Leaving material in spray gun

[Mike in Arkansas]

Is it okay to leave finishing material in a spray gun for a few days or do I need to clean it after every use? I'm referring to Shellac or water based lacquer. thanks

[PDQ]

Cleanliness is next to godliness. =20

It also keeps the spray gun in good working order.

--=20 PDQ

[Mike Marlow]

As long as it does not dry you're really ok. I never leave any materials in any of my guns. That's just a long standing practice of mine. I've never liked the idea of spray materials drying in the tips of my guns. Some stuff can be about impossible to clean out once it dries. I do know of painters who will leave primers in a gun over night to use them again the next day.

My personal advice - clean it every time you use it.

[Pop]

If you want reliable, always-ready service from your spray gun, clean it out EVERY time you are ready to stop using it for more than a few hours, say lunch or a quickie inthe afternoon, etc, and it'll hardly ever give you any problems. The first time you can't get dried material out of a nozzle, the orfice, or spray angler, you'll really appreciate keeping it clean thereafter, but why go thru it? You'll appreciate it even more the first time you're half way thru a job and a piece breaks loose and plugs/partially blocks something. I had a neighbor took meticulour care of his spray gun. But he was always complaining it had to "rest" every few minutes of use. I glanced at it, grapped a piece of wire, poked thru the blocked airhole in the top of the canister, and he bragged about me for weeks! I was his guru after t hat .

They're so easy and fast to clean, it's really not a problem to leave fifteen mintues at the end of evry job for a thorough cleaning and wipe down of the sprayer and hoses/couplings, etc., if needed. Also, never leave water sitting inside anything; blow it out, wipe it out, whatever it takes. You'll have lots fewer surprises down the line.

HTH

Pop

[Tom H]

Some watersoluable products contain additives that will interact with aluminum, if in contact for extend periods. Not sure what's in them to cause the problem, but I've read it on several labels. If you have aluminum parts in your gun this could cause a problem.

[Sweet Sawdust]

[Mike in Arkansas]

Thanks everyone. Looks pert near unanimous.

[Mike Marlow]

Hey Mike - one additional thought. Most materials have a pot life and it's usually specified by the manufacturer. Pot life will be affected by additives such as reducers and/or retarders, so you have to pay attention to the details. I still recommend mixing up only what you will shoot in a given session, but if you need to span a day or two, check with the manufacturer of the product you're shooting and inquire about the pot life.

No matter what you decide - clean the gun with the appropriate solvent before putting it up. Pot life is good information with respect to how long the material will last once mixed up, but you still have to treat that gun with tender loving care.