The fire extinguisher variants are cool but I don't have the space to keep a big cylinder. The paintball CO2 cylinders look to be about the right size. They can hold 10oz of CO2 - I guess that's 10 fluid oz, which would should be be roughly 2.6l if I calculate correct. Anyone tried this?
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This is what I used - take off spray attachment, pump up with a kink in the hose, push onto valve (core removed) and release at will.
Did that work. I have one of those and think the release valve would vent before getting to a high enough pressure.
I used to use the tyre inflator CO2 canisters, which are 16g. Not sure what that is in oz.
FWIW I now use the ghetto drinks bottle method, surprisingly easy to make! 🙂
http://singletrackworld.com/forum/topic/ghetto-tubeless-inflator-total-cost-9p/page/5#post-8051163
5 years old and still going strong 🙂
Yeah, it worked really well. Seated the (26") tyre, I left it there for about an hour for the sealant to set and then pulled off the pipe and quickly stuck the core back in before too much air came out.
I then popped the spray attachment back on and did the garden 😉
+1 for the same method as Blobonastick, £10 pressure sprayer from Screwfix. I superglued the pressure release valve and haven't had any problems inflating and seating any tyres so far.
I have one of those and think the release valve would vent before getting to a high enough pressure.
Plugged it on mine with the cut off nozzle end from a mastic tube. Don't ever need to get it beyond 50psi to seat a tyre.
Health and Safety, eh?
I made this from bits at work. Hasn't failed me yet. Similar to the method you are thinking of using with a paintball cyclinder.
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Second time lucky. Apologies if this don't work, you'll have to take my word for it. [img] 
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I had a course at work today on the risks of compressed air.
I'm looking at my pop bottle 'ghetto' inflator through slightly different eyes now.
Might be time to get something designed for the job
anyone know where I can get the adaptors/fittings so that I can use a fire extinguisher?
My rwhites lemonade bottle is going strong after 2 years