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Offset Tuning Plate Design Questions

 
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FullQuiver6
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Joined: 09 Aug 2010
Posts: 33

PostPosted: Tue Aug 10 10 2:13 am    Post subject: Offset Tuning Plate Design Questions Reply with quote

Hello All,

I just got a new offset smoker (Old Country 20") and have done my first seasoning/smoking run. I was very happy with the temperatures I was able to achieve and hold (I ran it at about 325 for 2 hours and then at about 225 for five hours). I do have some temperature gradient through the smoker and would like to even that out. The OC has a short baffle (about 6") over the opening into the fire box which angles down steeply into the smoking chamber. I was thinking about bolting a plate extension onto this baffle that would run into the smoking chamber. I would kike to get some advice from the gurus here as to the best design for this plate. Should I maintain the same angle as the baffle (easiest) or break an angle into the new plate so that it runs level with the cooking grate? Some other angle? What dimensions would you suggest? Full width of the smoke chamber? Full length of the smoke chamber? What material is best? Should it have holes in it or be solid? Please advise...
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k.a.m.
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Joined: 12 Dec 2007
Posts: 26018
Location: Southeast Texas.

PostPosted: Tue Aug 10 10 8:45 am    Post subject: Reply with quote

FullQuiver6, the easiest solution to your quest would be to cut some 1/4'' plate the length of your
deflector width, make the plates about 6'' wide and depending on the length of the cooker will determine
how many you need to space them for adjustable airflow. You now have tuning plates and have not drilled
into your cooker. If you decide this mod works you can add angle iron for the plates to slide on.
Here is a pic of my son-in-laws 20'' OKJoe I installed tuning plates in it along with a few other mods.

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FullQuiver6
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Joined: 09 Aug 2010
Posts: 33

PostPosted: Tue Aug 10 10 11:01 am    Post subject: Reply with quote

Thanks k.a.m. - that is pretty elegant. I like that it is adjustable and that you don't need to drill a lot of holes. What material did you use? Did you experiment with the spacing or use some pre-defined formula? You could probably use the rails to support grates for large scale direct grilling too if need be...
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PhilipWicker
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Joined: 07 Apr 2010
Posts: 172
Location: Mooresville NC

PostPosted: Wed Aug 11 10 12:51 pm    Post subject: Reply with quote

FullQuiver6, I have the exact cooker. Infact, I reached out to k.a.m. personally to get his take on tuning plates since I had some of the same concerns that you have. I followed his advice, and I have my OC dialed in perfectly. I had my steel supplier cut me four 1/4" thick 6"x 15 3/4" plates. The first plate will sit next to the baffle will set perfectly over the end of it. The first gap is around 1/4" the next gap is around 1/2" and the next gap is around 1". That leaves you with around 1 remaining inch of opening where the stack is. I didn't go as far as welding angle iron in the bottom for the plates to sit on. The 15 3/4" width is wide enough to where you can just set the plates along the bottom. Do exactly that, and you'll be in business. I love my OC. Not many folks seem to have them. I've noticed very minimal leaks around the doors so it holds heat very well. Another mod I did was making a charcoal basket, which I highly recommend. The cooker is extremely efficient I've noticed. The draw from the firebox to the stack is phenomenal. I've done about 4-6 cooks on it thus far, and I've gotten very consistent results with it. Enjoy it and if you have any questions, I may be able to answer them.
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FullQuiver6
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Joined: 09 Aug 2010
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PostPosted: Wed Aug 11 10 7:39 pm    Post subject: Reply with quote

Philip,

Thanks for that feedback - that is exactly what I needed to know. I have already contacted a local fabricator to start the charcoal basket project. I am trying to decide whether to make it deep (it can be as deep as 10" and fit in the fire box) or make it shallower. I was thinking a shallower basket (say 8") could be flipped over and used as an auxiliary fire grate to get the coals closer to the grill for doing steaks. What are the dimensions on your basket? What material did you use?

I'm glad to hear that someone else bought the OC and likes it. I had not seen any feedback on it positive or negative. After reviewing all the mods people did here (and elsewhere) and researching offset features and prices, it looked like the best combination of baseline features and price I could get. As a bonus I got it during the Louisiana tax holiday and the store knocked off 10% due to a scuff in the finish (saved me about $80)
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k.a.m.
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Joined: 12 Dec 2007
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PostPosted: Wed Aug 11 10 7:51 pm    Post subject: Reply with quote

FullQuiver6, as PhilipWicker mentioned I used 1/4'' plate for the plates. and spacing will vary on your cooker and your needs. The plates can be shifted to allow for warmer spots or even cooks.
Here is a link to the mods I did to my son-in-laws. It is a 20'' model but I think they will work on any of them.
http://thesmokering.com/forum/viewtopic.php?t=31210
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FullQuiver6
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Joined: 09 Aug 2010
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PostPosted: Wed Aug 11 10 8:12 pm    Post subject: Reply with quote

Thanks k.a.m. - I will add the plates to my fabrication order today. Unfortunately, I am not gifted in the ways of the welder and the air chisel...
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FQ6 - Husband to one - Dad to six (19,16,12,8,8,Cool

