Kentucky KM 171 neck crack

[texaspaul]

I just received a black top KM 171 in the mail not packed in a hard case or packed very well.. I carried it to a shaded back patio and unpacked it an hour later. There are several finish cracks in the neck that appeared (not there until bridge placement and tuned to pitch).
Because of the dark burgundy stain it is difficult to determine if it is only finish or wood, my fear is that it is the wood. I sent a picture to the seller to decided what Jf anything could be done (Amazon Marketplace vendor). They issued a total refund and said to keep it or toss it.
It stays in tune, but the cracks keep showing up at different places running roughly parallel to each other and to the finger board.
I am trying to decide whether to just let it go in till it lets go if it does or back off the tension check the neck for stability by applying a small amount of pressure at the head stock to see if there is movement or sounds suggesting structural damage?
I could post pictures but they don't reveal much and just don't show with the dark stain.

[High Lonesome Valley]

Might just want, with the strings still tight, to take some great wood glue (Elmer's type), start pushing it into the cracked areas. Spend a lot of time doing it every which way, if you feel a tang, push it against it, rub it in for, say, for 10 minutes or so. Clean up, untighten strings, if glue pushes out it's a wood crack, if it doesn't, it's probably not cracked. Regardless, I'd put a little back pressure on the neck as a clamp, I set the mando upside down, supported at either end and put a couple of books on it. You wasted ten minutes of your life and a little glue, and it just might be a crack. Of course, if glue pushes out, clean it. Let it dry overnight with strings loose.

Now and again, a freebie. Congrats.

[Folkmusician.com]

I think we are going to have to see pictures. What I am envisioning sounds like finish cracks if they are running down the neck lengthwise, but what I am picturing and what you are seeing may be totally different.

[texaspaul]

This is the only blemish that shows and yes the cracks run up and down the neck roughly parallel to each other this is the colosest to the center and the shortest. The others are a little more angled from the center V of the neck towards the fingerboard binding.

[texaspaul]

I really don't feel the neck or head stock move much but then I'm really no trying to put any pressure in it. The ones closer to the fingerboard are simply cracks no finish separations or chips yet to show in a picture. The picture above was the first other began to appear later.

[High Lonesome Valley]

This is the only blemish that shows and yes the cracks run up and down the neck roughly parallel to each other this is the colosest to the center and the shortest. The others are a little more angled from the center V of the neck towards the fingerboard binding.

Looks like it was dropped or something dropped on it, maybe sitting in the corner or during shipping, the wood shifted and cracked the finish, which isn't as pliable as wood. Seen this often, it's not a fatal issue at all. Probably a check-type surface crack. Give the glue a shot. Even if it's a through crack, you can push glue all the way in. You can spot fill the finish cracks afterwards or not.

Warning: the location indicates that, if a through crack, you could possible push the glue through to the adjusting rod. An hour or so after gluing, turn adjusting rod, now loosened, either way 180 degrees, for a total of 360 degrees, to ensure the rod doesn't get glued up. Do this again maybe 4 hours in, then the next day before you tighten strings and retighten the rod.

[texaspaul]

[QUOTE=High Lonesome Valley;1312647]Looks like it was dropped or something dropped on it, maybe sitting in the corner or during shipping, the wood shifted and cracked the finish, which isn't as pliable as wood. Seen this often, it's not a fatal issue at all. Probably a check-type surface crack. Give the glue a shot. Even if it's a through crack, you can push glue all the way in. You can spot fill the finish cracks afterwards or not.

I have several wood glues on hand. Titebond II, Elmer's Carpenters Glue and Gorilla Wood Glue. They seem the same to me, but I will probably use the Titebond. My question is should I dilute the glue with a little water to insure penetration or use it un diluted right out if the bottle.

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[multidon]

Do not use any of the glues you mentioned as having on hand! Ideally you should use hot hide glue for this as it is thin enough to be sure it penetrates. Failing this, the only other glue I would consider is original Titebond. Do not try to save a few pennies by using an inappropriate glue just because it is on hand. A small bottle of original Titebond will be 5 bucks well spent. Do not dilute it. It is not made to be diluted. Instead massage it into the cracks both pressing and rubbing. Wipe of the excess with a damp rag and you are done. Also when the glue cures this is a good candidate for a speed neck job.

