Spraying Water based Poly

[Zacharytanner]

Hi Guys,
I am tired of getting less then stellar results  spraying poly using my compressor and IR 270G HVLP gun.
What are you guys using?

Thanks,
Frank

 

[tiralie]

Hi Guys,
I am tired of getting less then stellar results  spraying poly using my compressor and IR 270G HVLP gun.
What are you guys using?

Thanks,
Frank

Frank:
Depending on how much I need to spray I use my 4 stage Fuji HVLP, (my favourite cause it's a quick clean up) or CAT H2O gravity or CAT H2O CPR with a pressure pot and about 28-29 PSI at the gun.
What's your problem?
Tim

 

[Zacharytanner]

I just spent 2 days spraying with no problems and last night I can't get the poly to spray and when it does it spits out... I clean the guy after every use and strain the poly thru stockings and after this last issue I am fed up..... I was spraying Zar ultra poly

Thanks,
Frank

 

[duburban]

switch to one of the known for spraying materials if you want those kind of results. i did water based over paint once and it took forever to build up because i had to spray so thin to avoid runs.

 

[Zacharytanner]

Do you mean gun or poly? Either way what do you reccommend

 

[tiralie]

I just spent 2 days spraying with no problems and last night I can't get the poly to spray and when it does it spits out... I clean the guy after every use and strain the poly thru stockings and after this last issue I am fed up..... I was spraying Zar ultra poly

Thanks,
Frank

If it worked ok for 2 days, it should work again. Poly dries very quickly so you probably have some blocked air holes in air cap.
I thought I was cleaning my gun, but had the same problem.
Look closely at your air cap. I usually take it off and hold it up to the light. If you cannot see light through the small holes on the horns to the left and right of fluid nozzle, soak the cap in your cleaner/solvent and then use a nylon tooth brush to brush the dried poly out of the holes. This will take a couple passes. If you have a cleaning kit, or a very fine needle you can try to poke the dried Poly out of the holes but I prefer to use the tooth brush as I don't want to make those holes larger.
If these holes are clean, change or get another cap and see if the problem persists.
I hope that helps.
Tim

 

[tiralie]

I was spraying Zar ultra poly

Frank:
Do you mean the "Zar Interior Ultra Max Waterborne Oil Modified Polyurethane"?

 

[JeromeM]

I just spent 2 days spraying with no problems and last night I can't get the poly to spray and when it does it spits out... I clean the guy after every use and strain the poly thru stockings and after this last issue I am fed up..... I was spraying Zar ultra poly

Thanks,
Frank

Yours is a classic case of a gun that needs cleaning. It is usually the air cap as has been said.

The tooth brush method will not damage the air cap, but if the finish has hardened then you need better tools http://www.axminster.co.uk/axminster-axminster-spray-gun-cleaning-kit-prod362793/ is the cleaning kit I have. It has a range of precision needles  for gun nozzles and air caps.

Though it is possible to be a non return valve that has got some finish in it, if you use a pressure cup. That would need replacing.

Most of my finish is now sprayed water based poly.

 

[duburban]

try your sherwin williams for some of their lacquers. i think they have a water based version. all i'm saying is that when i went from messing with spraying water based, oil based, latex/oil paints to finally getting some lacquer in the gun i was blown away. its easy to read as your applying and dries fast and clean! perhaps its time to sample some of the high end water based like general/homestead.

 

[woodie]

I have sprayed Target Coating water based finishes with really good results. I'm using an Apollo 4 stage HVLP. 

 

[nydesign]

I use the enduro products sold by General now. They look great and spray really well.
I just took apart my accuspray gun completely, the entire inside was choked with paint.
it's amazing any air was getting through it at all.