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View Full Version : Built a UDS! Cooked things! Can't control temps! PRON!


NC-Q
04-01-2013, 10:30 PM
A few weeks ago I just finished building a UDS after reading approximately 1 ba-zillion articles and posts (including the entire 'big' thread). I've done approximately 7 or so cooks and test burns on it to try to get a feel for it, but I still haven't achieved what I would like to think of as "UDS Zen." To me, my vision of UDS Zen would look something like this: I do anything other than stare at the thermometer for a period of approximately 30 mins and when I come back, the temperature is somewhat the same as when I left. OK, so maybe I'm exaggerating a little bit, but I've been cooking on a Silver Smoker with a few of the typical mods for a number of years, and have grown quite used to nearly constant fiddling and monitoring. I expect that. I expected to be able to control my UDS temps better than I have. I've still been able to turn out a few tasty things in the process:
https://dl.dropbox.com/u/52619636/2013-03-29-19.59.25-copy.jpg
Some Ribs.
https://dl.dropbox.com/u/52619636/2013-03-29-19.59.32-copy.jpg
Some More Ribs.
https://dl.dropbox.com/u/52619636/2013-04-01-20.25.56-copy.jpg
A Chicken.

Oh yeah, and here's the UDS:

https://dl.dropbox.com/u/52619636/2013-03-22-17.17.10-copy.jpg


So I've gotten a few theories as to why my temps are so out of control and feel free to offer any feedback, or not, as I know these very questions have been addressed in the past. I guess I'm just looking for some clairvoyant UDS insight:

1. Wind- It's windy here in Charleston. Perhaps adding a chimney would help with the ups and downs?
2. Patience- Some people have suggested that it takes a while for the temps to "settle in." I'm not sure how long I'll need to keep messin' with it, but I don't seem to be recognizing any patterns yet. I have 3 1" pipe nipples for intakes, 2 with caps, 1 with a ball valve. I have been adjusting them in the typical fashion (capping and adjusting with valve), but it seems to only wnat to climb or fall no matter what I set it on. Maybe I'm just not being patient enough for the temps to stabilize, I've waited up to an hour between adjustments.
3. Leaks- I don't think this is a big issue, but it could be. I'm able to shut the thing completely down if I close off the air intakes and the damper, so I don't think it leaks too much. Only faint wisps of smoke come from around the rim (the lid fits pretty durn well).
4. Ashes- I built my basket out of expando and a weber charcoal grate from an 18 incher. Standard stuff. It's 3 inches off the bottom of the drum. I've been simply lighting about 1/4 of a chimney of kingsford blue and putting them in the center of the basket filled about 1/2 way... Not using the coffee can method, perhaps this may help?

So I wasn't planning on writing a novella for my first "real" post to the forums, but I guess y'all seem like a nice enough crowd, I'm frustrated and full of chicken, so why not?

4uweque
04-01-2013, 10:37 PM
Looks really nice, my only suggestion would be to add a chimney, about 7 inches. That's the only thing different on mine and it cooks like it has a thermostat.

NC-Q
04-01-2013, 10:42 PM
Thanks, I will drop by Lowes and pick up some pipe tomorrow for a chimney. I haven't used the damper for anything other than shutting it down so far, don't suppose I will ever need to based on what I've gathered here.

olewarthog
04-02-2013, 01:54 PM
start with fewer lit coals. I only start about with about 10-12 briqs. I watch the temps as it starts to rise after adding the lit coals. If I plan on cooking at 250-260, I cap one nipple at 200. I cap the second nipple at 225. At 240, I close the ball valve about half way. Most of the time, mine will then settle in between 250-260. If it goes past 260, I'll nudge the valve closed a little more. If it stops short of 250, I'll nudge it open a little. The key is to start with a small controlled fire & catch your target temp on the way up. If you get too big of a fire mass, you will be wiggle that valve all day trying to get it under control.

I will add this. my drum did like to continue to creep up in temp until I used some red RTV silicone around the lid. However my lid did let quite a bit of smoke out until I sealed it.

hcj3rd
04-02-2013, 02:22 PM
My drum never has had any wild temp fluctuations. Mine is built identical to yours except I have a 6" x 2" threaded pipe for exhaust. I think if you add the exhaust it will probably draft better. The only other reason to have temp swings is air leakage somewhere. Be sure not to leave the lid off for any length of time or you will have a temp spike. If I have to open the lid I get in and out quick.

gmag
04-02-2013, 02:29 PM
Looks good. UDS's seem to be gaining a ton of popularity...makes me want to build my own!

Just BS
04-02-2013, 02:41 PM
I think we all have the same frustrations when we stepped into the world of BBQ'ing on the UDS. Shoot. I used to walk around with the thermo reciever and stare at it every 30 seconds... now I leave it on the counter and check on it every now and again, but the difference between 250 and 262 ain't worth stressing over. Besides it'll be 247 in a bit anyways.

But I digress. Have you cooked with a cap off and your ball valve closed yet? I'm running 3/4" intakes, so we're a bit different, but once I figured out what my UDS's temp was with a constant intake, it help me better understand how to control the ball valve. NOTE: Once you add an exhaust your temps will increase.

