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prkaye

Well Known Member
the paint i'm using for my interior is PPG evolution, FDG (single stage polyurethane enamel). I forget exactly what ratio the guy said to mix the hardener... i think it was 2 parts paint to 1 part hardener.
I got the quick reference chart for this paint from the PPG website. It says for mix ratio for this paint 2:1:1/2 . I'm confused why there are three numbers in this ratio... I only have two things to mix. Should I do it 2:1 (paint:hardener) ??

Any particular tips with this paint? PSI setting for my HVLP gun (cheap gun hooked to my compressor), distance of nozzle from surface being painted etc?
 
Mix rato

Phil,
The mix ratio would be: 2 parts paint to 1 part catylist to 1/2 part reducer. As for the spray gun : HVLP's usually require around 10psi at the spray cap, this would probably require 45 psi at the handle unless the gun is set up to operate off a turbin. I would check with the mfg. to determine what your gun requires. Be sure to use a "Fresh Air" breathing mask.
Dick
 
reducer!

Ah.... reducer. The guys at the paint shop didn't say antying about reducer (and didn't sell me any). Perhaps this is why I have been getting an orange-peely texture on my practice pieces. For the interior I actually like this rough textured finish... is it acceptable not to use any reducer to achieve this?
 
Reduced

Yes, you can spray the product without reducer, as you indicated, the results would be less than perfect. As for the distance from the surface to hold the gun, 10" to 12" is usually a good starting point. Again, several factors to consider. Air pressure, viscosity of paint, size of the "Fan", adjustable,. Painting is not rocket science and pratcise will improve results.
Dick
 
Couple more questions about this paint:

1) What is the difference between a "high solids hardener" and a "medium solids hardener" ? The reason I ask is that on the info sheet for the FDG paint it lists the hardener as F3270 Medium solids. But the guy sold me F3260 high solids-fast. Is this OK, or should I go back and get him to exchange it?

2) Is "reducer" the same as "thinner" ? On the data sheet there are a whole bunch listed: "extra fast thinner", "fast thinner", "medium thinner" etc. What does the speed refer to, and which one do I want?
 
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N661DJ said:
Yes, you can spray the product without reducer, as you indicated, the results would be less than perfect. As for the distance from the surface to hold the gun, 10" to 12" is usually a good starting point. Again, several factors to consider. Air pressure, viscosity of paint, size of the "Fan", adjustable,. Painting is not rocket science and pratcise will improve results.
Dick
Click to expand...

I would respectfully suggest that 12 inches is about twice as far as you should be. The paint gets broken up as it leaves the gun and will actually reform large droplets if you spray too far away from the surface. About 6-7 inches gives a nice controlled pattern with most guns.
 
prkaye said:
Couple 2) Is "reducer" the same as "thinner" ? On the data sheet there are a whole bunch listed: "extra fast thinner", "fast thinner", "medium thinner" etc. What does the speed refer to, and which one do I want?
Click to expand...

Thinner is the same as reducer. Usually, there are recommended temps for each speed of thinner. If it's cold out, you use the fast stuff and if it's hot, you use the slow to keep things form drying too quickly. Again, the instructions should have recommendations for different temps.
 
thanks

Ok, that makes sense about the thinner... it's cool out so I'll get a faster one. What about teh high vs low solids in the hardener? what does this mean?
 
ARG!

Arg, I got the thinner and tried it with the paint, but I STILL can't seem to get a smooth finish. I always get a uniform distribution of small bumps. It looks either like there are all sorts of particles imbedded in the paint, or like it is being sprayed with a fine splatter. I've played around with the pressure, fan width, distance from surface, even now tried thinning the paint. Same result.
Is this mostly likely because:

a) I'm using a very inexpensive HVLP gun?
b) I'm using a "high solids hardener" instead of the "medium solids hardener" called-out for? (i still don't really know what this means, but the guy at the paint store said the one i am using is the one everbody uses for PPG Evolution FPG).
c) I got the guy to add a whole bunch of flattener to the paint (could flattener be causing these bumps??)

Help! I'm stuck... I don't know whether I want to go spend another $150 on a better HVLP gun, or another $40 on a different hardener, if it's not going to change the results. On the one hand i don't mind this textured finish for the interior, but on the other hand I don't like that i'm not able to control this.
 
Two things

Hi Phil,

Two things I can think of.

One is to clean your surface. If you have dust settling on your part, you may want to use a tack rag to pick up the tiny debris on the surface. They're sticky cheese cloth like rags with some sort of waxy feeling coating. It picks up stuff readily.

Also, I filter the paint before I place it in the hvlp gun (I have a cheap one too). They're paper funnel filters, and take out any tiny lumps that would not have mixed properly in your paint.

Give me a shout tonight, as I can let you have some tack cloth and filtering funnels.

