Reverse Flow Smoker Build Question

[Destroyr350]

I am going to be building a reverse flow smoker and have a question about baffle design. The smoker will be rolled out of 10 gauge steel will have a 30" OD and will be 6ft long. Should be right about 220 Gallons. I have been browsing around and see various baffle designs. Whats the best? Should the height at the end opposite the firebox be adjustable?

[SmokinFF]

Let me take a crack at this. Keep in mind, I'm no expert. Most BP are welded in leaving an opening opposite the FB the same size as your throat opening. I haven't seen one with adjustable height, but some are built with adjustable opening. You can put it in at a bit of an angle for drain purposes, but basically flat across. Hope that helps, if not someone smarter will be along soon.

[bluecatfish]

SmokinFF is right on.

[Smokeone]

Yep SFF is right. (Man, that hurts to say. )
I'm sure Gizmo will be along, he has experimented with the adjustable BP opening. I've used one with the adjustable baffle, but I never ran it anywhere but wide open.

[Gizmo]

I could only get a 10 to 15 degree swing using the adjustable BP so I quit.

And that's all I have to say about that ….

[Destroyr350]

I wasn't thinking that an adjustable baffle would make a significant difference, I still may put one in for the hell of it. Any suggestions on the angle of the baffle plate? Waiting for the quote to roll a 6' x 10' sheet for my cooking chamber. Need to get this started for a competition in April.

[Big T]

I always put the BP level front to back and side to side. I'm not sure there's any benefit to putting it on an angle. If you wanted to raise it up you could raise your tongue jack or put a thin piece of wood under the front legs depending on what style you build.

[Big Steve]

I always put the BP level front to back and side to side. I'm not sure there's any benefit to putting it on an angle. If you wanted to raise it up you could raise your tongue jack or put a thin piece of wood under the front legs depending on what style you build.

But then your fire would be angled.

[dwwantasmoker]

Big T wrote:I always put the BP level front to back and side to side. I'm not sure there's any benefit to putting it on an angle. If you wanted to raise it up you could raise your tongue jack or put a thin piece of wood under the front legs depending on what style you build.

Big Steve wrote:
But then your fire would be angled.

That's the way I think every day Angled I would put it how ever you can live with it Destroyr350 If your plan is to install a drain I would angle it a little to the drain, but that's just my 1/2 cent
im sure that's all its worth.

[Gizmo]

Level.
Removable.
Set in a 3/4 to 1" angle-iron frame to form a lip around it - looks like a shallow pan.
No drain - I just remove most of the grease with a sheetrocker's broadknife when needed.

but that's just me ….

[Big Steve]

Level.
Removable.

What is the advantage of having a removable BP? We are getting ready to weld ours into place and if you professionals know of an advantage for not welding the BP I'd like to know before we have regrets. Thanks.

[Big T]

I weld mine solid. The only advantage that I can think of would be on a small cooker to make it liter for loading in your truck. I don't have any regrets.

[Gizmo]

You certainly don't have to make the BP removable but BigT just said the very reason I made my first BP removable - knock down storage for hauling on Edgar.

I've had other unique reasons for making my BP's removable…..

Edna was a converted pellet drive and they always have a "blast shield" that performs a very similar function that I had to build removable because you have to be able to get to the fire pot for other reasons.

Eli was a vertical with an automatic cut-off that closed as the door was opened to prevent the fire from spiking - that BP had to come out for servicing the cut-off mechanism.

Smokin Johnny's BP had to be cut after each of the first 3 burns to "tune" out the hot spots.

Earl for weight/loading reasons again.

Egor because he has a 40" wide exposed edge on the BP at the gap so he needed an angle iron frame on that edge for support - so might as well frame out the BP and just drop it in.

After all those designs I guess I got in the habit and felt like I needed to be able to get into that area for an annual cleaning. I don't put drains on my cookers - just scrape the grease out every so often. I'm funny that way.

[Tinker]

Do you use any type of gasket seal between the baffle plate and the frame it sits in or just sit in the frame metal to metal an don't worry about any leaks

[Gizmo]

Usually just metal to metal but Egor is getting a small (1/4") fire-rope seal because he did want to leak a little. I wish I had done it earlier because it's much easier to install before you cook on it while the steel is good and clean ……

[Big Steve]

OK I get that having a gap between the FB and BP is bad, having a gap between BP and cook chamber isn't good and having some way to either lengthen or shorten the BP to help tune is good. Am I on target?
On our design we have about a 4.5" gap between the BP and the cook chamber end cap. We're building according to plans we bought from Frank. One slight difference is we originally spec'd out the end to be "dished" or "domed", materials changed and now we're using flat plate. Any concerns?
Since we're trailer mounted I don't see a weight benefit to having the bp removable, so we'll weld it in sold. At least that's the plan now.

[Gizmo]

My suggestion would be to go ahead and weld it since it's trailer mounted. As a precaution you might make a cardboard template right now while you can inside a clean cooker and just hang it on the wall so you have it if you need it. The cardboard template would be to trace onto a piece of scrap sheet-metal to make a tuning plate that will fill the gap in completely to the inside wall of the end cap and come back to 2 or 3 inches overlap on the end of the BP. If you ever want to "tune" the gap you simply make the plate and tack weld it (or magnets) in place and cook with it and keep moving it until you get what you want then weld it (or a permanent version) into place and you're done forever.

[Big Steve]

We'll have some material leftover. Nice suggestion and we'll follow it.

[Destroyr350]

I will be making the BP removable, Just in case I decide to mess around with tuning plates or make changes. I am making a V shaped plate w/o drain for now. Its official, Just sent over my AutoCAD drawings to have everything rolled and cut. Heres what I came up with.

Cook Chamber 30"ID x 48" (About 150 Gallons)
FireBox = exterior 26" x 24" after insulation interior 24.75" x 22"
FB to CC = 100 sq in
3- 42" x 26" Racks
1- 42" x 19" Rack

[Gizmo]

Yep1 … All those numbers look familiar - close to Egor's

[Mo Smoke]

Just bumping this post back up to see if you have any pics of the build we can check out, and to chime in on the removable BP theory.
I thought about having a removable BP to be able to switch out with a grate that can be used as a coal shelf if I want to grill over a fire instead of using the firebox to smoke. A couple of people have suggested I use a basket to place the coals in that could sit on top of the BP, and that is the option I'll use depending on the dimensions I end up, (fb to cc opening, height of the BP, distance to cook shelf and whatnot).

[Gizmo]

The build pics are the threads;
Edgar is underway (older),
Earl,
Egor

Earl and Egor are both from the past 6 months but they're all removable BP's