Masterbuilt Electric Smoker Mailbox Mod

by Kevin Wilson

mailbox mod


The Masterbuilt Electric Smoker is a good smoker, but it may work better for you after completing the "mailbox mod". The mailbox mod essentially moves the chip holder outside of the smoker. Typically, a mailbox (or other metal box) is situated next to the smoker and connected to the smoker's chip loader hole with aluminum dryer duct. This makes it easier to add chips, monitor the chips and keep the chips lit.

In this page I'll walk through the construction of my mailbox mod. You may follow it to complete your own mailbox mod, or just get some ideas. There are many, many different ways to complete the mod. My process was limited to the materials I found on sale or had laying around. I was also limited by my available tools. Also, my wife doesn't like it when I blow a bunch of money on crazy schemes (like attaching a mailbox to a smoker) so my budget was constrained.

Why go through all the trouble of attaching a mailbox to your smoker? How does the mailbox mod improve the smoker? Well... the inside of the smoker just isn't a great place for the chips. First, you have to open the smoker door to observe and access the chips. While you can add chips with the loader, I find it a bit cumbersome. Sometimes I'd find that my chips had piled up on one side of the chip holder. Occasionally the loader was difficult to pull, push or turn. If the chips went out, the door must be opened to retrieve the chip holder, and once again to get the chip holder back in. Opening the door of your smoker should be kept to an absolute minimum. Every time the door is opened you lose precious heat, moisture and smoke. Opening the door can significantly extend your cooking time due to the heat loss. As the old saying goes, "If you're looking, you ain't cooking". The inside of the smoker should be very humid to keep the meat moist, but a humid environment isn't conducive to smoldering chips. An external chip holder solves all these issues.

Required Tools and Materials

The image above is my completed setup.

First, I built a simple stand. You can download my SketchUp file for the dimensions. Of course, you can make the stand however you want, or not use one at all. I won't go into too much detail about the stand because that could become it's own page.

mailbox mod stand

After the stand was completed I started on the mailbox. I found this mailbox on sale for under $9. It's galvanized steel with black paint. Galvanized steel has a zinc plating. Zinc can make you sick and some people are concerned about using galvanized steel with food. Generally I'd avoid using it, even though the FDA has approved galvanized steel to contact food but in this case I think it's acceptable because the zinc plating is stable until it reaches almost 400 hundred degrees (F). Even at this temperature the zinc plating only begins to peel, which shouldn't be a problem if it's away from the food in the chip holder. The temperature must increase to over 800 degrees to melt zinc, which is when it can cause some health issues. Many people have used the mailbox mod with galvanized steel without reporting any issues. I was more concerned if the paint would tolerate the heat. So far is seems fine. Actually, the surface of my mailbox never gets hotter than it would out in the sun on a hot summer day. I can always hold my hand on it for at least 1 second.

First, I held my 90 degree elbow against the side of the mailbox and traced around it with a white china marker / grease pen.

mailbox mod

I wanted the hole near the top of the mailbox, but the top of the mailbox is rounded so I had to tilt the 90 degree elbow as I traced around it so it stayed flush with the mailbox. Without getting into a bunch of complicated geometry, just know that when a cylinder (like the 90 degree elbow) intersects a curved surface (like the mailbox) the hole will be oval.

mailbox mod

After tracing the 90 degree elbow, I found the center of the circle. There's many ways to find the center, but remember that this doesn't have to be perfect and that the hole may be oval. Then I drilled a hole in the center. Next I drew 16 lines equally spaced around the circumference to the center. The easiest way to do this is to draw an "x" (your first 4 lines) then draw 4 more lines half way between the existing 4 lines. Now you have 8 lines. Finally, draw 8 more lines half way between the existing lines.

mailbox mod

Now cut along the lines with a dremel and a cut off wheel. I cut just a tiny bit past the line I drew around the 90 degree elbow to make sure the hole would be big enough. Try not to let the metal wrap around the dremel. This will make a lot of very loud, annoying noise, so make sure to wear hearing protection.

mailbox mod

Now bend the tabs up with a pair of pliers. You can try to bend them into the mailbox if you want a really nice look, but I suspect it's a lot more trouble than it's worth.

mailbox mod

The tabs are sharp so be careful. This is a good time to cut the pointy ends off of the tabs, if you want to. Be sure to leave enough tab for the duct clamp. Carefully fit the 90 degree elbow into the hole. My hole was a bit too small. I couldn't get the dremel in there with the tabs sticking up so I used a hacksaw to extend a few of the cuts a little further. After that the 90 degree elbow fit right in. Be sure to get the 90 degree elbow rotated to the proper orientation.

mailbox mod

With the elbow in, put the duct clamp on. You don't need to tighten it too much, just get it snug so the 90 degree elbow doesn't move.

mailbox mod

My mailbox door will rotate down and extend under the bottom of the mailbox when it's opened. This means the mailbox won't sit flush with whatever its sitting on when the door is opened. To solve this you can position the front of the mailbox to hang off the front of the shelf, or you can raise the mailbox up about 1/2".

mailbox mod

I opted to raise the mailbox with some 2x4s. This also makes it easy to secure the mailbox to the shelf.

mailbox mod

I cut the 2x4s to the width of the mailbox and secured them from the sides with a few screws. Then I secured the mailbox to the shelf with a few screws from under the shelf into the 2x4s.

mailbox mod

Next I removed the vent from the top of the smoker. It's held on with a bolt and a nut.

mailbox mod

The vent has a tab that's bent down to stop it from turning past the vent hole. I used a pair of pliers to bend the tab up so it's flush with the rest of the vent. Next I held the vent against the mailbox door, marked the center and drilled a hole. Then I mounted the vent to the mailbox door with the bolt and nut.

I had originally panned to drill 4 vent holes in the door, about 5/8" diameter, but I decided to use the vent cover from the top of the smoker. With the vent in place, mark the center position for the vent holes in the door. Drill some pilot holes, or just go right to the 5/8" bit - whatever works best for you.

mailbox mod

I decided to use the dremel and a grout removal bit (that's the only bit I had that would work) to make the vent holes match the vent cover. It required a lot of careful cutting. In retrospect I probably should have just drilled some vent holes and moved on.

mailbox mod

I got the vents cut. Not perfect, but it'll work. Next is the "guts" inside the smoker.

mailbox mod mailbox mod

Since this stuff isn't doing much anymore, I figured I'd take it out. It's only held in my 2 screws and 1 bolt. I put a cheap aluminum pan over the heating coil. Update - I've removed the aluminum pan and the heating coil is doing fine. The water pan keeps almost all of the drippings off it.

The other 90 degree elbow just fits in the hole for the wood chip loader. Simply connect the elbows with a length of aluminum dryer duct and you're done. Now let's test it...

mailbox mod

I started up the smoker and checked the draft after a couple minutes. No problems there! I only see smoke coming out of the front of the mailbox when it's very windy, so the draft seems to be good.

Time for an actual test.

mailbox mod

Awesome brisket! Everything seems to be working great.


After adding the mailbox mod to my Masterbuild Electric Smoker I've found that managing the chips has become much easier. Completing the modifications was fairly cheap and easy. If you're having trouble with the chips in your smoker, I'd definitely recommend trying the mailbox mod.


Keeping records each time you operate the smoker is the best way to improve your smoking skill. I have a Smoking Data Log sheet (xls spreadsheet format) available for download.

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