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Do I still need to sand the model if I use Tamiya polishing compound?


Redryder74
05-30-2015, 11:56 PM
I have the coarse, fine, and polish Tamiya compounds. This is my first car model. I don't have any polishing cloths but I do have fine grit sandpaper. Can I just use the Tamiya stuff instead of polishing cloths or sandpaper? Other questions ...

1. Do I use the Tamiya coarse on the body even before priming?
2. What about on the primed model, or painted model?
3. If I'm going to clear coat the decals, and polish the clear coat, do I need to polish the paint job before applying decals?
4. Can I use Carnauba wax (from my actual car) to wax the kit?

Thanks in advance!

MPWR
05-31-2015, 09:07 AM
1- No. Inspect the body and sand off mold lines and any other imperfections. Lightly sanding all surfaces will help the primer (and therefore paint) adhere. Once the body is inspected/corrected/sanded, wash it with water and dish soap. Let it dry, and it is ready for primer.

2- Primer should be sanded as necessary. In truth it is the make or break step in painting- the step that takes the most time and effort. I typically will spray 3-6 sessions of primer over the course of several days, sanding with fine paper in between. When priming is done, the body is smooth, consistent, and without flaws. If the primer is right, painting is easy- almost like an afterthought. If primer is not done right, there's nothing you can do with paint, clearcoat, or decals to correct it.

3- No. The paint does not need to be sanded or polished unless there is a flaw that needs to be corrected (like a piece of debris has got caught in the paint). If this happens, gently sand out the debris, then apply more paint. Paint should be sprayed on in many light coats instead of one or two heavy wet coats. I typically spray 4-8 coats, leaving an hour or two to dry and inspect in between spraying. Once the paint is fully opaque, you're done with paint. Applying more won't give you any more depth. If you are spraying a metallic or pearl color, the last coat should be a light, even mist coat, and it must not be sanded.

3.5- Give it a day or so, then decal it. Give it another day, and then start clear coating. Do the clear coat just like painting (above). It is critical if using lacquer clear that the first several layers be fine, light mistcoats. Be slow and patient, or you may dissolve the paint and decals under it. (I usually spray 6-10 coats, an hour or two or more in between).

4- Let it dry a week, then polish it with Tamiya compounds and a soft cloth. Once you're done and happy with it, carnuba wax is a great option.

Mr Plumb
05-31-2015, 01:30 PM
1- No. Inspect the body and sand off mold lines and any other imperfections. Lightly sanding all surfaces will help the primer (and therefore paint) adhere. Once the body is inspected/corrected/sanded, wash it with water and dish soap. Let it dry, and it is ready for primer.

2- Primer should be sanded as necessary. In truth it is the make or break step in painting- the step that takes the most time and effort. I typically will spray 3-6 sessions of primer over the course of several days, sanding with fine paper in between. When priming is done, the body is smooth, consistent, and without flaws. If the primer is right, painting is easy- almost like an afterthought. If primer is not done right, there's nothing you can do with paint, clearcoat, or decals to correct it.

3- No. The paint does not need to be sanded or polished unless there is a flaw that needs to be corrected (like a piece of debris has got caught in the paint). If this happens, gently sand out the debris, then apply more paint. Paint should be sprayed on in many light coats instead of one or two heavy wet coats. I typically spray 4-8 coats, leaving an hour or two to dry and inspect in between spraying. Once the paint is fully opaque, you're done with paint. Applying more won't give you any more depth. If you are spraying a metallic or pearl color, the last coat should be a light, even mist coat, and it must not be sanded.

3.5- Give it a day or so, then decal it. Give it another day, and then start clear coating. Do the clear coat just like painting (above). It is critical if using lacquer clear that the first several layers be fine, light mistcoats. Be slow and patient, or you may dissolve the paint and decals under it. (I usually spray 6-10 coats, an hour or two or more in between).

4- Let it dry a week, then polish it with Tamiya compounds and a soft cloth. Once you're done and happy with it, carnuba wax is a great option.

Agree 100% on this, great post!

