Maybe I should find a luthier forum to post this, but I’ll post it here anyway.
Overview:
Detail of the damage in question:
This instrument is a flat-top octave mandolin, with a 2.75" deep body. The sides are made of solid mahogany. What I want to know is:
• Structurally, how bad is this damage?
• What kinds of conditions would make it worse?
• How much do you think it might cost to make this structurally perfect again, yet acoustically adequate? In other words, it doesn’t need to appear beautiful, I just want a strong repair that doesn’t effect how it sounds - so how much might that cost to achieve?
That just looks like a surface scratch to me. Unless it’s deeper than it looks, I’d leave it alone.
You could drop some water-thin cyanoacrylate glue (aka Crazy Glue) into the area if it’s really a crack. This is one way I fix whistle cracks with great success.
Try placing your mouth around the area, get a good seal with your lips and see if you can blow air through it. If not, you might just want to drop some lacquer into the scratch to fill it up a bit. Use a toothpick.
Does the crack flex at all when you press in on it? I ask this because it may not be a structurally bad as you think. If the blow knocked a interior brace loose, thats one thing, but many, many instruments have cracks with out any acoustical changes whatsoever.
Does the crack cause a buzzing sound? (A followup to the above question) If there is a buzz, then yes you will need to fix it. If you don’t care about the appearance, then this is something you could do yourself by wicking a drop or two (just a drop or two) of thin superglue into the crack. You then “clamp” it with some masking tape in front of and behind the crack. You don’t want to run the tape over the crack as it may stick to the glue, and you want to be able to quickly wipe off any glue squeeze out with a damp cloth.
If using a suoerglue worries you, then you could repair it with any good carpenters glue such as TiteBond. The method is similar to that above, but the thicker glue needs to be worked into the crack which can be done by gently flexing the crack back and forth, or even a stiff piece of paper such as the edge of a business card to force the glue into the crack.
Now if you are looking for a more professional repair, that can be done which would require some refinishing work as well. How much it would cost would all depend on the hourly shop rates. Don’t expect an inviisble repair though as that gouge will be hard to hide.
Take heart friend, much worse has been repaired. I’ve repaired worse myself and I’m a hack. But to be honest, as long as it’s not a moving crack and there’s no internal damage, a little battle damage doesn’t affect the tone noticably. Unless it’s deeper than a surface scratch (and it doesn’t look too bad in the pics), I’d leave it. My mandolins have a lot more ‘character’ marks than that.
I’m pretty sure it is a crack, because I witnessed the accident. The impact mark is a combination of gouge and dent. That is the primary damage from a VHS cassette that fell from the top of a bookshelf and hit the instrument while it was seated, pointing head-up, in a guitar stand. The long thin line happened from the shock of the impact, and apparently is not a scratch but a crack that starts where the dent crosses it, and just fades out at the ends. So it could be all the way through at the point of the dent, and then becomes just a crack in the finish as it goes toward the ends. It doesn’t move or add noise to the sound. I’m pretty sure that the bracing is still secure.
If I just leave it be, I’ll still be wondering about which environments could make it worse. So I was wondering what kind of environments that might be.
• Sitting in a parked car for a couple hours (Winter? Summer?) while in it’s case?
• Abrupt temperature changes?
• Heated buildings/rooms during winter?
• Humidity changes?
It’s been my (limited) experience that the primary threat isn’t any of those, but the vibration of playing. The crack, being propagated as it is along the grain, might well worsen if not stabilized. However, since it doesn’t move under pressure, it may not go all the way through the wood except perhaps at the point of impact itself. The superglue trick (applied only to the center of the impact site) would prevent further damage until it can be attended to by a luthier. Working carefully, you won’t do anything a luthier can’t undo. If you are concerned about your ability to do it successfully, use a glue such as TiteBond or simple Elmer’s white glue. Although it might be unsightly for the time being, the damage would be stable enough to play the instrument without further concern. Indeed, you could probably play it for a lifetime without further problems.
If you choose to apply a glue, use a fine tool like a sewing needle and work slowly and carefully. If you use white glue or TiteBond, a little water mixed in will help smooth the process.
The other issues you’ve mentioned are all best avoided for any instrument, cracked or otherwise. Don’t expose your mandolin to those conditions if at all possible. Keep it properly humidified and avoid extremes of temperature, and most of all, sudden changes.
That crack is something to have an expert examine, but don’t worry over it too much for the moment. Mandolins, despite their seeming fragility, are remarkably robust structures. It takes a lot to damage them beyond repair.
The reassuring opinions you’ve been offered sound about right to me. It looks, IMO, superficial and I’d leave it be if it were mine.
That said, I’m with rh and s1m0n. Check out the guys on mandolincafe’s builders/repair section. Those guys know all there is to no about mando/zouk structural and cosmetic issues and are very helpful. Loads of top-notch mando luthiers there.
Lads, that’s not a superficial crack. See the ding? The side’s been pushed in by a falling object. Since it’s a thin piece of wood that’s been bent under heat and pressure, there are stresses in the wood that can act on the crack, causing it to worsen over time. Additionally, dryness can exacerbate any stress/movement. Just banging some glue of any sort down into the crack won’t provide any mechanical advantage to prevent this, either. What’s needed is a pair of small cleats, or wooden patches, at the ends of the crack (on the inside of course). Have a qualified technician do the repair, if you want peace of mind.
