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Tips for a soundpost patch?


cmjohnson
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I'm about to attempt my first soundpost patch repair on a 14" viola. The instrument was dropped and the soundpost blew right through

the top and left a long U-shaped break in the top as well. The piece that got knocked out of the hole is not available.

The U-shaped split will be easy enough to handle. (The top is already off the instrument.) I'll be fixing that before attempting the

soundpost patch.

I have some well matched spruce for the soundpost patch. Similar grain spacing, etc. It should match up well and if it doesn't,

it's nobody's fault but mine.

But, if you have any specific hints or tips on the technique and method of soundpost patching for me before I start shaving wood,

I'd very much like to read them.

Chris

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I would start by gluing the cracks and making a cast of the top.

The best way to deal with a hole is to carefully remove a wood shaving in line with the hole, prepare a bed for the patch with the top thickness feathering down to zero around the hole and glue the shaving across the hole with the grains aligned. Then the shaving is blended in with the patch bed and a patch is fitted over it. This way the wood visible from the outside at the hole has the same grain and other characteristics as the wood surrounding the hole.

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I'm about to attempt my first soundpost patch repair on a 14" viola. The instrument was dropped and the soundpost blew right through

the top and left a long U-shaped break in the top as well. The piece that got knocked out of the hole is not available.

Chris

Do you HAVE to do it? If it is a kid's junior viola, get one wholesale and sell it to him at cost. That is likely 50% what he paid. They will thank you. Then you can do something more worth while.

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Yes. This is a project that you should only undertake if you are very hard up for things to do.

I see it as a skill builder, and when the instrument is repaired I put it up for sale. It should be worth about 400 dollars in well repaired

shape, given the cost of this particular model in as new condition, and I could certainly use 400 dollars whenever it happens to come along.

Or would you prefer that I wait to attempt my first soundpost patch job on the next 25,000 dollar violin to come along with said problem?

I think you'd cringe at the thought. So would I. Decently made student instruments are very good for learning repair skills.

Chris

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Right attitude, for sure. :) It's what you have, so it's what you have to start with.

A couple of cautions. An instrument with a sprayed, or very even unblemished color finish is going to be a challenge, cosmetically. Really no place to hide. You'll ned to take care to align the crack correctly or you'll get a peak or gully. Check threads concerning pillars and other cleating methods.

Taking wood and moving it over, as Brad mentioned, is probably the way to go here... wood should be taken from the area you will make into the patch bed

I believe there is an article in the Strad by Grubaugh & Seifert concerning guiding in a patch. Probably good to review. There are other methods (multiple guide cleats) as well.

I put up a pictorial on casting a while back.

Someone (who has done this repair) who you can visit with in person would be a plus...

Good luck.

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I've inspected the top and the wood is well on the quarter, without any runout to speak of.

The finish is an oil varnish, brushed on, not sprayed, and this type is pretty easy even for me to touch up.

The soundpost left a very clear dent in the bottom surface of the top where it broke out. The actual missing

piece is nearly square.

I'm very careful to be sure that the two sides of the break line up perfectly when gluing. I recently got

experience with repairing a violin (same brand as this, incidentally, a Keith, Curtis, and Clifton) with two

breaks in the top and frankly you'd be hard pressed to see that it was ever damaged. The alignment of

the broken areas is essentially perfect. I didn't rush the job and even the cleats are nicely shaped.

The biggest thing I'm concerned about with this soundpost patch is, what's the preferred form for repairing

the missing area? Should I drill out the hole to a perfectly round hole with tapered sides? Oval? What's the preferredd shape?

Chris

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I've inspected the top and the wood is well on the quarter, without any runout to speak of.

The finish is an oil varnish, brushed on, not sprayed, and this type is pretty easy even for me to touch up.

The soundpost left a very clear dent in the bottom surface of the top where it broke out. The actual missing

piece is nearly square.

