Sunday, January 26, 2014

Update on my UDS

I've been using this UDS for a few months now, and here's what I've cooked on it thus far.  3 pork shoulders, 2 briskets, 1 rack of ribs, and several links of sausage from the local meat market.  Here are some things I've learned about my UDS and cooking with it.

1.  Sunlight is its friend.  I have learned the cooking temperature will change significantly between being in the shadows and in sunlight.  I cook in my backyard, generally on the east side of my house.  As the sun transitions to the west the shadow from the house will cover the smoker and in a short while the temperature drops about 15 degrees.  The same is true in the morning as the sun rises and sunlight hits it in the morning when I started it early: the temperature will climb.


Here comes the shadow. 

2.  It can hold a temperature pretty darn well.  I'm still not terribly comfortable with "set it and forget it."  But unlike the stick burner I was using where I would check it several times an hour, I'm not afraid to get it going early in the morning, then go back to sleep for a couple of hours because I'm confident the temperature will be at or near where I set it.  With that said, I do need to keep sunlight and shadows in mind.  The most impressive temperature success story was a pork shoulder I cooked when it rained hard for about an hour in cool temperatures (maybe 55 degrees), and the UDS kept trucking once I opened the intake valves a little bit extra.

3.  Getting it fired up.  Using the "minion method" for starting the charcoal, and using about 20-25 briquettes for the starting batch, I can get the temperature up and stabilized in about 30-45 minutes from adding the starting batch of charcoal to the rest of the pile.

4.  Max cooking time.  The longest it has gone on one load of fuel was when I cooked a 10 lb brisket using a 20 lb bag of Kingsford Charcoal and about 2-3 lbs of oak wood.  It went for 15 hours before it no longer had enough fuel to keep it going above 200 degrees.  When I inspected it later, I found maybe 1 lb of fuel remaining, but the ash catcher pan was nearly full.  Even if it had more charcoal, it was struggling to get air with the ash piling up as it had.  To combat this, for my next long cook I will install long bolts attached to the charcoal grate as legs that will raise the grate up a little higher off the ash pan and will hopefully encourage more airflow.

Here are some photos from a few cooks thus far...


2nd cook.  Spilled grease on it.  It's fully "ugly" now.
Nighttime ops.  Running steady a 3:00 AM. 

 
First pork shoulder.  Excellent.

First thing I cooked was a pork shoulder since it's so forgiving.
 
Ribs were great.


St Louis cut.  Ribs aren't my favorite, but these were great.  Nice short cook compared to the shoulders & briskets.

I threw these raw deer sausages on with about an hour to go for the ribs. 
 

This is my 2nd brisket.  Very proud of this one.

I cut a little too thick on the flat side of the brisket, but it was tender and had a nice fat cap.

I've used hickory chunks for the pork shoulder and ribs.
I used oak chunks with my brisket.  Here is my first use of the minion method for starting the charcoal.  It gets hotter much faster this way.


Wednesday, October 9, 2013

UDS Frequently Asked Questions


FAQs and Resources for the UDS

Be sure to visit my other posts for a list of parts, how to build the charcoal basket, and how to assemble the UDS.

Go Google "UDS" or "ugly drum smoker" and dozens, maybe hundreds, of web pages show up in the search results directing you to numerous message boards and blogs.  There are lots of resources out there, and some are better than others.  The big message boards such as BBQ Brethren and the Smoke Ring have lots of boards with good discussions going. 

The main message board regarding UDS builds that many will point to as the end-all, be-all for UDS discussions is on BBQ Brethren.  The thread started in 2007 and is still going with hundreds and hundreds of pages (over 700 at this point) and thousands of messages.  It is truly the "mother of all UDS threads" as its moderators indicate at the top of page 1 in the thread.  It is full of valuable insight and history of the UDS, but to be honest, at this point is too big of a beast to tackle in its entirety.  I've read a few hundred pages of the thread, skimmed through middle pages, and have cheated toward the end of it as well.  It's pretty much at the point that people ask a question that has probably been asked dozens of times previously in the thread but could not be found (you have to be a member to gain access to their search function). 

I decided to cobble together many of the questions and topics that are brought up in UDS threads and in other builders' blogs.  I by no means am an expert.  I've built one UDS and steered clear of more elaborate designs due to lack of funds and admittedly some lack of skill.  Hopefully these FAQs will be of some use to the incoming novice who wants to give the UDS a try.  The bottom line on the UDS is it's cheap, relatively easy to put together on your own, and is forgiving. 

First, before the FAQs, here are links to some message board threads, blogs, and videos of UDS builds out there that I referenced quite a bit.  You will likely find them useful as well.

The BBQ Brethren Mother of All UDS Threads.  It's worth a look.  Most of the basic info is covered in the first 30-40 pages of the thread.    

