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Any Cleat tricks . .


apartmentluthier

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Hi Michael:

If I am going to use cleats on a crack, I start by determining at which location(s) they will be of most use (which is not how most of us are "taught" to do it...), then radiate outwards, upwards, or downwards, if/as/when required.

I disagree *slightly* with your ideas about the effect of force and the feeble ability of cleats to resist it. Example: In cases near the f holes on cellos (interior, not lower wing), especially if the wood is cracked on the bias or near the intersection of a patch, installing a cleat has been the only thing I've found that keeps the crack closed reliably. The pressure of the bridge in this area can cause problems on the top toward the f... A well shaped one gives just enough support to prevent the top surface from opening. Same goes for cracks near the bridge feet, above, below or next to the bassbar (where the bar actually does pull down), lower "f wing" (where it seems the player can't help but push, but I use a slightly different type of cleat here), and some bias cracks on slab backs (at the nasty places). Oh... and anything running toward the post. I just don't want to see those cracks travel...

On clean flank cracks, or clean cracks near the center of the fiddle, I'm with you.

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I am pretty much in the same camp. The problem is that more often than not, I am trying to "prop up" someone else's botched job. I would say that 85 percent of my crack repairs go uncleated. I ran into this particularly nasty one, which spawned this thread, in where there are places which are not ideal. I am especially concerned about three cracks that are parallel to each other right where the chinrest rides, two of those being knife-edge and messed up from the last guy's work.

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I believe most saddle cracks in very old instruments are caused by shrinkage of the top as it dries out over time. The ebony tail saddle is very unlikely to shrink enough to leave any space in the cutout of the belly. Leaving the wood a little thicker over the tail block and on either side of the tail saddle might help in modern instruments, if the wood is well seasoned.

I make my cleats rectangular in shape, out of the oldest fine grained pine/spruce I can find. I precut to 10mm x 5mm and thin to .5mm or less. This way, I feel the cleats add strength to already weakened wood yet remain flexible due to their being so thin.

No crack is completely secure, even when the glue used is exceedingly thin and hot when put in. How I do the spacing depends on the location of the crack, as well as the thickness of the wood along the crack. Thinner wood gets closer spacing, evenly divided, according to the length. The thicker areas are naturally stronger, and the spacing can be farther apart.

I believe full length belly cracks should always be cleated. I do a very careful cross grained inlay patch for sound post area reinforcements. Sometimes, depending on the angle of the crack through the wood, and if pieces have been broken out, I feel it totally proper for the instruments sake, to saw out the crack, then fit, as best can be matched, a new piece of wood back in the cut out, then cleat it securely.

ShowLetter-3.jpg

Does anyone have any suggestions as to restoring this old thing? It bears a Micael Deconet label dated 1754, but the moderator and noted expert, Mr. Jeffrey Holmes doesn't think it belongs, and has pointed out why. I do agree with his opinion.

John

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In the post i made `blast from the past`, which is from 1933(but from a book years before), it says soundpost inlays have gone out of fashion and i think it says veneers are the prefered option. I thought this was a rather recent developement.

Is the post patch still necessary for something like a well glued crack with a couple of cleats right next to the outside of the treble bridge foot?

What about a back post patch that has opened on the outside but inside still seems secure,would the best option be to redo the patch?

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Haha, did that person actually fit a bass bar right over several of those cleats? Or did they cut the cleats off and glue the ends on the other side of the bass bar to complete the visual effect?

Fiddlecollector: I agree, it's a nice looking pattern. For some reason, it reminds me of pictures I saw from World War 2 books of the pattern of "dragon's teeth" anti-tank obstacles and things put on the beaches to prevent landing craft from beaching.

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Hmmm.

Looks like smallPox doctor.

Burn It Immediately.

Why so many cletes?

To me the rationale of installation is:

1)only clete old/insecure cracks, new cracks should glue fine if they do not have other problems

2)make clete at acute grain angle 90 deg or 45 deg

3)make clete as thin as necessary because the cross angle fibers and glue are very strong (0.5mm)

4)do not inlay clete as it detracts from reversal of fix and may promote other problems

5) keep clete small 5x10mm

Should I be adding a #6 to this list that says. "Clete nearest the source of the fracture". The idea being that this is the point of the most stress and more cletes along the crack really are not bearing a large portion of the stress that is trying to open the crack. Am I wrong? Should I be placing a bunch of cletes? What other rules of clete or changes above should I be thinking about?

I ask because I have a $25 Czech violin with a doubly cracked top integral bassbar as a candidate.

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The "over-the-top" approaches to repairs are often very neatly done. It seems that some "restorers" are more concerned with impressing people with their expertise, rather than doing what's best for the instrument (hence they proudly sign their achievement). The bow-tie cleats you mentioned are a classic example - I've never seen this ... and hope I never will!

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