Time flies like an arrow; fruit flies like a banana (Groucho Marx)
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PhilipWicker
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Joined: 07 Apr 2010
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Location: Mooresville NC

PostPosted: Wed Aug 11 10 8:46 pm    Post subject: Reply with quote

FullQuiver6,

Here is a link that will show you my basket that I made:

http://thesmokering.com/forum/viewtopic.php?t=40943&highlight=basket

I used angle iron and 3/4 #9 expanded metal. The dimensions are 12x12x8. I used a mig welder, and as you mentioned, you are no welder. I borrowed one from a friend, and with very little experience behind the wheel of a welder, I didn't do half bad however, the ole angle grinder had to step in and clean some of my beads up. Otherwise, print out a picture of my basket and find a local person that can throw one together for you.
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FullQuiver6
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Joined: 09 Aug 2010
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PostPosted: Thu Aug 12 10 6:52 am    Post subject: Reply with quote

Thanks guys - I really appreciate the ideas. I can't wait to get mine reconfigured!
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FQ6 - Husband to one - Dad to six (19,16,12,8,8,Cool

Time flies like an arrow; fruit flies like a banana (Groucho Marx)
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Camper Bob
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Joined: 18 Jul 2014
Posts: 94

PostPosted: Wed Jul 23 14 12:13 am    Post subject: Offset tuning plate Reply with quote

I have been reading a lot about tuning plates, but I haven't seen any data on the difference in temps between the fire box side and the far side of the cooking chamber. Any data out there?
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k.a.m.
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Joined: 12 Dec 2007
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PostPosted: Wed Jul 23 14 6:48 am    Post subject: Re: Offset tuning plate Reply with quote

Camper Bob wrote:
I have been reading a lot about tuning plates, but I haven't seen any data on the difference in temps between the fire box side and the far side of the cooking chamber. Any data out there?

Camper Bob, this is really all the data I need.
Taken from a cook we did earlier this year.
Here are the briskets fixing to get panned.


For those that have doubts about tuning plates.
#2 digital is the right grate next to the firebox. the other is the left opposite the firebox.

272° on my left grate and 279° on my right firebox side.
7° difference left to right in the middle of a brisket cook.
I hope this helps. Very Happy
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Camper Bob
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Joined: 18 Jul 2014
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PostPosted: Sat Jul 26 14 10:45 am    Post subject: Offset tuning plate Reply with quote

Thanks so much for your "picturesque" response. I haven't replied sooner as I realized I had a lot more to do. And this is what I have been up to. I read where my Horizon plate has some air leakage around the sides of the baffle that are against the fire box. Although the fit is pretty snug I did stuff some aluminum foil on both sides to stop any heat leakage. Additionally, I found that my smoker lid had warped a little bit and even adding some insulation tape, did not stop the outflow of air when my Rock Stoker cycled. I drilled and added some pressure clamps to hold the doors totally shut and this should that problem. However, when just checking the overall temp of the smoker with only one fire sensor placed in the middle of the grill I was able to maintain a temp difference of only one or two degrees during a three hour smoke from where I wanted the smoker to heat up to. However, I initially noticed when I had two sensors to sample the heat at each end of the grill, I did have about 30 degrees difference. So now with the sides stuffed with foil, and the clamps installed, I should be right on the money. Will smoke some sausages tomorrow with two heat sensors, one at each end of the grill to monitor the temps. Will advise.
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Camper Bob
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PostPosted: Mon Jul 28 14 10:33 pm    Post subject: Offset tuning plate Reply with quote

After taking temps at both ends, somewhat disappointed. About a 30 degree difference. Not sure how to proceed.
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SoEzzy
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Joined: 13 Oct 2006
Posts: 13183
Location: SLC, UT

PostPosted: Mon Jul 28 14 11:17 pm    Post subject: Reply with quote

Is the pit dead level? this will make a difference.

Have you tuned the gaps yet?

Which end is hotter?

If it's the firebox end that is hotter you can add another plate that sits 1" below the first diffuser plate, and close the gaps a little to push more heat further. If it's the other end, open the gaps so there is more heat near the firebox end.

It can take 4 or 5 hours of tuning to get a pit to run at smaller differences than 30°, so you have a good place to start.

Try and maintain the fire at the same level while you are tuning the plates, don't just add a load of fuel and spend time aiming for a different temperature than you were starting at.

Did you map out the front, middle and back temperatures on the left, center and right of the cooker?

Keep going with it, one change at a time, you'll get it closer, it's only a matter of time & patience!
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zilla
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Joined: 09 Jul 2005
Posts: 1190
Location: Universal City, Texas

PostPosted: Wed Jul 30 14 10:32 am    Post subject: Reply with quote

Let me start by saying that there is nothing wrong with the uneven temps in an offset BBQ pit. That is one of the inherent characteristics of this crude cooking machine. So many folks have tried to turn the offset into something it's not, a high tech wood fired oven. I have read countless threads about why the offset is inferior to other types of cookers when it comes to temps. To me these folks are missing the beauty of the offset and the different temperature zones it has.

