30# Propane tank firebox addition to Smoke Vault

[LhornR]

Ok folks...here is my project I've started. Please feel free to critique the design/build ant way you see fit...I can take it. I'm mainly looking for a better smoke via stick burning and being able to keep the heat very low. The smoker is gas and is very hard to keep the heat under 200°F without modding it. So the firebox for smoke and low heat..and if I need higher temps I can fire up the gas as well.

So far I have the 8" x 10" door cut and have aquired two 4"x4" square tubes 8" long and one 3". I'm figuring 8" for the stack and one to cut in to the side to connect a 4" aluminum flex pipe to the smoker. The 3" will be for the bottom ash door.

I'm not sure about the air intake sizing yet. I have 3- 2" pipes in the drawing as the area is close to the 4x4 tube.

Also not sure about the baffle plate. I have 2'x 3' sheet of stainless steel that's .035" thick I'd like to use as the baffle and as a grate on the bottom. I'm not sure if it will be able to handle the heat without seriously drooping.

The aluminum flex pipe I'm looking into is rated to 420°F...do you think the exhaust port will see temps over that? Also...as far as a door latch..will one at the center be ok or should I incorporate two? I plan on running 1"x1/8" flat bar around the door gap. That and the hinges will be plug welded. Speaking of which...though I was a welder for 27+ years I dont have one so I have a friend that will be welding everything up once I get the parts gathered and pre-fitted.

Another question...anyone know what exactly the black coating on the inside of the propane tank is? This thing has some seriously tough paint to remove too...any tips for that?

So this is my rough drawing so far. I do want to get this up off the ground as with failed back surgery low to the ground things are painful. Lemme know what you think.

And my smoker in current form...it will need a lift kit as well.

 

[SmokinAl]

I’m no builder, but will be watching!
Al

 

[bauchjw]

Bump. I can’t help, but know there are a few here that can!

 

[mike243]

I would guess the paint on the inside is to stop rust from forming, it may be epoxy never heard anybody say, a high heat fire might get rid but it needs to go some how

 

[JLeonard]

Like you I'm looking at raising my MG gas smoker up some. I'll be watching to see how you raise yours up.

Jim

 

[Fueling Around]

Been years since cutting up a lp tank. I don't remember an interior coating.
Hopefully a media blaster will clean up the interior and exterior.

You should be fine with 420° ducting provided you watch the fire. Maybe add a damper in there too.
Why not make the new stand for the Smoke Vault long enough to incorporate the side burner? Then a piece of 4" exhaust pipe to connect the two.

 

[LhornR]

OK I'm an idiot! I brought the door in today to investigate and found there is no coating. It's just black like the 4" tubing is..ya know..plain steel. Sight in only one eye just sucks.

JLeonard ...I started drawing the stand today. I'm thinking of just making another platform like structure and then cross bracing it. At first I thought of enclosing it with the ability to put the gas tank underneath the smoker..but having the tank so close to the burner might not be a good plan.

Fueling Around ... Do you mean have a damper on both the stack and the exhaust pipe? I was figuring to control how much heat/smoke goes to the smoker I could open/close the stack damper. Wont work?

That's not a bad idea having an all in one stand. It would be over 4' wide though and might get unruly trying to move it around...which I would have to do. I'll have to think about that.

Thanks for kicking this around with me guys.

 

[LhornR]

Oh..one more thing....do you guys think I should extend the smoke pipe into the smoker or not necessary? I'm planning to enlarge the one bottom vent to 4" and put a flange there to connect the flex pipe.

 

[Fueling Around]

OK I'm an idiot! I brought the door in today to investigate and found there is no coating. It's just black like the 4" tubing is..ya know..plain steel. Sight in only one eye just sucks.
...
Fueling Around ... Do you mean have a damper on both the stack and the exhaust pipe? I was figuring to control how much heat/smoke goes to the smoker I could open/close the stack damper. Wont work?

That's not a bad idea having an all in one stand. It would be over 4' wide though and might get unruly trying to move it around...which I would have to do. I'll have to think about that.

Thanks for kicking this around with me guys.

4 swivel castors and the 2 front ones with locking make a very versatile and maneuverable platform.
If both unit on a sold platform you don't need a flex pipe. A length of 4" exhaust pipe from your local muffler shop will make the connection.
I'm thinking a stack that tees into the exhaust pipe into the Smoke Vault. Yes damper on both the exhaust and stack.

