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After finishing (FP), my end grafts are perfectly smooth to the touch & to the eye. But after 6 months or so, I can clearly feel the joints. My woods are well seasoned & acclimated to my shop. What am I doing wrong?

Nothing, that's totally normal wood behavior.

Different woods will react differently to changes in humidity, thus the feel of the joint when you pass your finger on it. Having wood that is 'acclimated' doesn't mean it's dead matter; it will still move depending on the relative humidity around it.

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Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

6 months? Mine show after a week or two.

I like it.

If everything is too flat and shiny, it reminds me of those painted on rosettes on cheap classical guitars. I was pleasantly surprised with an inlay recently, which I used multiple pieces of ebony on, even though it's pretty much pitch black and the pieces touching together could have been done in one large piece. But after the shellac had time to dry, you can see the seams between pieces, and a bit of the grain showing the orientation of each piece. It looks "real" (because it is)

Its a good idea to let the glue fully dry and for all the additional water introduced into the joint to leave the wood before you start sanding or scraping the end graft flush. If you sand too early and level it, the wood will keep drying and shrinking and leave lines or cracks through the finish at the joins.
Cheers
Dom

My guess is you are using a PVA glue like Titebond. These glues will shrink into the finish. Hot hide, fish glue, or polyurethane glue won't shrink and will stay nice and level. I used to use polyurethane but switched to fish glue since it is way less messy and far less toxic.

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--Reynolds Large

Sometimes as everything gets nice and tight, it actually seems to squeeze the glue a little, forming a thin ridge in places. This scrapes off.

I agree with Todd, the real problem is that the guitar is built of wood.

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