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my first post here. i started out with a french polish on a western red cedar top, and it's the first time with the red cedar. i've spent a considerable about of time building layers with the french polish, but it still is way too easy to leave an indentation with the finger nail, especially parallel with the grain. i was a little surprised with how soft the cedar top was to begin with. so my thought was to do several coats with ktm9, which i am also using for the back and sides, to finish off the top. i've found that shellac is recommended for the sealer coat under ktm9, so my assumption is that it doesn't matter how much shellac has been built up, the ktm9 should stick just fine. am i correct in this assumption?

The shellac will harden over time, but you can do it the other way easy enough. Someone else can give you proper instruction and advice and perhaps think of something we haven't thought of before. If it were up to me, I'd say do another session or two of the shellac and let it harden a considerable amount of time and test it then. If you are still unsatisfied with the results, break out the KTM9

i have done considerable sessions with the french polish, and it has been atleast two weeks since my last session, and it's still way too soft. what are others experience with french polish on cedar? does it require a significant increase in sessions versus a spruce top?

I'm not absolutely certain, but you might have a problem if your shellac isn't 100% dewaxed. I believe that that is what is called for under waterborne finishes.

That is correct.
Also it will not work if you used any oil with your F.P.
Mike

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Mike Collins

so basically it's a no go. onward i go with the french polish then. guess i'll continue to build sessions until it withstands pressure on top of the super soft cedar top. thanks for the help guys.

Shellac is not a tough finish, probably because it is so thin in the first place. You can easily dent it between the grain even with the hardest spruce, let alone cedar....You should add more sessions until it gains sufficient visual depth and all wood features are well filled, then stop. Either way don't expect it to withstand nail or pick contacts too well, not now and not in 2 years time.

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Build log

On the bright side if you keep the guitar you can easily fix the finish whenever you please.