1st build from compressor tank questions

Tjam9 · Post by **Tjam9** » January 4th, 2017, 10:05 pm

Hi there, I am new to this forum and to building a smoker. I am interested in building a smoker similar to the one pictured. I have a 30 gallon compressor for the cc and about 20 gallon compressor for the FB. Based on the pit size calculator my fb is too big.

Is it necessary to cut the size down or does the calculator adjust for the tank size by adding a bigger chimney length and air intake size?

Based upon the picture I attached would the total length of the chimney include the chimney between the 2 tanks or only what is above the cc? And if it would include the chimneys between the tanks do I add the length of both of those to the length of the chimney that is above the cc?

Also if it says the air intake needs to be 16 in² then a 4x4 square hole should work correct?

What does throats size mean? Any other recommendations? My calculation is below.

Volume Volume (in³)
Cook Chamber Size 30 gal. 6,930.00 in³

Firebox Size 14 in. 35 in.
Actual Volume (in³) Recomended Volume (in³)
5,387.83 in³ 2,310.00 in³
% of recommended size. 233.24%

Chimney Size 4 in.
Rec. Chimney volume 269.391570045 in³
Rec. Chimney Length 21.4483734113 in.

Length Width Intake Area (in²) Count
Air Intake 4 in. 4 in. 16.16 in² 1.01

Throat Area (in²)
Throat Size 43.1026512073 in.

Tjam9 · Post by **Tjam9** » January 4th, 2017, 10:12 pm

What I have so far.

Post by **Big T** » January 4th, 2017, 10:46 pm

Welcome to the forum. The pit calculator is designed for offset pits more so than verticals. I'm not sure how well the above design will cook evenly the way it's set up. I would recommend something similar to what FM built a while back, they were pretty sweet little cookers. Here's a link to his build viewtopic.php?f=17&t=3836

Tjam9 · Post by **Tjam9** » January 4th, 2017, 10:51 pm

Thanks Big T. What if I put a baffle similar to what FM did, do you think that could help cook more even?

Post by **Big T** » January 4th, 2017, 11:08 pm

It's hard to say but it's harder to get the same amount of heat out of 2 different tubes than 1 tube. It's a nice looking smoker but I'd go with one that cooks good over one that looks good seeing as the amount of work that goes into building them.

Post by **Tom_Heath** » January 4th, 2017, 11:30 pm

If I was given the job to make this cooker run even,,,,,,,

I would have to try using a piece of 4 inch and bridge the two uprights on the inside of the firebox. I would open a six inch wide gap in the center and install a center divider. In theory this would take heated air from a center point in the fire box and channel it into two different uprights to the cc.

Not sure if that would even work, but I would try it.

Or build ur fire accordingly to one side of the FB and cook hot and fast on one side and low on the other side.

Just my 2 cents. I don't often have ideas but when I do , they are good ones.

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Tjam9 · Post by **Tjam9** » January 5th, 2017, 12:12 am

I'm not completely following Tom. When you say bridge are you talking about connecting the two into one inside the fb with 4" square tubing? Any chance you would have a picture of what you mean. Sounds like a great idea to channel into the center. Thanks for the help.

Tjam9 · Post by **Tjam9** » January 6th, 2017, 12:58 am

Would this work if I just used one tube from the FB to the cc? Or if I did the same design and didn't cut the hole for the second tube (use it as structural support only) and maybe do a reverse flow design in the firebox? Thanks.

Tjam9 · Post by **Tjam9** » January 6th, 2017, 1:03 am

Or maybe even a baffle similar to this?

Post by **Rodcrafter** » January 6th, 2017, 7:30 am

Yes, and yes. I mean using just one opening for the throat (air movement) into the CC. Then the second as a support will work. I would shorten the tubes to as short as I could still weld around. Then use the BP you suggested above the throat. Should work fine.

Making memories!

Tjam9 · Post by **Tjam9** » January 6th, 2017, 3:26 pm

Thank you for the reply. Much appreciated. I'll give this a shot and see how it works.

Post by **Tom_Heath** » January 6th, 2017, 5:30 pm

Yes I meant connect both pipes and make one feed hole at the firebox. And yes to using one for support and one for draft

And yes using one only in center and use a diverter plate like shown above.

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Post by **Big T** » January 6th, 2017, 7:45 pm

So Tom basically you are saying yes ?

Post by **Tom_Heath** » January 7th, 2017, 7:36 am

Why yes, yes I am.

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Tjam9 · Post by **Tjam9** » January 7th, 2017, 1:53 pm

Haha. Thanks guys. I have so many options now. Amazing!

Tjam9 · Post by **Tjam9** » January 7th, 2017, 3:10 pm

Big T said, "The pit calculator is designed for offset pits more so than verticals." Does that mean I don't need to worry about the throat size, chimney length or FB size on this type of design or should I still try to use that calculation?.

Also I am thinking about either doing what we discussed above, using one 4" tube to feed the cc and the other as a support and then using the baffle (pictured above open on both ends) with the chimney in the center of the cc.

The second option I am thinking about doing is that same thing (one 4" tube feeding and one supporting) but instead of having the baffle open on both sides, only having the baffle open on one side and moving the chimney to the same side as the 4" feed tube so that this would be a reverse flow.

Any opinions on which way you think would work best. I'm excited to give this a try and post pics and let everybody know how it works. Thanks

mp4 · Post by **mp4** » January 7th, 2017, 3:53 pm

I like the center chimney myself. You may want to think about making the BP gap smaller on the left side than the right to balance out the flow as much as possible.

Post by **Rodcrafter** » January 7th, 2017, 6:18 pm

Yeah what MP4 said.

You know I believe if you don't shorten the length of the tubes the 4" tube will not have enough flow. You may have to burn a really hot fire to get the temperature you want. I guess I thought you were using 6" square tube.

Making memories!

Tjam9 · Post by **Tjam9** » January 7th, 2017, 6:30 pm

Thanks guys. That's a good idea to make the left side smaller on the BP.

Post by **Big T** » January 7th, 2017, 9:56 pm

Check out this build from a while back. It's the same style that you're shooting for with a little different design.viewtopic.php?f=11&t=3101

Tjam9 · Post by **Tjam9** » January 7th, 2017, 10:24 pm

Thanks Big T. That's an awesome build. That helps out a lot.

Tjam9 · Post by **Tjam9** » January 10th, 2017, 10:10 pm

Officially started the build. Door cut and hinges on. I leveled the smoker left to right and then I used a center head to find dead center at 12 o clock position. I added 2" toward the back of the smoker and made my top cut.

This video shows what I mean: https://youtu.be/mgTZO_pYFLU

I then used a center head to find dead center of the 9 o clock position and this was my bottom cut. I welded my hinges on the top before I finished my cuts so everything would line up perfect and It wouldn't warp. Worked out good so far.

One question I have is, when I do my burn after I finish the build will all the rust and oil cook off from inside the tank or should I clean that with something?

Post by **Big T** » January 10th, 2017, 11:09 pm

I would burn it out now and use a wire wheel to clean it up. You'll still have to clean it up a little bit when you're done but it won't be near as hard.

Post by **Rodcrafter** » January 11th, 2017, 9:25 am

Yeah what he said

Making memories!

Tjam9 · Post by **Tjam9** » January 11th, 2017, 10:26 am

Ok will do. Thanks guys.

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