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I would say that's preferable to telling one or more of the three they don't know anything, even if one believes it to be true. My own interest in exploring the materials and construction of instruments was the result of a renowned repairperson doing shoddy work on one of my guitars. So, in my opinion, no side of this lutherie trinity is immune to criticism, or holds an inherent right to an exalted position.

Anyway, this is an interesting thread, with some excellent information. Over time I have evolved my techniques so that I can use animal protein glues exclusively. I don't know that this makes any meaningful difference, but it's a fun challenge and has a kind of "old time" feeling that I enjoy. It also seems to have made my own efforts at fixing mistakes somewhat easier than they might have been otherwise.

I give my instruments away to friends and family living here in the relatively benign climate of the Pacific Northwest and things seem to be holding up well. My daughter moved to Austin, TX in February and her guitar was fine when we visited in April. I'll be checking it carefully during our return at Christmas, as I'm curious to see how it does under the starkly different environmental conditions.

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George :-)

Care to share your process for putting the top / back onto the rims? I'm used to doing the gobar method where the plate being joined is up. I wonder if I should switch to the method of the plate being down? Seems like you get a more immediate contact between the plate and the rims just due to the weight of the rims and the mold. I watched a couple videos where the builder was also going with the plate down.

Brad

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jfmcenna wrote:
"The first book I had on guitar building way back in the day was David Russel Youngs book."

DRY stopped making guitars years ago, and now makes very traditional bows for violins and such. You could say he's ducked the consequences of his early folly. He also makes more money than he used to....

I started doing repairs before I started making instruments, mostly because I had to. All I could afford was cheap imports, and they needed lots of repairs, sometimes as soon as I got them home. Although I don't do repairs any more unless I have to, I learned a lot about what doesn't work, and avoid that stuff when I build.

When it doubt it's almost always a good idea to go with the traditional way. It may not be the best way you could think of, and could well need to be repaired down the road, but at least when that happens they'll know how to do it. That said, I wholly agree with David Farmer that the Spanish heel should be used even less commonly than medicinal leeches. Even a glued in dovetail is better, and there are much better ways than that. Some traditions should be abandoned.

Several years ago there was a maker on the Folk Harp mailing list who extolled the wonders of polyurethane glue to assemble the half-lap head joint. This is the most highly stressed joint in the instrument, carrying all of the tension and a lot of torque: keep in mind that even small harps can have 600-800# of total tension, and many will be double that. After a few years he mentioned that one of his early ones had come back with a peel failure in that joint. Soon he had more, and after a few months he accepted the idea that all of the ones he'd made up to then would be coming back in eventually. They would all need to have the arm and pillar replaced, since there's no way to clean that stuff off without removing wood. Shortly after that he stopped posting. When it seems too good to be true....

Most of the 'affordable' student violins these days are assembled with white glue. Repair shops consider then to be throw-aways. The stuff is the equivalent of bubble gum; it won't hold anything, but you can't get it apart easily either. Avoid that and liquid hide glues.

One of my recurring mental projects has been a router spinning a thin slitting saw to just slice off the tops and backs of those dang things. If it could be done in 5 minutes it might make saving some of them worthwhile. laminated basses too.

Crank up the heat and work fast. Alternatively, you might try experimenting with fish glue.

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George :-)

Ha! I was about to reply earlier and decided not to open that can of worms, but since the top is popped:

I use fish glue for all joints other than the binding as I like the stress free CA method for binding.

It works great for me, and I make no claims beyond that,
Mike

I won't answer for Brad, but fish glue certainly works for this. With a moderately heated room, some preheating of the plates (and a little preparation), you also have enough time to use regular hide glue. Another method is to do it in stages, this is a common technique with cellos and double basses. You add glue to the parts, let it dry, and then re-activate it with heat and moisture as you go around the perimeter.

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Rian Gitar og Mandolin

For me personally, I'm going to stick to the hide glue for now. What is meant by heat and moisture in this case? Is it as simple as a damp rag and an iron, similar to taking off a fretboard or steaming a dent out? Or are we talking about a steam machine of some sort? Is there integrity issues with a reheated joint compared to a joint done in a single step?


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A warm spatula or a thin brush and some hot water, plus a hair dryer if needed. Be careful with heat and moisture around the soundboard's and back's center joints. No fancy tools needed, and no issues with the glue joint. This is one of the beauties with hide glue, and one reason it is so popular with instrument makers. But as I said, it is not necessary to use this method with smaller instruments, where you can glue it all up at once with some planning. Or use fish glue, its fine.

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Rian Gitar og Mandolin

What about a 1/16" slotting bit. Should be able to fit a binding jig, or in this case a debinding jig.