Anyways, your food looks good. Enjoy it! BBQ, like life, is more about the journey than it is the destination.

J-Rod
04-02-2013, 02:41 PM
What others said. A chimney might help you, not so much with lowering temps but especially with battling the wind. On my UDS I got one 1-1/2" downdraft style inlet with ball valve and a 2"x6" chimney and it holds steady like like a champ, even when it's windy as hell. The last big cook I did for a bunch of people was out on a farm with zero trees for windblock. I couldn't believe how the two cookers basically gave the wind the finger and cooked at a steady 250 for hours.

EDIT- you are still learning your pit too, it takes time to get a "program" down for each particular pit. You'll get there.

Just BS
04-02-2013, 02:52 PM
Are ya using briquets or lump. Briquets will give ya a stedier temp...lump will taste better (IMHO). But your temps will change when bigger or smaller lumps get going, especially on gusty wind days.

Also wanted to say that a 1" open cap might push you over 300*, but since you're full of chickens I'd just cook one or two of them if you choose to try my experiment.

Bludawg
04-02-2013, 03:26 PM
What temps are you wanting to cook at? I cook at 300 My drum is constructed just like yours with the exception of all my intakes are 3/4" I start with a Full basket of lump and dump a 1/2 a hot chimney on top. And wait 10 min before dropping it in the drum with all intakes open. At 250 I cap 1 and close the ball valve by 1/4 it settles in at 300 on the button. I'm cooking with in 20 min from light up. Sometimes it will creep up 25 deg but I'm fine with that. Adjustments normally take about 15 min to show up on the thermo. For what is worth the West Tx wind never quits blowing I guess because of all the Suckers in DC.

Kloogee
04-02-2013, 08:21 PM
I may have overlooked it in your post, but what temp are you trying to cook at and what type of fluctuations are you talking about?

Those details may help with additional guidance from the brethren.

ETA: It could be that what you consider a wild fluctuation is what others consider normal. Maybe not, but worth it to throw the details out there.

Budman1
04-02-2013, 08:45 PM
I use lump also, and have very few problems.

Meat Burner
04-02-2013, 08:48 PM
Definitely agree with adding the exhaust. A whisp of smoke around the lid is not an issue. The whole patience thing and starting with a small initial fire extremely important. Bring the temp up a little isn't a problem but bringing the temp down can be very difficult. Keep after it and you will master it bro!

Qbert60
04-02-2013, 09:00 PM
When I fire up my UDS, I get the temp up to about 300*, then start closing the inlets until I get to 250* - 275*. It's easier to get temp back down then it is to get it up.

flyingbassman5
04-02-2013, 09:05 PM
Give it a few cooks and she will settle down. Plus you will start to learn the way she likes to be handled.

Mine likes to be started with about 12 briquettes in the center and with 1 of the 4 intakes 100% open makes her rock 275 all day. Usually let her take about an hour to get up to temp.

She'll come around..

jmoney7269
04-02-2013, 09:08 PM
I think we all have the same frustrations when we stepped into the world of BBQ'ing on the UDS. Shoot. I used to walk around with the thermo reciever and stare at it every 30 seconds... now I leave it on the counter and check on it every now and again, but the difference between 250 and 262 ain't worth stressing over. Besides it'll be 247 in a bit anyways.

But I digress. Have you cooked with a cap off and your ball valve closed yet? I'm running 3/4" intakes, so we're a bit different, but once I figured out what my UDS's temp was with a constant intake, it help me better understand how to control the ball valve. NOTE: Once you add an exhaust your temps will increase.

Anyways, your food looks good. Enjoy it! BBQ, like life, is more about the journey than it is the destination.

Good stuff +1

Meat Burner
04-02-2013, 09:12 PM
When I fire up my UDS, I get the temp up to about 300*, then start closing the inlets until I get to 250* - 275*. It's easier to get temp back down then it is to get it up.

:shocked: I have never ever heard anyone on this forum make that statement. Catching the temp on the way up on a UDS is recommended and works.

NC-Q
04-02-2013, 10:32 PM
Thanks for all the awesome comments and advice.

To answer the questions posed:
I'm cooking on Kingsford Blue. I have used lump before in my offset and like it, but think that while learning how my new baby runs, I'll be sticking with it for consistency's sake.

The temperature variations I was getting were between 250-315 in the span of 15 mins, and 325-385 in 20 mins or so. I wasn't happy with that. I think I know why now though...

Long term I'm primarily going to be trying to cruise around 225. I built this UDS mostly with dreams of delicious shoulders dancing through my head. They were just a royal pain to do on my silver smoker, though I've done it for years. Usually do whole hogs on rebar over makeshift cinder block pits with roofing metal as a lid... So don't get me wrong, this is a major improvement :grin: I think I'm going to keep cooking the chickens on my offset in the long run, but I digress.


