Help with SW P60 Primer

[RVG8tor]

I have done 3 priming sessions so far with my build, the second was better than the first but the last one was not. The issue I have is that instead of a nice green tint, I am getting a speckled egg sort of finish. The speckled finish still sets up nice and hard so I have used the parts. On my second session I mixed up a larger batch but I still used the 1 to 1.5 ratio. This time it started out a little speckled but then dried to a nice green translucent shade like I think it should.

Anyone else out there run into this and know how to fix this issue. Thanks in advance.

Cheers

[whifof100ll]

I think it may be related to temperature or humidity. What were the environmental conditions when you shot the paint?

[szicree]

What type of gun and how much air are you putting through it? It sounds like maybe the gun isn't breaking up the paint.

[RVG8tor]

Originally Posted by whifof100ll

I think it may be related to temperature or humidity. What were the environmental conditions when you shot the paint?

I am doing the painting in my garage in a small booth that exhausts the air out side. I am using a gun from HF, it is a full HVLP gun. I use some instructions from another builder on setting up the pressure, flow and fan size so I don't think that is mt issue.

My garage is basement level is indirectly heated from duct work in the garage ceiling. My garage stays a steady 60 degrees this time of year, and not too humid. Does any of this info give some insight?

Thanks

[Captain_John]

Mike, I am thinking dirty gun.

Have you taken it apart and cleaned the innards lately?

Take the nozzle off, unscrew the orifice and I am willing to bet there is caked paint inside.

Don't forget to soak the nozzle and shoot clean air through the ports on the side(s)!

CJ

[szicree]

Things like humididty and temp can make some difference, but unless it's REALLY cold or hot, this probably is not the problem. I've never shot the SW primer, but am assuming that if mixed per instruction, it should behave ok. This brings me back to gun setup. Let's say the gun specifies a max inlet pressure of 29psi. This is pressure at the inlet with the trigger pulled. The pressure at the compressor is not a reliable indicator. Actually, a gauge at the gun is probably not as good as simply spraying some test patterns. If the air is too low, you can still get a very good fan shape, but you'll see pretty large speckles around the outside of the pattern. Turning up the air to the gun will make them get smaller and smaller until eventually more air will not produce further improvment. That's about where you should be. More air than this will simply fill the booth with paint and defeat the point of the HVLP. Also, I've seen a lot of folks hold the gun waaaay too far away. At about six inches from the gun's nozzle, the paint is at its most atomized. As it travels farther away from the gun, the little droplets will collide with each other and form very large droplets. Not good. It may seem like being far from the work allows you to paint quickly, but it produces a poor finish. What I'm trying to say here is that before we start blaming ventilation, humidity, temperature, mixing methods, product nuances, etc., that we consider the most common problem: spraygun technique. I really hope some of this info helps.

[bullojm1]

Originally Posted by RVG8tor

I use some instructions from another builder on setting up the pressure, flow and fan size so I don't think that is mt issue.

Mike,

I used some instructions I found online for a HF HVLP gun and my results were terrible the first couple of times. I didn't start nailing it until I really learned what each of the three knobs controlled.

From what you say about the speckled finish, I would say your tip pressure isn't high enough (I had the same issue on mine). On my HF HVLP gun there is a screw right next to the air inlet that changes the tip pressure. Try playing with that.

[rvbuilder2002]

Originally Posted by RVG8tor

I am doing the painting in my garage in a small booth that exhausts the air out side. I am using a gun from HF, it is a full HVLP gun. I use some instructions from another builder on setting up the pressure, flow and fan size so I don't think that is mt issue.

My garage is basement level is indirectly heated from duct work in the garage ceiling. My garage stays a steady 60 degrees this time of year, and not too humid. Does any of this info give some insight?

Thanks

I have sprayed P60-G2 a lot.

Sometimes you get a can that is a little thicker than it is supposed to be or it may have thickened a bit since you first opened it.
First of all make sure the can is mixed real well.
Then try reducing it an additional 10% with the catalist/reducer and see what happens. I can almost guarantee this will fix your problem.

[wingtime]

I found that you can't let P60 that has been catalized sit in the pot too long before spraying. Don't mix anymore than your gun can hold and shoot it ASAP. P60 left mixed in a pot will get a "skin" that will make it spray "sputtery"

I'm using a imported HVLP gun similar to the HF types. They key in that name is low pressure. Try turning your pressure down to about 30 psi or so. Too high of a pressure or the gun set incorrectly will cause it to dry before hit hits your part, preventing it from flowing out.

[panhandler1956]

I am no expert, but I had a similar issue and it was water (Harbour Freight HVLP).
My dryer in line on the compressor hose uses desiccant and it was bad. I replaced the desiccant it shot fine.
Good luck!