New Build: The MUDS

I have nearly completed a "mini ugly drum smoker" or MUDS.

I walked into an ACE hardware store and saw some large lard cans, and that got the wheels turning. Those cans have very thin walls, however, and I was afraid that they would not take the heat. For that reason, I am experimenting with a komodo-esque clay pot firebox.

I can fire this up as soon as tomorrow for testing, but I was wondering if I should paint it first and wait. What do you guys think?

Pictures follow:

Here are the basic components:


The lard can on the left is the food chamber. It has holes drilled in the bottom to allow smoke and heat to enter from the fire chamber (the can on the right). The food chamber is permantly attached to the lid for the fire chamber, but the holes in the fire chamber lid are misaligned by design from those in the food chamber bottom so that the direct radiant heat from the coals does not get directly to the food. The design has an inherent baffle.

If the description above is not clear, consider that the bottom of the lard can is raised about 1/4" due to the seam around the outside. When this can is fastened to the lid below, there is a 1/4 inch dead-space or plenum formed. We must cut holes in both the top (bottom of food chamber can) and bottom (lid for fire chamber) surfaces of the plenum for smoke and heat to get through, but we mis-align these holes on purpose so that the smoke must bend around to get through. So, the infrared radiation from the fire is blocked. Cooking is indirect.

The following shows the stacking of the clay elements. The firebox is placed on top of a clay ash chamber. The square hole in the side of the ash chamber will be placed in the fire chamber to align with the intake hole (intake air damper):


Here is a view looking into the fire chamber (at the firebox) from above:


Note that if we remove the grid from the food chamber and install it directly over the firebox, we have converted to a grill:


The shot above also shows the bottom magnetic slide damper. There is a similar damper on the top:


Here is a view of the two main components. Note that the left-hand assembly (food chamber) has a lard-can lid permanantly attached to it's bottom. The smoke plenum is between the lid and the bottom of the food chamber can:


Here is a top view showing the cooking grid. If you look closely, you might be able to see the smoke holes in the bottom surface of the can:


...and finally the completed cooker:


In operation, the handles on the lower lard can will be used to move the entire cooker. The side handles on the upper lard can, when lifted, separate the food chamber from the firebox. This makes re-fueling possible (but I hope that it will not be necessary during a cook). The top handle, of course, provides access to the contents of the food chamber.

This has been a fun build, and I am tempted to give this unit a test run tomorrow. There is a chance that the thin walls of these cans will not be up to the task, even with the ceramic firebox, so I would not advise anyone to try to follow in my footsteps until I have done some real testing with this cooker. Sizing of intake and outlet ports was done by pure SWAG. I may need to tune things later...

I've never built a UDS, but I assume that I will want to spray the cook chamber with oil before the first firing to build up a patina and season the inside. I'll be looking for whatever advice you guys can throw me before first firing.

Thanks,
Don

I fired this thing up today.
It has been going steady since about 1:30PM, or more than 6 hours so far.

Temperature control was a bit squirrelly at first, but after an hour or so I was able to stabalize the food chamber at around 250F. It seems totally un-necessary to use the bottom damper at all. I can leave the bottom hole wide open and simply adjust the top magnet.

There is no discoloration of the metal from the heat. The thin-ness of the metal was a bit of a convern, but this has not caused a problem.

At around 4:30PM, I threw a couple foil-wrapped potatoes on, since I was going to do a couple steaks on the BGE tonight, I figured "why waste the heat". So, I guess the cooker has technically been thru it's first cook!

I used an external thermal probe to measure the internal temperature and found that the cheap-farking thermometer I installed reads about 30 degrees low. Oh well, I guess it that is the only issue, I should consider myself lucky.

I'm going to leave the baby burning for a while to see what kind of longevity I get from the fire.

Don

It would certainly be better to use the bottom vent in the context that the fire would not tend to "run away" if the top section was removed for re-fueling.

Being lazy, it was easier to adjust the top and leave the bottom alone, however...

Regarding LT's comment --- this is no egg, it has limitations that the egg does not have. The top compartment is not insulated, so you burn more fuel, and you need to make adjustments if the external temperature changes. It is true that the design of the firebox was heavily influenced by the egg, however. I own two eggs, and they are my primary cookers. This thing is an experiment. This unit may be the thing I take on trips, however. I have not found a reasonalble or practical way to transport my eggs!

The unit has been burning for 8 hours now, so it will definately be possible to do a cook with this thing and get a night's sleep. I sort of expect it to peter out after about 12 hours. One thing that is cool about this design is that if you do need to re-fuel, removing the top section does not cause a huge amount of cool air to enter the cooking chamber. The baffle at the bottom of the cooking chamber slows down the exchange of outside air, and once you set the cooking chamber down on the driveway or ground, the air exchange is slowed down even further.

Forgot to mention earlier that I made no effort to scrounge for used or surplus parts. Everything was purchased new, and I came in at around $60. It should be possible to build a similar cooker for much cheaper if parts were scrounged. The lard cans were about $12 each new.

Don

No galvanized metal at all. The expanded grate will rust, I imagine, unless the patina is enough to protect it. The cans are steel or tin plated steel.

No food pics yet, because so far I've only done a few (uninteresting) foiled baked potatoes in them during the test cook. I'll post more interesting pics as soon as I can.

On a negative note, I have noticed a crack in the firebox since the test firing. This weekend sometime, I will pull it out of the can and evaluate. If the clay pot falls apart in my hands, I may need to re-think the firebox strategy. If it holds together, then perhaps the stress in the clay pot is already relieved and I can continue to use it.

An alternate approach would be a large clay "saucer" on the bottom of the can to protect the floor, then put in a conventional raised expanded steel charcoal basket.

Don

Mark,

What diameter pipe did you employ? If there is material available that is either 2" smaller or larger in diameter than a 55 gallon drum, then there would be an interesting potential to design an awesome dual-envelope insulated UDS!

Don

Aqua,
The cans are about 12" wide at the top, 11" wide at the bottom. The height is about 14", I think (I can measure and let you know for sure if you need). The grid is 11" dia.

Wampus,
I am aware of the scrounge costs of the UDS and used smokers. This was a concept build. I figure anybody trying to follow my tracks could do a lot better cost-wise than me by scrounging for materials. It is probably possible to find used cans, raid the wife's flower pot stash, etc...

Don