Featured New Oklahoma Joe Highland - Reverse Conversion, Input needed

[PhilHum]

Hi there,

I've been reading through all the great info on this forum for a while, but this is my first time posting.

I'm based out in Switzerland, and so getting hold of decent BBQs is challenging. Anyway I just managed to find and picked up a new OKJ Highland.
I really wanted the reverse, but they only export this one model. So i'll be doing a reverse conversion.

It's stock as of now, but for the mods i've planned to;

- Complete FB seal welds
- FB to CC weld inside and out.
- Move to stack to the right hand, back side of the CC at grate level.
- Install latches on CC and FB (got a pack of 6, so I can be creative).
- FB and CC door seals
- Weld a plate at the top of the FB/CC entry to reduce the fire inlet size
- Build a baffle plate; straight not angled, which will sit against the FB/CC plate.
- Drain tap on the left side bottom of the CC for ease of cleaning.

It's difficult to get the mods over here (shipping from the US is painfully expensive due to weight). So the baffle etc. i'll have fabricated.
Here are my question, especially for the baffle and FB.

I see a few people have reduced the FB/CC inlet size (welded a plate over the top) and have the used a straight baffle (instead of angles to cover the original FB top).
Like below, but I don' think i'd go as low as this, and maybe just cover the top 1/3.



I guess this gets the fire under the baffle without the need for an angled plate on the baffle (and i think it looks clean).

I've seen some baffles on here which are about 30" x 16 1/2". Does that sound about right?
I intended to build it with lips around too, bit like this from xxsmokedoutxx



My idea was that, I'd use the baffle to catch most of the cooking fat etc. then take it out to clean occasionally.

I'd be interested if anyone has any photos of the baffle sitting in the CC, and how it sits against the FB entry.
I'll probably use 1/8" as I can get that here (thicker is difficult to find and expensive). I'd maybe like to go thicker, but is there much advantage in doing so?

Not sure whether to just lay in the baffle, hoping that the weight will sufficiently seal it on the sides, or drop in some rails for it to sit on for a better seal all round (this would be on the sides, and on the FB weld plate if i did this).
FB heat seal here, concerns me somewhat, but maybe i can extend the plate into the CC, so there's a seal below the baffle.

I've seen some great (although a little older) threads from totallybasted and xxsmokedoutxx but if anyone can help me with some input, feedback etc. especially on the baffle and FB plate, that would be great!

Thanks in advance!

 

[kilo charlie]

Welcome to SMF!

The "experts" should be along soon to assist you!

 

[PhilHum]

Welcome to SMF!

The "experts" should be along soon to assist you!

Many thanks Charlie, appreciate it.

 

[JLeonard]

Welcome from Mississippi! Look forward to your posts.

Jim

 

[PhilHum]

Welcome from Mississippi! Look forward to your posts.

Jim

Many thanks Jim!

I've wanted to do this project for a while now, and i'm looking forward to it.
I'll be posting updates as a proceed.

 

[civilsmoker]

My suggestion is to think about it the mods as "I'm building a RF" rather than "converting a OS". The first thing to do is go through the RF tutorial and calculate the opening size needed for the CC from the FB. This will tell you were the RF plate should sit in the chamber as well as how much opening to seal off with the plate as shown in your picture. I have attached my Copper Pot build because there are lots of pictures of the FB to CC and the RF Plate and how they fit together. Just ignore the vertical camber and such. But this will give you an "image" to see how the plate and FB should fit.

https://www.smokingmeatforums.com/t...-and-others-ready-to-use-rev5-6-19-15.172425/

Secondly I would consider doubling up the 1/8" plate thickness of the RF plate to equal 1/4, just make sure its tight and no air gap. The RF plate thickness is important to the radiant heat and consistency. Once cut it should fit pretty snug but its ok to have a slight gap because it will help with welding it round so its water and air tight.

Good luck and post pics as you go.

https://www.smokingmeatforums.com/t...h-vertical-cabinet-aka-the-copper-pot.268790/

 

[PhilHum]

My suggestion is to think about it the mods as "I'm building a RF" rather than "converting a OS". The first thing to do is go through the RF tutorial and calculate the opening size needed for the CC from the FB. This will tell you were the RF plate should sit in the chamber as well as how much opening to seal off with the plate as shown in your picture. I have attached my Copper Pot build because there are lots of pictures of the FB to CC and the RF Plate and how they fit together. Just ignore the vertical camber and such. But this will give you an "image" to see how the plate and FB should fit.

https://www.smokingmeatforums.com/t...-and-others-ready-to-use-rev5-6-19-15.172425/

Secondly I would consider doubling up the 1/8" plate thickness of the RF plate to equal 1/4, just make sure its tight and no air gap. The RF plate thickness is important to the radiant heat and consistency. Once cut it should fit pretty snug but its ok to have a slight gap because it will help with welding it round so its water and air tight.