I'm very careful to be sure that the two sides of the break line up perfectly when gluing. I recently got

experience with repairing a violin (same brand as this, incidentally, a Keith, Curtis, and Clifton) with two

breaks in the top and frankly you'd be hard pressed to see that it was ever damaged. The alignment of

the broken areas is essentially perfect. I didn't rush the job and even the cleats are nicely shaped.

The biggest thing I'm concerned about with this soundpost patch is, what's the preferred form for repairing

the missing area? Should I drill out the hole to a perfectly round hole with tapered sides? Oval? What's the preferredd shape?

With all due respect, you suggested this was an learning opportunity... and it should be. You'll never recover the cost of repair, if done correctly, with this instrument (Bulgarian or whatever it is)... but you do have an opportunity to learn. Can't learn if you don't "listen". Frankly, the occasions when I do get a little frustrated on the board is when someone is looking for a way to shortcut a repair ("Hey, I need advice on the right way to do this, but I really just want to do a passable job") or they want to take the opportunity to go the distance and do it right, but don't understand what they may not know and just charge ahead without pausing to see if there's something they might have missed... 'cause they're focussed on what they perceive the "biggest" problem is. I understand both situations... but if one wants to learn how to do things well, they are both short sighted.

I did not offer any advice until I read that you essentially wanted to do this right... but you're quickly falling into the second group.

You may want to re-read my post. I said "An instrument with a sprayed, or very even unblemished color finish is going to be a challenge". Ie. New, un-antiqued instruments are harder to retouch than old or antiqued ones. It's the even coating that's going to get you... not the original application or material. You will be touching in an area that is quite visible on an outside curve.

BTW: Unless I know the maker, history of the maker, etc., it's pretty difficult for me to distinguish between oil and spirit varnish. Both can have similar appearances. Both can be either resistant, or easily soluble with spirit. Promotional do-da should be taken with a grain of salt, if that's what you're going by... or maybe you're just better than I am... or a a chemist with a lab. :)

The harlequin effect on the halves of the top often does indicate that there is runoff (the top is not quite on the split), so I'd tend to agree with Salve's observation based on photos alone. I'm not speaking of what is normally referred to as "the quarter". It's the angle the wood was split (or most likely sawed) in the other plane.

Especially on the outward curve of the arch, in an area that has received trauma, and where the crack goes cross grain, it's not just "lining up the crack" that's important. It's also critical that you are able to manipulate the line of the arch to avoid a peak or gully... and if you do that by squeezing the crack between plastic with clamps, you will get a gully (the glue swells, then shrinks back). The cleat systems I mentioned is meant to assist in lining up the crack/arch. They are temporary. After gluing they are removed.

post-17-1272729470.jpg

What you do have going for you is that it's a clean crack. If you do "everything right", it should look pretty decent.

You are correct... square lines across the grain of a through-patch is to be avoided... but a round drill hole isn't the way to go either. I'd consider trying to feather out with the grain on the sides and finding a gentle curve that works across the grain.

Anyway, good luck. I suggest you perform the searches I suggested.

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what's the preferred form for repairing the missing area? Should I drill out the hole to a perfectly round hole with tapered sides? Oval? What's the preferredd shape?

The exact shape is not critical, but keep two things in mind: 1. You want to keep the hole small. Don't unnecessarily enlarge it. 2. An irregular shape will be less likely to be noticeable after the repair is finished, so try to avoid straight smooth lines and sharp angles.

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While you can get a lot of information here on the forum, it would be very helpful if you had some kind of book or tutorial, that fully describes the process of fitting a soundpost patch. Your statement: "The biggest thing I'm concerned about with this soundpost patch is, what's the preferred form for repairing the missing area? Should I drill out the hole to a perfectly round hole with tapered sides? Oval? What's the preferredd shape?" leads me to believe that you don't have the proper information yet. The repair of a through hole is quite complicated. Buy a copy of Weisshaar & Shipman. The $400 that you expect to get for the completed instrument will cover the cost.

