This instructable is about how to use a soda maker gas cylinder to build a working CO2 fire extinguisher.
Soda cylinders are readily available and easy to refill, although you have to make sure the thread on top of the bottle looks the same as mine, otherwise the handle won`t fit. I couldn`t find any specs of the thread, but the cylinder I use is an Alco2jet-60 from Germany. Maybe you check first before you start to print the parts.
The advantage of C02 over powder is that it leaves no residue, which
is especially welcome when you are working with optical equipment, e.g. a laser cutter. Check wikipedia where to use CO2: https://en.wikipedia.org/wiki/Fire_extinguisher
As this is my first instructable and English isn`t my first language- hope, you understand anyway.
Safety note: this extinguisher is not going to replace a commercially available one! I am not responsible for any damages caused by this device. Use your common sense, always wear eye protection and gloves, especially when testing, and don`t point the nozzle at other persons!
Step 1: The Parts
The whole extinguisher consists of three 3D printed parts, a gasket, an O-ring, a brass rod and a safety pin:
Handle, trigger, retainer: print or get them printed.
Plunger: brass rod 4mm x 38mm (you might have to shorten it a bit: once got the device assembled you will see)
Gasket: OD 17mm x ID 10mm x 4mm , used in water installations
O-ring: OD 3,15 x ID 1,8mm ( should slide nicely over the brass rod and holds it in place)
Safety pin: cotter pin 4mm, cut to 38 mm
Gas cylinder: Alco2jet 60 or similar, as long as the thread is the same it should work.
Step 2: Print, Sand, Paint
Download the zip file and get the parts printed. Use high density for maximum strenght.
Remove support material and sand smooth.
Test if you can screw the bottle into the handle- if not, you will have to rework the thread of the handle with a file and sandpaper. It depends largely on the accuracy of your printer- you want a tight fit so no gas leaks, but not too tight.
Also the brass rod should slide nicely through the holes in the handle and the retainer- if not, use a 4mm drill bit to enlarge the holes.
I did some acetone vapor treatment afterwards (I used ABS), it gave me a better finish and also seems to strengthens the parts.
I also didn`t like the colour of my prints, so I went for a more traditional extinguisher look: black and red.
Use primer first, then spraypaint. Make sur not to paint the thread and any holes, cover them with tape.
Step 3: Assembly
- Slide the O- ring over the brass rod. Use some grease to make it slide easily, make sure its not too tight.
- Put the assembly into the handle from underneath- press it in all the way. The fins help with the alignment, you cannot go wrong.
- Put in the gasket.
- Now you can screw the handle onto the gas cylinder.
- The brass rod should protrude approx. 3,5mm from the handle- if not, replace or sand down.
- Press in the trigger, secure with the safety pin- tada, you are done!
Step 4: How to Use It
- Hold the extinguisher by the handle
- Pull the safety pin
- Aim it at the fire
- Press the trigger with your thumb
- After you are done, put back in safety pin.
The extinguisher can be used several times until the bottle is empty.
I am going upload a video of how it works with some real fire action soon.
Cheers, and have fun building it!
Update: video is online, look at the next step:
Step 5: Testing
I did some tests on various materials, like paper, cardboard and gasoline, and the extinguisher worked better than expected.
The velocity of the gas stream is quite high, so it blew the burning paper around- but maybe this even happens with commercially available extinguishers. There were no problems with heavier stuff, and even gasoline- watch the video!
I might try to enlarge the diameter of the gas nozzle in the handle a bit to slow the gas stream. But overall, I am very happy with the result. The bottle got quite cold after a while, but the valve still operated without a flaw.
And I did approx. 25 short 1 to 2 second bursts, and there is still gas left in the bottle.