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My memory is so good, sometimes I remember things that never happened.

Exactly Brian. Someday...............

Here's the problem. http://www.ebay.com/itm/Crescent-4-4-Full-Size-Student-Violin-Starter-Kit-Includes-Crescenttm-Digital-E-/122531026910?_trksid=p2141725.m3641.l6368

$48 and free shipping.

One thing I also like to highlight is that following "conventional" methods makes things more predictable in the future. Its not necessarily "better" - but it is predictable.

For example... Professionals and people familiar with conventonal methods do things a particular way. They follow an accepted standard of "workmanlike" work. As such - the problems that crop up are "typical" problems and you know where to look.... Non-professionals may well decide to do random, stupid, and unpredictable things like: Run water in electrical conduit or drain pipe, "drywall" using layers of newspaper, chicken wire, toothpaste, flour, and glue... Hide Clothes hangers and fence wire up inside walls as electrical wire.. And the list goes on...

And so it goes for guitars. Wonderful and perplexing "repairs" such as the much lampooned "pour and shake" joinery, hardware store additions, nails, drywall screws, Gorilla "tone" glue slathered everywhere, and strange miscellaneous random acts of "improvement" such as ignoring all the work that has gone into sorting out intonation......

Alright, Brad.

First youtube FWIW.

I don't build much but this is what I did most recently. I have no idea why a took a video of this. Proly cuz my memory's not so hot.

Four french fry lights keep it pretty casual. Two keeping the top warm, one centered over each block.
the top has a 1/4" wide gasket layer stuck to some thin Luan ply (or something) taped to it.

My normal HH bottle. Stainless nuts inside to keep it upright and down in the water. Ring finger is used as a fence. Give the bottle a little squeeze when it's upright, then when it's flipped, you can keep gravity from forcing it out.

Sandwich contraption, bottom to top:
Granite plate (favorite tool!), 25' radius dish, back, rim, top, ply/gasket ring, 65' MDF dish cut to dread outline, cast iron 14" tablesaw wing(heavy!), 9"x11" granite plate, special luthiers 25 Lbs. barbell, very light clamp over blocks.

Cheers.

That is super helpful, Dave. Looks like the elapsed time from first applying the glue until the first weight is applied (the tablesaw wing) is right at one minute.

The dish shaped as the body is brilliant!

The luan ply is actually taped to the top? It appears they are attached in the video, but want to check. Just a couple tabs I assume to make it easy to separate and keep things aligned during glueup?


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Great video Dave!

Here is another one by Mario P. https://www.youtube.com/watch?v=TC78Z9zFG0I

'Cello maker Jim Ham sizes all of the top/back ledge, block, and liner surfaces with HHG and allows it to dry. Then he dry clamps everything in place, getting the overhangs just right. Once that's done he removes a few clamps, uses steam introduced with a basketball needle to reactivate the glue, and replaces the clamps. This keeps everything lined up, minimizes glue squeeze out, and goes pretty fast.

Don Warnock used to glue in solid liners by painting them with glue which was allowed to gel, but not dry. Then he'd clamp in the liners using a wide caul of fairly heavy dead-soft aluminum on the outside. Once they were in place he'd use a small alcohol torch to warm up the aluminum where it stuck out below the clamps. This is similar to the method Torres is reputed to have used gluing on backs. In his case. working on a solera, the back braces were inlet into the liners and arched, and the edge of the rim dressed off to the appropriate angle all around. The braces were painted with glue, and the back was glued around the edges, using string to hold it down. Then he'd paint the area of the back where the braces were with a little bit of alcohol and set it on fire to warm the glue. They know this in part because of the way the glue squeeze out dripped. Sometimes he used too much alcohol and scorched the back wood a little, leaving a stripe across it that could not be scraped out. I've used a microwave oven to warm up hide glue when the shop was chilly. The list goes on.

"Most of the 'affordable' student violins these days are assembled with white glue. Repair shops consider then to be throw-aways. The stuff is the equivalent of bubble gum; it won't hold anything, but you can't get it apart easily either."

Vinegar will soften most white, yellow and organic glues and allow the parts to be separated.
If I were to go the "saw method" I think I would try an oscillating tool rather than a router or slitting saw.

This makes me appreciate all over again human mastery of electricity.
I bet Torres' mind would be blown at the ease of plugging in a heat lamp. Then maybe blown again that we still haven't found something better than boiled animal protein to stick instruments gether.