Man Cave Meals UDS Build.  My parts list is borrowed heavily from this.
http://mancavemeals.net/the-uds/

Grilling 24x7 UDS Build. This is a 3-part blog that is neatly organized and does a good job of explaining the build.  Also, it shows how to create a simple side table to attach to a UDS.
http://www.grilling24x7.com/UDS1.shtml

The Smoker King UDS Build.  Short, simple, to the point.
http://www.thesmokerking.com/talktome/archive/index.php/t-109.html

Ugly Drum Smoker Blog.  Has no unique name, but is a very detailed blog for a more advanced UDS build.  Uses vents for air intake, mounts his UDS on wheels, shows how to remove a closed top lid and installs a mounted kettle lid.
http://uglydrumsmoker.blogspot.com/?m=1

BBQ Pitbuilders.  A nice step-by-step.
http://bbqpitbuilders.blogspot.com/p/how-to-build-uds-tutorial.html

The Hog Blog.  Good photos, shows how he modified the drum so a kettle lid will fit properly.  He also added wheels to this UDS.
http://thehogblog.com/?p=2231

Sneakeey1 (aka Sneaky) UDS Build Videos on YouTube.  He's got several videos about his UDS; these two I think are the most useful in building.
His charcoal basket build, which I copied for the most part. 
http://www.youtube.com/watch?v=9qTvBFGNlrA
His overall build.  He cracks me up with the dollar bill.
http://www.youtube.com/watch?v=EUQbGTSXhdk

Amazing Ribs.  This is just a great site for finding all kinds of info about smoking food, recipes, equipment, and the science that drives barbeque. 
http://www.amazingribs.com/

Big Poppa's Smokers.  They provide a UDS kit, a one stop shop for all the gear you need for your smoker.  In retrospect, I think this would have been a far simpler route for building a UDS.  If nothing else, they have individual accessories for sale you may not be able to find elsewhere.
https://www.bigpoppasmokers.com/store/bbq-accessories/big-poppa-s-engineered-drum-smoker-kit

UDS FAQs

What is an Ugly Drum Smoker? 
An Ugly Drum Smoker (also known as UDS, Upright Drum Smoker, Barrel Smoker, Drum Smoker) is simple smoker design using a steel drum to cook in.  The drum sits upright with a fuel source of charcoal and wood sits at the bottom of the drum, draws air from holes at the very bottom of the unit, and cooks food on a rack usually about two feet above the fuel source.  The way it functions is similar to a Weber Smoky Mountain cooker or even a ceramic cooker like a Big Green Egg, but it can be constructed by even a novice and a low cost.

What kind of barrel do I need?
Ideally you want an open top steel barrel that is labeled as food grade.  Food grade barrels will normally have a plastic liner that must be removed.  Many on BBQ boards say they used barrels that once contained oil or other petroleum products and that is okay to use so long as you burn it out before using for cooking.  Some are not comfortable with using a barrel that had oil in it at one time (myself included), so if that is the case then stick with food grade.  Main thing is to avoid any barrel that had toxic materials in it.  Those can never be used for cooking.
Also, make sure the diameter is in excess of 21.5 inches to ensure a cooking grate will fit.

Where can I find a barrel?
Check Craigslist in your area.  Also look at machine repair centers, automotive shops, recycle centers, or if really having a hard time go check out the local junkyard.  Just be sure you get a barrel that never had anything toxic in it and something you can clean.  If in doubt, move on and look elsewhere.

Do I need to weld anything in building a UDS?
Absolutely not.  If you have access to the equipment and resources, sure, welding is great and can result in a sturdy smoker.  But it's not necessary.  All you need for tools are a drill (avoid cordless if you can), a step bit, wrenches, and a screwdriver.  That's the bare minimum and you can probably get by with that.  Additional tools that you might want will be a wire wheel brush for your drill and an angle grinder (or Dremel tool) for cleaning/sanding/cutting metal.

How should the barrel liner be removed?
Burn, burn, or blast.  The method for the cheap guy with space or understanding neighbors is to burn a hot fire for a few hours in the barrel.  Wood from pallets is ideal.  After a few hours the liner will have burnt off and the exterior paint will have bubbled off also. 

If you are not in a spot to burn a big fire but you have access to a weed burner (more formally known as a propane torch), that works really well and is probably more effective.  Burn from the outside to get the metal red hot, and the paint as well as the liner will be gone.  Burning from the inside of the barrel with a weed burner is not recommended as it could go from an oxygen starved environment and have a sudden flash as it's reintroduced to air toward the top of the barrel.  Harbor Freight sales torches online for $20-$30.

Whether you burn a fire or use a weed burner, you will need to clean the exterior and interior of the barrel.  Clean with a wire wheel on your drill, sander, or a hand held wire brush if you've got enough elbow grease..

Another option is to get the barrel sand blasted.  Sand blasting will normally run from $30 to $60 for something like a steel drum.  Sand blasting will remove everything and leave the barrel bare of paint and liner.  It may be worth it to avoid burning and cleaning.  Just remember the metal will be more susceptible to rust, so be prepared to paint and season soon after blasting/burning.  Also, if there was anything in your drum other than food product such as oil, many are more comfortable burning the barrel out with the idea of burning out.

What's the difference between a red liner and a tan liner?
A tan liner is supposed to be easier to remove.  If you have so the so-called "dreaded red liner" in your drum, that is tough and may take a few burns and significantly more elbow grease to get out.  Some say to avoid barrels with the red liner if at all possible.

My drum is bare on the inside.  Do I still need to burn or clean it out?
You probably need to burn it out regardless.  Lots of drums that look bare actually have a coat of some sort of rust inhibitor on the interior.  A burn out or sandblasting should take care of that.

