LPH400 - Not Totally Happy With Results

[RalphL]

I was little premature with my jubilation last week -- I had just purchased the LPH400 (1.4 FN, with orange and silver caps), and did a small test on an old fender that turned out nice. I've been restoring a '72 Camaro Z28, and today - using the orange cap, finally shot the base coat for the hood stripes - black base coat (PPG JB Shopline). When cured, one stripe turned nice and smooth - but with the other (left side), turned out a little 'rough looking' -like overspray(?) - is this called mottling? Anyway, this stripe was shot last, so no overspray would have been made from spraying the previous stripe. It's not too severe, and the clearcoat will certainly cover it... but, why the difference in the results of the two stripes? Not sure what I did wrong.

I use the Devilbiss Dekups system - and had set my gun at 16 psi with the trigger pulled fully back; the material control knob at 4 turns out from closed; the spray pattern was about 12 inches at a 7 inch distance. I also followed the instructions of Hub's chop sticks method.

Up to this point, I've shot the rest of the car using a Devilbiss 670 Plus. With that gun, I've been able to lay down the paint without problems, runs, sags, and little peel. The major problem however, is all the overspray - especially with the clear coat. I'm shooting in my garage -in a residential neighborhood, so overspray can be a problem.

The next step would be to shoot SPI universal clear using the silver cap, but unless I can improve my shooting, I may just have to stick with the Devilbiss and suffer through the overspray cloud!

I am certain that this gun is fine and the problems are related to my procedure (obviously, I am not a professional) - so, any help is appreciated.

Thank you - and my apologies for the long post!
Ralph

[RalphL]

After reading information throughout the forum, I believe I might have figured out at least part of the problem:

1. I had my spray adjustment set pretty much wide open; and
2. On the second stripe, I believe I was shooting at about 12 - 13 inches from the surface - and going at a faster pace than the other....

Tonight I will try to shoot the SPI universal clear - modifying my settings for a smaller spray pattern, and will shoot closer to the surface.

[Hub]

I was little premature with my jubilation last week -- I had just purchased the LPH400 (1.4 FN, with orange and silver caps), and did a small test on an old fender that turned out nice. I've been restoring a '72 Camaro Z28, and today - using the orange cap, finally shot the base coat for the hood stripes - black base coat (PPG JB Shopline). When cured, one stripe turned nice and smooth - but with the other (left side), turned out a little 'rough looking' -like overspray(?) - is this called mottling? Anyway, this stripe was shot last, so no overspray would have been made from spraying the previous stripe. It's not too severe, and the clearcoat will certainly cover it... but, why the difference in the results of the two stripes? Not sure what I did wrong.

I use the Devilbiss Dekups system - and had set my gun at 16 psi with the trigger pulled fully back; the material control knob at 4 turns out from closed; the spray pattern was about 12 inches at a 7 inch distance. I also followed the instructions of Hub's chop sticks method.

Up to this point, I've shot the rest of the car using a Devilbiss 670 Plus. With that gun, I've been able to lay down the paint without problems, runs, sags, and little peel. The major problem however, is all the overspray - especially with the clear coat. I'm shooting in my garage -in a residential neighborhood, so overspray can be a problem.

The next step would be to shoot SPI universal clear using the silver cap, but unless I can improve my shooting, I may just have to stick with the Devilbiss and suffer through the overspray cloud!

I am certain that this gun is fine and the problems are related to my procedure (obviously, I am not a professional) - so, any help is appreciated.

Thank you - and my apologies for the long post!
Ralph

Sorry to hear that, I much prefer jubilation. Mottling has a dapple look so not likely to show up in black.
Was the substrate the same on both sides of the hood Is the inlet pressure staying constant
What spray distance are you using Is the reducer being used match the ambient temperature
Less overspray will be produced if you spray faster, closer to the object and most importantly, spraying and staying perpendicular to the object. At the end of each stroke do you trigger the gun
Don't be too hard on yourself.
Cheers,
"HUB"

[RalphL]

Thanks Hub,

The answers to your questions are provided below. Any advice is appreciated!

Thank you.
Ralph

Was the substrate the same on both sides of the hood?
Yes

Is the inlet pressure staying constant?
Yes

What spray distance are you using?
Approx 12-13 inches

Is the reducer being used match the ambient temperature?
Yes

Less overspray will be produced if you spray faster, closer to the object and most importantly, spraying and staying perpendicular to the object. At the end of each stroke do you trigger the gun?
I generally just keep the trigger pulled and continue the right and left strokes. Also, I likely lost the perpendicular position.

[Hub]

Thanks Hub,

The answers to your questions are provided below. Any advice is appreciated!

Thank you.
Ralph

Was the substrate the same on both sides of the hood?
Yes

Is the inlet pressure staying constant?
Yes

What spray distance are you using?
Approx 12-13 inches [color=#FF0 000][/color]

Is the reducer being used match the ambient temperature?
Yes

Less overspray will be produced if you spray faster, closer to the object and most importantly, spraying and staying perpendicular to the object. At the end of each stroke do you trigger the gun?
I generally just keep the trigger pulled and continue the right and left strokes. Also, I likely lost the perpendicular position.

Spray distance -- try spraying at 6 inches and a little faster - result smoother finish - less overspray

Triggering the gun will produce less overspray and increase the transfer efficiency
Cheers,
"HUB"

[RalphL]

Hub.

I tried the settings and techniques that you had suggested - and switched from the Dekups system to the regular cup that had been 'chop-sticked', and got much better results with the clear coat (using silver cap). There's some peel, but I had planned to rub this out anyway.

THANK YOU!
Ralph

[Hub]

Hub.

I tried the settings and techniques that you had suggested - and switched from the Dekups system to the regular cup that had been 'chop-sticked', and got much better results with the clear coat (using silver cap). There's some peel, but I had planned to rub this out anyway.

THANK YOU!
Ralph

Like Tony the Tigger says THATS GRRREEEAAATTTT Now just think how much better you'll be with a little more practice.
Thanks for sharing the pix.
Cheers,
"HUB"