Sanding

Question from a newbie.....

Should I sand the body before spraying?

I haven't built models in a long time, but I never sanded the body completely. Just were I was going to do something custom and wanted to smooth out a surface. On some models that I painted though, I would prime it, helps the paint stick better and in some cases, the color shows better.:D

Yes. You should wash the bare plastic with warm water and dish soap, then sand it with a reasonably coarse sandpaper. I use 1800 grit for this first sanding.

The A-Number-One Reason: molding lines. A car body is cast from a complex multi-part mold, leaving mold lines that may not be evident at first, but will surely get in the way when you go to polish the final paint job.

I learned this the hard way on an MR2 I built. I thought I had removed the mold lines, but when I was polishing at the end I found the the mold lines on the rear of the car were hidden in the trunk panel lines. They didn't lie flush with the adjacent panels, so I ended up taking paint of the edges of the trunk. :bloated: :(

Then, as DVS says, a good coat of primer is called for. Then sand the primer to find any remaining flaws. This will be easy, because where there are raised lines, you will sand through the primer. Sand these down smooth, then you'll be ready to finish priming, and start painting.

:D

how do i get bubbles out of already dried paint? do i just let it dry, sand em down, and the paint again?

Originally posted by YellowMaranello
how do i get bubbles out of already dried paint? do i just let it dry, sand em down, and the paint again? How bad are the bubbles? Are they open like pock marks, or are they lumps under the surface?

I just hate it when a hair dries into the paint.

Originally posted by YellowMaranello
how do i get bubbles out of already dried paint? do i just let it dry, sand em down, and the paint again?

Yes you well have to sand them out to get a good finish.

I have found that the bubbles can be caused by spraying the car with too much paint (too thick)
If you see them appear as soon as you have finished spraying, try pricking them with a needle if there are not to many. Hopefully they will run in with the rest of the wet paint.

this is kind of an odd question coming from someone that has done lots of models. I have never primed, sanded, polished or any of that. i'm just wondering what kind of primer to get, how to polish the paint (is it like waxing??????) thats basically all i need to know, i want my R34 to be GREAT!

All you need to know is in my thread on the WRX!
Be wary of polishing too much paint off, and ending up looking at the basecoat or primer!
A situation where only experience will teach you how much is too much unfortunately!!!
But yeah, same idea as waxing really!

I use Tamiya Fine Surface Primer
After finishing painting the finish coat i use Tamiya Rubbing Compound then finally Tamiya Modelling Wax.
The end product is awesome when finished.

The wax can be used over decals too, it takes away any water markes and leaves a nice gloss on the decal.

Originally posted by YellowMaranello
how do i get bubbles out of already dried paint? do i just let it dry, sand em down, and the paint again?

Sometimes to, if they are not to bad, give it a light sand with 1200 grit paper(wet n dry) and very lightly try and sand them out.
Then use Tamiya Rubbing Compound, this will bring the gloss back out and take away the sanding marks if done correctly.

If the bubble has "pitted" the paint, then you will have to paint again.
But try the above first.

Originally posted by jay@af


Then, as DVS says, a good coat of primer is called for. Then sand the primer to find any remaining flaws. This will be easy, because where there are raised lines, you will sand through the primer. Sand these down smooth, then you'll be ready to finish priming, and start painting.

:D


So, after you sand the first coat of primer, and respray. Do you sand that other sprayed coat as well? Or leave it, then move on to the color?

Originally posted by kbslacker



So, after you sand the first coat of primer, and respray. Do you sand that other sprayed coat as well? Or leave it, then move on to the color?

Move on to the colour

I can see the importance of removing mould lines, but Primer???? Is it ABSOLUTLEY ESSENTIAL that I use Primer, or is Primer only if you want a perfect finish??????

Originally posted by Jimmy_11_cars
I can see the importance of removing mould lines, but Primer???? Is it ABSOLUTLEY ESSENTIAL that I use Primer, or is Primer only if you want a perfect finish??????


Yes, primer helps. I can tell you that. Here I have two seperate cars, done two seperate ways. One with primer, one without. It looks 10 times better with primer.

Primer helps more than you realize. :( I've learned that the hard way, too.

Primer helps the paint stick to the plastic, and that's really it's most important attribute.