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benchracer1 05-23-2013 12:09 PM

beyond frustration
I am in the process of trying to respray a car. I am using ss acrylic urethane (restoration shop) with my gun (Iwata lph 400) 1.4 tip and orange cap, The manufacturers recomendation is up to 1 quart per gallon for reducer, At that ratio i was getting a whole bunch of orange peel. The paint was coming out of the gun way to thick. Thinking maybe it was just trying shoot the single stage acrylic urethan with that gun was just not the ticket. I brole out the old devilbiss siphon gun and had the same problem tii i added a bit more reducer. What is the best way to get the viscosity correct when the manufacturers recomend isnt working? I was amazed how much more material the devilbiss uses. It will be nice to get the iwata figured out

Pats55 05-23-2013 12:25 PM

I had a similar situation with the Croix turbines where I kept getting orange peel. It was PPG single stage. I called the vendor maybe three times and each time he would say add more thinner. Later on I talked to my buddy Bob at the paint store and he said the same thing. So dump most of the cup out so not to ruin it and add a little thinner at a time until you get it to flow. Gun distance is also a factor. Hope this helps

MARTINSR 05-23-2013 01:02 PM

If you are getting a lot of orange peel with the manufacturers recommendations then all you have let is gun set up and application. I always look at it this way when a rep comes in and shoots paint on a demo, does he make up stuff and keep it a secret? Nope, he shoots it using the manufacturers recommendations he is working for and then shows the painter at the shop the same thing because it WORKS. He doesn't tell the painter at shop to make up stuff, you know what I mean?

You don't have enough air volume at the gun or something, something is not breaking up that paint as it comes out of the gun.


tech69 05-23-2013 01:12 PM

a 1.4 should give you good results with SS. consider the speed of your passes, temps, gun distance, and of course reduction. how hot was it when you sprayed? ideally you want 74 degrees and this is the number all manufactures go by according to my knowledge.

benchracer1 05-23-2013 01:40 PM

To acheive 10 psi at the gun tip what should the inlet pressure be? I have a feeling im going to be the local expert on sanding orange peel...LOL

Pats55 05-23-2013 01:47 PM

Let us know how you make out. Good luck

MARTINSR 05-23-2013 02:02 PM


Originally Posted by benchracer1 (Post 1678179)
To acheive 10 psi at the gun tip what should the inlet pressure be? I have a feeling im going to be the local expert on sanding orange peel...LOL

That is a hard one because if you don't have a proper air supply you don't know. Going by the gun manufacturers numbers are as close as you can get, it usually has a "max pressure" on the gun, this is to legally be an HVLP gun with the proper transfer efficiency it has a maximum inlet pressure. Going by that or a tad higher is the closest you can get. I say a tad higher because if you have a poor air supply with small pipes, with restrictive filters or couplers you can have pressure but not volume. So once you get the thing opened up your pressure drops because there is no volume to keep it up.


benchracer1 05-23-2013 05:40 PM

I have 5 coats on right now. I guess ill scuff it all with 400 and try again. would 2 more coats be ok? I dont want it to thick. What do you guys recomend?

MARTINSR 05-23-2013 06:04 PM

I have never used that particular product but 5 coats is generally quite a bit of material.


benchracer1 05-23-2013 06:46 PM

if I just colorsanded and buffed would 600 or 800 be to abrasive to start with? I was thinking with that much material i could knock it down aways with 400 and spray 2 coats and call it good.

benchracer1 05-23-2013 06:49 PM

What is frustrating is I have painted many cars and never had this problem. White paint old eyes I guess.

Pats55 05-23-2013 08:08 PM

tomorrow is another day. I'm not a professional painter. But I do remember that some of these paints called for five coats. I have used 600 and 800 to initially knocked down the orange peel, I to have grown oranges in my time.There are many pros on this board and I'm sure you'll get it straight. Maybe a suggestion. Don't paint the car until you get it right at the gun, just a thought.

benchracer1 05-24-2013 07:08 AM

I decided to turn on the radio and patiently sand her down a bit. I also am going to try to get the gun issue straightened out on a few extra doors i have aroun here. I can try a few different reductions and gun pressures. Obviously something I am doing wrong.

deadbodyman 05-25-2013 06:09 AM

4:1 means 4 parts color (paint) to 1 part "HARDNER"(not reducer)
Some brands mix the hardner and reducer together so you dont need to get a whole gallon of reducer and 3/4 of a gal goes unused but some dont...those will say 4;1:1 the last number is usually reducer.
In a perfect world of painting (a painters paradice,LOL) You can stick with the directions on the can (manufactures "recomendation") but for most of us (every day,real world painters) without the luxury of a climate controled paint booh,or a paint booth at all...we all know when it gets too hot we need Slower reducer and when we are using the slowest reducer and still its going on a little dry we need MORE reducer usually just a bit more(a cap full) to a full to a full gun cup will do it.
once it gest passed 100 degrees you may have to do other things to get it to go on like glass...
What does your activator say Slow med or fast??? or even extra slow...

Old Fool 05-25-2013 06:50 AM

After reading DBM's post I took a minute and looked up the tds for that product. As DBM said 4:1 is 4 ounces of paint and 1 ounce of au 4001 hardener. Adding a reducer is optional.

My question is what are you using? What numbers on the cans? Have you read the TDS for each one?

This reading might help too: Adjusting Your Gun

10 @ the gun is measured at the air cap, takes a spendy test rig to measure it.

With your Iwata I would try around 16 -18 to start with, then start cranking it up.

With hvlp the amount of air flow is almost as important as the pressure.

Air pressure at the regulator on the air compressor 100 psi, regulator at the gun 16 for a start, hi flow couplings, no filter balls at the gun are 3 easy steps to get headed in the right direction.

At the gun use a regulator , not a flow valve marketed as a regulator.

I'd step back and take a good look and see what is wrong instead of shooting more $$ at it. You will figure it out.

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