I recently spray painted an old cheap electric guitar with a can of Krylon canned spray paint. No complaints about the result, but, I could have done better. So, I have a few questions about my technique and the resulting texture.
For technique, generally (stress generally)I held the can about 1 foot away from the guitar, using kind of quick, sweeping motions. I didn’t particularly go in the same direction all of the time. Wasn’t regular in the coats, just sprayed where it looked like it needed it. Didn’t overdo waiting for the paint to dry when adding more paint.
This was my first project with canned paint, and the guitar is cheap and not all that great, so, naturally, I got impatient, and I wasn’t overly systematic.
Now, my questions:
The old finish on the guitar was pretty smooth/glossy/shiny/slick. Standard electric guitar finish. In some areas the new paint is smooth and glossy and in other areas the paint looks flat, and is a bit gritty/rough. What caused this, and why the difference?
In some areas of the new finish, it has the orange peel texture. How can one avoid orange peeling while painting with a can?
Can’t help much. Spray cans will vary a lot in the spray they produce so for fine finishes you want to keep the gun further away apply more lighter coats. It wastes a lot of paint to get it right. The flat finish might have been the result of contaminants on the surface, or different absorption of the paint in those areas. Orange peel might be the result of too thick a coat or contamination. But these are all guesses, I never tried to paint a guitar before. I’d suggest an inexpensive airbrush for something small like that.
You need to be careful painting over a pre-painted surface - the spray paint might dissolve the original paint, leading to a rough finish. Also, paint likes a little “tooth” (roughness) to adhere well. Sanding the surface lightly helps. “Orange Peel” is caused by holding the spray can too close. The paint comes out too thickly, and the force of the propellent makes little ripples in the thick layer. Next time, hold the can farther away, and put on several thin coats. Wait the recommend time between coats, or you will get orange peel / runs.
Concur w/ beowulff. IIRC from my days building model kits, the key to avoiding orange peel is to build up very light coats. Sanding before you start and some primer will go a long way toward creating an even finish, also.
The nice thing about a guitar body, unlike say a 1964 Buick Wildcat body, is that you can sand it right back down and try again.
Another thought, if the color is fine and all you want to do is even out the gloss of the finish, you can apply a clear coat.
You don’t always want paint to dry quickly. Krylon is great stuff when you do need fast drying, but for a smoother paint job, you want something that will remain liquid long enough to spread and smooth itself out before setting. Your smooth areas got just enough paint to stay liquid until the application smoothed out; the rough spots were from too far away or too light, meaning the spatters firmed up and dried before they spread.
Think of it as spattering mayo on a board. What hits are tiny lumps. They need time, before the solvent evaporates, to melt across the surface and form a layer instead of a thin pile of lumps. If they dry too fast, you get a lumpy, rough surface. Time to spread and blend, a smooth surface.
When they say “Multiple thin coats” the key to making that work is to let each coat dry thoroughly before applying the next. As the outer coat goes on, it thins the one under it, then shrinks a bit as it dries. The top coat will also dry faster than the one(s) underneath, because it can evaporate readily. If multiple coats (or a couple of thick coats) are still wet enough to be flexible, you’ll get the orange peel look as the top coat scrunches up the uncured coats beneath it.
Do one thin coat per day for a week for excellent results.
For the first ‘thin coat’ would you still see the ‘under surface’ in sections and specks (dots) of new color paint on others? Or do you basically need to turn the whole thing the new color?
You want the minimum amount of paint it takes to make the surface uniformly wet. In other words, no “specks” of new paint, but one continuous wet surface. If you have to worry about “covering up” the paint below, you’re not using primer and that means you haven’t really prepared the surface correctly.
The main thing that people don’t usually automatically understand is that “drying” and/or “curing” is an important part of “painting.” This is why you want “thin coats” with paint that hardens by evaporating off volatile compounds, so those compounds leave uniformly and consequently leave a uniform layer of solids behind. As has been said, when the paint is too thick, or is applied to a surface that is still drying, then it doesn’t dry uniformly and doesn’t leave behind a uniform surface.
The other main area where people get into trouble is by not preparing the surface correctly. On something like a guitar, if you’re not sanding, wiping, and priming with a primer designed for the paint you’re using before you spray your color coat, you’re really just fooling around.
