106 gallon offset build with "heat baffle box" UPDATED!!!

[sinor81]

Hello guys!
What do you think about this offset construction?

I hope my drawing is clear and you can see everything.
What do you think about this "heat baffle box" what I created? Does it break the airflow, or can be helpful?

[ThinBlue]

I'll never be the guy discouraging someone from trying something new, but my hunch is that you will just push your hotspot further to the left because it looks like you are just delaying where the hot air exits. What you may get with that design it a dramatic reduction in the line-of-sight radiant heat that your meat will get directly from the fire. At the same time though the other thing I would be concerned about it restricting the airflow too much. I would think you would need a lot more smoke stack than normal to adequately pull in a sufficient amount of heat. Hopefully someone with more experience than I can weigh in on this for you.

Quick question for you. What problem are you trying to solve with this design?

Sent from my GM1917 using Tapatalk

[sandro]

Agreed, that's gonna be very restricted in airflow. You can make up for it with a stronger pull, but that'll move your hot spot way waaay to the left and increase the jet of hot gases

[sinor81]

I'll never be the guy discouraging someone from trying something new, but my hunch is that you will just push your hotspot further to the left because it looks like you are just delaying where the hot air exits. What you may get with that design it a dramatic reduction in the line-of-sight radiant heat that your meat will get directly from the fire. At the same time though the other thing I would be concerned about it restricting the airflow too much. I would think you would need a lot more smoke stack than normal to adequately pull in a sufficient amount of heat. Hopefully someone with more experience than I can weigh in on this for you.

Quick question for you. What problem are you trying to solve with this design?

Sent from my GM1917 using Tapatalk

The smoke stack diameter is 7", and 51" tall.
My plan was to reduce the direct, radiant heat, and transfer to the grate, however, I would like the airflow to be good.

[Brewmaster]

If you completely remove the lower half-moon with the 1,18" slot in it, it'll work perfectly! No boxed-in heat is required. Honestly, it'll work better without that piece restricting airflow. Best of luck!

[sinor81]

If you completely remove the lower half-moon with the 1,18" slot in it, it'll work perfectly! No boxed-in heat is required. Honestly, it'll work better without that piece restricting airflow. Best of luck!

The top of the firebox is not be at grate level, grate is on 12,2" the top of the firebox is at 8,6", is that not a problem by airflow?
I was also thinking directing the heat upwards somehow. I looked at dacolson building, but there, the top of the firebox is at grate level, and by Franklin is also.

[Brewmaster]

I noticed your firebox is lowered a little in your drawing, which is fine but keep it to within maybe a couple inches. Plenty of builders install it a couple of inches or so below grate level, Franklin firebox is double-walled, so it's also installed below grate level.

Nothing wrong with directing the heat upwards if you want either but are you building from scratch or modifying something? Should be fairly simple to re-jig your plans to make it your own.

[sinor81]

I noticed your firebox is lowered a little in your drawing, which is fine but keep it to within maybe a couple inches. Plenty of builders install it a couple of inches or so below grate level, Franklin firebox is double-walled, so it's also installed below grate level.

Nothing wrong with directing the heat upwards if you want either but are you building from scratch or modifying something? Should be fairly simple to re-jig your plans to make it your own.

Is already built, like on the picture. I would like to modify it because I am not satisfied.
Placing the firebox higher would be more work.
I'll try it, if I modify as shown in the picture, how it works.

[ThinBlue]

Quick question for you. What problem are you trying to solve with this design?

The smoke stack diameter is 7", and 51" tall.
My plan was to reduce the direct, radiant heat, and transfer to the grate, however, I would like the airflow to be good.

The higher your throat opening is the smaller the window is for that line of sight radiant coming from your fire.

Just based off of that alone I think you would be better served to do something more traditional with your throat opening near grate level and then using an upward baffle to deflect the heat upward before hitting the grill grate.

Additionally, having the throat higher up will allow for the best possible airflow. Having it lower impedes airflow a bit because it will be fighting against nature. Having a higher throat allows you to have a smaller stack as well because it doesn't need to compensate for the restriction.

Sent from my GM1917 using Tapatalk

[sinor81]

Quick question for you. What problem are you trying to solve with this design?

The smoke stack diameter is 7", and 51" tall.
My plan was to reduce the direct, radiant heat, and transfer to the grate, however, I would like the airflow to be good.

The higher your throat opening is the smaller the window is for that line of sight radiant coming from your fire.

Just based off of that alone I think you would be better served to do something more traditional with your throat opening near grate level and then using an upward baffle to deflect the heat upward before hitting the grill grate.

Additionally, having the throat higher up will allow for the best possible airflow. Having it lower impedes airflow a bit because it will be fighting against nature. Having a higher throat allows you to have a smaller stack as well because it doesn't need to compensate for the restriction.

Sent from my GM1917 using Tapatalk

Okay, I understand, thank you.
I just removed the "heat box" and measured how high the firebox is. The top of the throat is 2,75" under the top of the grate.
I thought the distance was bigger, I remembered wrongly.

[Brewmaster]

That's pretty good firebox height placement, nothing wrong with that at all! You should almost be able to leave it as is, adding the shelf/baffle/plate above the grate, as it is in your first drawing. It's how Mill Scale and Franklin pits are setup.

