Sitting in base for 6 months...

Ls21lt

Ls21lt

Promoted Users
I've sprayed some motorcycle parts as per the perfect paint job guide lines, but I got some runs and trash in the white base.
I thought, I'll just sand them out...
Well life and 6 months go by, what do I need to do to pick up where I left off and spray more base and clear.
Paint was activated and been in a make shift booth never seeing sunlight.
Dave.
 
Basically start over then? I was hoping to avoid that, but I've heard base doesn't stick well to old base. Thanks for the advice.
 
What brand of basecoat? For most base's you can sand it out and then reapply a couple of coats. Sanding the base then attempting to clear it would not be advisable. Most likely you will sand through to the sealer trying to get the runs out anyways. I would sand it 600 wet. 400 wet is a little too coarse especially if you are new to this. 600 wet on the runs, then lightly sand the entire part with 600-800 wet, or use a gray scotchbrite pad and scuff the entire part after you have sanded the runs. Then re-apply at least 2 coats, sometimes 3 depending on the base.
If you are getting runs in your base, you need to look at how you have your gun adjusted and your technique spraying. Regardless of what gun it is, you should spray light-medium to medium coats. Never spray base wet especially if you are new to this.

If you have questions, ask them.:)
 
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All SPI materials, grey epoxy primer, pure white, universal clear... very new, this is my first project and definitely have runs due to my technique. Thanks for your help Chris.
 
Things to keep in mind when spraying base. Overlap your passes around 50%-75% depending on the gun and the base. Using a SATA HVLP 1.3 I'm usually overlapping closer to 75%. Using a SATA RP (which sprays much wetter) I'm going to be closer to 50%. Try setting up your gun like this. First open the fan all the way. Next turn your fluid needle in all the way. Then back it out 2 full turns. Spray some base on some masking paper taped to a wall. Observe the pattern. What you want is a nice full pattern. Keep adjusting till you have this. Not knowing your gun it's hard to give you specifics, but you want a full wettish pattern.
Draw imaginary straight lines through the piece you are spraying. Spray in straight lines. Don't follow body lines. Keep your gun head horizontal to the panel. Don't let it tilt one way or the other. Maintain consistent overlap pass after pass. Don't lose track of where you are.
Tell us the gun you are spraying with and myself or someone else can give you more specific settings.
 
Iwata lph400.
150 psi at the wall regulator, 30 psi from there through 50 ft of hose to gun. Regulator there to around 24-28.
 
Perhaps one of the other guys on here who use Iwatas could give you their settings. I only have used Sata's for the last 20 years so I'm not the one to give specifics about the Iwata.
 
Thanks for your help Chris. I'll give it another shot, I'm pretty sure I have runs from applying it to heavy, trying to get complete coverage during the second coat. I'm covering grey epoxy, I'll try for 4-5 coats this round.
 
I suspect you just posted your biggest issue. Base does not need to be sprayed real wet. I use an Iwata LPH400 but can't give you my settings. I dial it in on a blank piece of masking paper with each job. I do think the Iwata is a pretty slow gun and probably you just need to run you fluid valve in some (2 turns +/-) White is hard to see when you paint but with base coat it is better to be light than too heavy.

John
 
Well, it's been a long time since I used my LPH as a base gun, but 24-28 sounds kinda high for base. I'd want to be on the low side of that for sure. Clear is another story, I like to hit 28-30 on a full trigger pull with SPI clear.
 
For base with the lph400 I was at the following.

Air 23 at the gun
Fluid out 2.5 turns from closed
Fan in 1 turn from full.

I overlapped 50%, was about 5 in. from the panel, and traveled at a speed to put a nice medium coat on.
 
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Screenshot_20200413-080655_Amazon Shopping.jpg
 
Chris_Hamilton said:
Ditch the regulator at the gun, adjust the gun via the regulator at the wall (your second pic).
Click to expand...

I always wanted to try setting things up that way and eliminating one point of restriction, never got around to it though.

Do you run a gauge on your gun to know where you are or just use the wall one?
 
Just the wall. Honestly I never worry about PSI. Just adjust it till the gun is spraying the way I want it. If you are trying to spray at the lowest possible PSI, you can adjust the gun till it's atomizing nicely, then back down the pressure till you notice a difference in atomization. Bump it up till you see it atomizing properly again. This probably isn't for most but once you do this for a while you know when a gun is atomizing nicely and when it's not. Being in a non regulated area that is all I care about. Could care less what PSI it is.
 
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