Your 1/32" SS is worthless for this project. You need 3/16" for the diffuser and wood grate

 

[tbern]

watching along to see

 

[LhornR]

4 swivel castors and the 2 front ones with locking make a very versatile and maneuverable platform.
If both unit on a sold platform you don't need a flex pipe. A length of 4" exhaust pipe from your local muffler shop will make the connection.
I'm thinking a stack that tees into the exhaust pipe into the Smoke Vault. Yes damper on both the exhaust and stack.

Your 1/32" SS is worthless for this project. You need 3/16" for the diffuser and wood grate

Yeah that exhaust pipe setup would've been better probably. I'm gonna throw the SS in once I get it able to fire up to see what happens...no loss.

This is what I have so far. Lots of fun when you dont have the right tools. I even had to modify the teeth of a wood hole saw to get the holes cut but it made it. Another reason for square tubing...easier to cut the holes with a cutoff tool. The slugs from the hole will be perfect for the damper plates too. I also decided to tilt the exhaust port up a little..dunno...just seemed right. Looking at it mocked up I'm thinking for the tank size I guess the tubing could have been smaller. Oh well...my first build...more to come.

 

[Fueling Around]

...
The slugs from the hole will be perfect for the damper plates too. I also decided to tilt the exhaust port up a little..dunno...just seemed right. Looking at it mocked up I'm thinking for the tank size I guess the tubing could have been smaller. Oh well...my first build...more to come.
...

You can always damp down an oversize vent/chimney, but you cannot open an undersize

 

[LhornR]

I know I've been lagging here...but that seems to be my pace now days.

BUT...I finally got the tank stripped and almost everything prepped to take to the welder friend. I'll have to do the dampers once its back from the welder to be able to position the plates. Looking at it now I do think I got a little carried away with unnecessary complexity...but hey...it was something to do. I just hope it functions as needed after all of this. Yes...my temporary shop is in my kitchen.

 

[JLeonard]

I've been thinking of doing the same only using a camp stove kinda like this one and changing mine from propane to a wood burner.

Amazon.com: Survivor Lifestyle Cub Camp Stove Kit - 1 Cu. Ft, Model# 12-CSSKIT : Sports & Outdoors

Amazon.com: Survivor Lifestyle Cub Camp Stove Kit - 1 Cu. Ft, Model# 12-CSSKIT : Sports & Outdoors

www.amazon.com

Jim

 

[LhornR]

I've been thinking of doing the same only using a camp stove kinda like this one and changing mine from propane to a wood burner.

Amazon.com: Survivor Lifestyle Cub Camp Stove Kit - 1 Cu. Ft, Model# 12-CSSKIT : Sports & Outdoors

Amazon.com: Survivor Lifestyle Cub Camp Stove Kit - 1 Cu. Ft, Model# 12-CSSKIT : Sports & Outdoors

www.amazon.com

Jim

That would probably work great...wish I would have seen that before I got into this one. I looked at small stoves but they were either too big for my setup/need or too expensive. Let us know how it works out if you pull the trigger.

 

[LhornR]

OK I finally got my tank back from the welder guy. Turns out he wasnt a welder guy...he's a guy with a welder. Oh well...he did his best and for a case of beer I cant complain.

I just finished up putting the damper plates in. I need to get them some wood handles made up as well. On the baffle plate I doubled up two stainless steel sheets and riveted them together....so we'll see how that goes. I was going to fire it up and get it coated with boiled linseed oil today but as usual when I want to do something outside the damned wind is blasting away.

I will need to raise the smoker chest up about 12" to run the flex-pipe to. Then I can throw some ribs in there for a test run.

As received....

The baffle plate and base grate....

And how it looks now...

 

[bauchjw]

Awesome!

 

[LhornR]

I did the first burn in today and everything held up well. Didnt faze the baffle plate that got to about 700°F. Tank top and sides hit about 650°F.

I let it burn down and when it got to around 425°F I wiped it down with the boiled linseed oil. Waiting for the ashes to cool down so I can take a torch to the legs and hit them with oil.

Its an ugly duckling but as long as it works I guess. At one point I was getting what looked to be a sooty smoke with all vents open including the bottom...it was hard to tell with it being so bright out today. I'm guessing it was from too much wood/charcoal in the box. Any thoughts on that? It was oak wood from where they make swamp mats. It smoked fine in the smoker chest before.

 

[Newglide]

Got a steam punk meets Mad Max vibe. Very cool idea and well done. Have you connected it to the SM yet?

 

[LhornR]

Got a steam punk meets Mad Max vibe. Very cool idea and well done. Have you connected it to the SM yet?

Thanks. No not yet...I need to build a frame to raise the SM up about a foot to plumb the flex pipe into it.