Originally Posted by: manXcat
Cutting back.
Depends what type of paint the original paint is. i.e. (Nitro-) cellulose which is a type of lacquer, or polyurethane are the most common two finishes on guitars. Cellulose dates from way back but is still used on mainly vintage true to tradition high end guitars today. Most common today is polyurethane because it's tough as nails, long lasting and gives a great finish. But, an absolute b**** to sand.
You'll need to sand to key the existing surface for the new paint regardless if there are surface imperfections or not, and undercoat with a neutral undercoat if you want a proper job.
Due to the different solvents used in the chemically different types of paints, the new paint you choose to use needs to be chemically compatible with the paint already on the guitar unless you choose to strip it back to wood. So you need to identify what the existing paint type is before choosing your new paint type -or strip/cut it back to wood.
[br]If you just cut the body back to a dull black surface, then you'll want to use a compatible undercoat if you're going for a light colour like Yellow. For the shade and hue your intended proprietary "TV Yellow" is, over black I'd undercoat with undercoat white for optimum result, although you could get away with grey. Those are the two common undercoat colours. I've not seen TV Yellow first hand, and the images online distort the hue. it appears a honey yellow in some and bright mid yellow in others. If it's bright use a white undercoat, for mid or honey, white or grey. Over black which has just been keyed but hasn't been undercoated, any light colour properly applied (light uniform coats) will likely require three coats minimum to achieve full opacity and shade uniformity.
[br]For initial cut, use 400 grade wet and dry or you'll be there all of the day and half the night. I'd strip rather than sand unless the body top surface is flat, or difficult as it is to use a sanding block on a curved surface, you'll likely end up with dents and ridges. 800 to prep level the surface for undercoating and 1000/1200 on the finish coats unless you make a fist of the job heavy application, runs, etc and have to cut them back. Finish of with a Crystal Clear gloss coat over the final colour coat,cut, polish and buff and it'll look a million bucks.
GL and remember that with spray painting the job result will only be as good as the prep, tools, materials, time and effort put in.
This is great information. Thank you so much!!
