decanting spray cans

Can't comment on using straws but my method is to let the can rest upright for an hour or so to make sure the paint has settled in the bottom of the can, then use my pocket knife can-opener to pierce the top rim of the can (under a cloth - just in case) and leave it to de-pressurise.  Once it's gone quiet I then use the can-opener to remove the entire dome and decant the paint into a sealable jar.

I haven't tried piercing the cans before. Don't know if I want to! It certainly could work if you could depressurize the can all the way.

The straw method is good for small amounts, you can get just enough for the job and still have a fully pressurized rattle can for large spraying.

Store bought straws will be too large. Try one off a WD40 can (cleaned VERY carefully) or even go to a hobby store and buy some brass tubing in a small diameter.

I had done what your trying to do. The safest and best way to get paint out of a spray can since it is under pressure is to set the can in warm not hot water for about 20 minutes. Then turn the can upside down and depress the nozzle. Keep the spray nozzle depressed till all the pressure is out of the can. No paint will come out by doing this. Only the pressure will be released. When you think that all of the pressure is out ,set the can in warm water again and repeat the process to be sure all of the pressure is out and to be safe. Never ever drill a hole in the can without the pressure being gone. It could be a disaster. When all the pressure is out of the can you can drill a small hole in the bottom of the can and pour the paint out into your new clean jar, bottle or whatever. It works, I tried it. Remember , the pressure in the can is your enemy.

If you follow the instructions carefully, making sure at all times the paint is in the bottom of the can and the hole is in the top where the propellant gas is, there is actually no danger, but there are two extra precautions I forgot to include - do it outside and DON'T SMOKE!  Common sense really.

Drilling a can could leave pesky pieces of metal swarf in your paint and you can't stir the paint, or pour it, through a small hole.  Best to decant the lot quickly into a container so you can make the most efficient use of it.

Despite the dire warnings of what may happen if you puncture a pressure can it's no more dangerous than crossing the street if you do it properly.  You can practice it on a can whose pressure is almost spent.

Wrap some sandpaper around the handle of a hobby knife and sand a "notch" in the end of the straw.  This will conform to the nozzle and you spray all the apint out of the can if you wanted to without any mess.  Leave the paint in an open jar for a little while and gove it a stir occasionally to de-gas the paint.

Seems like a no-brainer to me, assuming you know how a spraycan works.  There's a plastic tube inside it that extends from the nozzle to the very bottom of the can.  If you're using the can upright, the compressed gas pushes down on the paint and send it up the tube and out the nozzle until all the paint  is gone.

Invert the can and the plastic tube is now extending _up_ from the nozzle into the compressed gas, since now the paint is sitting at the "bottom" of the can.  Open the nozzle and nothing will come out except compressed gas (after a few seconds of residual paint that was still in the plastic tube).  Keep it open until no more gas comes out.  You will then have a closed can with nothing but paint in it, which you can then safely open any way you wish.

If you're really a Nervous Nellie, you can do the heat-the-can-in-hot-water deal, but it really isn't necessary.

Stephan

In order to decant the paint out of the spray can, how would spraying the paint directly from the can into a funnel that sits in an empty jar. Or, why would a straw be necessary?

You might want to look at this video.  Be sure to watch part 2 also.

Don

I simply take a dart, or any sharp pointed object would work, I won't recommend the drill as small amount of swarf might get into the paint, and make a small hole at the top of the aerosol.

Once you have pierced the hole in the can, leave to sit for a while, I place mine in the spraybooth with the fan switched on, when all the gas has escaped, simply cut off the top with some metal shears then pour the contents into a glass jar, I leave it to sit for a while, as there is alway some gas mixed in with the paint, when it's de-gased I add the paint to small glass jar and pop on the lid, then add a label so you know whats inside.

Yup,  I agree with Don.  I decant my spray cans the same way as in the video.  Works everytime.

-Jesse

i hold the straw against the nozzle and point to the jar and spray the amount you need. i do this because i think whats a better storage that its own container? just like why would i want to decant the soup to another bowl if my fridge can fit the whole pot. i know you have to wait for it to degas, but i usually has multiple projects going on so waiting time is not a concern to me. i also heard people been punturing the can for years and have no problem, but why take the risk even there is none, just like why do you want to light up a cigerette on the bed if you can smoke at the living room. (i dont smoke though) i dont even bother to tape the straw to the nozzle because there is no mess at all. straws are free and disposable verses things like funnel that you have to clean it and store it.