Modifying the Smoke Hollow 47180t: The Deflector Plate

Monday I wrote about my first experience with my new Smoke Hollow 4-in-1 offset smoker. This outdoor appliance offers a lot of bang for the buck, but in factory condition there are a few modifications you might want to make. I previously alluded to several that have been detailed by Chris G. on his blog, Nibble Me This. In this new blog post I want to share with you a modification of my very own. Read on for the details on my deflector plate mod.

The Problem
Deflector plate mod? What’s the point in that? Well, the smoking section of the Smoke Hollow 47180t is a typical cheap offset smoker. It consists of a large chamber that houses the food you are smoking, a smaller offset chamber for your indirect heat source, and a hole where the two chambers connect for heat to flow from the source, across the food, and out the chimney. See diagram 1 below.

Diagram 1: The anatomy of an offset smoker. Image courtesy of http://dixiegrilling.com.

The inherent problem with this type of smoker is that the side closest to the heat source tends to become much hotter than the side away from it. Some estimate the difference to be as much as up to 50 degrees! The Toast Test (pictured below) demonstrates this phenomenon. The bread on the right side of the cooking chamber closest to the heat source got a lot toastier than the bread on the left side of the cooking chamber. Imagine this problem with two giant pork shoulders sitting on either side of the smoker for 12 hours of more! The one on the right would cook much faster than the one on the left. When cooking ‘low and slow’, temperature control is everything, so something must be done to remedy this problem.

The Toast Test. Image courtesy of http://www.amazingribs.com.

This problem is exaggerated with cheap offset smokers because they tend to be made of thinner materials and have leaky seams, compared to the more expensive models. The Smoke Hollow is no exception. While not a junky smoker, its materials are definitely on the thinner side, and the spot-welded seams tend to leak a lot of heat and smoke.

The Solution
Most simple offset smokers are very easy to modify to correct this problem. The answer is found in the installation of a deflector plate. A deflector plate is a piece of metal that lays across the opening where the two chambers connect that deflects the heat and smoke downward as it crosses from one chamber to the next. Rather than the heat immediately rising as it passes through the hole, it is forced downward and then up, creating a more even heat distribution inside the cooking chamber. This concept is illustrated well here (see Mod 3, PDF link).

But, wait! There’s just one more problem: The Smoke Hollow comes with an adjustable charcoal basket in the heating chamber.

The adjustable charcoal basket of the Smoke Hollow 47180t.

While a nice concept, the basket assembly sits right in front of the hole connecting the two chambers.

Viewing the smoke basket assembly from the firebox side.

Even worse is the fact that even at its highest point the arm that adjusts the smokebox up and down still blocks the hole.

The basket assembly arm still blocks the passageway.

Because of this design you are left with one of three options: 1. Forget a deflector plate and just deal with the heat variations; 2. Remove the charcoal basket assembly entirely, or heavily modify the cooking chamber by drilling and moving parts around; or 3. Use the left half of your brain and come up with a creative solution. Clearly options 1 and 2 aren’t good enough, so that left me with option 3. A creative solution it is!

My Custom Deflector Plate
I figured that since the basket assembly left me virtually no room for installing a typical deflector plate inside the cooking chamber, and since I didn’t want to remove the basket assembly altogether or start drilling holes and moving things around, I came up with a solution that required zero modification to the smoker itself, is very easy to pull off, and should do its job when completed.

The solution: Metal flashing.

A role of simple 10″ metal flashing can be purchased from Lowe’s for about $10.

That’s right. The same 10″ metal flashing I used to extend my chimney down to the level of the cooking grate can also be used to serve as a deflector plate. Given its thinness and pliability it can serve as the perfect material to fabricate for a cheap solution to the problem. Furthermore, instead of mounting a piece inside the cooking chamber – resulting in a tiny deflector plate angled almost 90 degrees straight down in order to clear the basket assembly – I elected to mount the deflector plate from inside the firebox chamber using the three existing mounting screws and route it through the connecting hole! More on this in a moment.

Sheets of metal flashing are easy to cut and shape into the exact dimensions you need.

The first thing I did was take all the necessary measurements of the space I would be working with. The cooking chamber is 18″ wide (measuring from front to back). The firebox is only 14″ wide. The hole connecting the two chambers measures 12″, with a 1.125″ lip extending into the cooking chamber. I began, therefore, with an 18″ length of flashing and began cutting it down to size. The resulting piece looked like this.

A sheet of 10″ metal flashing cut to fit as a deflector plate for the Smoke Hollow 47180t.

