Build question

Diesel Dave

Diesel Dave

Quintessential Chatty Farker
Joined
Aug 23, 2013
Messages
6,434
Reaction score
28,009
Points
0
Age
54
Location
In the woods
I have read a lot of the builds here.
My son and I are building a smoker/grill out of a 60 gal air compressor tank.
I found the calculator and figured out most of the details.

One question I have is why would the vent stack need to be so tall for a narrower diameter?

It says if I go with a single 4" pipe it'll need to be about 18" tall, if I remember correctly.
If I go with a 6" it only needs to be 8" tall or so......if I remember right......

The other question is.............would 1/2" of rock wool insulation sammiched in between steel, 1/8" outside and 1/4" inside, be ok for the fire box?

This is my first build and I'd like to get it right, or as close as possible.

Thanks for any and all help.

Dave
 
Welcome to the forum. As I understand it draft is controlled by the volume of the exhaust stack therefore larger diameter can be shorter, but 8 inches sounds kind of short. Also, most calculators assume you are measuting from the top of the cook chamber, if you either begin your exaust at the center of the chamber or extend it down to the cooking grate level, you will need to add that length. Most insulated fireboxes use 1"-2" of insulation. I think 1/4" inside and 1/8" outside will work fine. You might also want to consider lining the bottom of your firebox with 1/2 split firebricks and adjust your firebox dimensions accordingly. I think they are 1-1/4" thick and you can get them from Northern Tool (wood stove liners). Good luck, post some build pics.
 
Thanks a lot!
Like I said I was trying to remember the heights of the vent stack....notes aren't with me right now. So I'll adjust the fire box size to use 2" insulation on the sides and the fire bricks in the bottom. I didn't really think about the bottom, appreciate the help.
I'll start a build thread as soon as we get going a little farther than we are at this point, just have the door cut out and beginning to grind off the outside paint.
I have a 6" metal hole saw around here somewhere.....best go dig it out for the larger stack.
Would it be better to extend the stack down to at or near the cooking grate?

Really appreciate the help.

Dave
 
dwfisk said:
Welcome to the forum. As I understand it draft is controlled by the volume of the exhaust stack therefore larger diameter can be shorter, but 8 inches sounds kind of short. Also, most calculators assume you are measuting from the top of the cook chamber, if you either begin your exaust at the center of the chamber or extend it down to the cooking grate level, you will need to add that length. Most insulated fireboxes use 1"-2" of insulation. I think 1/4" inside and 1/8" outside will work fine. You might also want to consider lining the bottom of your firebox with 1/2 split firebricks and adjust your firebox dimensions accordingly. I think they are 1-1/4" thick and you can get them from Northern Tool (wood stove liners). Good luck, post some build pics.
Click to expand...


Welcome to the forum as well.......

I agree with DWFISK..... Calculate and consider all thicknesses and adjust for them in your dimensions.
 
"Would it be better to extend the stack down to at or near the cooking grate?"
Others will chime in I'm sure but for what it is worth I did when I built mine and I like the way it cooks. One thing you might want to consider: do a little research on reverse flow (RF) builds. A60 gallon might be a tad small for a RF but cooking on RF stickburber sure makes for some great Q.
 
well I'll wait to hear others opinions on the stack, but it sounds like to the cooking surface is the way to go.
I've looked at the RF builds and may do that on my next bigger build.
We are doing this one as a trial run so to speak. I have access to large propane tanks for our next build.
Also thinking about adding a small warming cabinet to this one, but we'll see how that goes.
And thinking about using fire bricks all the way around the box for insulation

Thanks again

Dave
 
You can always error on the side of making your stack taller than the calculator recommends, ours calculated out at 33"(for a 6"), we ended up going 44" with the idea that we could always cut it down if needed, glad we did go longer because it cooks/drafts awesome.
 
DownHomeQue I plan on using wood, are you referimg to a RF?
Your build is an inspiration!

Columbia1 thanks! I'll go 6" higher than the calculator recomends. I really appreciate the help

Dave
 
You must log in or register to reply here.

Similar threads

F
Reverse Flow Smoker Question
Replies
2
Views
270
seattlepitboss
S
K
Neese’s Sausage, part 2
Replies
2
Views
785
1MoreFord
1MoreFord
S
outdoor kitchens
Replies
15
Views
678
Headgear
Headgear
L
chips and splinters
Replies
4
Views
781
Smoked&Baked
S
J
can 2 turkeys fit rotisserie...
Replies
6
Views
620
cholloway
cholloway
Back
Top