Good luck and post pics as you go.

https://www.smokingmeatforums.com/t...h-vertical-cabinet-aka-the-copper-pot.268790/

Thanks so much Civil, appreciate all the great info and insight. Lot's to read through.

And what a fantastic build, your copper pot!

 

[PhilHum]

My suggestion is to think about it the mods as "I'm building a RF" rather than "converting a OS". The first thing to do is go through the RF tutorial and calculate the opening size needed for the CC from the FB. This will tell you were the RF plate should sit in the chamber as well as how much opening to seal off with the plate as shown in your picture. I have attached my Copper Pot build because there are lots of pictures of the FB to CC and the RF Plate and how they fit together. Just ignore the vertical camber and such. But this will give you an "image" to see how the plate and FB should fit.

https://www.smokingmeatforums.com/t...-and-others-ready-to-use-rev5-6-19-15.172425/

Secondly I would consider doubling up the 1/8" plate thickness of the RF plate to equal 1/4, just make sure its tight and no air gap. The RF plate thickness is important to the radiant heat and consistency. Once cut it should fit pretty snug but its ok to have a slight gap because it will help with welding it round so its water and air tight.

Good luck and post pics as you go.

https://www.smokingmeatforums.com/t...h-vertical-cabinet-aka-the-copper-pot.268790/

Would 1/2" be overkill? I can maybe get my hands on some.

 

[civilsmoker]

I/2 would be just fine for blocking the fire box but I think it would/may be too thick for the RF plate. 1/4” is ideal. I have 3/8 in the copper pot and wouldn’t want any thicker cause that is a lot of mass to get hot and keep hot. As an FYI the copper pot runs cooler at the lower grate because the mass of the RF plate. But once heated it is very stable.

I would personally opt for double 1/8 over 1/2. 1/2 is not easy to work with!

 

[PhilHum]

Hi there,

So we've had days of rain here in Europe... My OKJ has two covers on it, but still it's getting wet. So i've been a bit delayed with the measurements and calcs.

But today I ventured out, measured all the dimensions and entered them into the calculator, here's the results OKJ Calcs

Couple of comments, I struggled with the FB input calculations, due to the weird, irregular shape of the input. So guestimated the size at 3.3".
If anyone has a more accurate number, that would be great.

Chimney is definitely too small, but I guessed that already

Importantly, I got the FB Opening size, as it looks like the current opening is way too big, and needs reducing.
Here's the results below;

Here if someone can give me their FB opening dimensions, that would help me, so I know how much to leave open.

I think the baffle calcs from before seem to work, with the overall smoker dimensions.

 

[PhilHum]

So I looked at the area of 28.25" for the opening area.

The opening width is currently 9.45" and 5.8" height.

If I stay with 9.45" width and go to 3" height this will give me an area of 28.35". Most people seem to plate the top of the opening when reducing.

Or maybe I'll add small plate left and right and go slightly bigger in height to eliminate the irregular angles (slightly rounded) from the sides.

 

[PhilHum]

So I looked at the area of 28.25" for the opening area.

The opening width is currently 9.45" and 5.8" height.

If I stay with 9.45" width and go to 3" height this will give me an area of 28.35". Most people seem to plate the top of the opening when reducing.

Or maybe I'll add small plate left and right and go slightly bigger in height to eliminate the irregular angles (slightly rounded) from the sides.

On the calculation I posted before, if one of you smoker expert could take a look through I'd appreciate it, before the cutting and welding starts. Thanks.

 

[civilsmoker]

On the calculation I posted before, if one of you smoker expert could take a look through I'd appreciate it, before the cutting and welding starts. Thanks.

Can you take a pic of the inside to show the current shape of the opening? That will help with answering your question.....just off the cuff the the distance you state above seems a bit small but I need a pic to visualize the question...

 

[Brokenhandle]

Welcome from Iowa! Looking forward to seeing your build! And civilsmoker has ya covered... gotta love his copper pot and the awesome fire pics that go with it!

Ryan

 

[PhilHum]

Welcome from Iowa! Looking forward to seeing your build! And civilsmoker has ya covered... gotta love his copper pot and the awesome fire pics that go with it!

