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finish sinking, grain enhanced spruce top

PostPosted: Sat Feb 02, 2019 4:48 pm
by Brian Evans
I have a couple of guitars that I built last year, with EM6000 finish on both redwood and spruce. Carved arch tops finished about 8 months ago. Sanding schedule prior to finish was up to 400 grit, sanding sealer, then finish. Perfectly smooth when wet-sanded and polished, now a definite grain showing where the grain lines stand proud and the wood between the lines has sunk. Why and what to do? I don't want to refinish these, I'd like to understand what happened and should I - could I simply wet-sand and polish again? Or just enjoy the patina?

Edit - could this be related to humidity? House is around 40%, but a fair bit higher in summer.


Brian

Re: finish sinking, grain enhanced spruce top

PostPosted: Sat Feb 02, 2019 7:02 pm
by Bob Gramann
I have EM6000 and its predecessors for quite some time. The telegraphing of the grain lines is quite normal as the seasons change. It comes and goes. Sanding and refinishing will fix it for now, but when the seasons change again, it will visit like an old friend. I think the same happens with any flexible finish.

I dropped off a black acoustic at one of the high end shops that sells my guitars. They were looking for those lines stating that it would be much more likely to sell if it didn’t look like it had a plastic finish.

I have a 100+ year old violin. Sometimes the grain lines are quite obvious. I’m hoping no one else writes in and says to redo it, that’s never accepted. I have a lot of instruments out in the wild now.

Re: finish sinking, grain enhanced spruce top

PostPosted: Sat Feb 02, 2019 7:48 pm
by Barry Daniels
I kind of like the look. Sort of relic vintage. But you can re-level and buff if it's not your cup of tea.

Currently, I am refinishing the top of a 70's Gibson and I let the Cardinal lacquer sit about 10 days before buffing. Their instructions say you only have to wait a week. But I have noticed considerable shrink back and grain telegraphing, which is exactly what I was hoping for to make the top look less new and match the back and sides.

Re: finish sinking, grain enhanced spruce top

PostPosted: Sat Feb 02, 2019 9:39 pm
by Brian Evans
If I didn't do anything wrong, I'll just enjoy them! I have moved them into a more humid room, just in case.

Re: finish sinking, grain enhanced spruce top

PostPosted: Sat Feb 16, 2019 5:37 pm
by Ryan Mazzocco
Thanks for this thread. I use EM6000, have on my last 5 guitars. I still have 2 of them and have noticed the same thing.