So I went to the local hardware store tonight and picked up some 2 inch pipe and devised an experiment.
First I added a smokestack: 12" of 2" pipe. I know this is probably too long, but my plan was to start long and just shorten as necessary.
Then I lit 12 briquettes of Kingsford blue, put in about 8 pounds more into my basket, a few lumps of hickory and then added the lit coals to the center of the basket. I got out a pen and paper and began to systematically record the temp and valve settings at 10 minute intervals. Into the drum the basket then went with one intake uncapped and the ball valve open. I capped at 200, then throttled it back to 1/2 on the ball valve at 200. It climbed to 225 and dropped to 213, where it stayed rock solid for 30 mins. What I learned was that with some very fine adjustments between 75% open on the ball valve and 90% will vary my temp from 215-240, but it seems to be leveling out, and is certainly much easier to control. I've been holding between 220-230 for two hours now though, with only extremely small adjustments to the valve. I'm going to just let it go all night at this point and see where I am first thing in the AM.

What I've learned:
1. Patience is key- I think I was overreacting to changes
2. The chimney seems to help a lot. I mean it was dramatic. I may shorten it from 12 inches, many people recommend shorter, but I may just roll with this, it seems to work
3. There's a sweet spot between 75% and 90% on the ball valve, the temp will vary between 210 at 75% and 250 at 90%. Extremely small adjustments in there let me dial the temp in.
4. The brethren are AWESOME. Thanks for all your input. And to think I've been doing this alone for all these years...

NC-Q
04-02-2013, 10:39 PM
Also after reading back over some of the other earlier comments, I found that adding the stack pretty much eliminated any of the remaining wisps of smoke that came from around the rim of the lid. Better draft I suppose.

JustBS:
I will definitely try out the "1 cap off- see where it lands" experiment. I think it would be good to know "terminal velocity" with one open cap. I agree that it would be good to know a "baseline" of sorts.

martyleach
04-02-2013, 10:44 PM
You are right that a little tweak of the ball valve can make a huge difference. I don't go to bed until I have it dialed in. If you don't pop the lid every 20 minutes these drums have a temp that they want to run at. Mine is about 250 but I have made others that seem to prefer 220 or 275. Glad you worked that out about the chimney.

NC-Q
04-03-2013, 07:23 AM
Update on progress:

Got it leveled out to around 225 before going to bed last night, and this morning, woke up to find it chugging along at 180- not bad! A shake of the drum to settle some ash and a tiny bump of the valve had it back up to 225 in a few mins. Best of all, barely any of the coal has been burned! I'm going to let it go all day while I'm at work and see how it is this evening. Thanks again everyone.

One more thing- there was about 1/4 inch of water in the bottom of the drum after running all night, I'm assuming it's condensation from the intake of our very humid coastal air?

willbird
04-03-2013, 08:34 AM
I put an Auber on mine, but playing with it au naturale I came to the conclusion that a "plain" opening, just the pipe nipple with a magnet covering part of it is a LOT easier to tune with than the ball valve for some reason. That could just have been wind from one direction the days I fiddled with it too.

Bill

Qbert60
04-03-2013, 11:37 AM
:shocked: I have never ever heard anyone on this forum make that statement. Catching the temp on the way up on a UDS is recommended and works.

If you "Try" to catch the temp coming up, I believe you have better chance of dropping it to fast. I do the same thing with my offset. Let the temp get to 350* then close the inlets/exhaust to dial it in. Seems logical to me.

NC-Q
04-08-2013, 12:17 AM
So the addition of the smokestack made a big difference for me with the wind doing a shoulder today. I got a 12 inch piece of pipe and left it 12 inches, figured I could shorten it as needed to tune it in. But it got me thinking, is there any reason I should even shorten it? What would the rationale be for me to take it down to, say, 8 inches?

Ole Man Dan
04-08-2013, 10:53 AM
The only thing I would add is to try to keep the open intake out of the wind. I position my valve, down wind. The wind can cause your temps to go up and down.

CambuiAl
05-27-2013, 06:01 PM
Interesting thread with some really good information - thanks everyone. I did my first ever cook yesterday and had the roller-coaster of temperatures as I played with the various inlets (2 x 3/4" with nipples and 1 x 1.5" ball valve) and also the outlets (1 x 2" standard 'hole', 3 x 3/4" with caps). I am not using an accurate thermometer I don't think, but could see that small changes take a while to kick-in. That said, I found that having 1 of the 3/4" inlets open, one capped and the ball valve about 75% open down below, and everything except the 2" hole capped up top, gave me a steady temp of around 230F once I made a chimney change:

I placed one of these over the 2" hole and swiveled it around to see how it liked to face. With this facing into the breeze, the temperatures rose (I think I was forcing more air in?) and down if I had the breeze blowing over it (sucking more of the hotel air out?) but it certainly helped when facing directly away from the direction of the breeze. The nice thing about this quick and dirty fix is that it can be quickly adjusted as and when the breeze changes - I just need to build a wind-sock for my BBQ area now!

http://i42.tinypic.com/b3rfwz.jpg

Hawg Father of Seoul
05-27-2013, 06:12 PM
Make a smaller diameter fire basket if you want lower temps.