500 gallon reverse flow build

Hello, great sight and info here. I have been building a reverse flow 500 gallon smoker for my brother. I'm a fabricator/ welder and have experience with metal but not smokers. He came to me a few months ago with a 500 gallon diesel tank and a websight , feldons pit calculator and said use it to get my measurements. Fast forward a few months and I'm 2/3s done with the project and was doing some research on calculating double stack heights cause feldons web doesn't say anything about using 2 stacks. While researching I came across this sight that is saying that feldons websight is flawed for reverseflows and all my measurements are wrong. My question is what effect will this have on the smoker? From what I can tell my intake dampers and hole going to the cooking chamber is a little smaller than it should be. To fix this it will be allot of work I wasn't counting on and really don't want to do it unless the smoker won't work as is. Second question is doing my research I found out 2 six inch pipes have the same carrying capacity as an 8 inch pipe. So I used 8 inch pipe measurements in the calculator and it came to around 3 foot for the 6 inch double stacks. Does that sound about right?Thanks to everyone that puts out the effort on these sights so ppl like me can build our dreams.

 

Thanks for the welcome. I'm using 6 inch cause that's what I have. My brother is wanting this for his church and the materials are donated for the most part and it's up to me to make it work. I do have some extra plate I could make a rectangle box stack.

 

Thanks Gary,
So you think I should go 44" height on the double stack then? As far as performance do you think with me going by feldons calculator measurements it
will be sufficient? It will be easier to fix now then later if I have too change anything.
The church mainly uses their smokers for fund raising, church picnics and at times local bbq competitions. It doesn't have to be the best out there just needs to produce good grub.
Thx James

 

Thanks again Gary.

 

New question. I made the changes to the firebox to conform to the measurements this sight recommends. Made bigger Fb intakes including 1 in the top of the door, and i cut the opening to the cc bigger to get the recommended opening. My new question is I have a downward slope going to a drain on the baffle. I was originally going have a drop of 1" over 5ft sloping away from the fb. But because of the changes that drop will be 2 " over that 5 ft length to the drain. Is a downward slope of 2" over that 5ft going to hurt anything?. It will be allot of work to change, but I want this smoker to work properly. Thx

 

Yes sir.

 

Thanks for the replies. This tank is wide and there's plenty of space under the rf plate. I had to trim some of the rf plate where the drain is to get enough room at the end going to the cc, I'm pretty close to what is recommended there just a little shy.

 

I'm about to start on the cooking grates. I plan on making upper and lower levels that slide out. Im using 1" angle iron and expanded metal. I looked for a good forum thread that would give me a basic how too but couldn't find one.I got in my head how I think they should be made but would like to see how ppl with more experience have made them. Does anyone have a link to a tutorial or build I can read over? Also these grates will be 4' x 5' and is expected to hold a whole hog. Should I split them up so they aren't so big, for example 2.5' x 4' and have two
Thanks.

 

I have 3/16 angle 1 by 1. The expanded metal looks to be 3/4" flat expanded metal. Not sure on the gauge but it's around an 1/8". I can measure it ltr if needed. I like the look of the expanded metal on the bottom of the angle the best as well. I can buy different angle if needed, I was hoping this 1" angle will work as that is what I have. I get the building of the rack itself but where are the stops recommended to be put. How far out should the racks slide out and still be stable for the weight?

 

Thx everyone for letting me pick your brains.