I do exactly the same as feed^. If you have the core to hand you can pull the tube off stick your finger over the hole then screw the core in quickly without losing much air. Top it up with track pump. If I know I’m going to be wanting it I fill it from compressor at work to about 120psi!!. It will stay charged for months too.

Are the powder extinguishers well rated as pressure vessels compared to the CO2 ones? My only complaint with the version I’ll be building is that a 2kg CO2 extinguisher is of a decent size and a 1kg size would have been preferable (though seemingly unavailable). But I do know that it will readily take very high pressures.

I’ve got the power shot it works well on good wheels, but not all, has anyone just gone hog and bought a small air compressor on eBay such as a wolf or cobra for £75-85
They have 24L inflate to 116psi and use 2.5hp engine

Are they any good

I made mine from an old MIG welding CO2 bottle – 1/4 BSP fittings & I can charge from a track pump or one of those 12volt car tyre inflators.

To date I’ve been borrowing the neighbours cheap mini compressor, like you describe, the only issue was getting the flow/volume right for it to work well. Was fine once pressure was built up and I took the core out.

Time to sort my own solution now though; was planning to buy a mini compressor but after this and the Air Shot thread I’ll follow the home made path now.

I wish I had more time to make one, but prefer to be riding in my spare time so £60 for the air shot On tredz using the £5 off £30 spend is good enough

Well mine is still working fine & took less time to build than many spend inflating a single tyre.

Gets a tad annoying when all your mates pop round to use it mind…….

Couple of quid for stickers…bargain!