You might check out this guy's youtube site which has a lot of good in-depth advice on mods for an OKJ Highland.
Here's another one:
Be sure to season the inside or your new Highland before your first cook.
There have been lots of complaints from folks who say the paint peeled off their firebox after the first or second use which looks horrible and promotes rust. So I also seasoned the outside of my firebox with bacon grease before my first cook as recommended by somebody somewhere and the firebox seems to be holding up very well. I spray it with veg oil every cook or two. It still looks amazingly good after almost two years. There is a little rust on the bottom. Bonus - it gives you a great excuse to cook some bacon!
FYI: The steel thickness is 2.2 mm on the cook chamber and stack and 2.5 mm on the firebox, according to my caliper. By comparison, the steel on a Weber kettle and SnS kettle is 1.2 mm thickness. The steel on a OKJ Bronco is 2.5 mm. The steel on a Mill Scale 94 is 6.35 mm (quarter inch). And the steel on a Chud's custom offset is 9.5 mm (three-eighths inch).
My mods over the past 21 months:
- gasket tape around cook door - seals door and protects door-mounted gauge calibrations
- ash bucket for under firebox door
- charcoal basket - mine is stainless steel with no rust
- fire bricks - 3 in firebox, 3 in cook chamber - protects bottom and improves thermal density
- baffle plates custom fit for Highland - but not bolted together - for temp tuning
- water pan custom fit for Highland baffle
- welders blanket over top half of cook chamber for heat retention
- probe port rubber grommet on left side drilled with step bit
- grease bucket with liner
- four 18" stack extensions to improve draft - I got mine at advanced auto for $8 each on sale
- stack extension 18" with damper from bbqsmokermods - I wanted a damper up there
- 2nd thermometer to check right-to-left temp equilibrium at a glance
- shelf grate behind firebox to put splits when opening firebox door (see smoketrailsbbq)
- little wire basket which fits inside the handle on the left to hold SmokeX, spray bottle, etc
- little mirror to peer up through door vent opening into firebox to check flame
- ash scraper tool for firebox with exact correct geometric curve
- added half-height cinderblocks for the smoker to rest on lifts the cook chamber to hip level
- cover - same one GonnaSmoke recommends above
My mods total around $350 so far, I think. I have no leaks in the cook chamber and I have even temps right to left on the grate and on the top with no temperature spike problems.
Be advised: The stack extension pipe from bbqsmokermods is not "super heavy pipe" or "extra thick pipe" as they claim in their listing. It's actually "extra thin." That is, it is significantly less thick than your stock stack. The pipe of their stack extension measures 1.4 mm thick compared to your stock stack which is 2.2 mm thick. Interestingly, the thickness of the other extensions which I purchased from Advanced Auto which are actually tailpipe exhaust extensions are also 1.4 mm thick. Nonetheless, their listing states:
The extra thick pipe improves draft over the common exhaust pipe mod. This is because the thicker pipe retains heat better than thin wall exhuast [sic]
pipe. So the quality of this product improves its function over normal pipe. But the fact is, their pipe is not any thicker than an exhaust pipe and is actually thinner than the stock stack which makes their conclusion suspect. Nonetheless the collar of the bbq extension is very thick, almost a quarter inch, and the damper plates are about half as thick. This gives it a lot of weight and makes the extension look and "feel" industrial and very thick. It is not. Also, it does not weigh "almost 9 lbs!" as they claim, it actually weighs 6 lbs 2 oz. according to my postal scale. I mentioned these things in the 4-star review I wrote for them and they thanked me by not posting my review.
One other point about the baffle plates from bbqsmokermods - as far as its size, it is customized to fit the Highland, but you'll find that the firebox bolts get in the way and unfortunately there are no pre-drilled holes to match the placement of the baffle against the firebox bolts on the right-side bulkhead. This means the plate's right side will hit those bolts and not snug up against the bulkhead as it is designed. This means convective air and smoke will escape over that gap along the top and sail right over whatever it is you're cooking and out the stack. You could just leave it like that if you wanted, but that's not best. You could also drill oversized holes - larger than the bolt heads - which would allow the baffle to snug up loosely, but that's not best either. The baffle plates are relatively thick steel - 2.7 mm which is thicker than the stock steel on the Highland - and the bend in the baffle plate reinforces its strength, which means it can be used to add to the integrity of the right side cook chamber bulkhead that the firebox bolts onto. Why is that important? You'll find over time that the bulkhead will begin to bow out slightly due to the repeated expansion/contraction of the steel (because the steel is so thin) and as the wall bows out, the firebox will begin to sag due to its weight pulling on the middle of the cook chamber bulkhead. But if you drill appropriate bolt-sized holes into the baffle plate where the top two firebox bolts are located, you can bolt the center of the baffle's right side to the bulkhead using the top two existing fire box bolts (or longer ones as needed). You can ignore the pre-drilled holes in the baffle plate. As you torque down the two center firebox bolts, this will pull the bowed bulkhead back into its original shape and correct the firebox sagging problem.
Stock photo - you will have to drill those two center firebox bolt holes yourself:
https://bbqsmokermods.com/pub/media...e78fccba877b2195fbb8f0adf1b0/i/m/img_3651.jpg
And another minor problem - there are two small triangular parts to the baffle plate which you will assemble onto the plate. These exist to block the large leak on the sides which would exist due to the two 45 degree bends in the baffle. Unfortunately, those right-angle corners of the triangular parts will hit the circular weld of the firebox wall and interfere with the baffle snug-up with the wall, so you will want to grind down those two sharp corner tips just a bit so they don't hit the weld.
One other mod: I cut the baffle plate at the lower 45 degree fold near the firebox with an angle grinder and a cutting wheel to enable me to fine-tune the right-to-left temps to perfection by making very slight adjustments to the very narrow exposed crack opening with a flathead screwdriver. This has enabled me to achieve perfectly even temps from right to left. It also makes it simple to remove the baffle plate for a particular cook, if I wish. The part of the baffle that's bolted to the bulkhead will stay in place and act as a heat deflector to block that harsh radiant heat. See "Moberg secrets" on youtube.
Mods I didn't do:
Gasket around firebox door - didn't do it*
Latches on sides of cook chamber door - no need for them for my door
Stove gasket cement in various places at fire box - didn't do it*
*
leaks around the firebox are air intake leaks, most of which feed the fire, and so don't bother me too much
Other stuff I got:
wood splitter wedge - works amazingly well
10 ton hydraulic log splitter from Harbor Freight - for those thick logs
Have fun!
