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> my adventures in painting the car thread, I sanded off the paint! Need to make sure I'm fixing it correctly.
914 RZ-1
post Jul 11 2018, 09:55 PM
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So I painted my car. Got some orange peel, thought I'd see if anyone had ideas for getting rid of/minimizing it.

After painting:
Attached Image

After sanding with 1000 grit. The lighter areas are where I sanded, the darker areas are the lower points of the orange peel:
Attached Image

Option 1:
I'm thinking I need to go to 800 grit, then 1000, 1500, 2000, then polish. Before I do I thought I'd see if anyone else thinks this is a good idea based on what they may have done.

Option 2:
I can re-paint it. I'm thinking I will sand with 400 grit to rough up the surface and then re-spray.

Option 3:
I can polish it more, but the orange peel is still noticeable on the smaller pieces I've tried. I used a Torq X polisher, white pad, Chemical Guys V32 polish. I thought it might get smoother as I polished it with finer and finer pads/compounds, but I don't want to burn thru the paint. I put 3 coats of paint on.
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porschetub
post Jul 11 2018, 11:30 PM
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Oh dear,let it dry and start again,your paint is too thick ...not enough reducer ,or you are possibly running low air pressure,with single pack I run 35-40 PSI,on the top clearcoat I run same pressure and a bit more thinners,from mermory I go 1:2 ratio basecoat then 1:5 ratio on clear ,then I go piss thin on the last clearcoat.
I'am a DIY car painter have done lots of cars but I forget details cause it's such a PITA to do,love painting but the prep makes me want to (IMG:style_emoticons/default/barf.gif) (IMG:style_emoticons/default/barf.gif) .
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Front yard mechanic
post Jul 12 2018, 07:30 AM
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Option 2 my vote
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Cairo94507
post Jul 12 2018, 07:38 AM
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That's a bit of orange peel for sure. I would tape all the edges on one panel (don't want to sand or burn through) and wet sand it some more to see if you can get 90% of that flattened out and then try polishing. Just take your time. Good luck. (IMG:style_emoticons/default/beerchug.gif)
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burton73
post Jul 12 2018, 10:24 AM
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You are going to need to go through the grits by starting with a heavier grit. Very easy so you do not go through it. Think of it as mountains and valleys. You need to sand the mountains down to the valleys. Tape the edges as someone said so you do not go to fare on them with the color sanding.

You need to CK it all the time so you do not remove too much.

Do not sand with that much pressure. You will get it. The worst you can do is need to repaint so give it a shot. It takes an eye. When it is flat all over go to finer grit. Remember when you have it flat all you need to do is remove the last scratch and put the finer scratch in. I go in a different direction and when the scratches are going in the new direction go finer till you are sure you are at a fine scratch where you can buff from.

Bob B


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Andyrew
post Jul 12 2018, 11:05 AM
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Single stage? What paint are you using?

Go 30% more reducer than you were using. Change your air pressure at gun regulator to 30psi, Adjust your spray to 6-8" of surface.

Spray test piece with another 3 coats after 400grit wetsand and clean up with wax/grease remover.

Show us what you've got. Be careful with runs.

If you plan to wetsand always do 4+ coats. or 2+ coats after full coverage. I did 7 on mine. it took 3 to get full coverage. I wet sanded out 1-2 coats and have 5 coats on the car and can wetsand the car again 2 times to eliminate imperfections down the line.
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Andyrew
post Jul 12 2018, 11:06 AM
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What temp reducer are you using? and how hot was it in the booth at spray? Its really hot out and normal reducer is designed to be sprayed at about 70deg.
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mb911
post Jul 12 2018, 11:08 AM
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I would wet sand again.. Then see what you have left to buff. Anyone that's painted before has run into this before at least once.
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jmitro
post Jul 12 2018, 11:33 AM
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definitely need to wet sand with finer and finer grits; don't wet sand with anything finer than 1000 unless you want to just paint the panel again. or be sanding from now until 2020. Trust me, it takes a lot of sanding to get the panel flawless;

no reason to use polish until you've got to at least 1500 if not 2000 grit.

