Sanding and Painting Models?

[Roger U]

So many of you do really nice paint jobs on your models. I'm wondering what is the recommended procedure for sanding and painting models?  I've read that you should use several grits of sandpaper getting finer and finer. Do you use a finer grit of sandpaper after each coat of paint or what is the procedure? Does it vary with how many coats of paint you spray on the model?  I haven't built a model since the 1960s and didn't do much sanding back then.

[espo]

Man, your going to get information overload on this question. There may be as many similar answers as there are members here. For myself I prefer to start with removing problems I can see with out any primer first. I'll deepen body panel lines and trim parts that will get foiled at a later stage of the prep for painting. After correcting everything that I can see I'll sand the body with a very low grit sanding stick. This will show areas that aren't even with the rest of the body. Next I would either rinse the body under water or blow away and dust with an air brush in order to start with the cleanest  body possible. I would apply a very light coat of primer and allow to dry. I start my sanding again with a 1500 or higher  grit sanding pad and this should give you a better idea of just how smooth the surface is and will expose any high and low spots. Using a lower number sanding material can course scratches that will have to be sanded out and create more work for you. After correcting the high and low spots or any other imperfections that you notice I would give the body one last very thin but uniform coat of primer.  The color of the primer used may effect the appearance of your final color coats. This is something that you should practice on say a plastic picnic spoon. I would spray one spoon with the gray primer and another with a white primer if you're going for a light color and red primer if you're going for a color in that range. I would then spray you color of choice on all three spoons and allow to dry. A later spray of clear or flat clear will give you a good idea of how your color will look when finished. Which ever looks best to you will make the color selection for the final primer coat. After the final primer coat I would use as fine of grit sanding pad that you have and go over the body one final time with little or no pressure and let the sanding pad smooth out the surface.  Before the first color coat I would recheck your panel lines, use a sharp #11 blade to mark the parting line between the body and any chrome trim you may be foiling later. With a couple coats of paint and clear the parting lines get harder to find when you're foiling the trim. The first couple of coats of color should be light and about 5 to 10 minutes apart. This is an area that many builders take different paths and over time and trial you will find which way works for you, this is only how I do it for myself. After the first color coats have dried you will want to see if you're getting the even coverage you want and if you're getting any finish problems. Should you start to see some orange peal type finish as an example you will want to re sand the surface smooth again and try and correct the way you're spraying. Some of this you may have noticed when you were practicing on the spoons. When you have the finish as smooth as you can get it you can spray a better coverage of body color in a coat or two. Now you need to allow the color finish to dry and over night may not be long enough. With a smooth looking surface you can go on to color sanding if you feel it is needed. This is wear you need to let the sanding pad do the sanding and I would start with a 2000 or higher pad. Starting with a small area and I prefer a small cup of water to dip the sanding pad in to clean it from time to time. You will quickly see if you need to go to a higher number or a lower number depending on how the finish looks. You don't want any scratches but a slight dulling of the surface that you can spray your clear coats over. The smoother you can get the colored surface the less work on the final clear coats. The clear surface should be smooth enough that it would only need a light polishing with some compound and wax.  I have tried to just give you some ideas of how I do this. As I mentioned you will hear from many others and they will do somethings different and that's how we all get better by hearing and seeing how others approach  the process. There is no right way or wrong way, just the way that works best for you.  

[Roger U]

Thank you for all the very useful and detailed information.  This gives me a good idea where to start and what to look for while trying to figure out what I should be doing.

[StevenGuthmiller]

Personally, I almost never sand between coats of primer.

 

As David mentioned above, I do all of my body prep then shoot a light coat of primer to check for areas that might need more work.

If all is good, I shoot several more light coats of primer allowing at least a couple of hours of cure time between each.

As long as there is no dust or other blemishes between coats, I don't sand.

Then it's just a matter of doing the same with the color and clear coats.

 

Rather than spend a lot of time sanding between every coat of primer, paint and clear, I prefer to use that time polishing the final clear coat.

To this point it has worked very well for me.

I rarely wind up stripping a body for a repaint.

 

Keep in mind that I use automotive lacquers almost entirely.

The type of paint that you use will make a big difference on the techniques that you should use to achieve the best results.

 

I admit that my method of using as many as 5 coats each of primer, paint and clear is unorthodox among modelers, but it is a process that I have developed over nearly 50 years of building and it rarely fails me.

 

 

 

 

 

 

 

 

 

Steve

 

Edited October 20, 2020 by StevenGuthmiller

[Bills72sj]

2 hours ago, StevenGuthmiller said:

Personally, I almost never sand between coats of primer.

 

As David mentioned above, I do all of my body prep then shoot a light coat of primer to check for areas that might need more work.

If all is good, I shoot several more light coats of primer allowing at least a couple of hours of cure time between each.

As long as there is no dust or other blemishes between coats, I don't sand.

Then it's just a matter of doing the same with the color and clear coats.

 

Rather than spend a lot of time sanding between every coat of primer, paint and clear, I prefer to use that time polishing the final clear coat.

To this point it has worked very well for me.

I rarely wind up stripping a body for a repaint.

 

Keep in mind that I use automotive lacquers almost entirely.

The type of paint that you use will make a big difference on the techniques that you should use to achieve the best results.