Alfio
 
Paint

prkaye said:
Arg, I got the thinner and tried it with the paint, but I STILL can't seem to get a smooth finish. I always get a uniform distribution of small bumps. It looks either like there are all sorts of particles imbedded in the paint, or like it is being sprayed with a fine splatter. I've played around with the pressure, fan width, distance from surface, even now tried thinning the paint. Same result.
Is this mostly likely because:

a) I'm using a very inexpensive HVLP gun?
b) I'm using a "high solids hardener" instead of the "medium solids hardener" called-out for? (i still don't really know what this means, but the guy at the paint store said the one i am using is the one everbody uses for PPG Evolution FPG).
c) I got the guy to add a whole bunch of flattener to the paint (could flattener be causing these bumps??)

Help! I'm stuck... I don't know whether I want to go spend another $150 on a better HVLP gun, or another $40 on a different hardener, if it's not going to change the results. On the one hand i don't mind this textured finish for the interior, but on the other hand I don't like that i'm not able to control this.
Click to expand...
Phil,
Are you straining your paint after mixing, before putting it in the paint cup? How are you mixing your paint after all of the add ons are measured out? Don't know what HVLP that you are using, but if it one of those cheapo Harbor Freight guns and you are using high build solids there may be your problem. Are you using the correct tip/needle combo for your paint. Big difference here. Too fine a tip/needle and you won't get correct atomization of paint and you will get a textured fine like you are discribing. Hard to tell without seeing result. Is it more like 'orange peel' than textured? Local body shop around, dealership, etc? If no one available to help you, why not shoot a sample piece and take to bodyshop, dealership paint guy and ask their opinion. I've found that usually painters are very receptive to helping each other out.
Good luck,
Mike H 9A/8A hung engine mount, landing gear-she's getting legs!!!
 
- Never thought of filtering the paint... i'll try that.

- just been mixing it in the cup with a clean screwdriver as a stir-stick.

- surface is clean, freshly primed before painting.

- My gun is a $40 HVLP gun that I hook up to my compressor. Got it from a local place called "princess auto" that carries a lot of very inexpensive stuff.

- Yes, using the correct needle for my paint (1.4mm). As for pressure, my gun just says "15-45 PSI". The paint says cap pressure should be 10psi, so I've been setting hte regulator at the handle between 40 and 50 psi (no visible difference between the two.

- When I spray each coat, how much coverage should I be going for? A light dusting, or should it look real wet and fully covered (almost running but not quite)?
 
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prkaye said:
- My gun is a $40 HVLP gun that I hook up to my compressor. Got it from a local place called "princess auto" that carries a lot of very inexpensive stuff.

- Yes, using the correct needle for my paint (1.4mm). As for pressure, my gun just says "15-45 PSI". The paint says cap pressure should be 10psi, so I've been setting hte regulator at the handle between 40 and 50 psi (no visible difference between the two.

- When I spray each coat, how much coverage should I be going for? A light dusting, or should it look real wet and fully covered (almost running but not quite)?
Click to expand...

First make sure the gun is clean. Take out the needle and make sure there is nothing gummed up in there.

40-50 psi sounds about right. That's at the gun, right? Keep the supply line pressure all the way up.

Adjust the paint supply needle and the fan needle until you get a very stretched out oval, almost a straight line, that is the same height as the distance the tip is from the surface. So if you are holding the tip 30 cm away form the surface you want the spray pattern around 25-30 cm tall.

Start with a light to medium coat, then wait. As in 20-30 minutes. I was just talking to the local PPG salesman yesterday about this. He was saying most people just don't let it setup enough. The second coat can now be much heavier because the slight setup first coat will hold the paint and keep it from running.

As far as the gun goes. I'm sure someone that is really good at painting can get good results from any gun. That's not me. I've found a good gun makes a big difference. I have a Devilbiss Plus. It's made to be used with smaller compressors. It atomizes great. Also check out the DeKups system. Makes clean up so much easier, and you can shoot upside down.
 
Study required

Phil,

You need to have p-sheets for the paint you are using. Don't have em? Stop now and get them. P-sheets are also known as product sheets or tech sheets. They tell you exactly how the factory expects the paint to be mixed and used.

http://corporateportal.ppg.com/NA/Refinish/ppgrefinish/2-0-Products/

In general, todays p-sheet specs the minimum reducer, because it makes the product VOC spec look better. Using urethane, you want each coat to flow out properly. For an amateur with inexpensive equipment, using about 50% more reducer will result in easier spraying and better flow-out. It will also result in a thinner coat, which may require a second or third coat for best results. It can also result in blushing or solvent pops if adequate flash time is not observed. Be sure to match the reducer speed to the environmental conditions you expect to spray at.

Unfamiliar with terms like "flash time", "reducer speed", "flow out" and the like? Get a book on auto painting, or Google DIY auto painting until you have a grasp of the basics.

Stop wasting expensive paint. :D

Don't forget, urethane paint in particular is bad for your lungs. Very bad. Protect yourself!
 
N916K

If you wait 20-30 minutes between coats doesn't this mean you have to clean out the gun and mix up a new batch????? :confused:
 
RVadmirer said:
If you wait 20-30 minutes between coats doesn't this mean you have to clean out the gun and mix up a new batch????? :confused:
Click to expand...

No, it will be fine. Or course if it's hot then you need to use a high temp reducer to slow things down.
 
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