Fixing/stopping tiny finish crack with super glue

markuus99

Junior Member
Messages
61
While fitting a neck into the body I just received, the neck pocket was a bit too snug. I didn't force it and backed off, but apparently I did just enough to cause a very small finish crack on the treble side of the neck pocket, I think just in the clearcoat.

Crack is teeny, but don't want this to get bigger. Planning on putting a tiny drop of thin CA glue (specifically Stew Mac 10/thin super glue) to secure the crack.

Is it a reasonable plan for me to simply put in a drop or two of thin super glue and immediately wipe away the excess with a dry cloth or paper towel? Thinking enough glue will wick into the crack to keep it solid. Planning on using one of the little "whip tips" StewMac includes with the glue.

image_67177985(1).jpg

Anything else I should consider or watch out for here? No cosmetic concerns, other than I just don't want to make this look worse.


Not worried about the neck pocket being snug. I think I just need to knock back some finish/slightly enlarge the pocket with some light sanding. The neck I was fitting isn't the one I'm actually using for this build, so I think I'll wait to fit the actual neck I'm using before modifying the pocket at all, but either way I don't think it's way off.
 
@mayfly Was thinking immediately wiping off would remove the excess and not leave an ugly blob of super glue. Would like to avoid having any cleanup with a taped razor blade or fine sandpaper or anything like that.

If I somehow get a smudge of superglue anywhere outside the immediate vicinity of the crack, a little bit of acetone should take care of that I think. Just would keep the acetone well away from the glue in the crack.
 
I've done that with finish cracks on acoustic guitar tops. Clean first with naphtha. Let it dry. Apply two tiny drops with the point of a sewing needle into the crack. Most will go into the crack. Let it dry, I'd not wipe it for fear of smudging. repeat if necessary. but avoid making a lump.

lightly buff the spot with 600 grit sand paper, then 1000 grit, then 1500 grit, then hit it with meguire's scratch x. I've used my wife's sewing needles, and got the CA at home depot. Swirl removal from the automotive store. Nothing special. go for it, you won't hurt anything.

And the acetone will ruin your finish.
 
Okay no wiping then! Really wanted to avoid sandpaper and buffing, but sounds like that is the way. I have polishing paper in a range of grits, so will use little squares of that. Maybe will gently wet sand with mineral spirits (not water).

Will try the sewing needle method over dropping directly with the whip tip. The crack is super small and looks like a small eyelash, so won't take much glue at all.
 
@Rick How would you apply the glue to the needle? Drop a bit onto the needle and then apply to crack? Dip the needle in the glue?

I have the StewMac thin super glue which apparently cures in 3-4 seconds.
 
Mmh that cures fast. What you have to do is figure out a way to get a small amount of glue into the Crack. If the applicator tip is small enough I'd just drop a bit into the Crack with the applicator. Practice 3 or 4 times on a piece of card board, then just go for it. It'll all smooth out when you buff it. No worries.
 
Opened the super glue and experimented a bit on some scrap. The thin superglue doesn’t cure as fast as they say, and can be put in a small container without drying right up. But it doesn’t seem to want to get picked up by the needle- think it just doesn’t have enough viscosity. Going to try some of the 20/medium viscosity. Just using the dropper will work too but there will be some excess.

Tried wiping (again on scrap) and good call on not doing that. It just leaves a smear.

Will post results when I get there…
 
You can also get a small pipette to suck up the glue. I've taken the applicator and just dropped the glue into the crack, besides using the needle method. The crack just sucks it in.
 
@Rick I ended up ordering this, which is made for precisely dispensing very small amounts of thin super glue into tiny gaps using capillary action.

StewMac sells another version of the glue looper, but this version is for placing even smaller amounts of glue. Think this will do the job nicely and help me minimize the amount of glue I’ll need to clean up.
 
Markuus a method that works very well for me is to take a Q-tip and saturate it in your super glue. If your glue is the thin type just wipe the q-tip on the inside of the neckpocket where the crack is. If the crack goes all the way to the neckpocket which I am sure it does it will soak into the crack. It looks like the crack that forms when trying to put neck into a tight pocket. It should seep into the crack without getting glue on the surface of your finish. Good Luck.
 
@Knorris yes good call! I will try that with the looper and the crack should hopefully drink up the glue from the side in the pocket. Will try the q-tip as well if needed. I’ll need to scrape out some paint from the neck pocket with a blade after I flow in the glue so some superglue in the pocket shouldn’t be an issue. It’s so small I can only just barely feel it with my fingernail so won’t take much.

Just want to make sure the crack is stable. Making it less visible would be a bonus but it’s tiny anyway so less of a concern.
 
One thought from my experience: Wiping CA tends to end up with a smeared mess. If I want to clean up excess, I touch the corner of a paper towel to the glue, and it wicks into the towel.

Also: Acetone is the way to clean it up. But acetone may not be safe for the finish on the guitar, so keep that in mind. You might be able to test the acetone on a hidden part of the finish, i.e. under the bridge.
 
@electric__steve yes definitely. I gave up on the wiping idea after advice here and trying it on scrap.

I have used acetone before on a Warmoth poly finish and it didn’t do anything to the poly. However, trying to avoid that either way. Hopefully can avoid any glue to speak of on the surface of the finish by letting the crack drink it up from the side in the pocket.

Appreciate all the input here!

Should hopefully be able to give this a try on the body this next week. Glue looper arriving on Monday, so will try that and/or a q-tip.
 
@Knorris So okay was trying out the q-tip thing (on scrap) and dipped one into super glue and IT STARTED SMOKING. Apparently superglue making cotton swabs combust is a known thing and people sometimes almost burn their house down doing this. Mine never caught fire thankfully. I soaked the q-tips in water before disposing.

But the reaction was slow enough that I was able to try this on the scrap and it worked like a charm. Glue gets pulled into the crack from the side and doesn’t get on the too surface. This approach worked better for me than the glue looper. There’s a small blob of glue left on the side of the crack, but I’ll be able to remove that from the pocket.

So I like this technique but might try to find a non-cotton alternative that won’t spontaneously combust!
 
Last edited:
@Knorris So okay was trying out the q-tip thing (on scrap) and dipped one into super glue and IT STARTED SMOKING. Apparently superglue making cotton swabs combust is a known thing and people sometimes almost burn their house down doing this. Mine never caught fire thankfully. I soaked the q-tips in water before disposing.

But the reaction was slow enough that I was able to try this on the scrap and it worked like a charm. Glue gets pulled into the crack from the side and doesn’t get on the too surface. This approach worked better for me than the glue looper. There’s a small blob of glue left on the side of the crack, but I’ll be able to remove that from the pocket.

So I like this technique but might try to find a non-cotton alternative that won’t spontaneously combust!
@markuus99 I am glad that method worked out for you although I have never experienced the CA glue reacting like that so fast. Either way, I am also glad you didn't catch it on fire.
 
I've sprayed accelerator on a large blob of CA and it'll sizzle and smoke too. I think the chemical reaction that cures CA has to be exothermic, so when large amounts cure quickly, they get surprisingly hot. I did not know that cotton swabs can trigger that reaction though!

You can use a razor blade as a scraper to scrape off the glue in the neck pocket, and to open up the pocket so the neck isn't so tight.
 
Back
Top