Reducing PPG Concept Urethane

I shot my first batch of PPG concept today, and it shot slower (and had more orange peel) than I expected. When I was shooting the primer, I accidentally over reduced it - and discovered that it sprayed much better. Smoother finish and faster spray.

I mixed the PPG per the instructions: 4 paint, 2 reducer, 1 hardener. I'm wondering if "over reducing" will make it spray better.

And also what are the risks of using too much reducer. I know it may run, but is there anything other than runs that I should be watching for?


Thanks,

John

On Saturday, January 23, 2016 at 6:42:21 PM UTC-5, wrote:
I shot my first batch of PPG concept today, and it shot slower (and had more orange peel) than I expected. When I was shooting the primer, I accidentally over reduced it - and discovered that it sprayed much better. Smoother finish and faster spray.

I mixed the PPG per the instructions: 4 paint, 2 reducer, 1 hardener. I'm wondering if "over reducing" will make it spray better.

And also what are the risks of using too much reducer. I know it may run, but is there anything other than runs that I should be watching for?


Thanks,

John

I mix 8 to 5 to 2. This is 25% more reducer. Flows better. Better flow for me means less likelihood of going too heavy and making runs.
Good luck
UH

Thanks! Do you make any adjustments for cold weather?

On Saturday, January 23, 2016 at 8:46:48 PM UTC-5, wrote:
Thanks! Do you make any adjustments for cold weather?

No.
Using slower reducer also helps flow out at the expense of recoat time. Even in cool(70 or less) shop I use medium temp reducer to get better flow out. It adds a few minutes between coats but makes it easier to get a bit better result.
For acrylic urethane I use a turbine HVLP system which gives a big pattern and has no water in the air. I can't make myself use my $400 gun for polyester topcoat so I do get a few fish eyes in that.
FWIW
UH

Keep paint products in heated office/house for 24 hours before shooting. Add reducer/thinner until happy with viscosity. Adjust gun meticulously. Keep gun clean or use $40 guns and replace often. Spray multiple coats rather than one thick one with California Curtains "runs". Adjust air pressure to your liking. You want good atomization. Use water traps (that's plural). Good lighting in work area.

Manufactures recommendations are just that. My mentor laughed when I first showed him the instructions. Yea right was his response.

Good luck.

Lane

On Sunday, January 24, 2016 at 12:32:25 PM UTC-5, wrote:

For acrylic urethane I use a turbine HVLP system which gives a big pattern and has no water in the air. I can't make myself use my $400 gun for polyester topcoat so I do get a few fish eyes in that.
FWIW
UH

I know guys that are serious about painting are particular about
what goes through their guns -- never put primer through their
favorite gun and so on. But what's the rationale for this? It
seems to me that the paint follows such a short path through
the gun that it can't cause any serious wear. At least for
gravity feed guns. Are there other issues?

Jim Beckman

On Wednesday, January 27, 2016 at 7:44:01 AM UTC-5, wrote:
On Sunday, January 24, 2016 at 12:32:25 PM UTC-5, wrote:

For acrylic urethane I use a turbine HVLP system which gives a big pattern and has no water in the air. I can't make myself use my $400 gun for polyester topcoat so I do get a few fish eyes in that.
FWIW
UH

I know guys that are serious about painting are particular about
what goes through their guns -- never put primer through their
favorite gun and so on. But what's the rationale for this? It
seems to me that the paint follows such a short path through
the gun that it can't cause any serious wear. At least for
gravity feed guns. Are there other issues?

Jim Beckman

i have a favorite gun, i'll put primer and topcoat through it. it just needs to be thoroughly cleaned. if there is residual junk in the gun, even stuff around the cup lid, it can end up in your topcoat. thats probably why most people are weird about it. the primer itself has no negative effects on the guns ability to shoot paint.

On Wednesday, January 27, 2016 at 7:44:01 AM UTC-5, wrote:
On Sunday, January 24, 2016 at 12:32:25 PM UTC-5, wrote:

For acrylic urethane I use a turbine HVLP system which gives a big pattern and has no water in the air. I can't make myself use my $400 gun for polyester topcoat so I do get a few fish eyes in that.
FWIW
UH

I know guys that are serious about painting are particular about
what goes through their guns -- never put primer through their
favorite gun and so on. But what's the rationale for this? It
seems to me that the paint follows such a short path through
the gun that it can't cause any serious wear. At least for
gravity feed guns. Are there other issues?

Jim Beckman

The gun I use for AU has a smaller tip than the one I use for thicker filler. This makes it a bit easier to get a better pattern to atomize better which is less of a factor with spray filler. It is also a bit harder to get perfectly clean so I just switch guns. With filler I'm trying to put on a lot of stuff quickly. With finish coats, I'm trying for better finish quality.
UH

The nozzle will elongate over time in the direction of the fan. It is believed that the fillers in primer will erode the nozzle faster. Hold an old nozzle up to the light and this elongantion will show.
I shot gelcoat on this replacement right wing yesterday........heated the paint to about 80f, which helped, but it still needed 10% thinner. Two wet coats gave orange peal to the max. Shot a 'leveling' coat with an additional ounce of thinner and fan opened up with gun a foot above the work........it looks pretty good. Must have 30 pin holes in places I inspected with a light and even a magnifying glass..............where (how) do they form? Catalyzed a tad of paint and filled the pin-holes with a tiny brush. The bump will disappear with wet sanding.......hopefully with 800 wet and then buff out after curing for about a week.
I hate painting, but it is the final thing that must be done after a repair!
;) JJ

Do you make any adjustments for cool weather?