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I am repairing a deep narrow grove in a guitar back that was finished with PSL about 3 years ago. The grove was sanded nearly to raw wood with 220 grit and carefully brushed with alcohol and filled with multiple layer of 3 year old PSL and mounded up slightly. The repair was allowed to cure 6 weeks and then scraped and dry sanded to 500 grit. It looked good. Then wet sanded to 4000 grit and a slightly reduced grove reappeared. Hand polishing with 3M rubbing compound, everything looked good except the reduced grove, and witness lines which are fading. What to do to eliminate the grove?

Also, can other water based finishes be used over PSL? I have several guitars with PSL finishes.

The trouble is the layers don't burn into each other which is the main reason I have stopped using WB finish's. One thing I found that does help a little is to put a litte acetone on the repair area just before you recoat. It evaporates very quickly but sooftens the finish a little and then drop fill or brush on your finish into the repair and give plenty of drying time before you try to level.John How38779.7086342593

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