Fresh PPG paint work

[BikerDrew]

Yesterday, I painted the front end of my Black 2001 Mercedes SLK 320 with PPG urethane base and clear coat (DBC and DCU2021 with DCX 61 hardner). I air dryed the surface in the shade with temps at 61-83f. Today I plan to sand the surface with overnight soaked 2000 grit paper.

I have a rotory and all three pads. I have a orbital with two pads (yellow and a polihing pad) I have 82, 83 and 85, as well as #7 and access to other products as necesary. I read other threads of this but was wondering if it is too soon to polish?

Thanks in advance! Drew

Yeh, I submit photos when it is finished.

[Mike Phillips]

Re: Fresh PPG paint work

Originally posted by BikerDrew
I read other threads of this but was wondering if it is too soon to polish?

Hi BikerDrew,

Welcome to Meguiar's Online!

If it's been 24 hours and it's dust free, then it should be ready for wet-sanding and machine buffing. If the paper you're using our Nikken #2000?

If you haven't done a lot of wet-sanding and buffing to remove your sanding marks, you might want to watch these videos before starting, works best if you have high speed Internet access.

How to remove paint defects

Or you can purchase it here except that you're working within a window of time that you will be better off to sand and buff sooner rather than later as it will be easier to get your sanding marks out.

Professional Education Series Video

[BikerDrew]

Thanks Mike

Thanks Mike for the info.

I have done a bit of work previously on this vehical with the rotory, do to neglect and latex paint overspray.

The paper I have is 3M imperial #2000 and Nikkin #1500.

Should I follow with 83 or 85 ? I am confident on my being careful either way.


Drew

[Mike Phillips]

Meguiar's always teaches the philosophy of using the least aggressive product to get the job done. After you finish wet sanding the paint, you can do a couple of test spots to see what combination of products is working best to remove the sanding marks and restore a swirl free high gloss finish.

Here are the pad to product recommendations for compounds for removing your sanding marks.

M85 Diamond Cut Compound with a Wool Cutting pad applied with a rotary buffer.

M84 Compound Power Cleaner with our W-7006 or W-70000 foam cutting pad applied with a rotary buffer.

After using one of the above choices to remove your sanding marks, then re-polish each panel using M83 Dual Action Cleaner Polish using either a W-8000 or W-8006 foam polishing pad to remove any swirls or buffer haze left over by the compounding process.

After your second polishing step, re-polish each panel again using the dual action polisher with M80 Speed Glaze on a W-8006 foam polishing pad on the 5.0 speed setting.

Stop here, wipe off any left over reside and wait till the recommended time to pass before applying wax.

[the other pc]

I would highly recommend using Meguiar's/Nikken sandpaper for all of your hand sanding. If you mix brands the Nikken should the last paper (finest grit) to touch your paint before compounding.

The uniformity of the grit on Nikken papers substantially reduces the amount of compounding necessary to remove the scratch pattern. You'll have less work and get better results.


PC.

[Mike Phillips]

Originally posted by the other pc
I would highly recommend using Meguiar's/Nikken sandpaper for all of your hand sanding. If you mix brands the Nikken should the last paper (finest grit) to touch your paint before compounding.

The uniformity of the grit on Nikken papers substantially reduces the amount of compounding necessary to remove the scratch pattern. You'll have less work and get better results.


PC.

PC makes a very good point, you might in fact be better off just stopping at the #1500 Nikken and skip the other paper due to lack control over particle size and particle distribution

Personally, I wouldn't use anything but Nikken on any wet-sanding project. Just wouldn't do it.

[BikerDrew]

OK OK...

I'll head to the store and see if I can find 2500 and 2000 Nikken paper. Wish me luck!

[BikerDrew]

Well...

OK. The sanding went fine. All smooth and even. It took about and hour. Remember, it was just the front end. Then the buffer.

While using the red pad and 85 on low speed, I burned through the new paint in three spots. It kind of bunched up and broke free. The rest turned out fine... like glass. The burns happened on a curve (understandable) and on two flat areas. I thought screw it and finished the job to a point where someone must look for the damage to find it. That involved re-sanding the damaged areas and buffing to a smooth finish.

