Model Car List
57 Chevy Project
Box Stock
Instructor: Leon Tefft
Lesson #4
This will be the last step of painting the body before we move on to the engine build up phase.
Fifties cars were painted with lacquer only and didn't have a
clearcoat so maybe you're wondering why I'm using a clearcoat. Simply because I'm not painting a fifties car, I'm painting a nineties model and I want outstanding results when I'm finished. Fifties cars were shiny but didn't really have much depth to the paint finishes so I'll be using a simple trick to take advantage of the high gloss performance of a quality lacquer clearcoat without giving the finish an unrealistic depth.
I'm using PPG Hi-Performance Clear acrylic lacquer mixed with PPG DTL 105 lacquer thinner. I've used this for about 5 years now. It cures to a level of hardness well suited for rubbing out with a polishing kit, it doesn't yellow with age, and it provides a shine that surpasses any hobby paint I've ever used. I always paint bodies with the forethought that I'll be rubbing it out later with a polishing kit because there is always a measure of orange peel to be removed for a smooth finish. What I
concentrate on is keeping the orange peel to a minimum to make the task of rubbing out the finish later as easy as possible. Lacquer provides the ingredients needed for an outstanding paint finish but much of the magic comes later after we work on it with a polishing kit. If you don't now own a polishing kit like LMG's or Detail Master's I highly recommend you get one. These
are vital for a flawless finish.
To eliminate the depth of the clearcoat simply mix in a small amount of the color. Usually about 6 - 8 parts clearcoat to 1 part paint color clouds the paint finish enough to take out the depth while not having an effect on the gloss quality of the clearcoat. This can't be done with aerosol can paint so chalk this up as one more reason to go out and buy that airbrush! Decide if you want to do this before you start mixing your paint
as this will add a bit more work for those who are painting their car with a two-tone combination. You'll have to mask one color to paint the other and this will make the clearcoating process twice as long.
Remember before you begin that whatever the condition your paint
surface is in is what it will look like when you're done. Clearcoating paint is like laminating a picture - if you have dirt, orange peel, scratches, etc., on the paint it will be sealed there forever. The object here is to spray on enough clearcoat paint to build up enough layers so that when you rub out the finish later on you don't rub through the clearcoat down into the colorcoat. As you go along, if you get a dust particle stuck on the surface you're painting make sure you stop, let the surface dry sufficiently, sand off the problem with a 4000 or 6000 grit sanding cloth, then continue painting. Try to get the first two or three clearcoats right the first time if you are using a metallic or pearl paint because if you sand into them you will damage the appearance of the finish.
Since I'm using bright solid colors on my car I'm not going to be
clouding the clearcoat to save some trouble. If you choose to then remember to mask one color while painting the other. My surface is clean and just requires a dust off with my 1/2 inch sable hair paintbrush. Wash with dishwash soap and cool water if you need to, thoroughly dry, then dust off with a brush to eliminate lint particles.
I mix roughly 1 part clearcoat to 2 parts thinner. Wetter is better. Test the mix with your airbrush before you apply it to the surface you're painting. Spray an area and check for "cobwebbing" which looks like cotton candy. If this happens you need to add more thinner. Clean the airbrush and try it again until the cobwebbing is gone. Remember that this is easily
affected by changes in temperature. If your paint is spraying perfectly in 75 degrees it may cobweb in 80 degrees.
I always start with a very light mist coat followed immediately by a second light mist coat. If you spray on too much too quick the clearcoat solvents will eat into the colorcoat before it dries and react with it. This is not as important for solid colors but if you are clearcoating a metallic or pearl color this could distort or mottle the appearance requiring more colorcoats to repair it. Patience is what to keep in mind whenever painting. Also, spraying on mist coats helps keep airborne dust particles from sticking onto the surface. If you do get some though, they are much more easily removed. Remember to spray the underside of the body and edges too.
Next I spray on a light coat followed immediately by a second light coat. All four initial coats can be done in sequence in one step without the need for drying time since the lacquer dries so quickly. After these four coats I let the body dry for one half hour. Next I spray on two moderate coats then I let it dry for one hour. After this, I spray on a heavy wet coat. I apply the clearcoat on the outside first, then the underside, then in areas I don't expect to rub out later like the compound surfaces of the engine compartment. You'll see when you are painting that overspray landing on an area where you've just painted will tend to appear sort of rough from the wet overspray landing on, but not flowing into, the tacky drying paint area. That's why I paint hard to reach areas last so that the flow of the paint in these areas is not disturbed.
Flow = gloss and smoothness.
Not enough flow = orange peel.
Too much flow = paint runs.
Lacquer dries so quickly runs do not pose much of a problem but they can happen, especially when painting edges. Still, if it happens it can be rubbed out later. PPG lacquer flows well and dries quickly enough to prevent runs even with heavy coats. A few tries with this and you'll get a feel down for how heavily you can spray the paint to minimize orange peel before it begins to run.
After one hour of drying I spray on another heavy wet coat in the
same manner, let it dry for one hour, then a third heavy wet coat. For me this is usually enough to guard against rubbing into the finish later on with the polishing kit, but if you want one or two more coats for insurance then continue on with additional coats after one hour of drying for each. Once you're finished, set the body and other components aside and plan on
leaving them alone for about two weeks to fully cure. Keep them mounted so the painted surfaces don't touch anything while they are drying. They may feel dry to the touch much sooner but under the surface the paint isn't fully cured yet. If you attempt to rub out the finish too soon with a polishing kit you'll notice the deeper you sand into the finish the "gummier" the paint feels while rubbing it out. Can you tell I've done this before?
Remember the key word - patience!
Whew! That's it for the paint. It's all downhill from here.
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