Hi, welcome to my first Instructable! I'm going talk you through making a Budget Cardboard Cold Smoker, but first a little about me and why:

I’d always wanted to do more in the Kitchen and have a hobby I could really sink my teeth into and get serious about that wasn’t going to break the bank (initially!!).

I identified cold smoking as something that could potentially satisfy both of these areas and I built my first Cold Smoker from a cardboard box, following some instructions I found online which I then modified to suit my needs and upgraded it with some fresher ideas.

Following the success from making my own and how simple it was I thought that I’d build another one and do a step-by-step guide so more people on here can enjoy the satisfaction of cold smoking, with a view to building a more complex smoker if they decide it’s something they will take more seriously or just recycle a cardboard box if not. This also gave me the chance to further modify my original one and smooth out a couple of teething problems.

This instructable is split up into eight main parts:

Introduction
Tools Required (Step 1)
Materials Required and Material Selection (Step 2)
Box Assembly (Step 3)
Marking Up and Cutting the Holes (Step 4)
Racks (Step 5)
Making and Attaching the Chimney (Step 6)
Finished Result and Optional Extras (Step 7)
Authors Parting Thoughts

Health and Safety:

The boring bit, but I must cover it for my own peace of mind.

You will be using a sharp knife during this build so please take care not to damage yourself of the surface you are cutting on.
This is for building a cardboard smoker for COLD SMOKING use only, make sure that your chosen source of smoke does not come into contact with any of the cardboard or this could result in fire.
Don't use your smoker inside a structure or building.
Follow any food hygiene instructions to make sure what you are smoking and consuming is safe and well prepared.

Step 1: Tools Required

Sharp Knife
Straight Edge
Tape Measure
Hot Glue Gun
Small Wood Saw
Pencil/Pen
Optional: Wood Drill Bit (slightly smaller than your Dowel)

Step 2: Materials Required and Material Selection

Materials:

2 Small Nails
Fabric Tape/Duct Tape (Min 50mm Wide)
Wood Dowels/Metal Rods
Baking/Cooling Racks or Oven Racks
Small Metal Tray
2 x Plastic Cups
Bungee Cord/Tension Strap

Optional:

Mini Digital Thermometer
Weights (for holding it down and keeping steady)
Timer
Cork Mat

Material Selection:

Box Selection: Preferably for this Instructable you’ll need a taller/longer style box.

You’ll ideally want to select a box that is clean, dry and is free from any strong smells as this could affect the smoking process. It’s essential that the racks you have chosen will fit inside your box when it is assembled.

Tape: Get a roll of tape that will be strong enough to hold everything together. Some of the cheaper tapes out there aren’t tacky or strong enough.

Racks: Depending on what you decide to use this will affect your box selection. For this Instructable I’ve decided to use two ‘cooling racks’ and one rack from my own kitchen oven. If you are trying this for the first time then why not use the racks from your oven as they are easily removed from the smoker once you are done and it will save you some money.

Bungee/Tension Cord: This just needs to be long enough to go around the box when it is assembled to keep everything closed. Mine for this smoker is about 30cm long when slack and comfortably fits around the smoker keeping it closed.

Step 3: Box Assembly

Before you start to assemble it, mark up the smaller inner flaps for one side of the box (make sure that these are on the same side when its assembled or you will have trimmed a side that is needed to keep the box closed). Cut these off using a straight edge and the knife, take care not to cut all the way through or onto the surface below. Keep at least one of the offcuts as you will need it during Step 4.

The final inner flap cut will be a lot shorter as thats what will create a slight bit of tension for when the doors are closed. I tape this up as well to protect the edge. If you are confused by how many flaps should be cut you should have: 2 cut down ones on the same side, 1 short cut one and one left normal length on the same side.

Now you can tape up one side of the box, ensure that this won’t pop open during smoking. I taped the central line and then a strip either side of that overlapping to secure it down.

A strip of tape over the corners at the points where a natural hole is formed when the box is creased will prevent excessive smoke loss and air draw from the top that isn’t controlled. I again taped either side of the first strip creating an overlap.

Now the box is sealed you can now tape the inner flaps to stop them from curling during use. You may find these difficult to tape down as they pop up a bit. 2 strips of tape should solve this.

I also added a strip to the centre of the box, but that was purely for aesthetic reasons.

Step 4: Marking Up and Cutting the Holes

You’ll need to decide how many racks you want to put inside the smoker and mark up the holes on the side accordingly. I went with 3 racks due to the size of the box, however I could probably fit up to 4 in total comfortably, depending on how much. I want to smoke at once.