 

I admit that my method of using as many as 5 coats each of primer, paint and clear is unorthodox among modelers, but it is a process that I have developed over nearly 50 years of building and it rarely fails me.

Steve

 

Steve's results speak for themselves time and time again.

[Roger U]

Thank you David, Steve, and Bill . Your information gives some very good things to consider when painting models. I'll have to think over what you've said and, as you say,  experiment.

[StevenGuthmiller]

7 hours ago, Roger U said:

Thank you David, Steve, and Bill . Your information gives some very good things to consider when painting models. I'll have to think over what you've said and, as you say,  experiment.

That's really all that you can do.

Every builder has their own painting process.

You'll just have to take what advice that you can and develop your own system.

 

 

 

Steve

[Dave G.]

13 hours ago, StevenGuthmiller said:

That's really all that you can do.

Every builder has their own painting process.

You'll just have to take what advice that you can and develop your own system.

 

 

 

Steve

Man that green is dead on on the Ford, I owned a 390 powered 67 in that same green, beautiful car till the frame rotted out... Beautiful work right there on your model though, looks like it could be driven away.

[TransAmMike]

Steve, what automotive laquer do you use.  I'll be doing a Saturn Gold 71 Cutlass (as a replica of one I owned) and finding that color is kinda giving me fits.

[Snake45]

I've learned that every paint job is a law unto itself. Whether and/or when I sand, and with what, can depend on paint color, paint type, paint brand, whether or not it's going to be clear-coated, and maybe a half-dozen other possible variables. There's no substitute for experience. 

[StevenGuthmiller]

1 hour ago, Dave G. said:

Man that green is dead on on the Ford, I owned a 390 powered 67 in that same green, beautiful car till the frame rotted out... Beautiful work right there on your model though, looks like it could be driven away.

Thank you David!

 

 

Steve

[StevenGuthmiller]

59 minutes ago, TransAmMike said:

Steve, what automotive laquer do you use.  I'll be doing a Saturn Gold 71 Cutlass (as a replica of one I owned) and finding that color is kinda giving me fits.

Right now I'm using mostly Scale Finishes "base coat" lacquers.

I use MCW paints on occasion when they have the color that I am looking for.

 

The trade off between the two is that Scale Finishes carries nearly every color for a huge number of cars, so most colors are readily available.

My opinion is that MCW's metallic paints have a more "in scale" metallic finish than Scale Finishes, but their color palette is not as wide ranging.

But both are excellent paints!

 

The '64 Grand Prix above is "Sunfire Red" from Scale Finishes.

The '67 Ford is "Lime Gold" from MCW.

 

I didn't see 1971 Oldsmobile "Saturn Gold" on MCW's website, but Scale Finishes does carry it.

 

 

 

 

Steve

[Casey]

On 10/19/2020 at 4:38 PM, Roger U said:

So many of you do really nice paint jobs on your models. I'm wondering what is the recommended procedure for sanding and painting models? 

http://italianhorses.net/Tutorials/tutorials.htm

[TransAmMike]

Steve I see the Scalefinishes saturn gold.  I assume the basecoat is laquer.  2 oz enough for 1 model???

[StevenGuthmiller]

3 hours ago, TransAmMike said:

Steve I see the Scalefinishes saturn gold.  I assume the basecoat is laquer.  2 oz enough for 1 model???

Yes, the basecoat is lacquer.

2 oz. should be more than enough.

When I painted my '68 Olds 442, I used less than 1 oz.

 

 

 

Steve

[TransAmMike]

Thanks Steve, I'm definately thinking its the way to go.  Would any laquer primer work and what not too expensive clearcoat??

[StevenGuthmiller]

8 hours ago, TransAmMike said:

Thanks Steve, I'm definately thinking its the way to go.  Would any laquer primer work and what not too expensive clearcoat??

I use Duplicolor primer and clear, but you can use pretty much any good lacquer primer or clear coat that you wish.

 

 

 

Steve

[gtx6970]

Keep in mind if using an airbrush you can get away with more coats .

Rattle  cans ,,,IMO not so much

[jamesG]

A few things to remember are that good prep work is critical, the best paint job in the world won't matter if there are deep sanding scratches or "dents" in the body. 

Wash everything thoroughly with dish soap and water to remove any contaminants including oils from your hands.

Where nitrile gloves when handling your model to avoid getting oils from Your hands on it.

I like to freshly painted parts covered in an old cake pan with a loose fitting lid or my spray booth covered with plastic at least 'till it is dry to the touch to keep any dust off the fresh paint.

unpainted parts is the only thing I dry sand. After primer it is wet sand only.

Hope this helps you out.

[TransAmMike]

Good info here guys. Good to hear the Duplicolor clear works well.

[StevenGuthmiller]

6 hours ago, TransAmMike said:

Good info here guys. Good to hear the Duplicolor clear works well.

There are several different Duplicolor clears.

I use the one in the short can called "Perfect Match" "Protective Clear Coat Finish".

It works very well for me as I polish all of my models, but it doesn't gloss all that well straight from the can.

 

Just wanted to let you know that polishing will be very beneficial to the finish.

 

 

 

 

 

Steve

[TransAmMike]

Thanks Steve, I'll try it. As for polishing, The most I've ever done is light sand on blemishes then compound, polishing compound then liquid wax.

I have never used a clear topcoat yet on anything but I guess I probably should as I attempt to do more quality work.