If it's a reconditioned or otherwise previously used drum and is bare, you will be wise to clean it just the same to remove any residual waste or contaminants.  Mine had glue in it and was cleaned by the warehouse I bought it from, but I could still smell a funky odor

Should the paint on a new barrel be removed?
Yes.  Well, maybe not, but the cleaning process will likely result in needing a new coat of paint anyway.  The barrel is going to get hot when cooking and especially hot if you burn out a liner.  Most barrels don't have paint designed to withstand high heat, so it'll bubble and peel off.  Once you've cleaned the paint off, spray on some high heat paint that you can get from most hardware stores or auto part stores.  You might consider putting down high heat primer first to extend the life of the barrel.

If you end up with a barrel that has no liner and does not need to be burned out (again, it's still probably a good idea to burn/blast the barrel), so long as you do not cook with the lid off, which can send temperatures soaring, it's unlikely the barrel will get hot enough to affect the paint already on the drum, so you may not need to paint it.  And that ensures it meets the "ugly" criteria in the Ugly Drum Smoker.

What kind of paint should I use on the UDS?
Primer is not necessary but will help extend the life of the UDS.  Lowe's sells high heat spray primer (good up to 2000 degrees) in their paint section.  If you're looking in the BBQ/Grilling section, you will likely find only their 1200 degree flat black paint there.  The paint section will have more color choices that are also designed for high heat.  You may also be able to find high heat paint at automotive stores.

It will probably take two cans of primer to cover an entire drum thoroughly.  I needed just a tad more than two cans of black paint.  After two cans, I still had a few spots where the primer was visible.  A third can is nice to have for touching up dings and scratches it gets along the way.

There's a rubber ring on the lid of my drum.  How do I remove it?
Most can be removed using a screwdriver or chisel.  If the ring is stubborn and leaves residue, get a toothbrush style wire brush and use some WD-40 to scrape it away.  Any residual can be burned out.  Main thing is to get all the rubber off the lid.


Do I need the clamp ring that came with my drum's lid?
No, but some people like to use it to clamp the lid shut while smoking.  I read the account of one cook who ran into a problem where the lid didn't shut tight and the fire was drawing oxygen from the top of the barrel where the lid didn't seal.  He figured this out when all air intake holes were shut and the rig was still holding a high temperature.  It's likely it won't be an issue, so if you have a good seal with your lid, you should not need it.

How many air intake holes are needed and how big should they be?
Usually 3 or 4 intake holes.  If you elect to use threaded nipples, a 1" hole is needed for a 3/4" nipple to fit into.  If you decide to use magnets to cover holes and regulate air intake, then the size of the hole isn't as important.

If using threaded nipples and don't want to invest in a ball valve, then you're pretty much committed to opening & closing caps to control air flow.  In that case you might want to consider more holes of smaller diameters.  You may find your UDS has too big of temperature swings with opening or closing just one large hole.  Smaller holes can result in smaller temperature changes.

Another option is to install a vent system where a sliding piece of metal is used to open/cover several holes or one large hole you cut out with a jigsaw.  It does not seem like many UDS builders go this route, and I would assume it's because it's more trouble to install than pipe nipples or to just use magnets.

What size holes are needed for using threaded pipe nipples?
Most people use 3/4" nipples and those will fit snuggly into a 1" hole.  If using  1/2" nipples, they should thread into a 3/4" or 13/16" hole. 
3/4" nipple fits into 1" hole

Where should the air intake holes be placed?
Typically they are about two to three inches from the bottom of the drum and placed equal distances from one another around the circumference of the UDS.  The main thing is to keep the intake holes below the charcoal basket.  This will ensure proper drafting with the air coming in at the bottom to the fuel source and heat will rise up through the UDS and over your meat.  If the intake holes are too high, the fuel will not get enough oxygen and some heat will escape through the holes.

Note:  Placing the center of the hole two inches from the bottom of the drum is probably as low as you can go.  Remember the floor of the drum is normally raised off the ground a little (i.e. not flush with the bottom outer ring of the barrel).  Any lower than two inches and you are running a risk of being too close to the floor where your lock nuts may not have clearance to be threaded onto the inside half of the nipple.  Yes, I learned this the hard way when I put my holes a 1 1/2 inches.  I had to use a hammer to beat the drum floor down next to the holes so the lock nuts would fit.

Are there limitations with magnets?
You will find people who swear by them due to their simplicity and affordability.  And others will not use them because they are not reliable according to the naysayers.  I've read several posts on message boards about magnets falling off during a cook, which resulted in the temperature soaring up.  Those against magnets argue the heat somehow affects the magnet tape and it loses magnetic strength, thus runs the risk of falling off once hot.  I don't know how true that is, but my guess is a magnet that is large (not just big enough to cover the hole) and sturdy enough will probably hold up.  There's too many people who swear that magnets work great to discredit them.  I on the other hand am a Murphy's Law kind of person, and stick with the pipe nipples.

