The thing you put on paint to make it shine???


That would be a high gloss lacquer... or a clear coat lacquer of some kind. They come in a bunch of different kinds.... and you can even mix clear coats with types of filler to give it a hint of color. That's how Fender makes there vintage strat necks look vintage... they add a touch of yellow and brown filler.... And for transparent finishes on guitars they wet the wood and rub a dye powder grain filler onto the wood then paint over it with a clear lacquer paint with whichever desired color mixed into it....