After about 30 to 40 cooks (everyone a success) on mine, I thought I'd share some of the things I've learned and what I will do differently for the next one. One of the major things would be to start with a heavier gauge barrel. The thin gauge I started with makes it difficult to use conduit nuts, not enough thickness to really get them tight and they end up coming loose. Solved that by welding them in. This also made temps more stable by eliminating small air leaks. I also think the heavier gauge will be more efficient and help with temp stability in in rainy, windy, colder weather.
When I was building mine, I agonized over how to make the fire basket. Size, height, etc. Mine is simply a Lowe's 2x2 square cut in half with the ends bolted together into a hoop and then u-bolted to a replacement Weber fire grate with 4 inch bolts through the bottom. A cheap pizza pan was attached to these. I was concerned about the capacity and how even the burn would be, but have since learned that even this smallish basket works brilliantly, having run 24+ hours on a 225 degree burn using a 12lb bag of Kingsford with briquettes left over. There's no telling how long it would burn if I filled it completely.
Speaking of briquettes, I prefer them over lump for their consistent burning. You might not have as strong as smoke flavor as the lump, but you can adjust by adding more wood. Have had good luck with Kingsford and several other brands. Once I light the briquettes with my weed burner (best investment I ever made) and lower it in the drum, I set my 3/4 inch ball valve to about 90 percent open and leave the caps on the other two nipples. She will level out at 225 and go for as long as 5 or 6 hours before needing a good shake to drop the ashes and bring the temp back.
The next one I build will have two racks instead of one. Two butts or big slabs of spares leave room for little else, and I feel like there is sufficient room below for another rack, even with my flat lid. The 24 inch rule of thumb for is just that. For low and slow cooks, this should be fine, you're just trying to keep the meat far enough away to prevent your smoker from becoming a grill.
My 5 dollar Wally World 12 inch thermometer has been working like a champ. I clean it with a green pad and check the calibration every cook. So far, it is spot on. The only other thing I intend to add to my UDS is an IQ110. As steady as mine runs, I'm still not comfortable going to bed at night with a 50 dollar brisket in it for the next day. This should give me some piece of mind.
