side pipes on a uds

deerjackie · Jan 1, 2010

what are the pipes i have seen on some drums that go from top of barrel to the bottom? heat and smoke exchangers? looks like they are connected with a 90 degree elbow at both ends. thanks for the info. dj

smokin' dick · Jan 1, 2010

Those pipes are for air intake into the barrel. Usually they have a ball valve at the top for fine air control. This one is a 1" ball valve on a 1" pipe.

deerjackie · Jan 1, 2010

ok.so its placed there for easy reach correct?

deerjackie · Jan 1, 2010

i could nearly swear i saw one somewhere that re connected at the top like it was a re circ of some kind.

meateater · Jan 1, 2010

Yes, thats up at the top for ease of adjustment. I have a ball valve at the bottom of mine personally. To each his own preference, no right or wrong either way.

Post a pic if your building one!

badfrog · Jan 17, 2010

I have been reading alot the last few days and the last 3 hrs or so about how to build a UDS...my question is how do you load/add charcoal/wood to it or is it that if loaded properly and air vents set properly one load will be all that is needed. Otherwise it seems to me you would have to completely remove everything to add. I have never cooked with one, but thinking about building one just to try it out.

rbranstner · Jan 17, 2010

The "real" reason the ball valve/air intake is put on a pipe and extended to the top of the smoker is because after a long day of smoking or should I say drinking you might have trouble bending down to adjust that ball valve. Or in other words you might just take a tumble into your smoker. hahaha Or at least that is what I was told. I thought it was a fair point so I extended mine as well.
As for your question on loading your charcoal. It is all loaded from the top and you shoudl be able to get 10-15+ hours out of one basket depending on hot you are smoking and what size basket you have.

funk · Jan 23, 2010

I also spent the last few hours looking at how to build the UDS. From the pictures I have seen, most have 3 intakes at the bottom and one has the ball valve. From most of the pictures I have seen, the other two are capped. Are three intake necessary and if so, what is the purpose of the other two? Should all three have a valve on them? I am new to this, so I am trying to understand.

meateater · Jan 23, 2010

The idea of the valve at the bottom of the UDS is to bring fresh air under your fire box and being able to control the temp of your fire. Ford, chevy or dodge theres no right or wrong. Many different ways are shown here and they all produce some great food. Just gotta find your nitch. So smoke on!

countryboy19 · Jan 28, 2010

I'm a newb at UDS myself, but I think I know why they do this. There is only 1 ball valve because you only need 1 continuously variably air input. The other two can either be capped/uncapped. You only need to finely tune 1 input, rather than all 3. The 2 that have caps are your "coarse" adjustment, and the ball valve is the "fine" adjustment.

So lets say you need the equivalent of 2.15 air inputs. This would mean you uncap both of the capped ones, and then crack the ball valve open a little bit. If you only need the equivalent of 1.45 air inputs, you leave one of the inputs capped, and then crack your ball valve open slightly less than half.

Sure, you can put 3 ball valves on if you really want to, but they aren't cheap, and most of the time people build a UDS because they're cheap, not because they're fancy. You only need 1 ball valve, so why buy 3?

coffee_junkie · Jan 28, 2010

Yup what he said...I normally open all three to get it up to temp and get things moving along, then cap one, see what happens, usually end up then capping both and closing the ball valve 1/2 way. Sometimes the basket needs a "shake" so adjustment may be needed at that time also, but for the most part just set it and forget it.

blackened · Jan 28, 2010

Single 2 1/4" intake works well on mine..

earache_my_eye · Jan 29, 2010

You can save yourself some coin on the build by just using some flat, flexible fridge magnets over the intake holes. No need for the close nipples & caps, or even the ball valve setup. All total, it would knock about $12 - $15 off of your build.
Use the extra cash to buy Weber brand charcoal and cooking grates...they're MUCH nicer than the cheapies that are out there, IMHO.

Just my $.02,

Eric

roller · Jun 19, 2010

So are you saying that the only reason that most people build and use them is price and not the way they cook?

ddave · Jun 19, 2010

Roller said:
So are you saying that the only reason that most people build and use them is price and not the way they cook?

I don't think that is what he is saying at all. You can build them for a little money or you can spend a lot on them, it's up to you.

Great thing is BOTH will cook about the same. They cook great by the way.

Dave

duck killer 1 · Jun 19, 2010

a UDS is a great smoker! it is almost a true set it and forget it smoker! 10 to 14 hours at 225*F on 10 Lbs of charcoal.

ratdawg · Jun 19, 2010

Here is a new one that I just finished. I make them with the side pipe intake because I do not want to bend over to adjust it. I think the UDS style smokers work great. Like duck killer 1 said, it is pretty much set it and forget it.

elsparky · Nov 8, 2015

Whats the typical LENGTH and WIDTH of said pipes ? I'm contemplating building a UDS, and am curious.

smokinjoes · Dec 23, 2015

@ratdawg I really like what you have done there for fine control, no ball valves. I am wondering why the controls at top and bottom? Will they act differently on the smoker? I mean technically both would control air flow, what I am wondering is this. Can you control how much smoke is in the smoker with the top one as well as air flow? Would the amount of smoke be the same if say the top one was open 25% and the bottom open 75% vs top open 75% and the bottom open 25%.

I mean both would equal 100% of 1 pipe open and should equate to the same amount of air flow, does closing the top retain more smoke than leaving it wide open? There is a lot of volume in a 55g drum, I am not sure how that factors in if at all in regards to smoke retention vs air flow.

I would love to build my own UDS, but I am one of those guys who over thinks and over plans all the time. Seeing your dual controls there brought up some questions I hadn't considered yet. Thanks for that.

bill1 · Dec 25, 2015

SmokinJoes--I think what you're asking is the relative cross-sectional area of the exhaust port relative to the input port. The dominant view around these parts is that the exhaust should always be less restrictive (larger area) than the intake, otherwise you get "stagnant/acrid" smoke in your smoker. The opposing viewpoint is that a slight over-pressure in a smoker aids smoke diffusion into the meat, although the difference that a fraction of a psi would make would seem fairly inconsequential. Ratdawg's nice looking UDS (NLDS?) has a larger than normal intake (at least I estimate his intake area is larger than 3 times the normal 3/4 or 1" pipe intakes.) But with adjustable flow, it's better to err too big than too small. His also has wide adjustment on the exhaust. My recommendation would normally be to try to keep the areas of each roughly equal, if you're choking off the intake, do a similar amount on the exhaust.

side pipes on a uds

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