My only question that got me thinking, shouldn't you clear, polish then apply decals then clear over them again? Doesn't tat eliminate silvering?

thijs37
05-31-2015, 03:13 PM
1- No. Inspect the body and sand off mold lines and any other imperfections. Lightly sanding all surfaces will help the primer (and therefore paint) adhere. Once the body is inspected/corrected/sanded, wash it with water and dish soap. Let it dry, and it is ready for primer.

2- Primer should be sanded as necessary. In truth it is the make or break step in painting- the step that takes the most time and effort. I typically will spray 3-6 sessions of primer over the course of several days, sanding with fine paper in between. When priming is done, the body is smooth, consistent, and without flaws. If the primer is right, painting is easy- almost like an afterthought. If primer is not done right, there's nothing you can do with paint, clearcoat, or decals to correct it.

3- No. The paint does not need to be sanded or polished unless there is a flaw that needs to be corrected (like a piece of debris has got caught in the paint). If this happens, gently sand out the debris, then apply more paint. Paint should be sprayed on in many light coats instead of one or two heavy wet coats. I typically spray 4-8 coats, leaving an hour or two to dry and inspect in between spraying. Once the paint is fully opaque, you're done with paint. Applying more won't give you any more depth. If you are spraying a metallic or pearl color, the last coat should be a light, even mist coat, and it must not be sanded.

3.5- Give it a day or so, then decal it. Give it another day, and then start clear coating. Do the clear coat just like painting (above). It is critical if using lacquer clear that the first several layers be fine, light mistcoats. Be slow and patient, or you may dissolve the paint and decals under it. (I usually spray 6-10 coats, an hour or two or more in between).

4- Let it dry a week, then polish it with Tamiya compounds and a soft cloth. Once you're done and happy with it, carnuba wax is a great option.

i would like to make a small addition
Remove the mold lines with at least grid 600 or 800 and from that point on smoothen these area's by doubling the grid number! so from 600 you go on to 1200 and then on to 2000 or 2500...after that point sanded areas are smooth enough to prime and paint

stevenoble
05-31-2015, 05:00 PM
Agree 100% on this, great post!

My only question that got me thinking, shouldn't you clear, polish then apply decals then clear over them again? Doesn't tat eliminate silvering?

If you use gloss paints you don't need to clear them before you apply your decals. You won't get silvering on a gloss surface. Adding more clear is just an unnecessary step. However if you're using basecoat paints, or any paints that dry with a flat/matt finish, then a layer of clear is essential before your decals to help eliminate silvering.

MPWR
06-01-2015, 12:30 PM
My only question that got me thinking, shouldn't you clear, polish then apply decals then clear over them again? Doesn't tat eliminate silvering?

Like Steve says, decals need to be applied to a gloss surface. If the paint is sufficiently smooth/glossy, go ahead and apply the decals. If not then a couple layers of clear can be applied first to make that gloss surface.

i would like to make a small addition
Remove the mold lines with at least grid 600 or 800 and from that point on smoothen these area's by doubling the grid number! so from 600 you go on to 1200 and then on to 2000 or 2500...after that point sanded areas are smooth enough to prime and paint

You can do this if you want- but if you're using a good filling primer (such as Tamiya grey/white, or Mr Surfacer, or just about any automotive product) it isn't necessary. When preparing a plastic body for primer, I will generally use 400 or 600, and occasionally 320 if a lot of correction is required. But I don't use anything finer than 600, and spraying primer over a surface sanded only with 400 would be perfectly fine. Making a perfect smooth surface for paint is the job of the primer- let it do its job. Spraying primer on a slightly roughened plastic surface helps the primer bond to the plastic.

hogs29
06-08-2015, 10:43 AM
One thing you should watch for, depending on the decals and clear you are using, is applying the decals over the color, then clearing.
I had applied white numbers over a red paint, and when I cleared the clear pulled some of the red pigment through the decals. Now it must be said this was the only time I had anything like this happen and they were box stock Revell decals (not the greatest). Although I was using 2-part clear, which isn't really a "hot" solvent clear. Now I always put a thin barrier clear coat between the decals and color, normally just a coat of Tamiya or Mr Super Clear and I've yet to have it happen again.

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