Striping

R

Rgn1133

Promoted Users
Hi, I’m a part time hot rod car builder/painter. Do all my own work. I have a problem I’ve never encountered before. I have striping with a SOLID color. A light blue color. I’m using a lph 400 iwata gun with purple cap. And a silver for clear. Exactly what I’ve always used with metallics and never had issues.
Can anyone tell me pressures I should be shooting at or distance from panel? I’ve always shot at 12lb pressure for paint. Wide open air and fluid. 4 to 6 inches away and 80-90% lap. As per HUB from iwata.
What do I need to change? Please help. This is on the hood, the most important part on the truck, of course!,
 
Use the silver or orange cap for solid base. Purple cap is supposed to be for difficult metallics.

I would up the pressure and set fluid 2.5 turns out.
 
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the pressure is way too low. i had a couple lph400's that i sprayed with daily for prob 12 years or so. its been some years since i sold them but i remember those guns had a recommended pressure setting of 19psi but to get them to spray right you would need to run them 21-25. that is with the silver or the orange cap. the purple one may be a few psi less if i remember right. 14 maybe. the purple cap is a specialty item that i had but only used maybe 3 times in 5 years. its really not a good cap for regular spraying. i always used silver or orange.
 
The recommended pressure settings are always about keeping the gun compliant in VOC regulated areas. Nothing you need to worry about. Like Jim said most guns spray better above the recommended setting.
 
Jim C said:
the pressure is way too low. i had a couple lph400's that i sprayed with daily for prob 12 years or so. its been some years since i sold them but i remember those guns had a recommended pressure setting of 19psi but to get them to spray right you would need to run them 21-25. that is with the silver or the orange cap. the purple one may be a few psi less if i remember right. 14 maybe. the purple cap is a specialty item that i had but only used maybe 3 times in 5 years. its really not a good cap for regular spraying. i always used silver or orange.
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Thank you!! Does distance from panel matter? Should I back up to 8” or so away? Should lap be 50-60%? With the purple cap I was shooting a very hard metallic ice blue and was told to lap 90% and it worked great. As have all my metallics using the same method. But I thought it was used for all metallics. I’ll buy the orange cap now though.
I’ve never shot a solid color though. Always metallics.
Should I use the orange cap with clear also? Always used the silver for that.
Thank you so much for your advice. And everyone who has responded so far
 
Rgn1133 said:
Thank you!! Does distance from panel matter? Should I back up to 8” or so away? Should lap be 50-60%? With the purple cap I was shooting a very hard metallic ice blue and was told to lap 90% and it worked great. As have all my metallics using the same method. But I thought it was used for all metallics. I’ll buy the orange cap now though.
I’ve never shot a solid color though. Always metallics.
Should I use the orange cap with clear also? Always used the silver for that.
Thank you so much for your advice. And everyone who has responded so far
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Use the silver cap for clear like you’ve been doing. That gun likes to be really close to the panel. About 4 inches. And like the other said, increase your pressure to about 21 to 25 psi.

I’m just a front yard hack.
 
everyone has given good advise here. silver cap is for clear and single stage. orange is basecoat. purple is for hard to spray metallics in basecoat. you can spray that gun anywhere from 4-8" i am a close sprayer, usually i find myself at about 4" BUT if you having striping issues then a couple extra inches wont hurt. 6" is fine. 8" is a bit on the upper end. the purple cap has a crazy wide fan. its like a dropcoating cap. no need to be very far off the panel with that one. typical overlap is about 50% but if your striping then make it 75-80%.
 
So I'm going to start with about 20-25lb pressure at inlet. Then i'm going to turn my fluid control knob 2-1/2 turns out. and my fan control in to where i just start to see the fan start to close down. I'll do some test panels. Turn my cap sideways to check the pattern is running evenly down on each side.
Guess I just have to keep adjusting til I get i get.
Thanks for all the advice
 
Well I've got my spray pattern down a little tighter at 2 1/2 turns and my pressure at 20lbs. This makes a good even, crisp oval pattern. With the cap turned sideways I have good even runs through the whole pattern.
Going to lap about 75% and this should give me good coverage with no stripes as long as my laps are pretty consistent right?

Also, I'm thinking about buying a new gun. What do any of you recommend? I've had this gun about 10-12 years and thinking the technology is even better now and a new one might be even easier to use. Give me your thoughts
 
Rgn1133 said:
Well I've got my spray pattern down a little tighter at 2 1/2 turns and my pressure at 20lbs. This makes a good even, crisp oval pattern. With the cap turned sideways I have good even runs through the whole pattern.
Going to lap about 75% and this should give me good coverage with no stripes as long as my laps are pretty consistent right?

Also, I'm thinking about buying a new gun. What do any of you recommend? I've had this gun about 10-12 years and thinking the technology is even better now and a new one might be even easier to use. Give me your thoughts
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It’s a great gun. No need to replace it. Newer is not better in this case….

Used it to spray this base. Car won its class at the Dallas Autorama.
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Don
 
After doing some research, as understand it, this lph 400 is center heavy in its paint distribution. If that’s the case then if my maps aren’t consistently 75 or more that is going to create the streaks.
So would cutting the fan down even more help! I have it at 2 3/4 in now. Should I go to 3 or more?
 
you need to put a piece of masking paper on the flat wall of your booth and do tests to see how the gun is spraying. a super quick full trigger pull will tell you if its an even spray pattern or not and what you need to change on the settings. its really the only way to properly adjust the gun. there is no magic setting we can tell you for the gun. the settings will change for every paint you put in it. i can also tell you that iwata guns especially the lph400 are very finicky when it comes to cleanliness. they spray great but they need to be flawlessly clean to do so. it got the point where i would just store the head and air cap in the gun stripper bucket.
 
Rgn1133 said:
After doing some research, as understand it, this lph 400 is center heavy in its paint distribution. If that’s the case then if my maps aren’t consistently 75 or more that is going to create the streaks.
So would cutting the fan down even more help! I have it at 2 3/4 in now. Should I go to 3 or more?
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Watch that video I posted.
 
AAE said:
Watch that video I posted.
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I’ve done the paper on the wall to check the pattern. The cap and nozzle are clean because I’m very meticulous about cleaning them as soon as I finish spraying.
The pattern is a good even pattern on a light pull, but if you pull it to make it thick enough to run it runs in the middle more than the ends. Not an even run across the whole thing.
I thought narrowing the pattern might help to get it a little more uniform across the whole pattern.
I sprayed some silver metallic yesterday with the silver cap. Lapping a good 80%. No streaks no moddling. So I think I should be good now.
Just wondering if anyone thought I was right about the pattern narrowing
 
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