I have buffed a lot of paint with a rotary, always using low presure and allowing the tool to do the work. Well, I was able to easily remove the sanding marks and polish the majority of the paint to a very nice shine.

I don't know, it seems like either the paint was not hard enough, or the subsurface was not adhearing to the base coat properly. I preped it with 600grit and wiped it down with rubbing alcohol, then a tack rag.

I am a bit beaten over this. A lot of work , a few bucks and now I have to do it again.

I know... When I feel better , Ill post some. Drew

[Tim Lingor]

Hi Drew,

Did the paint bunching up look like this?



Tim

[BikerDrew]

YES!

[Tim Lingor]

That bunching of paint is caused when the paint gets too hot due to the friction of the rotary buffer. It usually occurs on edges, soft paint or generally with paint on composite panels. I did a write-up on wet sanding where I purposely did that to a composite panel to show what can happen. Do not feel bad...it can happen real easy!!!

When removing wet sanding marks with the rotary, I would use the #85 with the W-4000 wool pad. Meg's #85 was designed to be used with a wool pad. Or, you can use #84 with the W-7006 Cutting Pad (#84 was designed to be used with the cutting foam pad). Work the area until the product breaks down. But be very cognitive of the paint's temperature from the buffing process.

Agan, do not feel bad; it does happen easily on some paint.

Tim

[BikerDrew]

Tim,

I have a wool pad, but the video states it should be used after more agressive paper than I used (2000 grit). Next time I'll try it your way.

Is there any advantage to wet sanding the finish and allowing it to cure a while longer before polishing?

Is there a window of time after fresh clearcoat urethane paint where a HAND leveling process is appropriate on delicate edges?

I don't think I could cut a sanding mark out by hand. Well maybe if I looked like POPEYE.

Drew

[Mike Phillips]

I think I listed the two options earlier in this thread,

Originally posted by Mike Phillips
Here are the pad to product recommendations for compounds for removing your sanding marks.

* M85 Diamond Cut Compound with a Wool Cutting pad applied with a rotary buffer.

* M84 Compound Power Cleaner with our W-7006 or W-70000 foam cutting pad applied with a rotary buffer.

The M84 is a wetter product to provide more lubricity because the foam cutting pad needs this in order to help prevent generation too much heat. This is why we don't recommend the M85 with foam.

Sorry to hear about what happened. If you get a chance, try to watch the video link I posted as it also shows recommended product and pad combinations. When using the rotary buffer to buff on paint, use the hand test to see if you're getting to hot.

After working an area, place your bare hand on the paint, if you are able to comfortably place your hand on the finish you're probably in a heat range that's okay. If after placing your hand on the finish your fight or flight instincts immediately cause your to quickly jerk your hand away from the finish, then thats to hot. Stop buffing in this area and allow the paint to cool down.

Part of good technique when buffing with our foam pads is to always hold the buffer in a way that the pads are flat against the finish. When you do this, you have 100% surface contact between the pad and the paint, so be mindful that the potential for heat is very real.

[BikerDrew]

Mike;

Thanks for the help, but this repeat post does not answer my questions

[Mike Phillips]

Originally posted by BikerDrew
Tim,

I have a wool pad, but the video states it should be used after more aggressive paper than I used (2000 grit). Next time I'll try it your way.

The product recommendations are just guidelines as the rule of thumb is to use the least aggressive product and pad to get the job done. However that's within the #85/Wool Pad and #84/Foam Cutting Pad combinations.

Is there any advantage to wet sanding the finish and allowing it to cure a while longer before polishing?

The longer your wait, the harder the paint will become and the more difficult it will be to remove your sanding marks.

Is there a window of time after fresh clearcoat urethane paint where a HAND leveling process is appropriate on delicate edges?

I don't think I could cut a sanding mark out by hand. Well maybe if I looked like POPEYE.

Drew

The general rule of thumb is to only sand where you can get you pad safely while buffing. I have used ScratchX to remove #2500 grit sanding marks by hand on factory cured paint, but it did take a long time and a lot of passion. Softer paint would make it a lot easier, as would using a fiber applicator I was using foam.