I'm having trouble getting the conduit lock nut tightened onto the pipe nipple.  What's the problem?
I ran into this and didn't know what to do to get the lock nuts to tighten.  Not being familiar with conduit parts, I basically went caveman on them to get them to tighten up.  I originally bought 3/4" x 1 1/2" threaded pipe nipples per one of the plans out there on the internet, and by dumb luck I picked up a couple of "close" nipples.  The close nipples worked much better. 

One poster pointed out that most plans call for water pipe nipples but you have to get lock nuts from the electrical section of the hardware store.  Those are two different beasts.  If it were an electrical nipple, the lock nut would have no problem threading on.  According to this individual the water pipe nipples are have tapered threads, and the conduit lock nuts are made for conduit nipples which are straight threaded. 

That sounds like it makes sense, but the "close" nipples ended up working much better for me.  Remember even the tightest you get it, the nipple will still be susceptible to spinning over time.  To combat this, do not tighten the caps on too tight.  And if you have gaps between the nuts and barrel wall you cannot resolve, consider using J.B. Weld.  You can pick it up at automotive stores, and it can handle heat in excess of 500 degrees.  Let is cure for at least 24 hours.

Lastly, if you're not familiar with the lock nuts, you will see they are curved.  Unless you have a special wrench for tightening them, you'll be relegated to using a flat head screwdriver or chisel to tighten the nuts.  The outer lip goes against the barrel like so: (|)    Not )|(

Will a kettle (aka domed) lid fit on top of the barrel?  For example, a Weber kettle lid.
A kettle lid is a great addition to the UDS.  It allows space for an extra cooking grate at the very top of the UDS and will allow for you to cook bigger hunks of meat like turkeys or beer can chicken that you may not be able to do with the flat lid and a cooking grate at a normal location of 7" to 9" from the top of the drum.

Not all 55 gallon drums have the same dimensions.  Some are a bit wider than others, some taller.  You may luck out and find that a kettle lid from an old charcoal grill (normally a 22.5" Weber grill) fits just right on your drum.  Most are not so lucky and have to do a modification to the drum so that the kettle lid fits nicely and provides a good seal when closed.  Typically that modification is a flange or metal strip that is bolted or welded along the circumference of the drum at the open top.  Here is a link to a couple of threads on BBQ-Brethren where this is discussed along with some ideas. 

http://www.bbq-brethren.com/forum/showthread.php?t=40875

Is there a need to dump ash while cooking in order to keep airflow going to the fuel source?
Usually there is not.  Many report long cooks of 10 hours or more with steady temperatures using 10-12 pounds of charcoal or lump and never touching the charcoal basket.  Some say that if the fire basket is too narrow that it will increase the chances of ash building up and choking out the fire. 

If you want to have something in place to help should ash build up and need a good shake to clear it out, a good idea that will keep you from opening the lid and removing grate & food to get to the basket is to drill a hole in the side of the UDS closer to the bottom that you can put a rod through to poke at the charcoal.  That rod, sometimes referred to as a wiggle rod, will knock ash out and allow for airflow.

Is there a need to add more fuel during a cook?
There should not be.  Many UDS users report long cooks of 10 hours or more with steady temperatures using 10-12 pounds of charcoal or lump and never touching the fire basket.  I cooked a brisket for 15 hours or so on a 20 lb bag of Kingsford Charcoal.   Resist the urge to build a door on the side of your UDS with the thought of needing to add more fuel in mind.  It is a lot of extra work and not necessary.

How big should the charcoal basket be?
Lots of answers on this, but generally wider is considered better.  If too tall and narrow, the ash may get stuck and not fall out of the basket.  Anywhere from 9 inches to 16 inches tall.  Your height dimension may be dictated by what kind of expanded metal you get and whether you can trim it or not.  I used 12 inch high expanded metal and had no reason to lower it (nothing says I need to fill it all the way to the top of the basket with charcoal). 

As for diameter, most people use a 16 inch charcoal grate (Weber being the most popular option).  If your expanded metal is long enough to completely wrap around the grate, that is ideal but not necessary.  In my case I used two pieces of expanded metal that were 24 inches long.  Since I interweaved them on the ends, I lost about 2 total inches to the length resulting in a 46 inch long piece of expanded metal.  I wrapped it around into a circle that resulted in a diameter of about 14.5 inches.  Not wide enough to go around the edge of the grate, but plenty wide enough to do the job.  It easily holds 10-12 pounds of charcoal.

What type of expanded metal should I use for the charcoal basket?
Try to get 3/4" 9 gauge expanded metal.  The lower the gauge, the sturdier the metal, and that will last longer.  Unless they've recently increased their selection, Lowe's and Home Depot only sell 18 gauge.  Their 18 gauge pieces will be an attractive option because it's cheap and has easy to use dimensions, about $10 for a 12" x 24" piece.  It will be easy to form into your basket, but it likely won't hold up very long.  Check with a local machine shop or metal fabricator to see what options they have, and you can probably get sturdier metal going that route. Tractor Supply Company sells 13 gauge in various dimensions including 12" x 24", so I decided to give that a try.  After a half dozen cooks, I see no noticeable signs of strain on the expanded metal I bought, so I see 13 gauge as a suitable option.

