how to safely and effectively clean spray gunn

[Paulh Tremblay]

Just got finished spraying for the first time with a spray gun (Qual) and wanted some advice on how to clean it. I sprayed an Enduro tinted poly.

The manual says to just spray solvent through the gun. I filled the cup about 1/3 full of water and sprayed that into the sink. I then put a very small amount of mineral spirits and sprayed that too into the sink. About a minute into doing this, I think "holy crap!" I check the container of the mineral spirits, and sure enough, it says "combustible." Won't do that again.

Any advice on effectively and safely cleaning a spray gun? Since I will only be spraying water bourne products, I think I need to finish any cleaning job with denatured alcohol.

[Scott Holmes]

Acetone cleans water-borne finishes well as does ammonia and water. I would use a mask spraying either.

Mineral spirits down the sink is a real waste... spray it into a container; you can reuse it for a very long time.

[Rick Mosher]

To properly clean a spray gun it must be disassembled and the fluid passages cleaned with the proper solvent and brushes. There are gun cleaning kits available with different size brushes specifically for this job. If you just run solvent through the gun and then take it apart you will see traces of coating still inside the gun. This will build up over time and cause a lot of problems when spraying. There is a proper sequence to taking apart each spray gun. Usually that means removing the needle first to avoid damage and causing the gun to leak. Never submerse the gun in any solvent, the air passages are not intended for solvent and they can get particles that will come out when spraying. All fluid parts, fluid nozzle, fluid needle, air cap etc can be soaked in solvent and then cleaned with a soft brush. I like acetone or MEK but it depends on the finish you are using. The fluid nozzle should be removed using a box end wrench the proper size NOT a crescent wrench or pliers.

[scott vroom]

I rarely disassemble my HVLP gun after spraying waterborne. I pour leftover finish back into the can, wash the cup and nylon filter thoroughly, then run 2 quarts of warm water through the gun into a bucket, with nozzle wide open. I also remove and wash the large rubber gasket that seals the gun-cup connection, and scrub any residual dried finish from the top edge of the cup. I use my finger nail to scrape any residual finish off the spray tip and spray fan piece. I don't wire brush the feed tube or remove the needle. Works for me.

[Paulh Tremblay]

Acetone is even more flammable than mineral spirits, and denatured alcohol is used in camping stoves. I did find a non flammable brand of mineral spirits and a Krud Kutter for spray guns, so I'll try these products.

[Scott Holmes]

I use the acetone to clean the parts; not spray it thought the gun. Spraying it through the gun for 20 seconds will not be an issue unless you aim it at a flame.

"Non-flammable MS" sounds like a marketing guy that got very creative with his words.

[Jim Becker]

...and mineral spirits is not a solvent for most, if not all, water borne finishes. Neither is alcohol. I clean similar to Scott Vroom most of the time; I remove the spray cap and needle assembly, etc., and run HOT water through every thing. Once in a while, I'll do a deeper clean and disassemble things a little more and clean with acetone in a dish outside.