Planning a Reverse Flow

[fagesbp]

Here is my initial sketch of what I plan to build for my outdoor kitchen. The firebox and baffle plate will be 1/4" plate and the cook chamber will be 3/16" plate (rectangular shape). I'm still contemplating the door and latch designs but this is just trying to get my volumes and openings right to make it draft and heat properly. My first question (of many, I'm sure) is this: Should I include the area under the baffle plate in my cc volume for calculating the firebox size, and therefore everything else?

I'm learning everything as I go so if I seem ignorant, it's because I am lol.

[SmokinFF]

The pic is kinda hard to read, but figure the whole CC to determine size.

[Clover Ridge Smokers]

As SFF said, use the entire CC in the calculation. I would suggest looking at this build for ideas on doors and hinges. This design worked out perfectly. viewtopic.php?f=11&t=3789&start=30

[fagesbp]

Ok thanks. Luckily that's how I figured it. I have been looking at that thread too

[fagesbp]

So I have decided to downsize a little. Same design but going with these dimensions now. How high off the baffle plate should my bottom cooking rack be? Clover in your build is there any particular reason you left the door so far from the firebox end or just aesthetic? I know the other end was likely to keep from having the rack over the baffle plate opening. I really like those doors and I think I'll do some very similar, but maybe try to make the latches different. I like the idea of having a latch going through the door and wedging closed from the inside. I'm trying to figure a way to make the cc doors latch that way. Maybe a cantilever type of thing that goes up when twisted.

[Clover Ridge Smokers]

The reason the doors are set in is no have the grate over the area right above the FB (hot spot) and on the other end we didn't want grate over the turn.

[fagesbp]

Ok thanks. I might just put that firebox side door about an inch from the end instead and use the hotspot for hotter cooking. I don't really want the grate over the turn either. It might look a little lopsided with a 5" space on that side and 1" on the other but It's only for me at home. This will be a stationary build on posts set in concrete. This is what I had in mind for the cc doors. A handle that turns and moves a couple rods and wedges them against some small blocks drilled or cut on a taper.

[Clover Ridge Smokers]

Sounds like you got a good plan

[Big T]

That'll work for latching the door but you really need to make sure that your cc is sealed up tight. I think that's the reason most guys make an external latch so there's one less hole to seal in the cc. jm2cw

[fagesbp]

The bottom hole would be through the inner frame inside the cc and the top hole I would cap with a piece of steel like a 1" cube drilled 1/2" deep so it would be all sealed. The taper should allow it to pull the doors tight. I could probably even put some chimney or oven gasket material around the inner door frame to make it seal very tightly if it leaks at all

[fagesbp]

And the hole going through the doors themselves will be bushinged to fit snug around whatever rod goes through the door

[Big T]

That should work

[fagesbp]

SO I got a quote for the steel. About $400 for a sheet of 3/16, a sheet of 1/4, a sheet of expanded metal, 5 sticks of 1x1x1/8 angle iron, and a stick of 1/2" cold roll. Seems pretty decent to me. I got a piece of 12" pipe from work I'll set in the ground to mount the smoker on. All I need is something for the exhaust and I think I'm mostly set. I'll have to start saving my allowance lol.

[Big T]

It sounds good to me.

[fagesbp]

I read somewhere that the throat size should be 1.5 times the calculator recommended area for a reverse flow because the calculator is based on a traditional offset. Is that true?

[fagesbp]

Is there a reason why the fb door shouldn't be on the same side as the cc doors? It would work a lot better in my kitchen if the fb door is facing inside.

[fagesbp]

Do you usually slope the baffle plate towards the drain by the bp to cc opening to make it drain that way? I was thinking that might cause some restriction with air flow.

[fagesbp]

[Big T]

1) Using the pit calculator on this site, 100% to 115% max on your FB anything more or less and you'll have temp issues. 2) There's no reason why the FB door can't be on the same side as the CC door. 3) I make my BP level with a 2'' grease dam on the end and a 2'' drain pipe, you can probably get by with a very small amount of fall on your BP if any at all. Most of the grease and drippings will burn off while you're cooking.

[fagesbp]

Should the throat be made bigger than the calculator recommendation to compensate for the turn in the reverse flow?

[Rev.Mike]

nope, if you make the throat opening the size the calculator calls for (and b p gap) you should have no problems, i would stick to the dimensions the calc calls for, but thats just me 4wiw

[Big T]

The pit calculator is designed for RF dimensions.

[Rodcrafter]

Yep, that will be good

[fagesbp]

Noted and revised. My throat will now be 20 x 3 and the baffle plate opening will be 3.25. I think I read to make the BP opening slightly larger than the throat. My baffle plate will go flush with the top of the throat. Now I just have to figure out how to put it all together with 0 fabrication experience.

[The Czar]

If by turn in the reverse flow you mean where the baffle plate gap at the opposite end from the FB and CC meet....no....that size is a very accurate measurement....