As mentioned above, level pit the end to end, and side to side. I think this is a very important step and one that is often overlooked. I see people snicker at me while I fuss with my bullet level backing the trailer to and fro, up on leveling blocks.

Some folks strive for even temperatures throughout that pit by endless fiddling with the tuning plates, and there is nothing wrong with that journey, if you enjoy all the mechanical nerdery BBQ has to offer, but some folks don't. I did this for endless hours when I first got my pit. It really was one of the joys of BBQ newness for me. It also helped me learn how my pit really worked. However, it eventually got tiresome so I tried something else. One inch gaps all the way down.

I have discovered over the years, that just dividing the hot spot equally was enough for me. My mobile Gator has six, eight inch movable/lockable plates and a six inch diverter, each separated by a 3/4" gap front to back in a 66" horizontal cooking chamber. That's it! about 250* end to end but 280 just past the diverter. I really like a sizzle area, it's very useful to me. I also have a cooler area I can use too. I use the same scheme on my backyard Gator but with one less plate.

When folks ask me these days how to set up tuning plates I tell them to set them at even gaps, then cook. The pit will tell you what to do. Then there is the other side of this equation which is fire management/air flow, but that is another topic all together......

Enjoy the journey and don't suffer the ride. Wink
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k.a.m.
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Joined: 12 Dec 2007
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Location: Southeast Texas.

PostPosted: Wed Jul 30 14 7:10 pm    Post subject: Reply with quote

zilla wrote:
Let me start by saying that there is nothing wrong with the uneven temps in an offset BBQ pit. That is one of the inherent characteristics of this crude cooking machine. So many folks have tried to turn the offset into something it's not, a high tech wood fired oven. I have read countless threads about why the offset is inferior to other types of cookers when it comes to temps. To me these folks are missing the beauty of the offset and the different temperature zones it has.

As mentioned above, level pit the end to end, and side to side. I think this is a very important step and one that is often overlooked. I see people snicker at me while I fuss with my bullet level backing the trailer to and fro, up on leveling blocks.

Some folks strive for even temperatures throughout that pit by endless fiddling with the tuning plates, and there is nothing wrong with that journey, if you enjoy all the mechanical nerdery BBQ has to offer, but some folks don't. I did this for endless hours when I first got my pit. It really was one of the joys of BBQ newness for me. It also helped me learn how my pit really worked. However, it eventually got tiresome so I tried something else. One inch gaps all the way down.

I have discovered over the years, that just dividing the hot spot equally was enough for me. My mobile Gator has six, eight inch movable/lockable plates and a six inch diverter, each separated by a 3/4" gap front to back in a 66" horizontal cooking chamber. That's it! about 250* end to end but 280 just past the diverter. I really like a sizzle area, it's very useful to me. I also have a cooler area I can use too. I use the same scheme on my backyard Gator but with one less plate.

When folks ask me these days how to set up tuning plates I tell them to set them at even gaps, then cook. The pit will tell you what to do. Then there is the other side of this equation which is fire management/air flow, but that is another topic all together......

Enjoy the journey and don't suffer the ride. Wink

I agree zilla, there is nothing wrong with uneven temps. in a cooker. As you said you have found what works best for you in your gators just as I have found where my plate placement needs to be, I never change the plate placement in my cooker.
As you know and I have said many times no two cookers operate the same, find out where your plates need to be and be happy.
There are times when the weather dictates how the cooker is operating, if I need lesser intake my temps may very as much as 30° I never worry about that I simply make adjustment of meat placement rather than plate adjustment. I learned long ago that I am cooking for enjoyment, I do not to let things like varying grate temps frustrate me I simply assess the situation, if I can easily tweak something it is done, if not I carry on. Very Happy

It is good to see you posting some my Friend, your knowledge is always a welcome sight. Very Happy
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Camper Bob
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Joined: 18 Jul 2014
Posts: 94

PostPosted: Wed Jul 30 14 8:26 pm    Post subject: Tuning Plate Reply with quote

Thanks for the great advice. I will get over trying to equalize the temps over the surface of the grill. The heat plate from Horizon is doing what it does and now I won't continue to angst over the temp variations, I am going to try a pork butt when we return from camping. We are participating in a block party welcoming and meeting some new neighbors. Should you read of a mass sickness in the Portland area, you could possibly attribute it to me. In all seriousness, again thanks for putting me at ease. I did also chat with the Horizon people and they mentioned a 40 degree difference from one side of the grill to the other was pretty normal with their plate installed. When the sun, moon and stars are in alignment a possible 25 degree difference is possible. I mentioned to them that I was possibly going to do a packer brisket later in the summer. They suggested turning the brisket end to end halfway through the smoke and all would be well. Sounds like great advice. I have been looking at your pit construction posts and I'm in awe at your talents in welding as well as your design prowess. I found the posts to be amazing and inspiring. Wow. Again thanks and will tell you how my sausage making class goes later in the summer. Safe Travels.
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