Leaving finish in sprayer

[Fred Belknap]

I like to spray my bowls with Minwax Polyurethane using a gravity feed $40spray gun. How long can I leave the finish in the gun? I would like to leave it over night and give another coat the next day.

[Dennis Ford]

I have not tried this (very rarely spray poly): wrapping the nozzle up in a disposable latex glove would keep oxygen out and delay the onset of problems.

[Dave Cullen]

Don't do that. Empty the gun, disassemble and clean it thoroughly after each use. Finish can harden in the nozzle passages and around the needle and make your life miserable otherwise.

[daryl moses]

Don't do that. Empty the gun, disassemble and clean it thoroughly after each use. Finish can harden in the nozzle passages and around the needle and make your life miserable otherwise.

X2. Not worth the risk.

[Doug Herzberg]

X2. Not worth the risk.

That's my thinking, too. I would disassemble and leave the parts in the appropriate solvent or at least remove the poly and run the solvent through the gun.

[Fred Belknap]

Thanks for the replies. Pretty much what I expected. I tried to spray some water base poly and it didn't work very well either. I see that others do it but not sure what they spray with.

[Robert Delhommer Sr]

Clean it properly, or put another container with solvent and spray that through to clean the passages.

[Dave Stricker]

Well, I've had a different experience. I use a $19 Harbor Freight spray gun and Sherwin Williams precatalized lacquer...the stuff that is used on kitchen cabinets. I haven't cleaned the gun or pot in about three years. I mix up about 12 ounces of finish and add it to whatever is left in the pot. It is a two part finish. I'm on my second gallon of finish now. I use a semigloss but it is available in gloss. You have to wear a chemical protection mask to mix and spray this stuff and I spray it in a garage with an open door for ventilation. In less than 10 minutes it is dry and can be resprayed. Nice hard durable finish. Buff with the Beal buffing system to a good shine. I usually wait until the next day to buff. Best finish that I have ever used. A turner in one of the clubs that I belong to is a retired cabinet maker and always has the most beautiful finish on his turnings and this is what he used. He didn't use Sherwin Williams but it was convenient for me to get. I don't know why it doesn't set up in the spray gun but it doesn't. I leave it sealed and hang it on the wall in an air conditioned shop. This is what works for me.

[Faust M. Ruggiero]

Think about investing in the 3M PPS system. I have a mini cup set up for my small gravity feed gun. When I'm done spraying (I use lacquer) I disconnect the disposable cup liner and pour a little solvent into the PPS adapter and spray it through the fan. Twice through usually does the trick. I hang up the gun and leave it till next time. A cup liner and cap costs me about a buck each but I get that back in saved solvent and time. Cleaning out a cup uses a lot of each. I only remove the spray cap and needle when I'm completely done spraying the project.
faust

[robert baccus]

I clean my lacquer guns when needed--about every 2 months. Poly could be very different--not a solvent type finish.

[Richard Casey]

I use a pre-catalysed lacquer and leave it in the gun for a week at a time, spray a coat morning and night, never had a problem with this very expensive gravity feed gun. The only issue i have found is at 30% thinners in my mix, they sometimes evaporate a little and the mix becomes a bit thicker, so tip it back into the quart can and add a bit of thinners and remix.
rgds,
Richard.

[Cary Falk]

I leave laquer in my gun all the time. I don't spray poly. It makes everything in the general area sticky. It may be a different animal if left in a gun.

[Stan Smith]

I really wish I was more conscientious about finishing. I use minwax wipe on poly a lot. I have an Earlex sprayer but have not sprayed water based lacquer through it. I've mainly sprayed latex and primer water based. They came out fine. Taking the gun apart and cleaning it is not difficult, but for me it's a p.i.t.a.. I've only left paint in the gun long enough to have lunch--never over night. I did buy an extra can for the gun just for cleaning. As has been said, leaving stuff in the gun for long periods can clog things up. To the folks whose lacquer doesn't clog their guns, you are very fortunate. However, if I tried that, the stuff would dried out the next morning.

[Geoff Whaling]

I like to spray my bowls with Minwax Polyurethane using a gravity feed $40spray gun. How long can I leave the finish in the gun? I would like to leave it over night and give another coat the next day.

I've used Minwax WOP as a wipe-on only and NC Lacquer applied via small Star HVLP spray outfits and very cheap hobby air brushes. I clean the spray outfits after each session per equipment and product specification & product data sheets. Not sure I would bother with WOP via spray application as its formulation is not suited to spray application.

Dave's experience with the cheap spray gun & Sherwin Williams precatalized lacquer probably has a lot to do with its long pot life and his particular shop environment. I would not do so here on the border to the wet/dry tropics in Australia I guess.

[Stan Smith]

Just to clarify mu post. I do not and never have sprayed wipe on poly. Wiping it on has worked just fine for me.