First UDS Test FAIL

[Shagdog]

Depends on what temp you want, but most likely one is not enough. The elbows and extended pipes do affect your intake. Without any elbows or extensions, I need 3 1/2 open to hit 300

 

[pbj]

I think your biggest problem is the fire basket not having enough space under it for good air flow to the fuel.

I won't comment on the paint job. I live in Minnesota...enough said

 

[T&S BBQ]

I don't have a UDS, so I can't really comment, but I love your paint job. I live the same dream as you. You'll probably figure out your drum before Chicago figures out how to win. Good luck

 

[bvbull200]

I stand corrected. The holes are 1/2" holes. I just went out there and measured. I will increase the exhaust holes to 3/4". Would that make a huge difference?

The way this thing was burning, it felt like I was smothering it and it just burnt the charcoal that I lit with the chimney.

With my setup, what is everyone's guess on how many valves should be open.

That slight increase in diameter of your exhaust holes will more than double the area of your total exhaust. I'm certain that is a contributing factor.

 

[mikemci]

Here's your answer:
Go to our local hardware store, pick up 3 ea. 1/4"x3" bolts or machine screws, 6 ea. fender washers, 3 ea. 1/4" nuts. Run them through that charcoal grate at approx. 120* apart and those legs will get the bottom of that charcoal basket above the 4 intake holes you have. That will give your lit coals the air that they are starving for. Leave the exhaust holes alone, it is plenty. I have 8 ea. holes in my lid, same as you. I have 3 ea. 3/4" inlets and mine runs at 300* all day long with only 1 1/2 inlets open. Fire is a bottom feeder.

 

[gatorman777]

Okay. That's the plan. I will raise the basket and open the exhaust to 3/4".

I will have to wait till Saturday since I need to work to support my new habit!!

I'll keep everyone posted. Thanks everyone!! What a great forum to come for help.

 

[jham0077]

Those 24" risers? I had to shorten mine to get higher temps out of it. The other suggestions wouldn't hurt. The risers are what jumped out at me.

 

[wrenfro12]

The numbers for reference ......remember A=π r^2
a .5 in hole is .19625 sqr inches
a .75 in hole is .4415625 sqr inches

8 .5 in holes is 1.57 sqr inches of exhaust
8 .75 in holes is 3.5325 sqr inches of exhaust
1 2 in hole is 3.14 sqr inches of exhaust

 

[Heisenberger]

The numbers for reference ......remember A=π r^2
a .5 in hole is .19625 sqr inches
a .75 in hole is .4415625 sqr inches

8 .5 in holes is 1.57 sqr inches of exhaust
8 .75 in holes is 3.5325 sqr inches of exhaust
1 2 in hole is 3.14 sqr inches of exhaust

Yep, this is your answer right here, it's all in the math. Small difference in hole size makes a big overall difference. It's hard to have too much exhaust. I actually use six 1'' holes on my 3rd gen UDS.

You probably need all 4 intakes open with the risers to get the temps you want. Just make sure you wait 20 or so minutes after making changes to the intake so you can observe the difference it makes. Also make sure your have room for ash buildup as mentioned.

 

[Bludawg]

I have 1 valve on mine and it is on a 12" riser and I have 2 3/4" nipples and a 2" exhaust. I cook over 300 on purpose. The thing that you need to remember is a 90 deg elblow in a pipe run induces a restriction reducing the volume of flow by 50% so in essence 1 3/4" pipe with an elbow will flow the same volume as a 3/8" line. So if you have 4 risers you have the equivalent of 2 3/4" straight lines,

 

[SmokinJohn]

Two things:

Change that paint scheme. da Bears are scaring the fire.

Next, find n8man's post on fire baskets. Follow it for your first three or four cooks.

Then change the scheme to something calm. Like the Jacksonville jaguars.

 

[MartinM]

I don't use risers just magnets.

I had a similar issue ... Raising the fire for better draft was a huge help.
It seems I may still have a little lacking exhaust but I'm reluctant to change anything because my drum cooks very well now.

I'll be looking forward to your progress and that first cook,

 

[bigjake690]

When I built my UDS I ran into similar quirks figuring it out. I agree with what some other people have said about raising the fire basket another couple of inches from the bottom of the barrel ( the pic you posted looked like it sits a bit low). I have also found that it lights off better if you place the burning coals lower in the basket and then put other coals on top, so the air wicks the fire up toward the exhaust. Some say that won't matter, but it seems to help me get up to temp and keep it there. I have three 3/4" inlets and usually only have one open to keep 225 degrees whether it is 80 degrees outside or 10 degrees in the winter.

I have also found that the biggest thing that keeps me from getting up to temp is if I don't clean the ash out of the bottom after a couple of cooks, because it blocks the air from passing through the fire basket.

TLDR; everyone else was right. Raise the fire basket, keep the ash cleaned out, and get a good light in the fire basket.

 

[Carbon]

I hate to say it, but it looks to me that you never had a good hot fire going from the get-go.

This.

Start with a bigger fire before you do anything else.

 

[gatorman777]

So....I had the chance to make the changes to my smoker. Made the holes 3/4" and raised the basket to 3". Originally was 1". Everything is good except one thing....

As soon as I placed the basket in the UDS, the temperature spiked to 300 degrees. I could not "catch it" on the way up. I have 3 vents off and 1 open half way. It's windy outside and I have been maintaining 265 for 6 hours.

Just for information, I lit up 1/2 a chimney worth of charcoal. Do you guys think I should lite less next time? I think I'm ready to cook some pork this Friday!!!

 

[Sweat'in Pig]

So....I had the chance to make the changes to my smoker. Made the holes 3/4" and raised the basket to 3". Originally was 1". Everything is good except one thing....

As soon as I placed the basket in the UDS, the temperature spiked to 300 degrees. I could not "catch it" on the way up. I have 3 vents off and 1 open half way. It's windy outside and I have been maintaining 265 for 6 hours.

Just for information, I lit up 1/2 a chimney worth of charcoal. Do you guys think I should lite less next time? I think I'm ready to cook some pork this Friday!!!

265 is a good temp... IMO 225 take forever

 

[Wickedcajun]

Bigger exhaust... Or maybe taller exhaust to draft properly

 

[gatorman777]

The verdict is in. It's been 12 hours and still cranking at 160 degrees!! I think raising the basket and making bigger exhausts did the trick!! Thanks everyone for your help.

 

[BigBobBQ]

Glad to hear that you have it all worked out and ready to go.

 

[MartinM]

I like 265... Mine runs 270.

Once you get used to running it you'll relax and just cook at the temp it runs at.

Glad to hear your second run was positive.
I also start with a half chimney. When your ready to light it up be ready to also assemble and cover your smoker.

That lid being off makes it spike quickly.

Same thing for cooking. I get everything ready..pop the lid off and either out the meat on or take it off. I use a remote meat probe so I don't need to peek.

Don't be in a hurry wait for the smoke to run clean then put your meat on.
You're gona love your new smoker!