Cold Smoking Modification

I have no further pictures of this unit other than what was in the thread, which you have already viewed. http://www.smokingmeatforums.com/t/243936/cleaning-up-your-act-clean-smoke-is-delicious-smoke

If space allows, I would suggest you place the piping in a horizontal position with each section on a slight incline. Before placing the cart before the horse, I suggest you start with the box in which you intend to place the smoke generator. The efficiency of it will determine the length of piping required to reduce heat to an acceptable limit. Many are using a small mailbox which requires more piping.

If you feel I can help with your build, please ask.

T

I am in awe of that build and have read that thread many times.

However, I am not convinced that you need to add that much pipe in order to both cool the smoke and condense the bad stuff.

I am still a relative neophyte, so bear that in mind as I offer the following suggestion. I also offer this because of what I learned in years of engineering, namely, you design in increments, and then start doing modifications. By doing things this way, you know if you are really making a difference, and you don't waste both time and money building what may turn out to be a severely "over-designed" contraption.

So, my recommendation is to build your mod and use just a few feet of tubing. Do a smoke and then inspect the tubing to see how much gunk is in the tubes. When I built my external "mailbox mod" I made a mistake and bought the wrong duct to extend the distance between the external can and the MES. Here is the thread that describes my experience:  Mailbox (Popcorn) Mod (with a small twist). As you will see if you read that thread, I ended up with nothing more than two short elbows between my external can and the MES. I am actually not tempted to add any more duct. Read below to understand why.

I started experimenting with using a filter instead of simply adding more and more and more lengths of duct, a design approach that results in a product that is tedious to build and install, impossible to clean, and difficult to store. I don't know what it might be like in a wind.

While my initial filter material was a total failure, the Scotch Brite stainless steel scrubbers are working amazingly well, and are collecting 100x more gunk than the duct. This is not a mindless statement but instead is based on actual measurement. I am able to clean every part of my external smoker in my ultrasonic cleaner between smokes. My little lengths of duct get light brown inside, but the filter gets full of gunk (I posted pics on the 2nd page of that thread). When I put the duct elbows into the cleaner, I can see the stuff come off, and the cleaning solution gets darker from the gunk, but is still somewhat clear. However, when I put the filter in there, the cleaning solution turns almost black. There simply is no comparison: the filters are far, far more efficient at collecting gunk that then duct.

There is a reason why you see filters in so many industrial processes involving cleaning particulate matter out of gasses.

Then, if you take a look at the pics of the can lid (on page two of that thread), you'll see that it has more gunk than anything else. If I were to sketch out a design of something that might work even better than my current design, I'd create something with the thinnest possible metal for the lid, and then create a cone-shaped container so that the top was as large as possible. You want the thin material so that the outside air keeps it at ambient temperature (if you put water into two glasses of different thicknesses, the thinner one will condense the water from the air more quickly).

So, even if you don't want to build something like I built, I would recommend you start with almost no duct, but then add a filter. Then, buy three feet of duct, insert that, and see how much stuff is in the duct after 5-10 hours of smoking, and compare that to what was collected in the filter and the can.

In case you don't get around to reading that other thread, here are a few pics from that thread to go with what I wrote above:

Before the smoke:


After the smoke:


I did not show the inside of the duct (shown at right), but it was very, very light brown -- absolutely nothing like the filter and the lid.

Not having a degree in engineering or an ultrasonic cleaner, I do have experience and attempt to use common sense.

As mentioned in my first post, it was recommended that we start from your firebox and go from there. Our target is to reduce the smoke temperature to ambient temperature or below. Using a thin material in the construction of your firebox will no doubt aid in keeping the firebox close to ambient temperature, but I prefer to keep the firebox below ambient so it is my preference to use a thicker material.

The use of a material within the piping may well aid in the collection of creosote and tars, and may aid in being able to shorten the pipe length as far as cleaning, but it would aid little in cooling. It would also interfere with the free flowing draft, which would have to be considered in the design of the cold smoker. If I were to use a filter material in my particular setup, I would place the material within the firebox itself rather than in the piping, but I have found no need for it.

In order to eliminate confusion, if you feel that I can help in the future, feel free to contact me via PM.

Good luck and enjoy working on your build.

T

That might be a good experiment too, running once with the filter close to the smoke, and again with it close to the pit.

I'm just wondering how much of what is condensing on the filter is desirable? Some color is a good thing right? I think​ if we were to filter everything out, there wouldn't be any smoke left to flavor the food. I know ssome of it is harsh tasting, but at what point is the bad stuff all gone? My tubing is pretty clean near the pit end, but certain parts of the pit are sticky from smoke on the inside. Is it any smoke encountering a lower temperature surface that causes that sticky resin to form, or direction of smoke velocity? Perhaps once the smoke is cooled sufficiently, the nasties are gone? I'm curious about all of this.

masonsjax said:

That might be a good experiment too, running once with the filter close to the smoke, and again with it close to the pit.

