Hey Paul... happy 4th of July!
A guitarist friend of mine just got the neck for his Fender Strat refretted and refin'd. He's now obtained some headstock decals to play around with (the original headstock decals were obliterated in the refin), and was asking me if I knew how he might go about "sealing in" the decals once he's put them on. Is there a simple method to do this on a surface that's otherwise already "shined, sealed and delivered"?
The headstock decal should be put on over a coat of finish that's been sanded with #600 paper, or if absolutely smooth, without sanding.
It then needs to be given a couple of coats of nitro (the usual finish for vintage Fender necks) to hold it in place and discourage yellowing.
Decals, in fact, are often composed of a clear nitro carrier, with the graphic silk-screened onto the nitro carrier. Coating an applied water-transfer decal will bond the finish coats to the decal, with durable results.
If you merely apply a water-transfer decal to a finished headstock without coating it afterwards, it will be very susceptible to peeling, scratching, and yellowing.
Since the instrument in question wasn't "vintage", I'll be sure to have my friend ask the luthier who did the work whether nitro or poly was used as the finish! If it turns out to have been finished in poly, does that then involve a completely different procedure, or would a couple of light coats of nitro still do the trick?
Again... many thanx, and much appreciation for your expertise!
There are two types of guitar finishes whose name begins with "poly", polyester and polyurethane. Polyester is used on lots of imports from China, Korea, and Malaysia (including Epis), as well as on Fenders made in Mexico and overseas. Polyurethane is used on Japanese Gretsches and assorted others including some Gibsons and all Ricks.
Procedures for recoating are the same, but durability of results varies. A neck finished in polyester will require scuffing and then can be topcoated with any type of finish, as it presents a mechanical bond-type surface. 400 grit is good; apply decal, topcoat with nitro is OK. Durability will be good.
A neck finished in polyurethane is handled in much the same way, but will have better durability when done.
A nitro-finished neck, however, will exhibit superior durability for the decal, due to the molecular bond afforded by nitro's solvent base, which will soften with subsequent coats and knit together.
Notice that I am rating durability in terms of the decal's resistance to abrasion and peeling. Topcoat durability, all things considered, is like comparing apples to oranges.
And, please, let's not get involved in that old "nitro is better" debate. That's an old guitarist's wife's tale that semi-knowledgeable parrots like to spout when their cages are clean and they have time on their wings...
