spraying paint and poly

[steve kidd]

i have a milwaukee airless/finish paint sprayer M4910-20. i have used it once and became frustrated. finish turned out ok but i brushed the rest of my doors. i really want to be able to use the sprayer but i need some advice, such as:

do you thin your paint and how much and with what do you thin with

do you use the hvlp or the airsprayer

what are the settings you are using when spraying

have you sprayed ploy, did you thin it, hvlp or airsprayer

 

i would appreciate all advice and hints. im really looking forward to being able to spray finishes but need a little direction. thank you all for your comments

 

[Jay Boutwell]

Hello Steve, I have never had experience with any of the milwaukee guns but I have used the airless sprayer which  is a "grayco" finish gun to spray both lacquers and polys.  I also use a hvlp grayco cx8 turbine gun for most of my large jobs spraying both finishes.  I normally do not thin the finish as I have found over the years that thinning has caused blushing in several incidents.  As long as I can push the  finish to the tip of the turbine it gives superior finishes.  There has been times when I have had to alter the tip size to get a nice automized fan spray using a larger tip size and alter the amount of air at the gun outlet due to the thickness of the finish.  This is especially true when using the catalyzed finishes which are very touchy with the thinning process.  As far as the pressure settings I have found that every can of finish and each day is different.  Due to the humidity of the air and the temperature it has became a matter of experience from trial and error and eventually you develope a knowledge as to how to adjust your technique from seeing how the gun is laying down the finish.  It took many sore fingers from sanding away the errors I got, before I figured it out.    I guess what I'm trying to say is that it is an art that developes from practice.  I know that because of operator techniques, no same setting of a gun will produce the same finish between two different operators.   Then the weather elements bring into play a different set of circumstances such as temperature and humidity, the more humid the less amount of finish application at a time, the higher the temperature the more finish applied at a time.  Again the elements determine the pressure settings and  the speed of the gun travel, such as too much pressure the more finish bounce back and landing causing the orange peel effect.  Too little pressure and the finish dries before it has time to flow out on the surface again giving you the "unhappy finish feeling."  It's simply an art and I'm sure you will master it.   I see you like building doors.  This is one of my more enjoyable things also.  I build many doors for not only my cabinetry but for several customers where I build a custom face frame and custom doors to fit.       

[steve kidd]

thanks for the info jay, im sure it will help. just havent taken the time to learn and pratice. yes i like building doors, from plain recesed flat panels to raised panels. some with a diamond shape for the raised panel. im sure there are many doors to be made. this is just a hobby but i have made doors for several people. just like you some were replacements and others were for a unique location. again thanks for the help, im sure we will talk again

[Michael Campbell]

Flotrol for latax and Penatrol for oil based are great products,  they will make an average painter a pro.  I suggest using these additives every time you spray.

[John Schaben]

I agree with you Mike so far as paint goes. Not sure they can be added to other finishes; ie. poly, varnish, etc.

Michael Campbell said:

Flotrol for latax and Penatrol for oil based are great products,  they will make an average painter a pro.  I suggest using these additives every time you spray.

[Jens Jensen]

Well I am a year late here but just purchased a HF HVLP gun to use or furniture restoring etc. The tip is a 1.4 and Ive been told to get  1.7 -2.0 for latex . I got tip the other day and I mixed up 10 oz.paint and 1 oz water and it was just a little on the thick side so  added 1/2 oz to it and it spayed just like a rattle can. I found a site last night that I will forward to you on how to spray .Good spraying to you

http://solowoodworker.com/wood/spraying.html

[Robert G. Higgins]

I am a big fan of Charles Niel woodworking. If you go to his site e has some tips onn spraying you can watch for free. He is currently producing a new vidio that covers all the problems incountered with spray finishes, runs, blotches, fisheyes, etc. I don't know how to direct you to his site like the others but it is Charlesniel woodworking.com. This might help anyone who is interested. It has helped me.

 

[Rick]

What do you guys do for a "spray booth."  That one website guy said he was in Texas and sprayed outside all the time.  I am in SW PA, and I don't have that luxury.  I got cold in the winter, humidity in the summer, a wife with super sensitivity (dear, what do you mean lacquer stinks?), and a basement shop in the garage.

Any suggestions?

[Jens Jensen]

I just started spaying and I live in wet NW and I can see right now that it will be many long awaited days to paint out side so I guess just drop some plastic down from overhead and spray inside

[Jay Boutwell]

Rick, I live in the wet northwest as well  (Oregon) and I do the same method as Jens above.  Drop down some plastic and add some Air filtration and circulation to rid the vapors.  Works however renders the shop useless until the finish dries.  Using a paint mask is a must and should be used anyway especially in the lacguer spraying as it is dangerous stuff.  Another word of caution when spraying lacquer, beware of any open flame or ignition sources such as any electrical spark from a light swith, air compressors or igniton of a water heater or pilot lights.  The vapors from lacguers can be highly explosive as well as toxic.  

[Rick]

I don't mind overspray on the floor, and I can turn an exhaust fan on, but the smell permeates the house. Some of the HVAC ductwork even runs through the garage.  The furnace return air just sucks fumes through the crevices.  No way to make that garage airtight.

Wifey gets a little upset even when I use a little primer.  My heater has an open flame, and that causes more problems.  Turning off the heater, and running the exhaust fan only helps a little.   Ugh!

[Jay Boutwell]

Rick I know what you mean.  It is a problem unless you are fortunate enough to have a dedicated room for finish.

About the best solution that I have came up with is using a good hvlp gun and this will cut down the overspray problem however the odor still lingers. I use a small hvlp gun that is pressurized from a compressor for very small jobs but resort to a graco turbine gun for large jobs like kitchen cabinet sets.  The turbine gun has less that 6 lbs of pressure and sprays heated air which helps the finish lay down flat  and allows more finish to be applied in a shorter time thus cutting down the amount of time you are exposed to the vapor smells.  I have even used this gun in occuppied homes to finish woodwork and will be pretty much odor free in about an  hour.  The big advantage to this is that is very little overspray and therefore you get more of your finish applied to the the surface of your project.  Good luck as summer time is still aways off.

[Rick]

Doug, I just bought that book.  Thanks for the recommendation. 

Douglas Harwood said:

I could get into why I never spray poly "varnish", HVLP versus air sprayer ect., save yourself a lot of grief and pick up a copy of "Understanding Wood Finishing" by Bob Flexner.  This can be purchased as used on Amazon.  This is not a full blown technique book, but cuts through all the crap on the internet and will dramatically reduce your frustration level, I promise.  This is considered the "Finisher's Bible by many, me included.  My best advice would be to read it, re read it, and keep it in your shop.