Need help on reverse flow build/conversion

Well...a few months ago I bought yet another smoker. It is a 500 gal. propane tank on a trailer and is really just a large grill. There is no firebox and no good way to add coals...going to change that one way or another. I have a friend who is a talented welder/fabricator and has built many pits of various designs. Neither of us has ever seen or used a reverse flow cooker...they just don't seem to exist in our area. So...I come to the Brethren seeking advice...I understand the basic design, but am pretty short on details. If you have been involved in building a reverse flow cooker of this size I would really appreciate your input.



View of the front. I am probably going to make the two doors into one in order to be able to get a whole hog on it.

Back side below. Those two small doors are the only way to add coals to the smoker.



If we end up going with a reverse flow these doors will probably be welded shut as there will be a firebox on the end.

Back end of the cooker. This is not a firebox...just a place to store wood or whatever.



So...what are your thoughts? I have material on hand & my builder is waiting on me to make up my mind. On the advice of a member here, I had a look at the Bubba grills...like 'em a lot and see no reason why this can't be made into something similar. All input appreciated...and can provide more pics if needed. Thanks...........John

Tank diameter

Lake Dogs,

What is the diameter of the tank on your Lang? I may be wrong, but I am thinking that the width on the firebox will need to be close to the diameter of the tank a few inches below the centerline. My cooking surface is a bit above the centerline of the tank...how far below the meat does the angled plate with the drain need to be? That distance will determine the location of the firebox and therefore it's width where it meets the tank. Make sense?

Per Lang's website, the firebox on the 84 is 24" square and appears to be mounted a bit below centerline of the tank. Sorry to bother you with that.

I'm thinking that the tank you are using will determine the size and location of the firebox.

It surprises me that your lower grate rests directly on the baffle. I would not have thought you could do that...learning something every day here.

And I do appreciate your willingness to help! Nice looking batch of ribs there too.

posey's_pork_pit said:

This is the image I gave to William and he did the rest. There is a spreadsheet floating around that will help you calculate the size of the firebox, opening from FB to cooker, and the smoke stack height based on the size of your barrel. I'll see if I can find it and post it for you. Hope this helps!

Click to expand...

Thank you! I just sent that to my builder & will try and meet with him this afternoon and go over it. I think I know the spreadsheet you are referring to. I looked at one when I bought the cooker and IIRC (and understood it called for a firebox so large that I nixed the idea of a reverse flow cooker...along with about an 8" exhaust stack. In looking at the 500 gal. smoker by Bubba Grills it appears that his firebox sort of tapers from the diameter of the tank where they meet up, down to a smaller dimension at the door...maybe 24"? Sure would like to turn up someone who has one of his 500 gal. models.

I truly appreciate everyone's help...........John

Thanks...since the cooker and I are not in the same place & I don't have the measurements I just went with cubic inches...231 to the gallon X 500=115500 cu. inches. Entering that number in the smoker volume field yields a firebox dimension of about 34" on all sides. That might be livable.

After I get done mowing I'll run down and take some measurements and double check those figures.

I really hope to be able to make this work. Both the builder and I understand how to convert this cooker to something "normal" for this area which would involve enlarging the doors on the backside and shoveling coals through that opening. Works fine & I've burnt a lot of wood cooking like that. It involves a lot more fabrication work than the reverse flow design however. That, and I just like trying different methods of cooking...and for this area, reverse flow is different.