There are several specifications used for expanded metal, but in addition to the gauge, the only other one you probably need to think about is the size.  Expanded metal is typically a diamond pattern, and the measurement between the short width of the diamond is important.  Go with 3/4" and avoid 1/2" if you find that.  1/2" inch is more narrow and could restrict airflow to your coals.  If that's all you have access to, it will likely be fine, but you may need to shake the basket from time to time during a cook to help ash fall out.

How do you fire up the charcoal basket?
For the most part you will fill the basket with your charcoal or lump.  Take a dozen briquettes or so, and start them in a chimney.  Once they're ashed over and good & hot, just dump them into the basket along with the other coals. 

Some like to use the minion method for starting their charcoal basket.  Take a metal can, a coffee can or something similarly sized, and cut both ends off.  Place it in the middle of the basket and fill in charcoal and wood around the can.  Get some charcoals going in a chimney and once ready, empty into the tin can.  Use tongs to remove the can, and now you've got your fire going directly in the middle of your fuel source.  The idea is this will keep the fire going evenly and will allow ash to empty out easier as opposed to it being on top of the pile. 
Note: I just started using the minion method on my sixth cook, and it is far more efficient than just dumping the lit coals on top of the pile.  It took maybe 30-40 minutes to have it at cooking temperature once I dumped the lit coals in as opposed to about an hour with how I had been doing it.

And of course if you have a weed burner, you can fire that up and hit the charcoal with it for  a minute or two and that will get it going easier than anything else.

What tool do I use to cut air holes?
The most common thing used is a step bit for your electric drill.  If you don't have one or  a friend who has one you can borrow, you will find they are expensive at the usual big box stores.  Try Amazon.com and search for step bits there.  You may be able to find one cheaper. 

Some have also used hole saw, but the step bit is easier to use, especially if you're not accustomed to using a hole saw.

Is there a cheaper option than a step bit?  Those things are expensive.
The big hardware stores sell step bits for a hefty price.  I haven't seen one with the necessary sizes for less than $30.  That's a bitter pill to swallow for something you will only drill a few holes with.

Go to Amazon and search for step bits there.  They sell a Neiko brand for about $12.  It's titanium coated and has the appropriate sizes.  It is likely not near as heavy duty as those sold at Lowe's or Home Depot, but will last through a few UDS builds.

And of course there's always the hole saw option.
This step bit is a Neiko brand purchased from Amazon.com and it works fine.
How do you control the temperature?
By controlling the air intake.  Lots of UDS builders install a ball valve for air intake control.  The ball valve option as it gives you the ability to fine tune the intake thus resulting in a better control of the temperature.  You don't have to use the ball valves (they can add extra cost to the build that you may not deem necessary).  In that case you just open or close holes at the bottom until you get the temperature you want.  If you choose that route, you might consider using more intake holes of smaller diameters.

Some UDS users use magnet strips over the intake holes to cover them up completely or to provide fine tuning by covering just portions of the holes.  This provides fine tuning at very little cost.

Also, remember that when you open the lid you are providing a lot of air to the fuel thus the temperature will increase rapidly.  If you have the lid off for too long, you'll see the temperature drop, but then possibly climb up too high once the lid is replaced.  Only open the lid when absolutely necessary and try not to leave it open too long so that you will avoid a big temperature spike.

Another option is to make a vent with a sliding cover.  The Big Poppa's website sells vent covers specially made for drum smokers.  If you decide on using a vent for air intake, give their product a look.  It may be easier than trying to fashion one yourself.

Some UDS builds have ball valves connected to the top of riser pipes.  Is the fire still able to draw air with the valves above the heat source?
Yes.  The airflow is still the same, with or without risers (extended pipes).  As long as the intake holes that the risers are connected to are below the charcoal basket, the air will be drawn down the pipe and into the drum.

Are the risers (pipe extensions) necessary?
No.  They may provide a cool-looking factor I suppose, but they drive up the cost of parts a little more (add two risers and two elbows at a minimum, and you've probably added $20-$25 in expenses).  Some guys say they have bad backs and need them so they're not squatting down to adjust airflow at the bottom of the drum.  That may be, but you're likely only going to mess with the airflow a little at the beginning of the cook with minor adjustments along the way, so you probably won't be in a hunched over squatted position for more than a few moments.

How many exhaust holes do I need?  Or should I use a smokestack/chimney/flue?
This is probably just preference.  Lots of people drill 8 holes equally spaced in a circle around the top of the lid, usually 1/2" to 3/4" in diameter.  Sneakeey1 (from the YouTube videos I referenced earlier) used four 1 1/2" elbows as mini-smokestacks on his lid. 

With a smoke stack, you should experience increased draft inside the UDS.  Some argue the increased airflow will increase temperature.  I don't know if that is true or not.  If you have a lid with bungholes, you can probably find a pipe to thread into the larger hole to use as a smoke stack.  My lid has a bung hole, but I'm using it without a smoke stack for the time being.

Note: It rained off & on during one of my cooks.  I fashioned a vent cover out of aluminum foil that looked like a little tin tent to keep out the moisture.  It was kept in place by a couple of bricks and worked fine.  I may install a vent cover later on, though.

How do you empty the ash out?
To avoid tipping the entire UDS over, which is obviously clumsy and more work than what most are willing to do, the most common technique is to place an ash pan below the charcoal grate to catch the ash as it falls.  The pan is wider than the charcoal grate but is not so wide that it cannot clear the bolts used to hold the grill grate in place. 