Ryan

Thank so much Ryan!

Great to be here, and I think you're right, Civil has been extremely helpful, and so it seems i'm in good hands!

 

[PhilHum]

Can you take a pic of the inside to show the current shape of the opening? That will help with answering your question.....just off the cuff the the distance you state above seems a bit small but I need a pic to visualize the question...

Hi Civil,

Thanks so much.

Here are some pics I took today (weather is still good luckily).

Excuse the dirt, garden is having a make-over.

Here's the weird shaped FB intake.
Dimensions - 2.5" top, 10.5" bottom, width 7.5" on the sides. Vertical height (mid point) 8.5"

FB to CC input, also an unusual shape.
Dimensions - 9.45" width (widest point) x 5.8" height.

Ignore the foil in the CC, just using it as temp grease trap.

Thanks again for your help!

 

[civilsmoker]

Ok, that is an odd shape for sure and due to the geometry of the FB to CC and such there will be losses over the "normal" build. Therefore I would increase the calculated area of the opening by at least 30%.....However, as an engineer, reversing into it.....this is what I would do (see the pic below)....It won't hurt to have "extra" opening and in this case will actually help overcome the losses. I would also up size the stack. I would also go with a 4" ID pipe 36 - 38 inches above.

I also wouldn't have an issue with 3/16" plate either...... Honestly a welding blanket over the CC if there is wind or extra cold will compensate for a lot as well. Hopefully this gives you some ideas.............

 

[civilsmoker]

PS...Your view from the garden is AWESOME!!!!!!

 

[PhilHum]

Ok, that is an odd shape for sure and due to the geometry of the FB to CC and such there will be losses over the "normal" build. Therefore I would increase the calculated area of the opening by at least 30%.....However, as an engineer, reversing into it.....this is what I would do (see the pic below)....It won't hurt to have "extra" opening and in this case will actually help overcome the losses. I would also up size the stack. I would also go with a 4" ID pipe 36 - 38 inches above.
View attachment 504930
I also wouldn't have an issue with 3/16" plate either...... Honestly a welding blanket over the CC if there is wind or extra cold will compensate for a lot as well. Hopefully this gives you some ideas.............

Thanks so much for the help! It's really appreciated.

So just to recap.

- Blanking plate on the top of the FB to CC input, then if flow restricted potentially opening further to the sides as required. If I add 30% to the volume (28.35" vol from the calculator, plus 30% = 36.86"), it would mean that the plate should be max 2" from the top of the opening . (9.45" x 3.9" = 36.86 volume. 5,8" height - 3.9" = 1,9"). I guess there's going to be a little more flow than the calculations show, due to the the added volume from the rounded edges.
- 2nd FB inlet, i'll look into this, thanks. Any idea roughly on size? I guess the input is variable anyway, so not such major consideration.
- Seem I can get a 4" stack here locally, although not the thickest, 1.5mm (18 gauge). Although I've read that the chimney thickness is less of a critical factor, hope this is correct.

On the losses, I hear you on the welding blanked. I'm also going to have everything welded and sealed. FB to CC, FB seams inside and out and anything else i can find which makes sense.

 

[civilsmoker]

Just a friendly "nudge" not to get hung up on the calculations too much.....they are based on lager smokers and smaller smokers like yours (and the copper pot) require increases to make them work good. Therefore they are a nice place to start but that's when you need to adjust to fit the particular geometry. IE if setting the plate 2.5 inches below the existing food plate left the entire opening then I wouldn't have an issue at all with that. The geometry of your FB has a "flow dam" at the very top were the heat wants to go. The larger the "flow dam" the more losses....furthermore your door edge seam is also above, so a place for losses to go....So I would keep that distance to a min....If I was welding it up I would almost be temped to lower the FB and remove the flow dam and and if a a reduction of the opening is needed I would do it on the bottom side.....just more food for thought....and realize I like to fab stuff, so I have a over achieving syndrome.....

With regard to the stack......flow over thickness any day (3"x25" will not be enough). As long as the welder can not "blow" the 18 gauge that should work. I would make your top FB vent opening 2.5 - 3 inches diameter. This will allow to control your fire better during cooks. Larger doesn't matter because you can control the size with the gate. Just for example, I run my lower gate open about 1/4 in so maybe 1.5 inches of area on most cooks but my upper gate is open to about 1.5 to 2 inches of area....IE I fee the top of the fire with clean cool air....for the Copper Pot it seems to really improve the smoke quality over anything......