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Spruce top grain lines visible.
http://www-.luthiersforum.com/forum/viewtopic.php?f=10101&t=57012		 Page 1 of 1
Author:  mikeyb2 [ Sat Mar 15, 2025 4:00 pm ]
Post subject:  Spruce top grain lines visible.
I've been patiently waiting 4 or 5 weeks for the laquer to cure on my recent build, so I could start wet sanding. It has had 13 spray coats of rattle can nitro, and in this time has shrunk back to reveal grain line ridges, which took some wet sanding to flatten. The question is, do I continue wet sanding or add some more coats of laquer to make up for the laquer lost in flattening. And, if the answer is more spray coats, how many?
I have built several guitars , but only a couple with a gloss finish and I didn't have this problem. Btw, humidity is controlled.
Thanks in advance. Mike.
Author:  Glen H [ Sat Mar 15, 2025 7:21 pm ]
Post subject:  Re: Spruce top grain lines visible.
If the finish is flat, and no pores are showing, and you have not sanded through anywhere, then IMO you are done. Take it to the buffer.
Author:  bobgramann [ Sat Mar 15, 2025 7:27 pm ]
Post subject:  Re: Spruce top grain lines visible.
And, spruce does that even when you think everything is perfect. If the grain lines come back, let them be.
Author:  mikeyb2 [ Sun Mar 16, 2025 3:57 am ]
Post subject:  Re: Spruce top grain lines visible.
Glen H wrote:
If the finish is flat, and no pores are showing, and you have not sanded through anywhere, then IMO you are done. Take it to the buffer.

Glen, the finish is now flat, but only sanded to 600, and needs to be taken further to 3000. Not sanded through yet, but that's what I'm worried about.
thanks Mike.
Author:  mikeyb2 [ Sun Mar 16, 2025 4:00 am ]
Post subject:  Re: Spruce top grain lines visible.
bobgramann wrote:
And, spruce does that even when you think everything is perfect. If the grain lines come back, let them be.

Bob, that's true and once it's finished and buffed I won't bother too much if they come back, but in the meantime I need it flat to finish it. Thanks Mike.
Author:  Glen H [ Sun Mar 16, 2025 7:39 am ]
Post subject:  Re: Spruce top grain lines visible.
mikeyb2 wrote:
Glen H wrote:
If the finish is flat, and no pores are showing, and you have not sanded through anywhere, then IMO you are done. Take it to the buffer.

Glen, the finish is now flat, but only sanded to 600, and needs to be taken further to 3000. Not sanded through yet, but that's what I'm worried about.
thanks Mike.


Continue on with the finer grits. If you sand through, then that answers your question. You need a couple more coats. The alternative is to add more coasts now as insurance and possibly add unnecessary finish.
Author:  mikeyb2 [ Sun Mar 16, 2025 8:33 am ]
Post subject:  Re: Spruce top grain lines visible.
Glen H wrote:
mikeyb2 wrote:
Glen H wrote:
If the finish is flat, and no pores are showing, and you have not sanded through anywhere, then IMO you are done. Take it to the buffer.

Glen, the finish is now flat, but only sanded to 600, and needs to be taken further to 3000. Not sanded through yet, but that's what I'm worried about.
thanks Mike.


Continue on with the finer grits. If you sand through, then that answers your question. You need a couple more coats. The alternative is to add more coasts now as insurance and possibly add unnecessary finish.

Thanks Glen, makes sense, I'll see how it goes. Mike.
Author:  phavriluk [ Mon Mar 17, 2025 11:57 am ]
Post subject:  Re: Spruce top grain lines visible.
Did all 13 applications of nitro get laid atop each other, one after the other, and no sanding in between? I used to do that painting cars. If so, I think it's time to think. Sanding down the top that has all 13 coats may well leave a too-thick layer of finish behind. Sanding between applications, rinse and repeat, until no more shiny spots appear, is what I try to do.

But each of us tries to do what works for their own shop.
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