A popular design for a charcoal basket & ash catcher is to connect the basket directly to the pan below either by bolting it together with long bolts or by welding.  A heavy duty pizza pan works well for that role.

My design has the basket rest on top of the pan, and they are not connected.  I pull them out of the drum separately. 

What kind of ball valves should be used for the air intake?
Most go with brass valves for durability.  Some posters on the BBQ boards have reported using plastic valves and say that so long as they are on an extended pipe (i.e. not connected directly to the intake holes) they will never get hot enough to melt.  I can't speak for that myself since I used a brass valve.

Those brass ball valves are expensive.  Do I really need two?
Lots of UDS builds feature two ball valves (I've even seen one UDS build online with four).  I don't think it's necessary for more than one.  And you can always place a second ball valve on one of your pipe nipples later if you feel it is helpful.

Do you need to use a diffuser plate?
No.  You will find on the BBQ message boards plenty of lively debates about the use of a diffuser plate in a UDS.  Some argue that the diffuser plate is needed to provide an indirect heating method which is what many associate with BBQ cooking, and it gives you a platform for a water pan.  Others argue that the distances from the heat source to the grill (usually about 24 inches) make the diffuser plate unnecessary, and they like the smoky flavor that comes from fat dripping onto the charcoals.  Some find a middle ground and use a pizza pan with holes in it to baffle the rising heat and give a semi-indirect feel.  I like the diffuser plate personally, but it's all technique.

If you use a diffuser plate, a 16 inch pizza pan will do just fine.  You can get a cheap one at Wal-Mart or a dollar store for less than $5.
My pizza pan diffuser. Some use a perforated pan to baffle the air.
How high should the diffuser plate be located?
It's all technique.  Most will split the difference between the heat source and the cooking grate and place the diffuser there.  Some even just put a diffuser pate (pizza pan) right on top of their charcoal basket, but I have no idea if that is effective or not.  My diffuser plate is 6 inches below the cooking grate.

Does the diffuser plate affect cooking temperatures?
Some say it does, some say it does not. I've tried it with & without.  If there is a temperature difference it is not noticeable for me.

Does the UDS cook faster than other styles of smokers?
The general feeling on message boards is that it does.  If not using a diffuser or water pan, the direct radiant heat will expedite the cook times.  I don't know.  The pork shoulders I have cooked at 225 degrees take about the same amount of time per pound as my buddy's who uses an electric smoker set at 225.

Does there need to be clearance between the bottom of the UDS and the ground when in use?
Yes.  Well, maybe not, but you will find if it's on grass that it will kill the grass underneath it in a very nice looking circle.  And you're risking fire if it has been dry.  One person on the BBQ boards reported decolorized  concrete from the UDS on it.

For me I did an initial burn before seasoning, I wanted to see what it's max effort could be and burn off any contaminants that may still reside in the barrel.  It got up to in excess of 500 degrees and even though it was sitting on bricks with a few inches of clearance over wet grass, it managed to leave a burnt out circle about a foot wide underneath the barrel.  So yeah, the temperature at the thermometer was 500+ degrees, but who knows how hot it was at the base where the source of the heat was.  I say put it on bricks at a minimum.  Some use drum dollies and others have built more elaborate UDSs with wheels which make it easier to move and elevates it off the ground.

How far from the top of the drum should the cooking grate be placed?
For a UDS that uses a flat lid, 7 to 8 inches from the top is the norm.  You may read on the message boards that it should be 24 inches from the charcoal basket, but some say the top of the basket and some say the bottom charcoal grate.  The answer is 24 inches from the bottom of the basket, the charcoal grate.  Most baskets are 10 inches high or taller, so 24 inches from the top would be at the very top of the UDS.  24 inches from the bottom puts it at around 7 or 8 inches from the top.  And remember, that's a rule of thumb only.

If you're using a kettle lid, a top cooking grate can be installed at about 1 inch from the top.

What diameter cooking grate does the UDS need?  Lots of people say a 22.5 inch grate, but my drum only measures 22 inches in diameter.
A Weber 22.5 inch grate is made for their 22.5 inch kettle grill.  It measures 21.5 inches in diameter, so it will fit in a 22 inch drum.  My understanding is other brands have the same measurements.

Should 3 or 4 bolts be used to support the grates?
Go with three.  It's unlikely you will be able to perfectly align the height of the holes you drill, so if you use four and the holes are not the exact same height for each, the grate will be wobbly.  Three will hold the grate just fine and will eliminate any wobble caused by uneven heights.

Where should the thermometer be placed?
Right below your cooking grate at minimum, but really it's up to you and probably doesn't matter too much so long as it's in a logical place.  Some builders have multiple thermometers on their UDSs. Those with kettle lids sometimes have another thermometer below the top cooking grate.  I've seen some in the lid, which may give you a better idea of the temperature in the center of the drum.  For mine, I have a lid with bungholes, and the exhaust is the larger hole.  Since that's on the side, my theory is the heat is mostly traveling that direction to escape anyway, so a single thermometer on the side of the drum right below the cooking grate is fine for me.

