other side of the trailer?

Here is a couple pictures of the other side to give you an Idea of how I am going to use it.

KingSmoke · Post by **KingSmoke** » March 14th, 2017, 12:13 pm

I like it, looks like plenty of room for wood, a cooler, and maybe a box for tools and stuff.

pr0wlunwoof · Post by **pr0wlunwoof** » March 14th, 2017, 12:20 pm

Here is the firebox build. I used ceramic wool as the insulation.

Squiggle · Post by **Squiggle** » March 14th, 2017, 3:38 pm

Looks awesome dude, well done!

temurf · Post by **temurf** » March 14th, 2017, 3:42 pm

Looking Good.

Post by **Big T** » March 14th, 2017, 4:00 pm

ajfoxy · Post by **ajfoxy** » March 14th, 2017, 4:34 pm

Looking good.

Post by **Pete Mazz** » March 15th, 2017, 3:59 am

Looking good!

Is there a reason you have the FB so far into the CC?

pr0wlunwoof · Post by **pr0wlunwoof** » March 15th, 2017, 6:30 am

I had a couple issues to solve. Weight distribution so the trailer wouldn't tip backwards and turn radius on the trailer so it would be less likely to jack knife. I don't think having it further in really effects much as the box is insulated so no impactfil direct heat transfer from it and it's reverse flow so the heat travels the length of the chamber before it contacts the meat.

forty_creek · Post by **forty_creek** » March 15th, 2017, 7:13 am

Not sure how much your planning to travel with it so you might check your axle rating if you do not already know and weigh the setup either way. It adds up quick.
Rule of thumb these guys have taught me is on a RF the axle pretty much needs to be as close to the FB as possible.
As far as the FB counter-sunk into the CC it can make a difference. You will most likely have a hot spot directly above the opening that ordinarily would not be as hot. Yours may not make that much of a difference. You could double the BP above this section to distort the direct heat...just a thought.
These guys helped me tremendously with my build. It sounds like you have it figured out. We are all here to help each other and pay it forward.
O and welcome if this is your first post!

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pr0wlunwoof · Post by **pr0wlunwoof** » March 15th, 2017, 7:29 am

Not sure what the axle is rated at. The tires are rated at 1820lbs. I am not planning on pulling this more than 20-30 miles at a time. If those plans change I will probably make some major modifications to insure I do not have any major issues.

I put a plate directly over the FB where it is Counter Sunk as I was not gonna use it as cooking area, but didn't want food to fall in if I decided to drive and cook at the same time.. That area wont be used when smoking.

I appreciate the constructive criticism. That is why I joined the forum. This is my first build and I know lessons learned save time, energy, and most importantly $$.

pr0wlunwoof · Post by **pr0wlunwoof** » March 15th, 2017, 7:36 am

Here is a picture of the inlet from FB to the CC.

I had a friend fashion me a burner from a cast iron pipe that runs the length of the CC. This way I can also use the cooker as a grill and to help preheat the CC while smoking.

pr0wlunwoof · Post by **pr0wlunwoof** » March 15th, 2017, 11:29 am

My current issue is trying to figure out how to do the firebox door latch. I am putting a wood stove gasket in the channel around the door as I want to be able to seal the firebox as much as possible to control the burn. I am thinking of doing a trailer side door style latch like this:

Has anyone had any experience with this type of latch. I will build it from scratch.

Post by **Rodcrafter** » March 16th, 2017, 3:12 pm

I like the work you're doing it looks great. I have a question though, is that throat made out of 2 pieces of 5" pipe? I only say that because looking at you numbers on the calc you used it was supposed to be a 10" pipe. Or at least it looks to me, trust me I wouldn't be saying it if I didn't think this isn't going to be a problem. A single 5" opening is only 19.+ each your calc said you needed 73" or so right?

pr0wlunwoof · Post by **pr0wlunwoof** » March 16th, 2017, 3:52 pm

It is 2 5" pipes. Good catch. I might have an issue. I am going to mess with it the next few days. If I experience issues I might be cutting those out to make a half moon.

What issue should I be looking for from having too small a throat from FB to CC.

I seasoned it last week and didn't notice a draw issue.

Post by **Rodcrafter** » March 17th, 2017, 7:27 am

I would expect it won't get hot enough with out a crazy fire. With the insulated FB (which is sweet) you should be able to run a very small fire and get the temp anywhere you want. The insulation should make her very easy on fuel.

pr0wlunwoof · Post by **pr0wlunwoof** » March 17th, 2017, 10:35 am

I will test it today and report back.

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pr0wlunwoof · Post by **pr0wlunwoof** » March 20th, 2017, 7:11 am

Cooked steaks, ribs, and chicken quarters. My conclusion is I need a larger hole in from the FB to the CC. To achieve 200+ I needed a substantial fire which caused the other issue of the area closest to the FB being 50+F more than the far right. I was barely using the CC surface area and was able to position the food where it had the right temps, but I would rather have a more even temp with a smaller fire.

Post by **Rodcrafter** » March 22nd, 2017, 6:06 pm

Yes I agree

Making memories!

Squiggle · Post by **Squiggle** » March 23rd, 2017, 3:39 am

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