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The exact shape is not critical, but keep two things in mind: 1. You want to keep the hole small. Don't unnecessarily enlarge it. 2. An irregular shape will be less likely to be noticeable after the repair is finished, so try to avoid straight smooth lines and sharp angles.

Last thing I'm going to suggest here, just as a clarification, as these threads tend to get used later as references... the one smooth straight line I think one should NOT avoid, is the one that goes along a grain line. Much easier to hide a feathered joint that ends in the winter grain than if you stray away from it. In other words, use them when you can, but watch the transition.

Cheers all. I think I'll lurk for a while.

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I'm trying to decipher the statistical reality of two violins from the same maker having two tops blow out. Are these violins from different places? or did they share some common injury, simultaneously sat on by an elephant perhaps? It seems that the possibility exists that this maker was either try to push graduation limits in all the wrong places or he had some bogus wood?

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Here's a brief tutorial that I found with a Google search. http://www.rocheviolins.com/html/soundpost_repair.html

The big difference with your repair, is that you'll have to scrape the "dish" all the way through at the hole, glue in parings from the inside, re-scrape the dish shape, and then chalk fit the patch before gluing.

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I will never be in a position to attempt to make a soundpost patch but I am intrigued by the process. Considering the current topic (a through hole): I understand the advantage of trimming the sides of the opening parallel and inline with the grain of the top (to help hide the repair), but wouldn’t that require an interesting and difficult shape be made at the top of the patch? This is assuming that when an oval patch intersects the outer surface of the top plate it would form an oval.

Chris K

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I think that the key here is the thin layer of matching wood parings glued into the through hole. After that is done, the rest of the patch would be quite conventional. The Weisshaar & Shipman book illustrates the through hole repair with parings quite well.

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I'm trying to decipher the statistical reality of two violins from the same maker having two tops blow out. Are these violins from different places? or did they share some common injury, simultaneously sat on by an elephant perhaps? It seems that the possibility exists that this maker was either try to push graduation limits in all the wrong places or he had some bogus wood?

These both came from the same high volume dealing violin shop that provides instruments (and repairs) to practically every student and every school within 100 miles. The KCC brand is the one they sell the most of, and that's a pretty good number of instruments. There's really no shortage of instruments that have been either damaged in shipping or by mishandling at a later time.

Chris

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  • 1 month later...

I'm finishing up a soundpost patch and thought someone might be interested in how I use super magnets to clamp cleats in place.

What I like most about using magnets is that they simply squeeze the parts together without introducing any twist as a series of long clamps might do. Using these magnets is also much faster than using clamps

The trick to using these plastic covered magnets is to pre-position them, then remove the top one, place the bottom one under the cleat and carefully replace the top one. These magnets can be tricky and a bit dangerous as they sometimes fly off if brought too close together.

If your xwife and current wife have ever met, you know what I mean :) :)

Oded

post-95-1276181604_thumb.jpg

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Here is what I did when I got in a viola of decent value. It was on the order of Roman Teller grade. I wrote a letter to the insurance company and said it was fully degraded because the punched hole was about the size of a dime with several pieces broken cross-grain.

Then I gave them a very nice deal on one of my own violas which at least had some sort of provenance, given that I am a known name at least here in Ohio.

I pushed all the pieces togeather and fixed the cross grained parts with thin superglue. I made a shoe to bridge the damage. This was from a foot from a deJacques bridge. There is a dimple to take a soundpost sharpened to a point.

It works very well sound-wise and I play it in orchestra. (I had been playing the one sold in orchestra.) Eventually, I may make a new top and revarnish it.

If I wanted to learn to do this repair for the future (and I did not), I would expect to have to do it a dozen times to get it half-right. To learn to repair this uniform color varnish (as Jeffrey says), I would have not confidence that ANYONE short of a dozen people in the world, could make it acceptable. And Jeffrey was soft-pedaling his comment, I am sure.

This grade of violin is most easily revarnished with lesser damage. You may as well practice varnishing as exotic repairs.

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