What kind of thermometer should I use for the UDS?
Whatever you prefer.  Most people go the cheap route.  You can get an $8 gauge from Amazon, and you see lots of people using it: Grill Pit Wood Smoker Temp Gauge - the one with the blue "smoke" zone and red "BBQ" zone.  Experienced pit masters and cooks will caution against the cheap dial gauges because they are often inaccurate.  I used the cheap brand, and I dropped my digital probe into the drum during the first cook to see how close the dial was to digital, and they were within 5-10 degrees of each other.  I acknowledge that precision may degrade over time, but it will do for now.

As I've mentioned before, I recommend utilizing the AmazingRibs.com website for expert opinions and reviews of products.  The main writer, Meathead, disdains the bimetal dial and highly recommends using a digital thermometer, as do many serious cooks.  The link below is to his write-up and reviews of common thermometers.  The one brand of bimetal dial thermometer that he does like and will recommend is the Tel-Tru BQ300. 

I used a cheap-o thermometer. It's close enough, and I'll upgrade later.

How do you season the UDS?
You've removed the liner and rust inhibitor that was once inside the barrel.  After cleaning it with your wire brush or having it sand blasted, it will be susceptible to corrosion.  It will be important to get the exterior painted and drum seasoned quickly.

Generally, most people use vegetable oil to coat the inside of the drum with it, and then get the drum good and hot to essentially bake that oil into the wall of the smoker.  The application method doesn't have to be complicated.  You can use a vegetable oil spray, pour some into a spray bottle to apply, or wipe it on.

Some builders like to help the seasoning along by throwing a "fattie" (a tube of ground breakfast sausage) on during that burn.  It will spew a lot of grease out which only helps to season the walls.

In any case, do not paint the interior of the drum, even if the paint is rated up to high heat temperatures.  

Are galvanized or zinc coated parts dangerous to use?
If you're not familiar with galvanized steel, it is steel that is been coated in a layer of zinc.  Zinc, when heated (really hot), will burn and let off toxic fumes.  The consensus for most UDS users is better safe than sorry.  If you have access to stainless steel parts or black steel, then it's probably worth the peace of mind to go that route.  If you spend any time on the UDS message boards, you'll see a lot of concern about the use of zinc coated or galvanized parts, especially in the early discussions about the UDS.  The idea is it gets hot in the drum and you run the risk of toxic fumes being emitted.  Later on in the discussions, it is pointed out that it is very unlikely that zinc coated parts will ever get hot enough to burn off.  The melting point for zinc is 787 degrees F.   If your drum is that hot, you have other problems. 

The coals themselves may get that hot, but you shouldn't have any hardware touching the coals.  If you have hardware that is zinc coated, some folks recommend starting up some coals in a chimney and after they're good and hot, toss the hardware into the chimney.  After several minutes the zinc will have burned off.  For me, I'd rather just spend the extra dollar on stainless steel hardware and not think about it.

Monday, October 7, 2013

UDS Build Instructions: Preparing & Assembling the Drum


PREPARE AND ASSEMBLE THE DRUM

Reference my other posts for a list of parts needed to build a UDS as well as how to assemble a no-weld charcoal basket.
The kind of drum you need for this project is a 55 gallon, food grade, open head, steel drum.  Check for drums on Craigslist.  Also, you can contact local machine shops, food distributors, and warehouses.  Or just do a Google search for barrels or drums in your area.  If it is food grade, it will likely have a liner on the inside that needs to be removed.

While not food grade, a lot of people use drums that once contained petroleum products and just made certain to burn it out really well.  Personally, I was not so sure about that idea and wanted to stick with a food grade drum.  I contacted a local barrel supply warehouse, and they knew exactly what I was building once I described what I was looking for.  They offered me an unlined used drum that had some sort of glue in it for $20.

For nearly every barrel, you probably need to do some cleaning.  If it had a liner in it, which are often tan or red in color, they need to be removed.  Even if it did not have a liner, many barrels have a rust inhibitor on the interior or has remnants of something like glue or petroleum that should be cleaned out.  Your options are to burn the drum with a big fire, burn the drum with a weed burner (aka propane torch), or have it sand blasted.  If burning, you need to put a wire wheel brush to the interior and exterior to clean carbon and paint off of the drum.  To save time, I found a local sandblasting operation who cleaned my drum for $40. 

If you burn your barrel out, at a minimum you should drill your air intake holes at the bottom of the drum so as to provide more airflow to the fire and keep it burning longer.  I recommend drilling all of your holes before doing any cleaning.  Here are the steps to follow.
Here's the lucky drum before work began.
 
Interior diameter is just shy of 22 inches, just big enough for a 22.5 inch grate, which is actually 21.5 inches in diameter.
Right at 35 inches in height.


1.  Get your tools & hardware ready, inspect the drum, remove rubber gasket on lid.  You may find a barrel without a gasket in the lid, but most will have one.  I was lucky enough that mine peeled right out.  If it's stubborn, you may need to take a wire brush and WD40 to it to get as much out as you can.  A good burn or sandblasting will get the rest.
Here's all the hardware I used.

This gasket came off easily.

