I want to paint using two airbrush containing different color paints and\or needle sizes. Swapping between them as required.
If I leave one airbrush to sit for too long while I'm using the other the paint dries in the nozzle and it clogs.
At there any techniques or tools that I can use to prevent this. Or at least to increase the time that I can leave one sitting idle for 10-15 minutes?
The following advice is actually from a website on spray painting nails, but it's the same principle, and seems like a very good way to prevent the airbrush interior from clogging:
After each use, empty the color cup by depressing the trigger until the paint runs out. Fill the color cup with airbrush cleaner and spray it onto a paper towel until the liquid sprays clear.
Some airbrush manufacturers also recommend leaving the color cup filled with cleaner between uses and at the end of each day so that residual paint doesn’t dry up inside and clog the gun.
I still don't have any experience with spray painting using a proper airbrush, so other users might have better advice, but this sounds like a good way to keep everything clean and useable. Good luck!
It depends on what you mean by an extended period of time, and it depends on the kind of paint and how fast it dries.
In addition to clogging the nozzle, the paint in the cup starts to thicken. Its spray characteristics will change as it thickens. Even if the lid forms a decent seal, there's air in the cup.
Some people will keep using the airbrush as long as the paint is still liquid and the airbrush can push it out. Other people clean out the airbrush as soon as they stop spraying, even if they will be using it again soon. Some people pick a time, like 10-15 minutes and clean it if they expect it to sit longer than that. Emptying the paint back into a proper container keeps it fresher and you'll get more uniform results.
So assuming you're talking about a time short of emptying and cleaning, and longer than a few minutes, what can you do to keep the nozzle from getting clogged? The main thing is sealing it from the air, preferably in contact with some solvent, to keep it from drying out.
If the airbrush didn't come with a nozzle cap, make one out of something like Sugru or Oogoo (homemade Sugru from silicone caulk and starch). It just needs to seal out air and not trap much air under the cap.
You can go an extra step by leaving a small clearance inside the cap and stick a little bit of paper towel in there soaked in an appropriate solvent for the paint (water if acrylic). The cap will hold that in contact with the nozzle and keep the paint from drying.
If you don't want to go through all that, cover the nozzle with a piece of tape that doesn't leave any residue (and leave a folded-over end to make removal easy). Or wrap the nozzle tightly with plastic cling wrap and tape that to keep it from loosening. You can use the wad of wet paper towel trick inside the cling wrap, just make everything a tight fit so there isn't air in the pocket.