Next I measured where the three screw holes needed to go. Remember, this plate is mounted inside the smokebox chamber and then routed through the connecting hole. It is not mounted inside the cooking chamber. The true beauty of this method is that it requires no drilling or modifying the existing smoker because you can mount the plate using the existing mounting screws that hold the smoker together.

The three 3/16″ screw holes to match the mounting screws inside the smokebox chamber.

Once the holes were drilled, all that was left was to pre-bend the plate at the point where the plate begins to enter the connecting hole. Having this bend made the installation a lot easier since I wasn’t trying to bend the plate after it was installed.

The deflector plate ready for installation.

Once the plate was cut, drilled, and bent it was a simple matter of inserting into the smoker. The pliability of the flashing made this the easiest step in the entire process. While my own measurements were perfect, unfortunately my cutting with a carpenter’s knife on my garage floor was not. But the flashing was easy enough to work with that installation went virtually without a hitch.

The deflector plate installed, as viewed from inside the smokebox chamber.

My biggest struggle was getting the mounting screws through the flashing and then through to the cooking chamber. My drill holes were slightly off, plus I had no one to help me hold everything together while I worked. But 10 minutes of focused effort got the job done.

The cooking chamber with the deflector plate installed.

The 10″ flashing – once you factor in the 3″ needed to mount in the smokebox chamber and clear the lip of the connecting hole – provides almost 8″ of deflection. This, in theory, should force the heat and smoke to rise up more towards the middle of the cooking chamber instead of primarily on the right side, hopefully serving to equalize the overal temperature a little better. In the pictures it looks as though the plate is really close to the bottom of the cooking chamber, threatening to constrict the airflow from one chamber to the other. This is misleading. The space between the left end of the plate and the bottom of the cooking chamber is barely shorter than the space between the top of the connecting hole and the bottom of the cooking chamber. Hence, this plate should not constrict the airflow, just extend it to the middle of the cooking chamber more evenly. Just to be safe, however, I plan on making sure all my seams are sealed in both chambers, especially where the lids close, just to make sure the air flows from right to left as needed. A high-temperature gasket is definitely in order here.

The airflow gap as viewed from within the cooking chamber. Not much smaller with the plate installed.

So there you have it. I have shown you how to install a makeshift deflector plate in the Smoke Hollow 47180t using common 10″ metal flashing without removing or modifying the charcoal basket assembly or drilling a single new hole. I have no idea if this will do what I expect it to do, but I sure look forward to testing it out. In the end, this mod can easily be removed if I decide it’s not accomplishing what it’s intended for. And if it comes to that, at the very least I got to spend an hour playing with my new smoker. :)

Update: Here is a picture of some babybacks I smoked after the installation. See commentary in the comment section below.

17 thoughts on “Modifying the Smoke Hollow 47180t: The Deflector Plate

  1. Nice hack. I wish I had the patience to slow cook. Sadly, I'm the burninator. It's funny, though. I think I'd like to make the smoker mods more than the actual cooking. Nice step by step walkthrough…

  2. For now I'm housing it in my garage. I have a suspicion that this thing will rust at the drop of a hat, plus I don't have a cover for it yet. The thing is over 80" wide, and a decent cover that wide that won't rot in a year would cost me about $70 or so. It came with some decent casters, so I might just keep it in the garage indefinitely and roll it into the driveway when I want to use it. Maybe I could get Troy to build me some sort of makeshift tent to keep it under out back???

  3. Sean, I’d love to hear how this worked. I have ordered my grill and am anxiously awaiting it’s arrival. Your site, among others, has been instrumental in helping me realize I need to mod my grill to make it just right. My question is that I’ve seen some grills that actually have a ‘duct’ that runs the length of the cooking chamber. And then it’s recommended that you ‘duct’ the chimney over to the side of the chamber next to the fire box, so that the smoke is forced all the way to one end, and then has to travel across the food to exit. Thoughts on this? And how has your mod worked? Thanks in advance!

  4. Scott,

    I have only used my smoker once since I installed the deflector plate. I smoked 2 racks of babybacks. (I took a picture of the finished product with my iPhone. See it in the updated post above.) I never rotated the ribs once, and they turned out perfectly. In the picture you’ll notice that one end on each of the racks is darker than the other. This is because the darker ends were much thinner, thus they cooked more. But notice that each rack’s darker section is on a different end. They cooked evenly! Problem solved.

