Cinder Block (CMU) Offset Smoker

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Introduction: Cinder Block (CMU) Offset Smoker

For a small fraction the price of a heavy steel smoker, you can setup a large capacity cinder block version. Not only will it be cheaper it will be better insulated. Follow the instructions attached for a very effective, efficient and not bad looking unit.

Step 1: Design & Dimension

Review design dimensions.

Step 2: Clear Area

  1. Clear appropriate sized area with offsets as needed.
  2. Soften and level dirt or ad layer of sand.

Step 3: Procure Cinder Blocks & Bricks

  • Cinder Block: 8x8x16 (Qty. 60)
  • Cinder Block (1/2): 8x8x8 (Qty. 15)
  • Cinder Block (Caps): 8x2x16 (Qty. 16)
  • Clay Brick: 4.5x9x1.75 (Qty. 24)

Step 4: Base Layers

  1. Place base layer of cinder blocks and use level to confirm flatness.
  2. Alternate seem on each level.
  3. Eliminate all air gaps.

Step 5: Complete Firebox

  1. Build firebox with rotated CMU bricks for air inlet and outlet as shown.

Step 6: Complete Chimney Structure

  1. With a chisel, break a 1/2 brick into half again so that the chimney has an opening as shown in picture.
  2. Stack chimney to 3 blocks high for appropriate air draw.

Step 7: Add Top Caps

  1. Place top caps on alternating seems from cinder blocks underneath. (Top caps will ad a flat surface for lids to seal better)

Step 8: Lid Construction

Lid Dimensions: 30.5" x 38" (Qty. 2)

  1. Cut plywood to dimensions.
  2. Procure Heat Shield Insulation (4 ft x 6 ft) and cut to same dimension as plywood.
  3. Using a staple gun, apply insulation to bottom side of wood.
  4. Fasten two lid pieces with hinges in middle and and handles.

Step 9: Add Clay Bricks

  1. Line the inner firebox with clay bricks for extra heat protection for the concrete blocks.

Step 10: Rebar Grate Support

  1. Measure off alignment for rebar supports. (3 places)
  2. Using a 1/2 inch concrete drill bit, drill holes through only one side of blocks.
  3. Insert 25" long, 3/8" rebar.
  4. Procure or cut, 3/4" X 13 ga. flattened expanded metal sheet to 22" x 53"
  5. Place expanded metal on top of rebar for a cook grate.

Step 11: Fire Box Lid

  1. Procure 29" x 31", 3/16" thick carbon steel plate.
  2. Drill and bolt in handles for easier removal (not shown)

3/16 steel plate is necessary for firebox as temperature here will be too extreme for thinner materials

Step 12: How to Use

Now you're ready to test it out!

  • Use a left over block as a damper for your incoming fire vent. Slide back and forth to adjust heat.
  • Leave stack vent open at all times.
  • Add another expanded metal grate over the fire-pit if you would like the option to grill over the fire. (Good for tri-tip and chicken)

(This specific pit has about a 20 degree difference from one side to the other....which is actually very impressive.)

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9 People Made This Project!

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36 Discussions

0
mikelandrum
mikelandrum

Question 2 days ago on Step 11

I am having a hard time finding the clay bricks in these dimensions. Any suggestions.

0
Haus2005
Haus2005

4 months ago

I have been wanting to do this for a long time. Im just gonna have to figure out the math and scale this back a little. Definitely dont need one this big.
This is fantastic though!! Great work!!

0
stephen.dobek
stephen.dobek

5 months ago

What insulation should I look for? I wasn’t sure I was finding the right thing at Home Depot. Hard to tell if something is food safe or not.

0
rathomas80
rathomas80

Reply 5 months ago

I think he said clay bricks to help with insulation. unless you were talking about the insulation on the lid. I'm about to start mine how long did it take you to create your brick smoker?

0
Rhk0862
Rhk0862

Question 5 months ago on Step 8

Hi I am almost finished with my smoker build. I am curious can I use any kind of insulating heat shield? Are there concerns that material like this might contaminate the food? Where would be the best place to get the material from Home Depot/Lowes or Auto parts store?

Rick

0
amkucera
amkucera

Question 6 months ago

Hey love your build. Building it this weekend. One question, where can pick up the thermometer you used? I looked all over Amazon and didn't see it. Thanks!!

0
jason_5hundy
jason_5hundy

Answer 6 months ago

It won't let me post the link on here, but look under "Remote Reading Panel-Mount Thermometers".

0
amkucera
amkucera

Reply 6 months ago

Great! Thanks for the info. Much appreciated! Do you find they work well/accurate?

0
jason_5hundy
jason_5hundy

Answer 6 months ago

I bought it on Mcmaster-Carr a while ago.

0
licenseless
licenseless

3 years ago

I might have missed it... But what is the overall cost of this? Considering how much of a surface area this gives and how much room it takes up... If the cost is low this could be something everyone should do.

0
elnino2783
elnino2783

Reply 3 years ago

Craigslist is an excellent resource for cheap cinder blocks. Some people give them away for free even.

0
licenseless
licenseless

Reply 2 years ago

hahahah I didnt even think of that. hahahah Great build

1
jason_5hundy
jason_5hundy

Reply 3 years ago

It can definitely be done for cheaper if you have better resources and do a little more shopping around. But it cost me right around $330 total. The blocks themselves cost about $125. Having the expanded metal and steel plate lid cut to size were a large part of the expenses as well.

0
davidapfeiffer
davidapfeiffer

3 years ago

F.Y.I. ... you need to "season" any exposed cinderblocks; i.e. do several pre-burns to coat and seal their surfaces, BECAUSE the cinderblock material is toxic, and you don't want THAT on your meat. Just sayin' ...

0
DanielR421
DanielR421

3 years ago

Question: Are you burning the wood directly on the ground in the firebox?

Would there be any benefit to raising the fire up using a heavy grate or a rebar mesh in order to allow the ash to fall below?

Also, how do you dispose of the ash accumulation? Through the vent hole seems labor intensive in addition to digging out your sand with it?

0
jason_5hundy
jason_5hundy

Reply 3 years ago

I'm burning wood directly on the ground. I start with a bed of hot charcoal and ad the splits on top. I've found no need for grates as the fire burns nice and even.

I just use a an ash shovel to scoop out from the top (with the lid firebox lid removed). Takes about 5 minutes if that. It's hard packed dirt underneath. No problems at all.

0
Robert DiffinS
Robert DiffinS

3 years ago

A great tutorial! I'm going to drill a couple more heights for rebar holes so I can try that "whole pig" thing.

0
CaptainNemo
CaptainNemo

3 years ago

Now you just have to add a pizza oven on the end with a additional fire box and you have it all. :-)

0
terry954
terry954

3 years ago

Good day, very cool. My son and I are making plans to do this while my wife is on vacation with her sisters. No need to explain why this is the preferred time is there!