What you don't want to happen

The Achilles' Heel of Luthiery
Kevin Sjostrand
Posts: 3712
Joined: Sat Feb 09, 2008 8:06 pm
Location: Visalia, CA

What you don't want to happen

Post by Kevin Sjostrand »

I am recovering, but this is one of those ugly moments in finishing your guitar
I have made 15 guitars, 12 of those sprayed with nitro and this is the first time this has happened to me.
I always wet sand the finish prior to buffing. So on my recent build I am doing this. I am always careful on the peghead with those tuner holes present, to not get a bunch of water running down those holes. So again, I was careful. All looked awesome after sanding. The neck has sat a week since I did this wet sanding. Nice and flat up to 2000 grit. On to the buffing wheels. Using the IP Menzerna compound. After just a little bit of buffing, slight pressure, hardly any heat build up, I saw the dreaded lifting and spliting of the finish on the back side at 3 of the tuner holes.........EGAD!!!! I've never had it happen before. Panic at first. Then I calmed down, and addressed the problem. I sanded back down flat with 320 grit. I PROBABLY should have waited a day or two, but I started respraying the back side, 4 good coats. I will lightly DRY sand tonight and see how it looks. I think I will not wet sand this area again, and on future guitar builds. Not worth the risk. I always figure a little lacquer gets down in there and I would not have issues.....but not this time.
So anyone else have this happen.....I'm sure it has. How did you handle it.
I am also going to hand polish this area on this guitar and not put it on the buffer again so heat is not going to swell up inside again.....sure hope I've done it right.
tippie53
Posts: 7011
Joined: Fri Mar 03, 2006 7:09 pm
Location: Hegins, Pa
Contact:

Re: What you don't want to happen

Post by tippie53 »

on the back of the headstock if the tuner hides it i don't worry too much
next time get the squishy ear plugs to plug the hole .
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
Kevin Sjostrand
Posts: 3712
Joined: Sat Feb 09, 2008 8:06 pm
Location: Visalia, CA

Re: What you don't want to happen

Post by Kevin Sjostrand »

John that sounds like the perfect plug for those holes, great idea. I will do that if/when I wet sand again. Thank you
phavriluk
Posts: 554
Joined: Mon Jul 09, 2012 9:49 pm

Re: What you don't want to happen

Post by phavriluk »

John, you've just helped more people than just Kevin! Wonderful idea, and it never occurred to me.

Thank you.
peter havriluk
mjmeehan
Posts: 191
Joined: Fri Aug 28, 2009 8:58 am
Location: Bethlehem, Pennsylvania

Re: What you don't want to happen

Post by mjmeehan »

Kevin, did the finish delaminate and pack buffing compound under the finish?

If so you can use a small piece of your final sanding grit paper and your finger to lightly sand a bevel on the edge of the tuner holes. This eliminates a hard edge to the lacquer inside the hole and is likely to be covered even by a bushing on the top of the headstock.. about a 1/16". Tuners that have washers give you even more wiggle room.
Better yet, if you have one, use a short, wide tipped reamer and gently turn a bevel on this edge.
Kevin Sjostrand
Posts: 3712
Joined: Sat Feb 09, 2008 8:06 pm
Location: Visalia, CA

Re: What you don't want to happen

Post by Kevin Sjostrand »

Thanks Ed and fellow.
It actually seemed that the veener, which is about .050 thick split...like the moisture got under it. Strange as I did not pour water all over this thing. Minimal moisture went into any hole. Veener was glued on with Titebond as usual. This only appeared when buffing....apply a little bit of friction heat.
It is all repaired now. I even buffed it again, but was careful to NOT create heat.

Ed I like the chamfered edge idea. I've not done this before. What do you all think about wiping some wax in the hole before wet sanding?
mjmeehan
Posts: 191
Joined: Fri Aug 28, 2009 8:58 am
Location: Bethlehem, Pennsylvania

Re: What you don't want to happen

Post by mjmeehan »

I really liked John's ear plug idea. Wax just sounds messy to me and just another thing that cold mess with the finish. But I don't wet sand so I can't speak to either method personally. I have polished many headplates and delam around the tuner holes can be common and something that is easier to prevent than to repair.
TEETERFAN
Posts: 342
Joined: Fri Sep 07, 2018 12:43 pm
Location: Kansas City, MO

Re: What you don't want to happen

Post by TEETERFAN »

Floor wax..Yes! I refinish lots of electric guitars with lots of screw holes in them and I had all kinds of swelling around them during wet sanding. For the last 15 years I pack all the hooes with Johnson Paste Wax. For tuner holes, I liberally apply it with q-tips. I am careful to not miss anything. No swelling, ever. One word of caution. Make sure the wax is silicone free. If not, it would be bad if you need to add a bit of finish (fisheyes).
Kevin Doty
Kansas City
tippie53
Posts: 7011
Joined: Fri Mar 03, 2006 7:09 pm
Location: Hegins, Pa
Contact:

Re: What you don't want to happen

Post by tippie53 »

one thing I learned
if you use a drill to open the holes after finish
spin it backwards you won't get chip out
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
TEETERFAN
Posts: 342
Joined: Fri Sep 07, 2018 12:43 pm
Location: Kansas City, MO

Re: What you don't want to happen

Post by TEETERFAN »

Thanks John. I do the reverse drill trick after I learned the hard way, myself. Great tip.
Kevin Doty
Kansas City
Post Reply