Testors one coat lacquer

[rickd13]

Does anyone have a system when using Testors one coat lacquers? My problem is that I did some rough body sanding before priming with Duplicolor primer. Then I used the one coat lacquer, but all of the scratches shown through. I stripped all the paint and tried again. This time I sanded all the way from 800 grit through 12,000 grit on the bare plastic. The plastic was fairly smooth when I was done.Then I painted just the hood without primer to see how it would look. I only gave it one coat so far, but you can still see even the fine scratches. It doesn't look that good to me. How can I make sure the scratches don't show through? Should I shoot a clear coat over the bare plastic before I paint my color? How do I make sure the scratches don't show through? Another problem I noticed when I painted the car was that there were spots on the trunk that show trough because of the way the plastic was molded on the underside of the trunk. How do I cover those spots so they don't show through on the top side of the trunk when I paint the car?

[scalenut]

not sure I follow, your seeing scratches in the paint coat after sanding down to 12,000 grit?

[rickd13]

not sure I follow, your seeing scratches in the paint coat after sanding down to 12,000 grit?

Even the very fine scratches are showing through the paint color. I sanded the bare plastic down to 12,000 grit. It was smooth, but not like when you polish out a paint color. It still has very fine scratch marks that are showing through after I spray the color. I tried painting just the hood of the car to see how it would look. I didn't use a primer the second time. I read that a lot of guys spray the one coat Testors without a primer and they have great success with it.

[rickd13]

if the primer is too hot it will craze the plastic, which may very well be raising those sanding scratches and the mold seams/grain.

I tried it on the hood of the car without a primer the second time and I'm still not satisfied with the results. Should I try the primer again? If I do use a primer, should I spray the color coat right over the primer without sanding the primer first? I'm afraid the sand scratches on the primer would show through. What about those spots I mentioned on the trunk area? There are two round dots that show through because the plastic on the underside of the trunk are the spots where the chassis attaches to the body. How do I keep them from showing through? I appreciate your help.

[Dave Ambrose]

I tried it on the hood of the car without a primer the second time and I'm still not satisfied with the results. Should I try the primer again? If I do use a primer, should I spray the color coat right over the primer without sanding the primer first? I'm afraid the sand scratches on the primer would show through. What about those spots I mentioned on the trunk area? There are two round dots that show through because the plastic on the underside of the trunk are the spots where the chassis attaches to the body. How do I keep them from showing through? I appreciate your help.

I use Model Master primer, sand with 600 grit paper, and I haven't had problems with scratches showing through the paint.

But, I've found that the Testor's lacquer isn't really one-coat. It usually takes a mist coat, and a couple of heavier coats to get good color. One other thing you need to do is make sure the model is degreased. I usually wipe it down with an alcohol dampened cloth. It takes off any oils without affecting the underlying paint.

I suspect that you're seeing ghosting where the plastic is stressed, and the solvents are softening it enough to show through the paint. If you brush liquid plastic cement on the affected area, it should relieve the stress. Then you can prime, fill, and sand out the area until it's really level.

Posting pictures will help us understand what's happening.

[rickd13]

I use Model Master primer, sand with 600 grit paper, and I haven't had problems with scratches showing through the paint.

But, I've found that the Testor's lacquer isn't really one-coat. It usually takes a mist coat, and a couple of heavier coats to get good color. One other thing you need to do is make sure the model is degreased. I usually wipe it down with an alcohol dampened cloth. It takes off any oils without affecting the underlying paint.

I suspect that you're seeing ghosting where the plastic is stressed, and the solvents are softening it enough to show through the paint. If you brush liquid plastic cement on the affected area, it should relieve the stress. Then you can prime, fill, and sand out the area until it's really level.

Posting pictures will help us understand what's happening.

I believe that you are right about the stressed plastic causing ghosting so I don't think that the circle dots that are showing through are even deep enough to have to be filled. What do I do if those spots do not need to be filled? Would you still use liquid cement? What kind of liquid cement would you use? Should I still use a filler and what kind of filler should I use? I have tried Testors contour putty as a filler but it sucks and is completely useless. Do you use the filler after you prime? Do you prime again after the filler has been sanded smooth?

Edited October 20, 2011 by rickd13

[Dave Ambrose]

I believe that you are right about the stressed plastic causing ghosting so I don't think that the circle dots that are showing through are even deep enough to have to be filled. What do I do if those spots do not need to be filled? Would you still use liquid cement? What kind of liquid cement would you use? Should I still use a filler and what kind of filler should I use? I have tried Testors contour putty as a filler but it sucks and is completely useless. Do you use the filler after you prime? Do you prime again after the filler has been sanded smooth?

First, I would still use liquid cement. Something like Tenax. Just lightly paint it over the stressed areas, or areas where you've shaved off things like door handles.

If you don't fill the depressions, you'll see them in the paint. You have a couple of choices. One is to thin the putty with lacquer thinner and brush it on. It will settle into the shallow depressions, adhere, and not be too painful to sand off. Or, you can build up some primer in the depressions. Brush the primer into the depressions, and sand it back smooth.

I've been using Squadron white putty. It's working well enough. You have to be careful to make sure it has enough solvent in it to adhere properly. If it starts to dry out, discard the old, and dispense some fresh putty. I hear Tamiya putty is top notch stuff, but I've never used it.

I always prime after puttying or filling.

One question - are you using some kind of sanding block? I usually use either a rubber eraser, or a "tadpole" on curved surfaces. Do not use fingers. They give too much and you don;t actually level out the surface like you want to.

You should be fine sanding the primer with 600 or 800 sandpaper.

This whole body prep process is somewhat tedious, but totally worthwhile. Keep your prime coats thin so you don't obscure all the detail, then fill, sand, and prime until you get it right. It makes all the difference.

[scalenut]

But, I've found that the Testor's lacquer isn't really one-coat. It usually takes a mist coat, and a couple of heavier coats to get good color.

According to Testors,it called "one coat" because it's designed to not need a primer or clear coat ... not because it's supposed to go actually on in one pass

Edited October 20, 2011 by scalenut

[rickd13]

Thanks guys.