Meanwhile, this is one thing I dislike about our new internet democracy. I would consider it a big mistake if the owner of this unfortunate instrument had followed some of the “advice” on this thread and bled some superglue into the repair area. What are the qualifications of the providers of this bad counsel? Just because you might fix a whistle crack with superglue doesn’t mean it’s the right thing on a crack in a mahogany side. As a professional luthier, I was appalled at the casualness with which this poor advice was dispensed. Cheers,
Well, in my 40 years of experience I’ve yet to meet a professional luthier who wasn’t able to deal with the tiny drop of glue needed to stabilize this sort of damage. Indeed, I’ve experienced this sort of damage to my instruments three times over the years and every time the professional luthiers have advised me to stabilize the damage to prevent further problems. Additionally, this same advice is frequently dispensed at places like mandolincafe. In two cases of my own, glue alone was used and the instruments continued to perform perfectly for their servicable lifetimes.
Cleating the crack is only one method of dealing with this damage. We do not even know if the original poster will want to go that route, as it may prove too expensive. Gluing cracks of this nature may not be the ultimate solution, but just as we cannot tell from the photos that this is more than superficial damage, I don’t believe that anyone can tell that it is severe damage. Only first-hand examination can define the best approach, and the advice to seek professional council has been given repeatedly.
The advice given here has taken the nature of first, reassuring the poster that the damage can be tended to, second, that the damage should be looked at by a repairman, and third, that, if need be, the damage can be stabilized through ordinary methods until it can be fully examined.
As for the casualness of the replies, I assure you that I spent far more time composing my reply than you spent in composing your chastisment. The thing about this new Internet Democracy of ours is that a question can be asked and advice ignorred. The poster is under no obligation to follow any advice given here. We are here to share our experience, and my experience includes the repair of three mandolins in similar states.
Look, sport, I don’t need a sea of words to make a simple point. Superglue is inappropriate, especiallly the water-thin kind, because of its tendency to wick into the surrounding wood. Despite what you say about the advice you yourself have received, I think the last thing any luthier wants is to try to work on a crack where the wood is already saturated with this plastic-y substance. Hide glue is about the only thing I’d recommend using to stabilize a crack like this, since it can be undone and redone over and over again. The average punter doesn’t have access to this glue, and besides, the situation isn’t so dire that something needs to be done immediately to save the instrument. Best thing to do is to leave it until a qualified pro can do the job right. Or, if you’re into doing it yourself, use the proper glue from the word go, which means either hide glue or aliphatic resin glue. Cleats are optional, but I’ve never omitted them in this situation, nor would any responsible luthier. The superglue “home haircut” is just not the answer here. Cheers,
If this gitfiddle has any real value, emotionally or monetarily, then it should never meet superglue.
As Rob points out, hide glue is what is used by luthiers, and “real” instrument repairs shouldn’t be attempted by amateurs. On the other hand, if it’s basically a “junker” that you don’t want to put money into, then have at it. Home repairs can work great, but they usually look like home repairs.
Another pro luthier here. Leave the superglue well alone, it’s a nightmare to deal with once it wicks into the wood, especially end grain. It also has a tendency to change the colour of the wood making any possible future ‘invisible’ repair impossible. Superglue may have it’s uses but sides/backs and tops of instruments? forget it.
Whether that crack will actually gets worse is hard to say. Certainly large fluctuations in humidity or it being subject to direct sunlight will increase the chances greatly. The normal repair for such a crack would be to place a linen repair patch on the inside of the rib. If you aren’t too concerned with the aesthetics and are looking to make it more structurally safe then I doubt the cost will run much above $60. A more involved and seamless repair would be much more but then that would involve touch up work and colour matching.
Good call, mignal. I agree that a linen patch would help to hold things together nicely. After re-reading my own post, I realised that I omitted to mention the cleat that I would most certainly put in the center of the crack to hold it together; the two on the ends would be to prevent it from running. That’s just my own personal choice; I’ve seen the cloth thing done often enough as well.
Regarding glue type, I would generally prefer aliphatic resin glue to repair a crack like the one in tweeto’s mandolin, despite what I seemed to say in my previous post. My suggestion of hide glue was intended as an emergency measure, appropriate on account of its ability to be undone and redone. The potential problem there is that hide glue and Titebond/Elmer’s glue are totally incompatible, so that a crack that has been glued once with hide glue must be reglued with same; if you want to switch glues, you must first wash all of the hide glue out of the grain. This is also why it can be difficult to successfully reglue braces on vintage instruments - another reason to keep the hide glue pot handy. I do use it often - it’s the most musical glue!
Finally, at the risk of being further wounded by italics, I have to point out that I totally disagree with the previously stated notion that the vibrations of playing are the greatest threat to the future stability of the crack in question. Not even a top crack is going to be that sensitive to vibration. Changes in temperature and humidity, especially rapid ones, are what’s to be guarded against here. Also, don’t finger the crack too much, or dirt and oil might get in and prevent proper glue adhesion. Cheers,
Hmmmm…since I was one of the ones that suggested using super glue, I guess I need to chime back in on this. First, if you reread my post, you’ll see that I said “if you don’t care about the appearance”.
FWIW, I have seen many repairs done with a thin CA glue, and have done some myself. It is a reasonable way of repairing a minor crack. When properly done, the repair is stronger han the surrounding wood.
Yes, the best way would be to install a repair patch on the inside, but that is not something that the usual user is equipped to do.
Also, since hide glue is again not something the average person has, and it does require some experience to use properly, Titebond is a reasonable alternative. I’m not trying to get into a Titebond vs hide glue discussion, but for those who advocate hide glue because it can be taken apart later, well, the same thing can be done with Titebond.
BTW, as far as being a “professional luthier”, well, let’s just say I do this for a living and leave it at that.
Since I’ve made a major financial contribution to that living over the years (we own or have owned at least 15 instruments made by harp - and his are all that I currently play) I’ll second that.
