Here's a redneck solution: Looks like it would work though.

 

Those "Air in a can" dusters use compressed freon I think. Not certain, but they have a long lived air supply. Simply pushing air back into an empty spray can will only give you a minute or so of useable air pressure. Still - if you have a bunch of those duster cans around you can refill them and keep them around for when you need a puff of air.

 

Used propane tanks are free.

Not around here they aren't. They get exchanged for a full tank or refilled. New ones run 40-70$ and would still have to be converted... Except for the guy who got my spare tank for free off my porch a few years back.

Haven't had any air cans since I retired long ago. Been using the Huff and Puff method and a brush which isn't the best way.

 

Nope, 20# propane tanks unlike compressed gas cylinders, are not dated for inspection. For that matter, they probably aren't even pressure tested nor rated for pressure. The ones that get exchanged get cleaned and repainted as needed or destroyed. Which is great when your tank gets old and rusty it can be exchanged for a better one. Cheaper here to take it to a gas supplier to have refilled though instead of exchanged. But most quick marts have an exchange rack and are convenient.

 

Here it is cheaper to buy the filled used tank outright than to buy a new empty tank. Here it's 15-20+$ to exchange empty for full depending on where. What they don't tell you is how much propane is actually in the tank. Most I think have 15lb in a 20lb tank. But anyway, I'm gonna kill 2 birds with one stone and get the 5-gal portable air tank to keep in the garage.

 

A regular 20lbs like this?

View attachment 241281

Like that but much much older. The one I have the guard ring around the valve is really close to the valve. And I know how to use a pipe wrench and what direction it goes. Have them from a small 8" to a big 48" aluminum Ridgid one. And many 14" ones that get the most use.

 

Wouldn't that be eligible for a Darwin Award wen you connect it to a tank full of propane to blow out dust of your drill?

How? It was empty when I started, and I filled and emptied it with air until the mercaptan smell was gone

Even used propane tanks aren't cheap. Found a 5-gal 125-psi air tank @ Tractor Supply for $33 but it would still need some correct hose and fittings.

Mine was a leftover from back in my Jeep hill climbing days in the 70's. It was on my camper trailer. Harbor Freight sells one too, comes with the hose and fittings.

Most I think have 15lb in a 20lb tank.

Yep they need to leave room for the liquid to out gas to go into the grill or what ever.

Here they are stamped and dated, pressure tested also

The new ones are, but they don't get recertified like a welding gas tank has to. The propane tanks have a 250PSI working pressure

 

Harbor Freight sells one too, comes with the hose and fittings.

It has a 4' hose and air chuck but will need to put in a quick disconnect for the blowoff and my gauge chuck.

 

Ok, ok. But if an unsuspecting person finds your special adapter and uses it on a real propane tank?

What unsuspecting person? Only a thief would have done that by breaking into my shop. They were originally made for a real propane tank, I am just using one for an air tank conversion, to make my life easier.
https://www.marshallexcelsior.com/m-pol-x-14-fnpt-single-piece-adapter

 

It has a 4' hose and air chuck but will need to put in a quick disconnect for the blowoff and my gauge chuck.

They sell those too.