    You’re right. This smoker is not perfect out of the box, but for the price it’s definitely a great deal and worth the extra headache. Actually, it’s not really a headache at all. Modifying your smoker is a right of passage for smoking enthusiasts, and I greatly enjoy the process – from researching the methods to actually making the changes.

    As for routing the smoke all across the chamber and then back across the meat before exiting the chimney, I think this is a nice setup. However, it won’t work on the Smoke Hollow as long as you plan on leaving the charcoal tray assembly in place like I did. And I would recommend leaving it, since this is where your water pan is stored (see picture above). The cooking chamber in the Smoke Hollow is small enough that the routing method you have described isn’t really necessary anyway, in my opinion.

    Glad my observations have assisted you thus far. Stay in contact with me on your own experience.

  5. Sean,

    That’s great news…I was hoping to not have to do the ducting because of exactly the point you raised. Your racks turned out great it appears! I’ll proceed with this mod, and I will definitely keep you updated once I actually take it out for the maiden voyage. :)

  6. Black and red J.B. Weld. See ‘Issue 2′ on the Nibble Me This blog here. You can buy it at your local Lowe’s. It’s very easy – though a bit messey – to apply. You’ll need about 2 packages of it to be able to seal all the seams of both the cooking chamber and firebox. Don’t bother with the gas side. The direct heating gets plenty hot.

  7. Sean,

    I just bought my grill and getting ready to assemble it. I am very appreciative of you guys that have come up with mods so I can handle it during the build process. My only question is when you installed the deflector plate mod doesn’t that block the ability for the charcoal grill rack to be raised or lowered?

  8. It impairs the ability to raise and lower the charcoal grate, for sure. But it does not disable it altogether. You can still drop the charcoal grate most of the way down since the flashing is flexible, but you probably can’t go all the way down without bending the flashing all to bits. The issue comes down to how you plan on using your equipment. Do you plan on using the charcoal grate a lot and the smoke box seldom, or the other way around? I have opted to grill with gas and smoke with charcoal, so the deflector plate was a no-brainer for me.

  9. Sean, I used a 24oz. tall boy for the exhaust extention. Just cut out the bottom and top of the can and it fits perfectly. For a cover go to Wal-Mart and get a 8×10 heavy duty tarp for $10, and a few bungee cords and your rock’in. ” Smoke On”:

  10. Hey Sean,

    I used the smoker yesterday and was using kingsford charcoal as the fuel. I could never seem to get the temp of the smoker above 200 degrees. I have done the gasket and jb weld and made a elevated charcoal rack out of expanded metal. When I went to clean up this morning i noticed my deflector plate was almost touching the bottom of the box. I fell this could have been the issue but was just wondering what you might have thought. Also what type of fuel are you using to achieve the temps you need? And as far as the venting goes where about are you setting the vents at?

    • Jeremy, I understand your frustration. I had problems the first few times I used this smoker as well. Perhaps the following suggestions will help:

      1. I went to Lowe’s and bought 4 pavers to put in the smoking chamber to add some thermal mass. I wrapped them in foil and put three of them in different corners. The fourth one I used to prop up the deflector plate, which had begun to sag and pinch off the opening, just like what appears to be happening to you. I think this is your primary problem, so you need to find a way to make sure air can flow as freely from one chamber to the other as possible.
      2. I use the blue and white bag Kingsford. I use a charcoal chimney starter to ignite it. When using this smoker, I begin by pouring an entire chimney full of unlit charcoal onto the charcoal rack and push it into a pile right next to the opening to the smoking chamber. Then I light another chimney full and pour it onto my first pile once lit. The entire pile of charcoals should occupy no more than half the surface area of your charcoal rack. If your charcoal is spread out across the entire rack then you’ll burn your coal out too fast and never get the tempts you want.
      3. If smoking for a prolonged period, you may need to add another chimney full of prelit charcoal to your firebox after about 2 hours.
      4. I always keep the front damper closed when I smoke. I never use it unless I am using charcoal in the smoking chamber for direct or 2-zone grilling. When smoking I always open the top vent to full, and then use the damper on the fire box to control my temps. When first heating it up I open the damper all the way until I get the smoker nice and hot. Once you open the smoking chamber to add your food you’ll lose some heat, so it’s best to either get it hotter than your target temp before adding your food or just add your food when you first light it up.

      I hope this helps. You’ll learn that even little things like the ambient outdoor temperature, presence of wind and direct sunlight, or how frequently (if at all) you open the lid during cooking can all impact your temps. Keep working on it and you’ll get it figured out. Feel free to ask any more questions here along the way.

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