I marked an offset centre line on the smoker box which is where I wanted my racks positioned, this leaves the rack not touching the back or the sides, and far enough away from the front of the box.

I used a scrap bit of cardboard to push 2 nails through at the width needed to support the racks. I then lined this up and press gently to make the dents to show where the holes need to be. A quick dot from a marker pen helps you to relocate these if you look away or your box has other similar marks. You’ll want the racks to be easily removable so you can clean them between smoking sessions. Depending on the type of racks you use will determine the best dowel positioning. You don't want them too far away from the edges of the rack or they could slip off if knocked.

Once these have been marked out, double check the height and position of them as you’ll need your racks to be nice and level to stop anything from sliding off. You can now either cut a cross in the box or use a wood drill bit in your hand to cut the hole. (I prefer using a drill bit twisted by hand).

My racks are 15 cm from the top, then 15 cm from that rack and a the final bottom rack is 20 cm from that one.

Step 5: Racks

Once the holes are cut out you can go ahead and slide your dowels through.

You can measure them up and cut them to size for the smoker box, that way you can secure them in place with a strip of tape. If you prefer you can leave them slightly longer so they protrude from the box. This will stop them from slipping or dropping inside. (That is my preferred method, although for this build I cut them to size).

You will see in the photos that there are two metal rods for the lower racks, thats because I ran out of dowel and had to improvise.

The racks can now be placed onto the dowel and they are ready for use!

Step 6: Making and Attaching the Chimney

Chimney Hole/Vent:

For the Chimney hole/vent I just positioned the a cup where I thought it would be best for smoke draw which is in the middle and more to the rear. Drawing around the cup gave me the dimensions needed to mark up and cut a square out. Doing it this way makes it easier to position later and has more surface area left to adhere the cup to it, plus its far quicker to cut out.

Chimney:

Take 2 identical Plastic Cups, mark up the slots to cut, approximately 48mm x 48mm. Use a sharp knife to cut the slot and then reinforce the edges with some strips of tape.

This will help to a) stop the cuts from splitting when in use and b) make a tighter seal when required to be fully closed. You can see in the photos it can be quite finely adjusted from open to closed with a simple lift and twist.

Step 7: Finished Result and Optional Extras

That should be your smoker good to go! Fold in the two larger flaps, then fold down the single flap and secure with the Bungee. This will keep it closed and still make it easy enough to access.

I added some folded over tape door handles too, which made opening the smoker much easier. With the handles being tape, they fold out of the way.

Optional Extras

Digital Thermometer: I got this pretty cheaply on Amazon, it allows me to monitor the temperature inside the smoker during use. If it is too high because it is in the sun it could cause the meat to spoil, too cold and it could freeze. As you can see in the pictures, the wire was quite long and I looped it around the top set of dowels and aimed it towards the centre of the smoker. The digital readout was secured by using tape.

Weights: I used a couple of 5 Kg Cast Iron Weights to make sure the smoker didn't tip or blow over during use.

Cork Mat: On top of the weights I placed a Cork Mat, just as a precaution for any heat transfer from the Smoke Generator.

Metal Tray: The baking tray is there to place the cold smoke generator on, it will catch any of the wood dust that falls during use and any potential embers that may become dislodged.

Timer: This is simply for monitoring how long you are smoking for, nothing else!

Step 8: Authors Parting Thoughts

This Cold Smoker can be used with a number of different Cold Smoke Generators, some of which can be made very easily using existing Instructables;

Food-D made this: https://www.instructables.com/id/Cold-Smoke-Gener...

and

MPshelutsky made this: https://www.instructables.com/id/Cold-Smoke-Gener...

Both of which are awesome, Food-Ds one is a quick and easy way to get up and running with your own Budget Cardboard Cold Smoker. Just remember to have the metal pan underneath so that the strainer isn't touching any of the cardboard when burning the wood dust!

You could also use the ProQ Cold Smoke Generator, which is a ready made maze generator and comes with the first batch of Oak wood dust to get you started. (See this in the photo above)

What to Smoke:

There are so many different methods and rules for cold smoking, my best bit of advice is to do some research on the internet and see what works best for you. Sounds like a bit of a cop-out doesn't it.....but honestly, what works for me might not be what works for you.

(My favourite though is a method for Scottish Smoked Salmon, oh and I always smoke a block of mature cheddar cheese whenever I smoke anything else)

I've really enjoyed making this Instructable for you to read and hopefully you make your own. Let me know how you get on and if you have any questions or feed back please get in touch!

Keep It Smokey