Another paint question related to polishing

[ERIK88]

Hey guys, I want to thank everyone in advance who responds . So I have. A question concerning polishing and waxing. Ok so as you guys know a lot of times when clearcoat is sprayed there is orange peel . A way to get rid of orange peel is to sand the clearcoat. So I sand with diff fine grits from micro mesh. I finally do the 12000 grit wet sand scrub and then apply a polish, rub and apply a wax. This is all done with a micro fiber cloth. So I'm aware that when I sand clearcoat, it's going to get dull, and it won't completely regain the original full shine. That's fine , it's still shiny enough. However I notice these light scratches I can't get rid off. Is that because I sanded or scrubbed too hard? Maybe it's normal?  I really don't think I should be seeing light swirl or scratch marks. I also used meguiiars and it didn't work. How can I keep everything smooth without light scratches?

[Quick GMC]

don't use microfiber, use a smooth polishing cloth. 

[Ace-Garageguy]

If you're still seeing scratches after polishing, it's because either you left deeper scratches in the paint that you didn't get out during your progressively finer and finer sanding, or you haven't polished enough.

Many modelers tend to not put enough effort into the sanding phases. Each successive sanding step is intended to remove, entirely, the deeper sanding scratches left by the previous grit. Just lightly rubbing it around on the car isn't getting the job done.

Polishing, unlike what a lot of folks seem to believe, isn't just "wipe it on and rub a little bit", either.

Polishing is an ABRASIVE process, and its purpose is to abrasively remove the last of the 12,000 grit scratches and restore the surface to its original gloss.

Do it all right, you won't see any scratches in the surface.

We do exactly the same steps on the big cars, but only sand to 3000 grit or so, usually. Polishing the final 3000-grit scratches out is done with a machine, but the same advice applies. A cloudy, dull surface or visible scratches simply mean the job isn't done yet.

Polishing is what brings the gloss back, not wax.

 

[BigTallDad]

don't use microfiber, use a smooth polishing cloth. 

I use an old flannel shirt

[ERIK88]

If you're still seeing scratches after polishing, it's because either you left deeper scratches in the paint that you didn't get out during your progressively finer and finer sanding, or you haven't polished enough.

Many modelers tend to not put enough effort into the sanding phases. Each successive sanding step is intended to remove, entirely, the deeper sanding scratches left by the previous grit. Just lightly rubbing it around on the car isn't getting the job done.

Polishing, unlike what a lot of folks seem to believe, isn't just "wipe it on and rub a little bit", either.

Polishing is an ABRASIVE process, and its purpose is to abrasively remove the last of the 12,000 grit scratches and restore the surface to its original gloss.

Do it all right, you won't see any scratches in the surface.

We do exactly the same steps on the big cars, but only sand to 3000 grit or so, usually. Polishing the final 3000-grit scratches out is done with a machine, but the same advice applies. A cloudy, dull surface or visible scratches simply mean the job isn't done yet.

Polishing is what brings the gloss back, not wax.

 

thanks a lot, I might not be scrubbing enough . I will try going at it again this time a little harder on the body. I'll share my results ;)

[ERIK88]

That was a lot of good information that was shared with me, deeply appreciated !

[Longbox55]

Another thing that might be giving you problems with the scratches is the sanding technique used. You always want to sand in straight lines as much as possible (sometimes that's hard to do on some parts). When you go to the next grit, you should try to sand at a different angle from the prior grit, say 45 to 90 degrees from the direction you sanded. This will prevent making any scratches deeper, and will aid in removing them.

[Ace-Garageguy]

Longbox55 makes a very good point.

Another habit I've developed over the years...change your sanding water and wash out your water container between sanding grits. Wash the car body and your hands as well.

I know this seems like a lot of additional messing about, but there have been times (on big cars too) where a piece of grit from a coarser piece of sandpaper has come loose and made a scratch when I've been sanding with a much finer grit. Changing out the water and washing off the model and your hands gets rid of anything that might scratch on the next successive step. And keep your sandpaper or pads CLEAN.

A single drop of detergent in your sanding water will act as a wetting agent too, and may help to keep your sandpaper from loading up.

When polishing, I'll complete an area about 1/6 the size of a credit card...about as big as the first joint of my thumb. Finish it, check for scratches and a nice clear gloss, and move on, overlapping into the next area.

[StevenGuthmiller]

Another thing to think about is the grit you're starting with.

beginning with a pretty heavy grit will give you pretty deep scratches to try to remove with the finer grits.

I used to have this problem myself, but since I started using multiple coats of Duplicolor clear with a sanding in between, I've gotten to the point where the paint is almost completely free of orange peel so that I can start with 4000 grit or finer.

When you start getting into the heavier grits, you're much more likely to wind up with deeper scratches which can be difficult to remove.

Here's my story on this.

To begin with, I've been using about 4 coats of Duplicolor primer. Why so many? I've had way too many issues with lacquer paint crazing the plastic if not adequately primed, so I figure more is better.

I rarely see any need to sand my primer coats. Duplicolor primer dries as smooth as can be, so I don't see a reason too. Orange peel usually rears it's head during color coats, not primer coats.

After several coats of lacquer color, (usually MCW, and often metallic) I shy away from sanding my color coats, especially metallic colors, because of issues with "smearing" the metallic in the paint & leaving areas that look "blushed".

So, where does that leave me for taking care of any orange peel in the paint? I deal with that entirely in the clear coats.

Duplicolor clear dries extremely thin with very little hiding of detail so multiple coats are possible. It also has pretty good leveling properties which will hide a little more of the orange peel with each successive coat.

I start with 3 or 4 coats. I want a good base for sanding so that I don't burn through to the paint, or worse, the primer. Then I give it a sanding before shooting the final 1 or 2 coats of clear.

The final clear coats will fill in any scratches from sanding & give you a nice smooth surface.

Duplicolor clear does not dry as shiny as other clears, so it needs polishing just to bring out the shine, but after doing it this way, I usually have little to no orange peel to deal with. Plus I have 5 or 6 coats of clear over the color, so the likelihood of burning through the paint during polishing is greatly diminished.

So, my point of this rambling is, the smoother your paint job, the finer the polishing pad, the less likely you are to have scratches.

 

Steve

[Ace-Garageguy]

Steve knows. Just look at some of his beautiful models, and it's obvious he's got the bugs worked out of the process.

[StevenGuthmiller]

Steve knows. Just look at some of his beautiful models, and it's obvious he's got the bugs worked out of the process.

Not all of them by any stretch Bill.

But I'm working on it.

I still dream of the perfect paint job.

Maybe I'll be able to achieve that goal before I die.

 

Steve

[ERIK88]

Wow what a good amount of info you guys have given me! Thank you for making this hobby much more enjoyable. Body paint has always been my struggle, but it looks like it won't be anymore thanks to the masters! All of these tips will be taken seriously and applied to my projects .