Sealing Tuner Holes Before Finishing - Luthier Tips du Jour Mailbag
In this episode, Robbie O’Brien talks about sealing the tuner holes before finishing to prevent the finish from cracking.
Video Transcription
[on-screen text reads: Luthier Tips du Jour Mailbag]
Mailbag question: Is there a way to keep the finish from swelling and cracking on the peghead?
Robert O'Brien: Today's Tips du Jour Mailbag question comes to us from Georgia. "Robert, I'm having trouble with the finish, swelling and cracking when wet sanding the finish on the peghead. Is there a way to keep this from happening, Mike in Georgia."
The root cause of this issue
Mike, this is really frustrating. Welcome to my world. What happens, Mike, is the moisture gets into the ingrain in the tuner holes that you've drilled, and this swells the wood and then the finish also swells. Then it dries out and shrinks back, and the finish shrinks back with it. That's asking a lot of a finish to be able to swell and then contract like that, or shrink back without cracking. However, the good news is there's a very easy solution for that. Let's go over to the bench and I'll show you how.
Seal the ingrain in the tuner holes
So here's my peghead, Mike. What I need to do is seal that ingrain in there so that the water and the moisture I use from the wet sanding, doesn't wick in there and swell the grain.
There's a very easy way of doing that. What I'm going to use to seal that ingrain is CA glue. Now, Mike, I use a lot of glue in my shop. You've seen quite a few videos over the years of me using CA glue. I like the hot stuff brand. I get it from LMI or Satellite City. There's a lot of uses for CA glue in luthiery.
What you don't want to do is open up the bottle and just try and pour it in there and just get it all over your bench, all over your peghead and all over yourself, and perhaps run the risk of sticking yourself to the bench. I had a friend once that had that happen to them. So let me show you an easy way of applying this. What I'm going to use is a small pipette. Now the problem is how to get it into the pipette from the bottle. Now you could just open up the lid here, take the cap off and do it that way. A lot of times your lids are sealed on there pretty good with the excess glue. Here's what I do. Take a piece of wax paper, dump a little bit of glue on there. Take your pipette and just suck it right up into the pipette.
Now your pipette is loaded and ready to go to work. Now what you don't want to do is get real happy with the glue here. So just wick a little bit in there and go to the next one, the capillary effect will take it right into the ingrain there [Robert rubs the end of the pipette around the ingrain in all of the tuner holes]. Then you can turn it over, hit it from the backside as well, and you can rinse and repeat as many times as needed to seal off that ingrain. That's a very easy way to keep that ingrain from swelling and running the risk of cracking your finish.
So Mike in Georgia, I hope you like this tip. However, be careful when using it. Don't glue yourself to your guitar or to your bench.
[on-screen text reads: More Luthier Tips and online courses available at www.obrienguitars.com. Private and small group guitar building and finishing instruction available.]
