One or Two Coats of Primer
12-06-2017, 10:06 AM
#1
One or Two Coats of Primer
Hi Guys - for you long time scale modelers, I have a question and need for understanding application of primer. Is it written somewhere that you spray on one coat of primer, then practically sand it all off, then spray on another coat of primer, and sand again prior to applying color? Is a second coat of primer really necessary? Is a 2nd coat of primer only necessary after filling dings, tiny holes, blemishes, shop rash, etc. or can you simply go ahead and spray on a base coat over epoxy fillers, balsa, bondo? Many thanks. Chic
12-06-2017, 10:40 AM
#2
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As far as I'm concerned the second coat is only necessary for additional filling and smoothing of the surface Chic. If the surface is acceptably smooth and you don't think it's necessary then I wouldn't bother. I very rarely leave a solid coat of primer on the airframe as it is just added weight in my opinion. I've never had an issue with the base coat of paint not sticking. My .02 cents only of course.
12-06-2017, 01:28 PM
#4
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Thanks for the vote of confidence Chic. Hope I don't do anything to lose your trust! In my experience there is no need to shoot primer over the spot fillers. However, I am shooting nothing but solvent based paints such as acrylic enamels, dope, epoxy, the old Chevron Perfect Paint, etc. Other than one project with Warbird Colors I have not tried any of the water based finishes so can't comment on those. If in doubt though there is really no reason not to shoot on a light coat of primer before base coating.
12-06-2017, 05:39 PM
#6
Here's how I did it for a A12. Dan
With so many paints disappearing from the store shelves, it’s hard to find substitutes that will perform the same way. Use what you have available in your area and what you are familiar with. Here is how I finished the prototype. It is a finishing technique I have achieved good results with on other models. Brush on a full strength coat of Valspar Lacquer Sanding Sealer NAS1420. A well-stocked paint store that caters to the professionals will carry this. It is usually used for furniture finishing. One of those two-inch inexpensive disposable brushes is ideal for this application. Sand lightly with 220-grit sandpaper. Apply ¾ fiberglass cloth over the surfaces brushing through it with the sealer thinned 100% with lacquer thinner. Sand lightly with 220-grit sandpaper. Brush on another thinned coat of the sealer. Sand with 220-grit sandpaper being careful not to cut into the cloth. Brush on two more coats of the thinned sealer. Try to fill the weave of the cloth as much as possible. Sand with 150-grit sandpaper to keep the surface flat and smooth.Spray on three coats of Pacific Coast Lacquer’s PCL 913 lacquer based primer thinned 125% with medium lacquer thinner. Sand the first coat with 100-grit sandpaper, the second coat with 150-grit sandpaper and the last coat with 320-grit sandpaper. You should now have a pretty good surface for your color coats.Apply a coat of Kilz that is thinned to two parts Kilz to one part naphtha. This will improve the adhesion of the final color coats. The prototype model was painted with Benjamin Moore’s oil based paints. It took two coats of paint, each thinned to a mixture of two parts paint and one part naphtha. The model was painted in a two color scheme, not necessarily representing any particular plane. All of the insignia and rudder stripes were painted with Rust-oleum. The letters on the wing were four inch vinyl letters available at a stationery store. The overall result was just what I was looking for.
With so many paints disappearing from the store shelves, it’s hard to find substitutes that will perform the same way. Use what you have available in your area and what you are familiar with. Here is how I finished the prototype. It is a finishing technique I have achieved good results with on other models. Brush on a full strength coat of Valspar Lacquer Sanding Sealer NAS1420. A well-stocked paint store that caters to the professionals will carry this. It is usually used for furniture finishing. One of those two-inch inexpensive disposable brushes is ideal for this application. Sand lightly with 220-grit sandpaper. Apply ¾ fiberglass cloth over the surfaces brushing through it with the sealer thinned 100% with lacquer thinner. Sand lightly with 220-grit sandpaper. Brush on another thinned coat of the sealer. Sand with 220-grit sandpaper being careful not to cut into the cloth. Brush on two more coats of the thinned sealer. Try to fill the weave of the cloth as much as possible. Sand with 150-grit sandpaper to keep the surface flat and smooth.Spray on three coats of Pacific Coast Lacquer’s PCL 913 lacquer based primer thinned 125% with medium lacquer thinner. Sand the first coat with 100-grit sandpaper, the second coat with 150-grit sandpaper and the last coat with 320-grit sandpaper. You should now have a pretty good surface for your color coats.Apply a coat of Kilz that is thinned to two parts Kilz to one part naphtha. This will improve the adhesion of the final color coats. The prototype model was painted with Benjamin Moore’s oil based paints. It took two coats of paint, each thinned to a mixture of two parts paint and one part naphtha. The model was painted in a two color scheme, not necessarily representing any particular plane. All of the insignia and rudder stripes were painted with Rust-oleum. The letters on the wing were four inch vinyl letters available at a stationery store. The overall result was just what I was looking for.
12-08-2017, 07:45 AM
#8
Chic, thanks for the compliment. It's a Curtis A12 and can be classified as a stand off and I mean way off scale. It would be disqualified at any scale contest. Dan.
https://www.bing.com/images/search?q...12&FORM=HDRSC2
https://www.bing.com/images/search?q...12&FORM=HDRSC2
