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clearcoat after sanding


Hemi Killer
08-21-2011, 02:02 PM
I used engine enamel to paint the body of my Boss 429. I wet sanded it smooth with Micro Mesh 3200 grit. In the right light, you can see the very, very fine marks from the 3200. Do I need to go higher before applying clear coat, or can I spray clear over this, then polish? There is good clarity in the paint.

racer93
08-21-2011, 02:17 PM
I used engine enamel to paint the body of my Boss 429. I wet sanded it smooth with Micro Mesh 3200 grit. In the right light, you can see the very, very fine marks from the 3200. Do I need to go higher before applying clear coat, or can I spray clear over this, then polish? There is good clarity in the paint.
Heck, I polish (if need be) my paint with 2k grit and then clear. The clear with 9 times out of 10 cover any fine scratches. It's when you clear over 800 grit sanding that things get iffy...

Really, it's best to only polish clears. Don't even worry about the paint unless you have a two-color job where a line needs sanding down. That's what I've been told by those better than me. Just my $0.02.

Hemi Killer
08-21-2011, 09:07 PM
thats wht I was hoping. My buddy came over and told me I had to get rid of all the evidence of sanding. He works at a high end body shop, I didn't think this was as necessary on a model. a cut compound should get it nice and prepared for a final polish

360spider
08-21-2011, 09:11 PM
Really, it's best to only polish clears.

That is not true. Polish clears only if paint is metallic. In fact, I don't even clear if paint is solid. Why add more coats?

racer93
08-22-2011, 12:12 AM
That is not true. Polish clears only if paint is metallic. In fact, I don't even clear if paint is solid. Why add more coats?
Simple--decals. In order to get the most accurate representation of very thin vinyl decals (on 1:1 cars) is to clear over and polish it out until smooth. You're not going to see something that is microns thick on a 1/20 or 1/12 scale car.

There are also many paints that require a top coat. See Zero Paints. A lot of acrylics are that way. *If done correctly* it does not add that much more thickness. At least it doesn't on my builds.

You may be able to get away with it on street cars but not on race cars or anything with a lot of decals. It just won't look quite right.

Daniel

hirofkd
08-22-2011, 12:44 AM
I used engine enamel to paint the body of my Boss 429. I wet sanded it smooth with Micro Mesh 3200 grit. In the right light, you can see the very, very fine marks from the 3200. Do I need to go higher before applying clear coat, or can I spray clear over this, then polish? There is good clarity in the paint.

3200 is one of the coarser abrasives, so you'll have to go even finer, like at 4000-8000 grit. The problem is, when you polish over and over, you'll always run the risk of exposing the primer, so make sure the base coat is thick enough, and if not, you might want to apply a few more very thin coats. In fact, those final coats might be able to fill the scratches.

drunken monkey
08-22-2011, 08:10 AM
you don't need to clear over solid gloss colour paint

360spider
08-22-2011, 09:56 AM
Simple--decals. In order to get the most accurate representation of very thin vinyl decals (on 1:1 cars) is to clear over and polish it out until smooth. You're not going to see something that is microns thick on a 1/20 or 1/12 scale car.

There are also many paints that require a top coat. See Zero Paints. A lot of acrylics are that way. *If done correctly* it does not add that much more thickness. At least it doesn't on my builds.

You may be able to get away with it on street cars but not on race cars or anything with a lot of decals. It just won't look quite right.

Daniel

I got it - you just like to argue. Fine by me, I'm not participating.

racer93
08-22-2011, 10:51 AM
I got it - you just like to argue. Fine by me, I'm not participating.

I'm not arguing with you--you called me out and I was defending my position. It's called a discussion.

drunken monkey
08-22-2011, 06:43 PM
you said
Really, it's best to only polish clears.

to which alex replied.
That is not true.

There is nothing wrong with what he was trying to say.
His only error was in trying to actually answer what the original poster asked about
i.e his enamel paint on his model.
Not decals.
Not 2 part paint (and if you're using a 2 part paint and only use 1 part, then well, you're just dumb).

As I said in my first post here; you don't need to clear over solid gloss colour paint.

What you (OP) really want to be doing, is to start thinking about using polishing compounds with a soft, lint free cloth.
Typically, the guys here will use Tamiya Coarse (Blue tube) followed by Tamiya Finish (Black tube). Some go an extra step after this and use premium car finishing products like Meguiars or Autoglym polishes.

Hemi Killer
08-22-2011, 07:23 PM
First of all, thank you everyone for their input, but I dont want this to turn into a heated debate thread.

I polish natural stone for a living. Marble, granite, travertine etc, with diamond abrasives and compounds. The general rule of thumb is the same, but the details do not translate to auto paint.

Like stone, i know there is more than one way to skin a cat when it comes to paint. sometimes I have to finish the stone mechanically as high as I can, other times I can jump to a compound halfway through, and sometimes a topical finish, or clear coat can be used.

I lack experience when it comes to painting bodies, and I think alot of it is because of how aggressive you need to be with stone. i constantly find myself burning through paint. I am learning how to lay down many layers without covering detail as I go.

I did 4 mist coats, then 1 heavy wet coat of enamel on this car. My hope is that I can clear, or compound polish sooner, rather than later. I think I can handle a few more abrasive steps, but I have come further than I have before to completing my model and I dont want to screw it up now.


If there are different paths to take I would like to hear them, but there is no need to to argue over whos more experienced. different strokes for different folks.


the specific paint I used is Duplicolor engine enamel. it cures within a few days.

I guess what my question is, is what would be the most logical procedure, from an experienced painters' perspective. Clear coating the engine enamel and polishing, or end up polishing the paint itself? No decals will be used.

while I am at it, i have a second paint question regarding my R390 GT build.

using Tamiya Spray cans, should I smooth the paint, decal, then clear. Or polish the paintm decal, then clear. what steps make the most sense?


I have built some nicely detailed cars, only to stick them in a box when it comes time to paint the bodies. It is becoming frustrating and I really need to get through this stage.

thank you

drunken monkey
08-22-2011, 08:09 PM
First of all, you've got to be careful with enamels.
If your wet coat is too thick, there is the possibility that the outer surface (skin) of the paint cures fully leaving the paint underneath soft; in which case, it will never fully cure as the cured skin prevents further solvent escape.

That is what makes enamels difficult to use compared to the prefered sythentic acrylic lacquers (i.e Tamiya TS and most automotive sprays).

Assuming all is well with your paint, I would do as suggested by Hirofkd anddo a wet sand with 4000-8000.
Normally, I do this with a little shaving gel as it feels better, to me, to have a lubricating barrier that might act as a carrier for the paint that is being removed. Of course, it just feels like it helps to me.
There is no proof it actually does anything.
Anyway.
The 8000 wet-sand should get you a smooth surface that a little polishing with compounds would bring up to shine nicely.

One thing I like to stress is that sanding is done not only to get rid of texture in the paint. More importantly, it is to make sure that the paint really is level.
To make paint shiney is actually quite easy.
The difficult bit is to make it perfectly flat and blemish free so that reflections have virtually no distortion in it.

In the case of your model, I would say go ahead with the finer grade wet-sanding and if you do go through to primer, then treat it as a learning excercise and apply another coat of paint.
It really is the only way to learn how thick your paint layers can be, how much paint you need, how hard/soft/gentle you sand etc etc.

After that, try sand again if neccessary then try the compounds.

Hemi Killer
08-23-2011, 05:32 PM
thank you. I will continue with the micro mesh...carefully

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