change the sandpaper frequently; it gets loaded quickly
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914 RZ-1
post Jul 12 2018, 06:53 PM
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Thanks to all. I appreciate you input.
I'm using single stage paint by R-M. Mix ratio: 4:1:1 (paint, reducer, hardener). It was in the 80's when I painted. I probably should have used reducer for higher temps. I painted the car body and used high temp reducer and it looks much better.
Gun is set at about 10-15 psi where the airline enters the gun. I can't see the readout very well anymore because the plastic cover on the gauge got fogged up when I tried to clean it with acetone.
I may have the paint amount too high as well (2.5 turns in from when the threads engage), so I'll try adjusting that.
I practiced, but it was a few months ago, so the conditions are different now. I only have 1.5 quarts of paint left. I could get more but I'm concerned about matching batches.
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Olympic 914
post Jul 12 2018, 07:20 PM
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many years ago I clipped the front end of my teener and only had about a mayonnaise jar of paint left. and the mix of the new paint was off. So we used the off-mix paint to build up and just put the old paint on for the last coat or two. perfect match that way.
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914 RZ-1
post Jul 13 2018, 12:32 PM
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Here is the result after wet-sanding with 800-1000-1500 then polishing with V32 and then V36 polish (Chemical Guys).

They are still some depressions from the orange peel that look like dots and there are some scratches. I thought I got these out; they appeared after I polished.

I'm thinking I need to paint one, maybe two, more coats so I have enough material to sand off.

Should I use a machine sander (DA), or keep doing it by hand?

Attached Image
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mb911
post Jul 13 2018, 03:20 PM
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QUOTE(914 RZ-1 @ Jul 13 2018, 10:32 AM) *

Here is the result after wet-sanding with 800-1000-1500 then polishing with V32 and then V36 polish (Chemical Guys).

They are still some depressions from the orange peel that look like dots and there are some scratches. I thought I got these out; they appeared after I polished.

I'm thinking I need to paint one, maybe two, more coats so I have enough material to sand off.

Should I use a machine sander (DA), or keep doing it by hand?



I would wet sand with 400, clean, prime and repaint.
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mepstein
post Jul 13 2018, 03:30 PM
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QUOTE(mb911 @ Jul 13 2018, 05:20 PM) *

QUOTE(914 RZ-1 @ Jul 13 2018, 10:32 AM) *

Here is the result after wet-sanding with 800-1000-1500 then polishing with V32 and then V36 polish (Chemical Guys).

They are still some depressions from the orange peel that look like dots and there are some scratches. I thought I got these out; they appeared after I polished.

I'm thinking I need to paint one, maybe two, more coats so I have enough material to sand off.

Should I use a machine sander (DA), or keep doing it by hand?




I would wet sand with 400, clean, prime and repaint.

(IMG:style_emoticons/default/agree.gif) that’s what our shop would do. You don’t want to machine sand unless you really know what you are doing.
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ValcoOscar
post Jul 13 2018, 03:31 PM
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Yeah Jeff...I kinda think you need more paint also.
Using a DA for prep is fine but I wouldn't recommend for color sanding.
Good going and keep posting updates!
BTW...check your mail tomorrow, I sent you something.

Oscar

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ConeDodger
post Jul 13 2018, 06:45 PM
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Option 4: peel it and eat it. (IMG:style_emoticons/default/av-943.gif)
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Andyrew
post Jul 13 2018, 07:55 PM
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Hand sand only. No DA sanding for color sanding.
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914GT
post Jul 13 2018, 08:46 PM
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Also, use a guide coat to show missed sanding scratches and low spots. A dry guide coat applies evenly and will show you when you have sanded it enough. There is a white guide coat available for darker paints and primers.
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914 RZ-1
post Jul 16 2018, 10:23 AM
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Here's the latest. I sanded with 400, cleaned with a red Scotch pad and something called "prep and wash" from R-M. I mixed the paint with a little extra reducer (4:1:1.5). The engine lid turned out decent:

Attached Image

The doors still got some orange peel. Not quite as bad as before, but still not what I was hoping for:

Attached Image

I turned down the amount of paint (1-2 turns) and sprayed at about 10-15psi at the gun.
It was 81 degrees and about 40-50% relative humidity. The first coat went on well, then I waited 15 minutes for the paint the flash, then did a second coat. The second coat seemed to have more orange peel.

When I paint, should I just paint a first coat then paint a second coat right away? In other words, go over the surface twice on the first coat?




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Spoke
post Jul 16 2018, 11:08 AM
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QUOTE(914 RZ-1 @ Jul 12 2018, 08:53 PM) *

It was in the 80's when I painted. I probably should have used reducer for higher temps.


I ran into the same issue with 70F reducer when it was about 90F. The paint dried so fast the orange peel never settled down to a sheen. Instead of getting the correct temp reducer I used a lot of reducer to thin out the paint. It went on better but still got some orange peel.
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