I’m a fairly new amateur/hobbyist acoustic guitar builder (working on my fourth guitar). On my current build, I have sprayed Ilva catalyzed urethane finish for the first time, and I’m using for the first time Eagle Abrasive sheets for the rubout; and I used an air sander with Meguiar’s polishes for the final polish. The process has gone well overall, resulting in the high gloss finish I was looking for (see attached video).
However, I must have gotten a little too aggressive, either when I was going through the EA sheets (1000, 1200, 1500, 2000, 2500, 3000), or with the polishing, because I’ve ended up with some rubbed-through spots, which include some on the front of the headstock, the heel cap, the binding, the edge of the fretboard, and the end graft. I already got some help from Ian earlier this week (on the Loothalong), suggesting I try his method of wiping on Gluboost, which I have been practicing and do intend to try with several of the areas.
My main question at this point is about the area of the end graft, which has several larger rubbed-through spots (see video). The spots seem to be primarily due to some “wavy” area on the tail, which was due to some repair work I had to do at an earlier stage to the edges of the ebony wedge. Because the rubbed-through spots go a little outside of the area of the wedge, I don’t think I can just try and mask off the wedge and either try to repair it with Gluboost, or even by spraying some additional urethane just there. I’m thinking I’m going to have to mask off the top & back, and respray the entire sides. Would you agree? And if so…
– how much do I sand before respraying?
– and as part of the sanding, should I go ahead and try and sand away those “wavy” spots at the tail end—which would probably be down to bare wood—or could I sand everything the same, respray, and just be more careful of those higher spots when rubbing out?
– if I do have to sand back to bare wood in that area of the tail, would I respray my seal coat (of thinner urethane) that I used?
– and do you have any other advice on any of this that I’m not thinking of!?
Thanks very much!
Robert Owens, Louisville, Kentucky