Everyone likes to enjoy an ice cold soda on a hot day. Even if that hot day is filled with flames. In this Instructable, I'll show you how to turn an old, empty fire extinguisher into a stylish mini fridge. Full disclosure, don't expect to be putting out any fires with this any time soon.
Step 1: Materials and Tools
1. Fire Extinguisher
2. 22-ohm resistors (6 of them)
4. Thin plywood
5. 1" by 1" rectangular wooden pole
6. Electrical tape
7. Heat sinks (2)
8. CPU fan
9. Peltier device
10. Thermal paste
(for items 7-10, you can either get separately or all together as a "Peltier cooling unit")
11. 9-volt power source
13. Thin fabric
14. Hinges (1 inch tall)
15. Clasp (1-2 inches)
1. Dremel (metal cutting bit)
2. Hot glue gun
3. Scroll saw
5. Rivet popper and rivets
Step 2: Empty the Extinguisher
First, you have to clean out the extinguisher before your work with it. Simply unscrew the cap, and pour any power out into a plastic bag. Tie the bag shut and throw it away, then rinse out the extinguisher with water. Don't worry about trying to polish the inside, as it'll be covered with the insulation.
Step 3: Cutting the Bottom
This part is going to take the longest. Clamp the extinguisher down so the bottom is facing up. There will be a bit of a lip on the extinguisher, before the flat part of the bottom. Get the Dremel and cut through the extinguisher where the lip meats the flat part. This will take a while because the metal at this part is thick, and the metal cutting disk has trouble with corners, which is the entire cut. Once you get through most of the metal, you can take a hammer and knock the circle out if you want to speed it up.
Step 4: Cut Out the Door
Next, You will need to cut out the door. This will be a lot faster than part 3. Cut a rectangle, from an inch to the bottom to where the top starts to curve. Make the side cut 1/3 of the extinguisher (or a 160 degree cut if you think of it as a unit circle). This time, make sure to not use a hammer, as you don't want your door to be all dented up.
Step 5: Attach Hinges and Clasps
For the hinges and clasp to fit the extinguisher, you have to get a pair of pliers and bend them to fit the curvature of the extinguisher. Then find where you want the hinges to sit on one side of the door, and mark the first two holes. Make a piolet hole with a drill, and work your way up using one size larger bits until the hole in the extinguisher is the same size as the hole in the hinge. Then pop a rivet in the hole and repeat until the hinge is securely fastened. Do this again, but on the other side of the door, with the clasp. (The clasp will act both as a handle to open it and a clasp to keep the door shut).
Step 6: Insulate
WARNING: Most insulation has fiberglass in it. Please be careful and wear proper eyewear, breathing mask, and gloves.
Other than worrying about safety measures, installing the insulation wasn't difficult. Around the door I used some adhesive foam, to make sure the door had a proper seal. Then I measured the spots that needed insulating, cut the insulation, and glued it in. Any glue (besides glue sticks) should work for this. I personally used some Elmer's spray on glue.
Step 7: Covering the Insulation
As I mentioned in the last step, insulation is not something you want to be touching. I got some scrap cloth and glued it over the insulation. I found that hot glue worked best for this. Once all the insulation is completely covered, it's safe to remove your gloves, glasses, and mask.
Step 8: Cooling Components
Assemble your cooling unit. If you have a pre-assembled unit, the move on to step 9, otherwise you will need to put it together yourself. Take the Peltier unit, and use some thermal paste to attach the heatsinks to either end. Then put the fan on the hot side heatsink (If you're not sure, run 6 volts through the Peltier device and see which side heats up). Try to put the cold side heat sink into the bottom of the extinguisher through the hole you cut in step 2. If it doesn't fit, you will need to take the Dremel and cut it down.
Step 9: Circuitry
This step will vary depending on how much voltage your device needs. For me, the fan needed a max 12 volts, and the Peltier device a max of 6 volts. I put six 22 ohm in parallel, then had them all connect back to the Peltier device. Then I put the ohm-Peltier node in parallel with the fan and connected it all back to the 9-volt power source. If your fan/Peltier device needs a different voltage to run, don't follow this example, because there's a change you may put too many volts into your stuff and break them. If you're unsure about how to set up/design a proper circuit, there's plenty of guides online. And remember, be safe when working with electricity. Don't turn anything on until you finished working, and cover any exposed wire with electrical tape.
Step 10: Touch Ups
Once you have your cooling unit powered, you can insert it through the hole in the bottom of the extinguisher. It'll take a while for it to cool down, but it will. Now you have a chance for some customization. The cooling unit and the wires were unsightly to me, so I decided to make a small box out of a thin sheet of birch plywood, and a small wooden rectangular pole for support. I cut the wood with a scroll saw, and hot glued it together. You can hide these components any way you want, or even not at all if you like them. Just remember that whatever you decide to do, make sure to leave a hole near the bottom so the fan can blow the hot air out of the cooling unit
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Trash to Treasure