Polish then paint...

[ccsmith51]

I built an SPA Panther. I have painted the fiberglass parts (wing tips, cowl, wheel pants) with gray primer so they look uniform. I will not paint the plane for a year or so.

It is constructed with flush pulled rivets.

I would like to do a basic polish of the aluminum to get a uniform finish on it. I am not looking for a mirror shine, just something to remove blotches and other blemishes.

A friend mentioned that polishing then painting is not a good idea as the polish may not be completely removed from the rivets, and then may cause an issue with the paint.

Any ideas on this? Has anyone polished then painted with no issues?

Thanks in advance.

[rwanttaja]

I built an SPA Panther. I have painted the fiberglass parts (wing tips, cowl, wheel pants) with gray primer so they look uniform. I will not paint the plane for a year or so.

It is constructed with flush pulled rivets.

I would like to do a basic polish of the aluminum to get a uniform finish on it. I am not looking for a mirror shine, just something to remove blotches and other blemishes.

A friend mentioned that polishing then painting is not a good idea as the polish may not be completely removed from the rivets, and then may cause an issue with the paint.

Any ideas on this? Has anyone polished then painted with no issues?

Thanks in advance.

Absolutely do not do this.

You need the paint to adhere to the surface you apply it to. The MORE surface, the more area that the paint "grips."

Take a look at these close-up drawings of the surface/paint interface. The image on the left represents a polished surface.



The image on the right shows a rough surface. Notice there's a lot more area for the paint to adhere to.

If you polish the surface before painting, you'll have problems with the paint flaking away. Most paints tell actually tell you to take emery cloth or sandpaper and roughen the surface before painting.

You're going to prime the aluminum surfaces first, of course. Lightly sand the surfaces, and make sure all the sanding residue is removed. Then apply the primer and let it try. LIGHTLY SAND THE PRIMER, add another coat of it. Then sand the primer again, and lather, rinse, repeat until the surface is the way you want it. Then lightly sand and apply how many more finish coats you want. Polish the finish coat after it's well cured.

Ron Wanttaja

[Ronald Franck]

Congratulations on completing your Panther!