DIY spray paint

Step 6 Pressurize

Time to pressurize the bottle and make this paint can come to life.

Hooking the valve to the bike pump I found I had good results at about 20psi. Experimenting here with different pressure may produce different effects. It's important to know that over pressurization will cause your paint bottle to fail, most likely at the nozzle connection. Start with a low psi and gradually work your way up.

Keep an eye on your connection during pressurization to ensure no leaks have spring. I had my bottle up to about 25psi and have yet to notice any leaks. Over-engineering your sealed connections is a good thing here.

Comments

[El Colombiano]

Thanks Mnieto2. Now i have some ideas to make a pain granade. presure + paint. Excelent..

[#OccupyInstruct]

in kinda getting the idea that it comes out in a stream because of the running, i would probably go up to at least 30-35 maybe even 40 PSI for a more even and lighter spray pattern instead of the stream.

[kurshiukas]

would not suggest over 35 PSI on plastic bottle. Unless it is hardened with ducktape - lots of it.

[#OccupyInstruct]

actually, thats not a bad idea... or you could use an aluminum bottle instead and pump it up to 50 if you figure out how to attach the spray cap to a metal lid or bolt that will fit inside the bottle to make it refillable

[Broom]

A tight-fit hole for the tube + epoxy/rubber cement would work. The force acting on the spray cap is proportional to the area exposed to the can contents, so a tight fit would only produce slight pressure, and the glue would hold.

[turbotonic27]

do you imagine if that bottle explodes from the preasure? paint all over the place :D

[mikeasaurus]

We had the same thoughts when were were priming it with paint for the first time. Start with a low PSI and work your way up, else risk a big mess!

[setsunakaede]

Don't worry too much about pressurising the whole thing (though the hole for the valve weakens stuff a lot...).
As long as the bottle was originally for soda drinks, it should easily handle 6-8 bar. I did so once for a water bottle rocket contest; the pump was the limiting factor here. We pressurised the bottles repeatedly up to about 7 bars and abused them as they tended to end their flights against concrete and metal walls...

If you want to go that high though, you might want to reconsider both valve-ends. Holes are weak points in pressurized containers.

[mnieto2]

good way to make a paint grenade....