2.  Drill your holes.  I used a step bit for drilling.  At the bottom of the drum are four 1" air intake holes that 3/4" pipe nipples will thread into.  I have two grates held by three 1/4" x  1 1/2" machine screws each.  And there is one final hole for a thermometer.  Here is my design.  Not quite CAD, is it?  I tried using string initially to measure the circumference of the drum and mark where the holes would go.  That was not as simple as I thought it would be, so I ended up using painters tape, which was much easier.


 
A straight edge proved easier to use than measuring tape.  Not pictured is the painters tape used to measure around the drum.

 
 
I drilled these just a tad too close to bottom of drum.

This is the back of the drum with my design.

3.  Clean your drum.  This will be the most time consuming part of the whole project.  If burning it out, wood pallets are a good fuel source.  Try to put the lid in a position where the fire can reach it as well.  If you use a weed burner, work the torch from the outside of the drum getting the exterior red hot.  That will take care of a liner on the inside as well.

Whether you burn with a fire or with a weed eater, you will need to clean out the debris, paint, and carbon from the drum.  Most people use a wire wheel brush attachment with an electric drill.  You should not have any hardware installed during a burn.

The other option is to have your drum sandblasted.  This will reduce your labor significantly, but be sure to still get the temperature up good an high in your first trial run to burn off any contaminants that may still reside in the interior wall of the barrel.
See how the paint is coming off during the burn.  On the right is a cleaned drum after a session with the wire brush.  (Not my drum)
My drum after sandblasting. 

4.  Paint the drum.  If you somehow score a drum with a bare interior and didn't need to be cleaned, you can probably skip this part since the UDS will likely not get hot enough to affect the paint that is already on it.  That said, most people need to burn or sandblast their barrel, so a new paint job is a good idea to extend the life of your smoker.  I used two cans of high heat spray primer followed by high heat flat black spray paint. 
After a coat of primer.

After two coats of flat black.  It could use another coat.

5.  Install the pipe nipples.  I used conduit lock nuts since so many other builders use them, and I'll be honest, I was at a loss on how fully tighten them.  You can see in my photo of hardware above that I actually used two 1 1/2" nipples (based on the plan I was following) and two close nipples. By dumb luck I picked up the close nipples that were mixed into the same box at the store.  I could not fully tighten the lock nuts on the 1 1/2" nipples, but had success with the close nipples.
Remember to get the ball valve in place before fully tightening the lock nuts on the front nipple.

I didn't get a photo with the conduit nuts on.
6.  Install remaining hardware and thermometer.  Use the 1 1/2" machine screws with washers and nuts to tighten into place.  Make sure your grill grates fit and rest properly.
Four air intake holes.  Six screws to hold two grates.  And the thermometer
at bottom of the photo.




Bottom grate with pizza pan for diffuser.

Top grate for cooking.  Everything fits and is (mostly) level.
 
7.  Add exhaust to the lid (if necessary).  Since my lid had bungholes, I elected to use just the big hole for exhaust.  After reading opinions of other UDS users I decided a smokestack, or flue, was not necessary.  I can always add one later, and PVC pipe will suffice if I do.

If your lid does not have bungholes, an easy and popular option is to drill six or eight 1/2" holes in a circular pattern in the lid (do this before paining and seasoning).  They don't need to be covered during the cook.

Also, I have not installed a handle yet but will soon.  It's simple enough.
 
8.  Season the UDS and test it out.  You're pretty much done.  You need to season your smoker to keep the inside from corroding.  If you haven't built the charcoal basket yet, see my other post on how to put one together.  It's easy.

Now is your chance to fire up your UDS and test it out.  If you sandblasted like I did, I think it's a good idea before you season to rinse the inside out with water, dry it down quickly, and then get it going at a high temperature for 30 minutes to burn off any remaining contaminants in the drum.

To season, spray or wipe vegetable oil along the wall of the drum, throw a couple of chunks of wood into your charcoal basket, and let it cook for a while.  The buildup of carbon on the wall will help resist condensation while cooking.  Take this opportunity to play with the air intake to see how well it holds temperatures at different settings.


I used about 5-6 lbs of charcoal & a few wood chunks for first burn.
Got it real hot (450-500 degrees) for about 30 minutes then brought temperature down.
Cheap-o thermometer is close enough for time being.  The UDS held temperature steady for a couple of hours before I extinguished it.
My lessons learned.  You may notice in my pictures that I am out of order from these steps.  I had it sandblasted first, then painted, and did the drilling last.  That was a mistake.  It left lots of scratches from drilling and installing hardware that I had to go back and touch up.
 
Sandblasting did a great job but left the surface of the drum a little rough.  Not a big deal, but I would prefer it to be smoother.
 
I drilled my air intake holes too low (at 1 1/2 inches from bottom of drum) and did not leave enough clearance for lock nuts inside the drum.  I used a hammer to beat the floor of the drum down a little to give clearance, but next time I will go no lower than 2 inches.

I think on my next drum I will look into using a vent design for air intake if I can find vent slide setup that works.  It would be a lot cheaper that nipples and ball valves and would arguably work just as well.

Okay, so that's it.  It's really not hard to put together.  The hardest part is finding a good barrel and cleaning it out.  Everything else can be done pretty quickly.  Good luck with yours.
Finished product, smoking a pork shoulder (Don't mind the spots from a spilled grease mishap).