Techniques

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How to paint with lacquers

by  Jose Antonio Solbes Shang

 

When we look at a car model, the first thing that strikes our eyes is the paint and its quality. Contrary to ships, airplanes, and tanks, car models of any kind (personal or competition) have one thing in common, the paint job must have a mirror like finish. This kind of finish depends on the materials and the painting techniques.


In this note I'll try to explain how I paint with a material that has been feared by many a modeler, I'm talking about automotive lacquers. Perhaps the fear comes from the fact that the substances in this material are so strong that they tend to "eat" into the coats and primer underneath, but I assure you that once you master the first step, which is the preparation of the body by means of a good "barrier" (primer), you will love this material. The only problem with lacquers is the aggressiveness of its solvents; in exchange of that, lacquers are very hard and the drying time is quite fast. Besides that, you can polish and wax the finish with the same products you use for your 1:1 scale automobile. And there is another advantage, once it has dried, you can lay almost any other material over it.

 

The subject is quite ample, and I don't want omissions of any kind, so I decided to divide the article in two parts: body priming, and painting.

 

Now lets talk about some very important details concerning the painting equipment. First of all, you need a good airbrush and a compressor with a pressure regulator. You can find lacquer paint in spray cans, but they don't give you the necessary kind of control for a good job. No matter the scale we are working on (except the 1/43), the airbrush must be equipped with an M head and tip; this is very important in order to get the adequate amounts of paint because, if you use a smaller head (fine) the paint will dry before hitting the surface; on the other hand, if you use too big a head, the extra paint will cover the fine details (specially in smaller scales).

 

As for the air pressure, I always set the control to 20 lbs. minimum, with 25 lbs. as a better option for the primer and the first 3 or 4 coats of paint; then, I lower the pressure to 20 lbs. for the following 4 coats, and finish with 17-18 lbs. for the final "wet" coats. More on these pressure changes when we get into the color coats.

 

Materials and equipment


This is a list of the necessary materials:


1. Lacquer primer; it can be gray, white, or oxide red, depending on the final coats. At this point I must say that the best primer I've ever used it's called VARIPRIMER and it's made by DuPont. The product has its own thinner and once properly mixed, you can apply it directly over any kind of plastic. I assure you that it wont etch it, and once dried, it becomes a bulletproof "barrier" against any kind of paint. There are others I've used successfully (like Dupli-Color, PPG's DZ3, and Plasti-Kote Sandable Primer), although my personal preference goes for the DuPont product.

 

2. Lacquer paint in the color you are going to use. Here again I prefer to use products by DuPont, or PPG; both brands are excellent and easy to find.

 

3. Thinner from the same brand, this is very important for the paint to mix perfectly, as well as getting a good flow and a smooth surface.

 

4. Some "old" cotton T-shirts. Yes, you read it right. When I say this I'm talking about very "washed" T-shirts. I can assure you that this is the material for polishing and waxing, as well as for the cleaning of your airbrushes.

 

5. Wet or dry sandpaper (600, 800, 1000, 1200, 1500), to wet sand between coats.

 

6. Very fine polishing liquids or pastes, Novus 2 is the favorite among lacquer users, and,

 

7. A good "full size car's" wax.

 

1.- Prepping for lacquers
First of all, you must do all the filling and puttying work and then wash all the parts with dishwashing detergent. Let air dry everything and you are ready for the primer. I would recommend wearing rubber gloves because the cotton ones leave a lot of fuzz. Once the parts dried you will proceed with the primer.

 

I always thin the primer in a 40-60 ratio (40% primer and 60% thinner).

 

The first coat must be "misted" from a distance of 20cm., that will take care of the "etching" problem common to all lacquers. Le it dry for 20 minutes and apply the second coat, although this time a little "wetter". Let the parts dry for another 20 minutes and lightly sand with #600 wet or dry sanding paper and water.

For all the sanding processes I always use a plastic container big enough to soak the parts in. Rinse everything and let dry for an hour; after that time, apply two more coats and wait for another hour before sanding the parts with #600 sandpaper. By this time you should have a perfectly smooth surface ready to receive the first color coats.

