This was for my Oklahoma Joe, but could be useful for others as well.
I was going to do some catering for friends, and realized that I really needed to get a few more ribs than my OKJ can handle. I usually get 8-9 baby backs on the bottom, but really needed 12-14. So I figured I'd find a way to get a second level going in the smoker. Now, there's probably a more city way of doing this, but I did what I had to do with the few days I had to do it.
I measured right under the exhaust hole on the left and got 16.5" in depth, and the opening is about 35.5" wide, though the internal chamber is a couple of inches wider. I sketched out a shelf with supports on the end that flared out to preserve as much space on the bottom grate as possible.
I started by going to a local welding place to see what kind of price I was looking at, and the quote I got was around $225-250. That was just way more than I wanted to pay for something like this, though I do appreciate the amount of time and materials it would have cost.
So, home version it was. I decided if I could find a grate I could bend something around to make the "legs". I looked all over and finally found the near-perfect size grate, 16 x 34. I found it on Amazon, but for more than I wanted to pay, plus the delivery couldn't be moved up and the guarantee delivery window was going to be two days before to two days after I needed it. We all know how that would have worked out.
I ended up looking up the company Amazon used, and got a hold of the guys at smokedaddyinc.com. Dennis answered the phone and was on the road, but he got me in touch with Dan in the shop, and they were able to get me two grates shipped out that day, and they arrived a day before I needed them. No shipping cost and a deal on the grates as well. Much appreciated!
Here's the mod I did if anyone else is so inclined. Cost me a total of about $70.
Step 1: cut one grate in 1/2. These will be the "legs".
Step 2: Bend 'em into a "squared U" shape. I chose to put the side and center railings on the outside of the bend, so I might be able to use them against the underside of the top grate when it sits on it. Note that the porcelain will flake off when bending these, so goggles are a pretty good idea during this step.
Step 4: Not pictured. Snip out the bars from the bottom part if you like, and trim out the center bar on the bottom. I didn't want to have some ribs laying half on and half off, and I also wanted to be able to take these out if I wanted to without having to move meat.
Step 5: Not pictured. Do a little bend job on the remaining bottom outside "rails" so that they go out to the back and front edges of the bottom grate. Also, you may need to file down or bend the jagged pieces where you snipped the racks.
Step 6: Set them on each side and make whatever bend adjustments, then set your other grate on top! (This was before I bent down the jagged edges.)
And here she is, loaded up! There was a very slight sag in the center, but not enough that I would mess with adding any support to it for this kind of load.
Not only did this work perfectly, I've done a couple of personal cooks since, and just used the top rack for more smoke (and the temp gauge is closer to it anyway).
Finally, no post would be complete without some finished product. I apologize for the blurriness. Camera on my phone has a crack in it. The pulled pork mac and cheese has the pork from the 4 butts I did the night before (no 2nd rack needed).
Now, everyone tell me about the $50 solution that is already on the market. ;)