Here is my little gasket ring Brad.
The 3ply is about .105" thick from Home Despot. It's cut to about 9/16" wide. It seems like a good balance of flexibility and stiffness at those dimensions.
The gasket is from Ace Hardware. 3/8"wide x 1/4" thick with adhesive on one side. Might have come in a roll? Pretty firm. a little firmer would be even better.
A couple of pieces of tape to the top so there is one less thing to line up when the heat is on.

I have the plate cut to the exact size of the outline before gluing. That way, with the body shaped caul, I can easily see the fit is good all the way around in a dry run. I'm not sure what the point of leaving an overhang just to trim it back after is. I find it's hard to see what's going on that way.

In terms of time, there's some low hanging fruit in the video. I start to put the first weight on having forgotten the MDF caul so I have to back track. I also think I used a toothpick locating pin in the binding area at the tail block. I found that a bit finicky and you can see it takes a while to situate. In the future I'd rather have a proper 3/16" locating pin on a tab in the top going into a hole in the mold.

You could use a press screw arrangement. but I think a key element is being able to lay one continuous bead of glue around 360 degrees pretty quickly.
Next time I might use a bottle jack and one 1 1/2" square go-bar against the ceiling.

When your coming from PVA glue, you have to get use to the volume of glue in the bead. You need more volume w/ hide.
Your PVA eyes will likely tell you it will be a squeeze out disaster but much more of it is ab(d?)sorbed.

David, that's a brilliant idea to put the gasket on ahead of time!

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Pat

I used this on a restoration so I could line up the top on a guitar just right. Works perfectly.

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Steve Smith
"Music is what feelings sound like"

My last few guitars were all done with 100% hot hide glue. My plate gluing process is not remarkable: work out an efficient clamping strategy, do a dry run, heat the parts, then work fast. It all comes together just fine, if you plan it right.

I do have a question for The Elders regarding another way to make the process less stressful: What about adding a little urea to the hot hide glue? I mean, I know it is done. I have used urea to create a fresher equivalent of Old Brown Glue, and it works great for things that need a lot of extra time. A concern some raise is the tendency of urea to weaken the glue, so I have only used it when the strength of the joint is not all that important. I do think strength is important for plate/rim joints, so I have not used it in this context. But maybe the use of a little urea (less than 5%) to just add a little more open time would allow more time here without significantly weakening the glue. Thoughts?

The thread's moving in a different direction, but I saw this and thought, "yes!"

I used a little blade in my Dremel along with the Stew-Mac base once to remove a top, then read that John Greven had done the same thing. It worked great!


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Yes, acetic acid does dissolve white glues, and seems to work faster when the glue is thicker. It's still not very good, though.

Some years back I had to remove the top from an upright bass that had taken a lot of damage when an ice sculpture fell on it. It had been very badly 'repaired' by a local shop, which made everything that much worse. Rather than piece in the places around the top edge that had chipped out they simply sanded about 3-4mm off the thickness, using a coarse disc sander, and then glued it on with Titebond. It took five hours to get it off with hot photographer's stop bath, which is a lot stronger acetic than household vinegar. The separating knife reacted with the acid, and stained the wood black all the way around. I've since learned that stainless steel works much better. The thing was a compendium of poor repair methods badly done. Needles to say it ran 'way over time, and there was no way I could recover all of the cost. At least it went out in far better shape. with a proper half edge, a large sound post patch, another at the upper end of the bass bar, new bass bar, and about a hundred studs over spliced and glued cracks. Basses don't get no respect.

The other white glue story concerns a violin that came in with the top pretty nearly flat along the axis on the bass bar side. It was not a bad fiddle, and I assumed that the bar had come unglued at the ends. Wrong. When I got it open the ends of the bar were still glued down, but the white glue ('Elmer's' type) had simply allowed things to shift in shear over time as the low bar and the top flattened out. The bar may not have been well fitted, allowing for a pretty thick glue line. The repair had been done in the '40s, iirc, and may have been the repairman's first experience with the stuff. I've seen this sort of thing more than once; white glue seems to have no resistance to shear at all over the long term.

Just imagine if those fellows had access to superglue... . Or worse.... Gorilla glue... Not only is it impervious to all normal chemicals making it impossible to remove.... It foams up and expands inside joints....

I really cringe when I hear the stories about instruments made using the old milk based Cascamite glues... Where they found out that the stuff turns to powder after about 20 years....

I have seen several violins come out of attics completely disassembled from years in the heat.... Its amazing that an entire violin worth of parts will fit into a shoe box.

I remember an episode of Gilligan's Island sort of like that, only it was glue derived from tree sap, and it let go after a few days. Planks started popping off the repairs they had made to the SS Minnow right as the boat was put back in the water.