Alvarez-Yairi Bridge Repair (Pin hole hairline crack)

[btaylor]

I just purchased a preowned and definitely played 1977 Alvarez-Yairi DY-74 that has a hairline fracture going through the pin holes. I have done some online research and it seems that many luthiers consider this repairable with superglue (water-thin) without having to do a bridge replacement. Has anyone encountered this and can make a recommendation? This guitar also has a non-separates crack in the top’s center. It doesn’t affect the sound at all. I was considering putting some cleats in, but there is a lot of bracing that “crosses” the cracked and I can see the glue oozed out some, so it seems that that would be the same as clearing? Again, any advice is appreciated! It’s a really cool guitar even though there’s a couple of issues and came with the original hard shell case. Signs of use as well, but I like that....seems to add that vintage character

[mirwa]

Nope, pull it and have it replaced.

Steve

[John Arnold]

Over the past 34 years, I have repaired hundreds of hairline bridge cracks between the pins. Very rarely, a crack will reappear, but a second repair with thin CA is all that has ever been required. If the crack extends outside the outer pin holes, I recommend bridge replacement.
As long as the seam separation stays tight, I would not cleat it.

[btaylor]

Thank you! I purchased some Loctite Brand Superglue "Liquid" that is clear and looks like water as far as the thickness. I haven't done the repair yet, but is that sufficient glue to use or does it need to be a "specialty" glue. I don't have a hobby shop within an hour of where I live, but could order something different if it is a must.

[John Arnold]

Loctite is fine. It may require more than one application.

[btaylor]

Originally Posted by John Arnold

Loctite is fine. It may require more than one application.

Thank you sir! Great help!

[mirwa]

It appears you have validation of the question you were asking.

However I will put a few follow up comments.

Superglue drip filling of a split in a bridge between pin holes is merely a cosmetic repair, that is you are cosmetically filling it in, to make it look pretty, it does not in any way make the bridge as strong as it once was.

When a bridge splits between the pin holes its indicative of another issue, typically worn bridge pin holes or worn bridge plate, the wear allows excess rotation of the pin in its respective position, this excess rotation of the bridge pin is what splits the bridge.

Filling the split with super glue and subsequently sanding it does not repair it at all, your using the glue basically as a filler, the grain lines have been seperated, strength in wood is achieved by close contact of long grain.

Many guitars go for years with splits and cracks between the pin holes, it does not stop them from being played, however the issue still remains, the pins have rotated greater than what their original design allowed, will they rotate more?, maybe / maybe not, if you find the bridge further cracks after using superglue, then clearly the pins are still having too much rotation for whatever reason it may be.

Steve

[btaylor]

Originally Posted by mirwa

It appears you have validation of the question you were asking.

However I will put a few follow up comments.

Superglue drip filling of a split in a bridge between pin holes is merely a cosmetic repair, that is you are cosmetically filling it in, to make it look pretty, it does not in any way make the bridge as strong as it once was.

When a bridge splits between the pin holes its indicative of another issue, typically worn bridge pin holes or worn bridge plate, the wear allows excess rotation of the pin in its respective position, this excess rotation of the bridge pin is what splits the bridge.

Filling the split with super glue and subsequently sanding it does not repair it at all, your using the glue basically as a filler, the grain lines have been seperated, strength in wood is achieved by close contact of long grain.

Many guitars go for years with splits and cracks between the pin holes, it does not stop them from being played, however the issue still remains, the pins have rotated greater than what their original design allowed, will they rotate more?, maybe / maybe not, if you find the bridge further cracks after using superglue, then clearly the pins are still having too much rotation for whatever reason it may be.

Steve

Thank you! I may put a platemate on it as I can barely see some wear in similar locations on the bridge plate underneath, but it is very faint.

[John Arnold]

Bridgeplate wear from string balls is a separate issue. It is easily repaired with CA and wood dust. I consider installing a PlateMaste to be a temporary solution. I would not be concerned with doing the CA bridge repair unless the bridgeplate is cracked between the holes.
Bridges crack because the pin holes are in line with the grain, and there is 180 +/- pounds pulling on the bridge. Couple that with the fact that rosewood or ebony are brittle woods, and you have a crack waiting to happen.

Superglue drip filling of a split in a bridge between pin holes is merely a cosmetic repair

I don't agree that CA repair of this is cosmetic only. CA is different from common wood glues.....it has some strength, even when filling gaps. When it cures, it is acrylic resin....essentially the same as Plexiglas.

[mirwa]

When it cures, it is acrylic resin....essentially the same as Plexiglas.

I like that quote, I drive a Suzuki APV (van), its made of steel and glass with some paint essentially identical to that Ferrari , I wonder if I can do a swap