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It is very important not to press too hard while sanding because this would take away the primer and leave the plastic exposed. Remember that these primer coats serve not only as a base for the paint, but as a barrier against the "etching" vice common to all lacquers. Rinse everything and let dry. I always insist on "letting dry" because if we dry the parts with a cloth, or other means, we have to rub the surface and that will create some static which will attract dust to the surface. This procedure is good for any kind of primer although, as I've mentioned in the materials paragraph, I highly recommend the VARIPRIMER; you can apply this product directly over the plastic surface with absolute confidence. Once the priming operation is finished, we'll let everything dry for 24 hours.

 

2.- Applying the lacquer
Now we are ready for the painting itself. We'll thin the lacquer in a 50-50 ratio (50% lacquer and 50% thinner) and apply three light coats, this will help us to create a barrier for the successive coats. Let the paint dry for half an hour between coats to give time enough for the lacquer to "gas out" the solvents. Don't spray successive coats of lacquer in a short period of time because solvents continue to build up with the consequent risk of ruining the plastic. If the lacquer tends to "string" or dry before it hits the surface, add more thinner. Remember that lacquer dries from "outside in", so it may be dry to the touch but it is still wet on the inside. After the drying time, lightly sand the surface with #600 sanding paper (wet) in order to get rid of the dust particles and the "orange peel" effect

 

Now we'll apply three or four coats, these coats will be heavy enough to give some gloss to the surface, and should be shot at 30 minute intervals. These coats will "even" the color. Wait for another couple of hours, sand the surface with #800 sanding paper and plenty of water, rinse everything and let dry. The final coats are the wet coats, although this time we will thin the lacquer in a 40-60 ratio (40% lacquer, 60% thinner) and lower the compressor pressure to 17-18 lbs. We are going to apply three coats with an interval of 30 minutes between each coat, to let the solvents evaporate before adding the next coat; the wet coats will leave a shiny surface almost ready for the polishing process. Let everything dry for another day.

 

At this time of the process the model has about three coats of primer and nine coats of paint, that will sound like a lot of paint, but remember that we've been sanding between coats and that takes some paint away. Before going on with the polishing process I must remind you not to get carried away and put on more coats than the recommended, remember that each coat adds an important amount of solvent with the risk of the solvent eating through the previous coats and find its way to the plastic.

 

3.- Polishing and waxing
At this point, we have spent three days and we are ready for the final polishing. We'll begin wet sanding every painted surface with #2000 sanding paper. This sanding stage is very important because it leaves the surface absolutely smooth and ready for the final rubbing with Novus 2 polish.

 

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If you can't find this product in your local area, you can use any polishing paste intended for acrylic materials, or small amounts of regular white toothpaste applied with a wet piece of cotton cloth; remember the "old" cotton T-shirts?, here is where this material will show its "value".

Once you have everything polished and shiny, we must wash and dry everything. Now is the proper time to apply all the decals over the painted surfaces and let them dry for a couple of days. Lastly, give the surface a good waxing job (decals and all), relax, and admire your work.

 

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Bodies painted following these techniques: Protar's Ferrari 126C2, 1/12 scale and Tamiya's  Benetton B192, 1/20 scale

 

I don't want to finish this article without mentioning the LMG Enterprises polishing kit, very well known among modelers throughout the USA. It consists basically of several abrasive cloths in #1800 through #12000 grits, (with the same function as the sanding paper that I've mentioned at the beginning of this paragraph), a rubber sanding block, a piece of flannel and two 1 oz. liquid polish bottles. Properly used these sanding cloths leave a very shiny and smooth surface. If we use this kit, we must begin with the lower numbers (1800, 2400, or 3200) and finish with the highest one (12000). The next number cloth takes away the fine scratches left by the coarser grit; this will leave the surface smooth and ready for the decals and the wax job.

 

Reflections on lacquers
Once you learn how to neutralize the "etching" vice common to all lacquers, you will see that this paint produces a first class finish. I think is very important to try all that has been written here in an extra piece of plastic (an old kit that you're not going to build) in order to avoid any "unpleasant" surprises. Remember that there are not two modelers alike and we always develop our "own" ways to do things; this is just my "personal" way and it works for me, but I sure hope it works for you too.

So, don't be afraid to use this kind of paint because I'm sure that as soon as you'll learn how to use it, you will love its shine and hardness beyond any comparison.
I wish this note will be helpful enough to those of you who don't use this paint, but would like to, and encourages you to give it a try, I assure you that you won't regret it.

Happy painting.


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