Cinderblock smokehouse, now with reverse flow

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Sleebus
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Cinderblock smokehouse, now with reverse flow

Post by Sleebus » Fri May 05, 2017 01:40

Y'all may remember the cinderblock pit I built a week or so ago in another thread

Well. I'm back with a new and improved version! Some quibbles with the last one:
  • Firebox is too small, requiring frequent tending
  • Small size makes it hard to load...gotta get down on your hands and knees
  • Larger firebox means the inlet has to move up, which will lead to...
  • The pit getting a fair bit hotter where the firebox inlet is
  • Inlet to the pit is oversized for the firebox per a BBQ pit calc page
So. We all know the solution to this: A bigger firebox and Reverse flow! But how do you do it? Well, it's actually pretty easy.

I had to tear the whole pit down, because I had to change the first course. Originally, I had the fire entrance to the pit on the first course. I want it now on the second, so to keep the proper stagger, I had to reset all the blocks. This is why no mortar is good!

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Now you can see the inlet placement with the second course

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I upgraded to 3/8" rebar for supporting the plate. This is where the reverse flow plate will sit.

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Required more aggressive cutting with the masonry blade to get the rebar to fit.

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Ok, reverse flow plate is in place, now to cut slots for the rebar to support the grate.

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There we go. So, you can see the reverse flow plate and the grate here. Slot is about 4" or so at the other end. The area of the slot matches the area of the inlet to the pit from the firebox. With the bigger firebox, now the inlet to the pit is the right ratio so it draws properly.

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Another view of the slot

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Oh yes, sweet, sweet room to make a decent fire.

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All back together. I need to trim the steel plate I'm using to control the inlet air. Looks like I'm gonna need to get handy and learn how to use a torch.

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So today, I didn't do any cooking. I just took it up to 400° to season the reverse flow plate...I had wiped it down with lacquer thinner to remove any stray hydrocarbons and then coated in peanut oil to season. The temp management seemed much more well behaved. The previous version would really swing pretty hard when you added a split.

Future improvements might be a stack with a damper, but what I've got now works pretty well.
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Butterbean
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Post by Butterbean » Fri May 05, 2017 02:41

I love reverse flow. That's the only way I will do BBQ.
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