Mike I understand the desire to do DIY projects especially if you have the necessary tools to get the job done properly. However the dimension you gave are:
Those dimensions are essentially the dimensions of the MES 40"
OD dim = 24.6” x 18.1” x 41.6”
Ok so it cost $299.00, but what you get is exceptional:
• Inside cabinet construction is stainless.
• Stainless steel door with window outer construction, and door seal.
• powder coat steel outer construction
• Thermostatically controlled for a perfect temperature every time; temperature ranges from 100º to 275ºF
• Push button precision digital control panel
• 0-24 hour digital timer with auto shut-off
• Built in meat probe
• Internal light
• Side loading wood chip tray (prevents having to open the door and lose heat to add wood).
• 100% insulated for energy efficient cooking
• Air damper for better smoke control
• Adjustable door latch
• Four smoking stainless racks allow ample room for turkey, sausage, chicken, ham, pork, fish, jerky, vegetables & more
• 40” (3.4 cu. ft.) of cooking area
• Stainless Steel heavy duty water pan
• Stainless Steel heavy duty interior drip tray
• Heavy Coated rear-mounted grease pan
• Adjustable mounting feet.
• 1200 watt 120v heat element
By the time you acquire all the above components and controls, paying shipping and your time spent just locating stuff. Plus the time necessary for construction and assembly, you can't touch the above for $300.
BBally's calc is just enough wattage/btu about 1024 BTUs to get to temp, it doesn't take into account how long, or recovery, or heat loss. If you desired to cook at 250º and the temp outside is 45º it may take 3 hours to achieve with only 300 watts. The original 40" MES came with a 750 watt element and there are many complaints about it's ability to attain the desired set cook temp, and if you open the door how fast it will recover to desired set temp. Thus
Masterbuilt upped the element to 1200 watts. You can find posts I have made that basically says 750 or 800 watts is all that is necessary provided you preheat for 2 hours in cold outdoor ambient conditions, and avoid large loads in such conditions. I think based on so many MES users experience 700-1000 watts would be a better all around choice.
If you want to do the DIY, you might want to consider what I posted here about
two stage heating. In fact by using two separate heat elements as I mention, you could put the 2nd smaller element with both a automatic and manual circuit. The manual circuit would have a rheostat controller to manually select less btus, and allow you to cold smoke. The auto circuit would work for the 2 stage process.
Back to original thought, certainly to some the fun and satisfaction of a DIY success alone is enough incentive to do the project. But from a practical perspective, it is doubtful that you can achieve the quality and function of a MES for significantly less $$. The only other reason to do such a build would be to build in features and functions not in the MES, some would include:
• two stage heating
• ability to efficiently cold smoke as well as normal meat smoking.
• PID controls with multiple inside cabinet sensor and multiple meat probes.
• Automatic wood chip feeder or smoke generator that would last at least 8 hours.
• Heavier construction, and better insulation, thus less heat loss.
Just some thoughts to chew on...