I'm just wondering how much of what is condensing on the filter is desirable? Some color is a good thing right? I think​ if we were to filter everything out, there wouldn't be any smoke left to flavor the food. I know ssome of it is harsh tasting, but at what point is the bad stuff all gone? My tubing is pretty clean near the pit end, but certain parts of the pit are sticky from smoke on the inside. Is it any smoke encountering a lower temperature surface that causes that sticky resin to form, or direction of smoke velocity? Perhaps once the smoke is cooled sufficiently, the nasties are gone? I'm curious about all of this.

Click to expand...

You have the right idea as far as your product chamber being tacky. This is why it is important, when cold smoking, that the smoke temperature be kept as close to the product chamber and your product being smoked temperature as possible. In short, it eliminates condensation.

T

Hawkce541 said:

 
Did you put the filter by the inlet side, or the outlet to the smoker?

Click to expand...

I put the filter at the point where the two elbows join together, i.e., at the midpoint between the can and the smoker.

Mr T 59874 said:

 
Not having a degree in engineering or an ultrasonic cleaner, I do have experience and attempt to use common sense.

Click to expand...

Geez, what did I do to deserve that?? I identified myself, as everyone does, when I joined the forum. I have an engineering degree, others have marketing degrees, some don't have any degrees. So what? And yes, I have an ultrasonic cleaner, and started a thread a few months ago to share with everyone why I thought it was a neat thing to have for those who want to have an easier time cleaning up after a smoke. Here is that thread: Ultrasonic Cleaner.

The thing that tweaked me was the implication that somehow I don't have common sense. Engineering is where science meets common sense.

Hawkce541 said:

 
The ones that get out of high school and go straight to college and come out "engineers" are lost in the sauce.  Those are the ones that can tell you theory, but can't comprehend when the theory doesn't work.

Click to expand...

You have a point there, but it is a matter of the training. The state schools actually do a pretty good job turning out engineers who actually know how a TV set works. By contrast, a lot of the "name brand" schools turn out engineers who know all the theory, but couldn't replace a fuse in their car.

I'm making plans to raise mine too, I'm 6'3" and it's a PITA to work with anything but the top shelf

Looks like you have her dialed in as your temps have met the goal of 1°- 2° of ambient. With the length of piping being used, the cabinet is doing a good job of acting as a heat sink.

Good job,

T

You said that you are building a base for the "product chamber" (I assume you mean the black smoker sitting on top). When you do that, you might want to give some thought to whether you have enough lateral stability for the whole thing. I live in earthquake land (California) and after a few decades of shaking, it becomes second nature to look at things and imagine them tipping over. Even if you don't have earthquakes, you do have wind, and you perhaps have kids or grandchildren who might come along and run into the thing. I'd imagine that the top is heavier than the bottom, something that will accentuate the tendency to tip over.

Filing cabinets are notorious for falling over when loaded on the top shelf, with the bottom shelves empty. People usually load them starting with the top, because it is easier to access the top without stooping over.

So, when you build your support for the top part, you might want to construct some feet, or something similar, that go sideways at least a couple of feet.

BTW, using a metal filing cabinet is really cool. My only other bit of advice on that is to make sure you do a good long smoke initially, before using it on food, just to make sure that the factory paint and residual oil on the drawer runners on the inside of the cabinet gets covered up pretty well. If the cabinet was made prior to the mid 1970s, the paint might contain lead. As long as it gets coated, you'll be fine. We had lead pipes at the home where I grew up but like millions of others, we had no problems because the pipes got coated with calcium and other residue from the hardness in the water, and lead didn't make it into the water. I think the same will be true in this case, as long as you get a coating started before you use it for food.

johnmeyer said:

 
You said that you are building a base for the "product chamber" (I assume you mean the black smoker sitting on top). When you do that, you might want to give some thought to whether you have enough lateral stability for the whole thing. I live in earthquake land (California) and after a few decades of shaking, it becomes second nature to look at things and imagine them tipping over. Even if you don't have earthquakes, you do have wind, and you perhaps have kids or grandchildren who might come along and run into the thing. I'd imagine that the top is heavier than the bottom, something that will accentuate the tendency to tip over.

Filing cabinets are notorious for falling over when loaded on the top shelf, with the bottom shelves empty. People usually load them starting with the top, because it is easier to access the top without stooping over.

So, when you build your support for the top part, you might want to construct some feet, or something similar, that go sideways at least a couple of feet.

BTW, using a metal filing cabinet is really cool. My only other bit of advice on that is to make sure you do a good long smoke initially, before using it on food, just to make sure that the factory paint and residual oil on the drawer runners on the inside of the cabinet gets covered up pretty well. If the cabinet was made prior to the mid 1970s, the paint might contain lead. As long as it gets coated, you'll be fine. We had lead pipes at the home where I grew up but like millions of others, we had no problems because the pipes got coated with calcium and other residue from the hardness in the water, and lead didn't make it into the water. I think the same will be true in this case, as long as you get a coating started before you use it for food.

Click to expand...

Good advice on all counts right there!