thirdstone Posted March 22, 2007 Report Share Posted March 22, 2007 I have a clear acrylic lacquor finish on a guitar that is about a year old and the problem is that any light/medium knock on the side causes the finish to chip rather too easily. Its too late now to fix it but does anyone know what went wrong so I can get a tougher finish next time? kev Quote Link to comment Share on other sites More sharing options...
Setch Posted March 22, 2007 Report Share Posted March 22, 2007 I'd guess at poor adhesion to the unlying surface. This means it's much easier for the finish to chip, since it doesn't have to break it's connection to the surface, just to the area of finish next to it. Thnis could be caused by an incompatability between the sealer/grain filler and the final finish, or between stain and top coat. The only real way to avoid this is to use tried and tested finishes, whether this means doing your own test panels and waiting a year to see how they stand up to time, or sticking with finishes which are already widely used and understood. Quote Link to comment Share on other sites More sharing options...
thirdstone Posted March 22, 2007 Author Report Share Posted March 22, 2007 I'd guess at poor adhesion to the unlying surface. This means it's much easier for the finish to chip, since it doesn't have to break it's connection to the surface, just to the area of finish next to it. Thnis could be caused by an incompatability between the sealer/grain filler and the final finish, or between stain and top coat. The only real way to avoid this is to use tried and tested finishes, whether this means doing your own test panels and waiting a year to see how they stand up to time, or sticking with finishes which are already widely used and understood. Yeah I think you are right. I had a terrible time with this spray job and I had to resort to using a sealer that was untried with the lacquor. Thanks Quote Link to comment Share on other sites More sharing options...
another doug Posted March 22, 2007 Report Share Posted March 22, 2007 My first lacquer finish was brittle like that. Turns out I sanded to too high a grit before spraying. Quote Link to comment Share on other sites More sharing options...
thirdstone Posted March 22, 2007 Author Report Share Posted March 22, 2007 Thats interesting, I sanded down to 1000grit before the sealer went on . I can't remember what I sanded the sealer down to, but it would have been at least 400 but more than likely 600-800 grit. For this instance I still suspect the first theory. Kev Quote Link to comment Share on other sites More sharing options...
suicidecustom Posted March 23, 2007 Report Share Posted March 23, 2007 i just read in a woodwoeking mag recently that sanding the wood to anything higher than 220 - 320 grit does absolutly nothing as far as making the grain/figure look better, infact it made it worse in most cases. in their tests they got best results between 220-320 grit. sanding to 1000 before sealer may be the problem, you never know. Quote Link to comment Share on other sites More sharing options...
Mattia Posted March 23, 2007 Report Share Posted March 23, 2007 1000 grit paper is verging on polishing. On Maple, I tend to go to 400, seal (shellac), scuff with 320, shoot topcoats. On most dark woods, 220 grit with the grain is more than fine enough. Quote Link to comment Share on other sites More sharing options...
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