How is the baffle/throat/box setup now? You mentioned you're not happy with how it's working, it'd be interesting to see what the current setup is. What are the other dimensions of the smoker? Chamber size and firebox size? Cheers

[sinor81]

That's pretty good firebox height placement, nothing wrong with that at all! You should almost be able to leave it as is, adding the shelf/baffle/plate above the grate, as it is in your first drawing. It's how Mill Scale and Franklin pits are setup.

How is the baffle/throat/box setup now? You mentioned you're not happy with how it's working, it'd be interesting to see what the current setup is. What are the other dimensions of the smoker? Chamber size and firebox size? Cheers

I just removed the "heat box", what you see on the first drawing, and I'm thinking about the next step
A - Should I put the firebox higher, grate level or, ca 1" under grate? And then add the shelf, or directing the heat upwards with the other method.
B - I don't move the firebox, and add the shelf, or try to direct the heat upwards, as you can see on the second drawing.

The dimensions are: CC - 24,41" X 52,56" FB - 23,62" X 27,48" Stack - 7" X 47,24"
I used the Pit Calculator and the Throat Calculator for Overlapping Cylindrical Tanks
Throat is little bigger than what I calculated with the TC, 7,84" X 17,75" is the calculated, on today's measurement is 9" X 18,5" For some reason I used outside measurements for the build, and that's why I came up with this number.

[sandro]

I'd follow the Millscale / Franklin design. Millscale attaches the firebox at grate level however the opening is 2" below it, as there's a 2" grease dam / lip all around the throat:

above grate level sits the baffle, measuring 22 1/2" long, 8 3/4" wide, 2 1/4" tall

[Brewmaster]

If I were you I'd just add the shelf/baffle Franklin/Millscale style and try it! Might work awesome as is with that mod. I don't think raising the firebox will make much difference, I mean we're talking about an inch or 2, it won't make a big difference, but it generally would have the effect of moving the hotspot further into the cooking grate, further away from the firebox. If that happens when you try it, the upward heat deflector idea will correct that.

[sinor81]

If I were you I'd just add the shelf/baffle Franklin/Millscale style and try it! Might work awesome as is with that mod. I don't think raising the firebox will make much difference, I mean we're talking about an inch or 2, it won't make a big difference, but it generally would have the effect of moving the hotspot further into the cooking grate, further away from the firebox. If that happens when you try it, the upward heat deflector idea will correct that.

I think so too, i don't replace the firebox first, just install a "Franklin shelf", and I will try to make a removable upward deflector, and test it with both.

What do you think of my throat opening? It's not big? It is completely open from the bottom of the cc to a height of 9" I need to install a dam? Because of the fat it is necessary in any way...so the throat size will decrease.

[Brewmaster]

Good plan!

The calculators are more the suggested minimum size for the throat, but yours isn't that much larger anyways so it's fine. That said a grease dam is a really good idea! I built one with the grease dam doubling as the upward deflector to the grate, I wouldn't be cooking in that area so there was no real need for the dam to actually be choking the throat size down. We've built and modified a few, only one had the throat sized from the calculator, and it ran the fussiest. Always easy to add a dam though. Testing is required!

[sinor81]

Good plan!

The calculators are more the suggested minimum size for the throat, but yours isn't that much larger anyways so it's fine. That said a grease dam is a really good idea! I built one with the grease dam doubling as the upward deflector to the grate, I wouldn't be cooking in that area so there was no real need for the dam to actually be choking the throat size down. We've built and modified a few, only one had the throat sized from the calculator, and it ran the fussiest. Always easy to add a dam though. Testing is required!

I'm here with the modify...lower half-moon with the slot removed, "heat box" removed, I had to cut out the back of the cc to access the box.
I left 2" from the bottom of the half-moon for the grease dam.
On the pictures, you can see where the throat is from the grate. The tape measure is in cm. About 2" from the bottom of the grate is the top of the throat. I measure and cut out the deflector plates...

[Brewmaster]

That's some great work, you nailed it! That dam is dam sexy! Super cool logo in the firebox door, you should post more pics!

It'll be interesting to see if it needs the heat directed up or not. Btw I saw mention of the stack at 7" diameter, do you use a damper on it?

[sinor81]

That's some great work, you nailed it! That dam is dam sexy! Super cool logo in the firebox door, you should post more pics!

It'll be interesting to see if it needs the heat directed up or not. Btw I saw mention of the stack at 7" diameter, do you use a damper on it?

Thanks
Yes i use damper.
I'm not a professional welder, I'm just learning.
I'll post some pictures later.
I made the baffle plates, a little welding is left.

[Brewmaster]

Well she's looking good so far, good luck getting 'er done!

[sinor81]

Well she's looking good so far, good luck getting 'er done!

Setup with "Franklin baffle"




Setup with "Upward baffle"




I just don't know when I can test it yet.

[sandro]

Man those look nice!

[sinor81]

Man those look nice!

Thanks Sandro!

[Barrion2018]

Well she's looking good so far, good luck getting 'er done!

I just don't know when I can test it yet.

Very nice!

As soon as you do have time, please post some pics of your cook.

Great job!

[Brewmaster]

That's some good looking baffle/deflector, good work!!