[High Lonesome Valley]

I would use a PVA glue on this, not hot hide glue, which I would only use on an older instrument for originality's sake The hassle and expense of hot hide glue precludes using it in this case. In my experience wood is more hydrophilic to PVA's than hide glue, essentially it pushes in easier. Additionally, using a thinner hide glue could reduce the psi strength below your minimum requirements.

I believe all the PVA glues you mentioned are greater than 3500 psi, which is more than overkill. If you develop a preference based on your own research, that's great. In the 70's, all that was available to we luthiers was white Elmers glue, Martin used it on their guitars, the cracks on your mando aren't even a joint, so I would use any of the glues you mentioned, realizing they all exceed your minimum requirements.

Titebond states you can dilute by 5%, but anymore would decrease psi strength. They state that Titebond lll, an essentially waterproof PVA, has the longest open time, I call it setup time. I never dilute PVA's. Just use more elbow grease.

[Pete Jenner]

What Don said.

[texaspaul]

Something that is a pet peeve of mine is the variety if products by sane company with similar names but are really different products there's liquid hide glue, original titebound Ii & Iii that's 4 different glues I never kniw which one is referred too in some of these posts. I just don't have the experience to know the difference in specialized application.

[multidon]

People make the mistake of thinking the higher number versions of Titebond must be improvements. Not so. They are different though. Luthiers have been using Original Titebond poly vinyl acetate for decades. It is tried and true. It is not waterproof and for interior applications only. This is a plus for luthiers because it is easily released for repairs. A neck joint can be released by injecting steam for example. Luthiers don't like to use any glues that are not reversible just in case. Titebond is chemically different and dries water resistant. So ok for the exterior of your house. But not easily reversible for the luthiers. Titebond 3 dries completely waterproof. It would be very difficult if not impossible to steam off a neck that had been glued with Titebond 3.

Hot hide glue is animal protein based and has to be mixed hot from dry flakes and water. Liquid hide glue has chemical additives to keep it liquid at room temperature.

Although epoxy, "super glue" (cyanoacrylate), and Duco types of cement have certain applications for instrument building, I have never heard of any luthier using anything for wood joinery other than hot hide glue, poly vinyl acetate, or some type of white glue such as LMI or Elmer's.

I hope this clears up some of the confusion, Texaspaul.

[Pete Jenner]

Paul, 99% of the time people here refer to Titebond, they are referring to Titebond original with the red label.

[texaspaul]

Than you Don, it certainly helps I guess reading the fine print on products but not nearly as much as experience. The shared experience on the Cafe is soo appreciated. I have several uniformed choices when it comes to repairs and clean ups.
In my early 20's, I had an old fiddle belonging to my Grandfather that was in pieces I stripped the top which was black with risin build up with steel wool then put a light coat of polyurethane with a paint brush, jammed the neck on and put it in a shadow box for my Grandmother. A year later I asked her if I could get it fixed to play.
Luckily no super glue. I did get a lecture about my techniques of refinishing. I have enjoyed playing the old fiddle. My Grandfather rough carved 2 of the tuning pegs from pine, so I get my tinkering and make do from him. He was always "IMPROVING" things.

[texaspaul]

Update on the mandolin. I see no loosening if the neck some changes noticed in finish near the finish around the observed crack lines. I took a felt pad and smoothed some of the edges. I had taken a wait and see track before using the glue. Based on information Given here I will strip the neck and use Original Titebond if repair is needed.

[multidon]

Stripping the neck should reveal whether the cracks are in the wood or not. Use medium fine and very fine sandpaper being careful not to remove wood only finish. Massage your Titebond into the cracks if any and let it cure overnight. You can sand the glue level with the wood easily once cured. Smooth with fine and very fine steel wool until it feels silky smooth. Look up speed neck threads to see some pictures of what it should look like. Some like to leave the wood bare because of the feel and others wipe on a couple of coats of 100 percent tung oil to protect the wood because it maintains the bare wood feel.

If you do all of this well, instead of your mandolin looking like it was damaged, it will look like it has had a custom added option. Many prefer the feel of a speed neck to the standard finished neck.

[texaspaul]

I just check things this morning held tune over night and no new evidence of damage may have had sudden temperature change at some point during shipping. I will try to do the speed neck procedure leaving at point going done from the head stock and up from the heel. There is a nice V to the neck.