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fiddlerjer

Joining plates: anyone use wood glue

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I was looking over the process for making front and back plates at http://makingtheviolin.com and noticed that the recommendation is to use hide glue when joining the two halves of the plate blank. Wouldn't it make more sense to use wood glue? Is there ever a situation where you would want to separate the two pieces?

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Some folks might be reluctant to jump in, because this topic has been discussed at length a number of times. 

The short version: due to the tendency of pva wood glues to creep under load, they are not generally considered a good choice for the plate joints. Due to the difficulty of reversing joints made with these glues, they are also not recommended for any of the other joints on a fiddle. 

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Not recommended...but people do. And they justify it all day. Perhaps because their joint is so bad you could stick a playing card in it, but pva glue helps it "carve out". Obviously this is not the stated reason (those are ever entertaining excuses...'but X does it, and it's fine'), but it is often the truth. 

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I will largely second the above, but with an important caveat: there are a very small handful of truly excellent makers who's work I have personally seen that have admitted at one time or another to using some sort of pva on these joints. 

That said, I don't recommend it. Properly prepared hot hide glue of the appropriate strength is totally sufficient, cheap as dirt, and demands an excellent joint, which is what you desperately need no matter what kind of glue you use.

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25 minutes ago, not telling said:

Not recommended...but people do. And they justify it all day. Perhaps because their joint is so bad you could stick a playing card in it, but pva glue helps it "carve out". Obviously this is not the stated reason (those are ever entertaining excuses...'but X does it, and it's fine'), but it is often the truth. 

Not advocating PVA, haven’t used it on a violin,and yes it will fill a gap, but, I personally know a few very fine makers who use it for good reason and get good results.also seen some pretty crappy hide glue joints that held well. 

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Yeah, I have heard some names of the PVA users, some of them well-known makers and some apparently good ones in the younger generations. It is not my problem what happens to their instruments in 50 years, nor is it their problem, since the check already cleared. I'm only being half glib. Maybe it doesn't matter. Obviously I don't know what happens to that kind of glue joint over time, and there's no one who does. So that is the one area I have the same knowledge as anyone. I'm only critical because some appear to be covering shoddy work with PVA as their tool, whereas good makers who use wood glue do so for different reasons. For example, on a bass, because it is a bass and because their actual joint is beyond reproach.

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23 minutes ago, lpr5184 said:

Another option is to leave the jointing and gluing and use one piece fronts and backs.

A good and valid point. These billets tend to be more expensive, but there's nothing wrong with one piece bellies and backs.

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On ‎11‎/‎15‎/‎2018 at 9:49 AM, JacksonMaberry said:

A good and valid point. These billets tend to be more expensive, but there's nothing wrong with one piece bellies and backs.

Not much more if you look around.

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4 hours ago, not telling said:

 Perhaps because their joint is so bad you could stick a playing card in it. 

I use wood glue because the label says it's non-toxic and paintable.

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Ok...this is bugging me. So what are the reasons to use Titebond for the center joint? Please add to this. So far I think it's mostly:

Lengthy working time

Forgiving of gappy joint

-->

Eases up the stress of the task enough to gamble about how Titebond holds up over many decades

Strong glue, probably stronger than hide glue in most cases according to experiments of an eminent MN'er which were discussed in some old thread here

waterproof, weatherproof (to greater extent than animal glue). 

Super cheap

Super easy, zero prep...i.e., zero ways to screw up the glue itself since the user doesn't prepare it

Aggressive antiquing means possible issue with center seam popping open.

Passage of time inexorably means progress and thus greater and greater human achievement--so Titebond is automatically superior to hide glue for all uses. No proof needed. It's a tautology actually. You cannot argue with progress. Doing so would bring everyone back to the dark ages. Stop hating science.

(Your reasons here)

-------------

Why not to?

It's too new a product to know what happens over a lot of time. It may flake apart into powdery or stringy plasticy bits after a few decades. Do you really know? Nope.

Do you care? Yes.

Also, creep is a major issue with Titebond, sometimes immediately and sometimes within months.

But-as devil's advocate I am very curious-is this true with the type of load and angles of the butt joint with violin plates specifically? Is a hide glue center joint impossible to introduce creep into? Has anyone seen this happen on a violin?  (I once thought I would test aspects of this myself and of course I didn't. That would require making at least rough arches several times and wasting a bunch of them with a Titebond joint, which I couldn't get perfect enough to get valid results anyway,  just to partially answer something that won't even affect those who will never switch to PVA.)

Can't really think of other reasons why *not* to use wood glue. Oh yeah, principles and standards and tradition and history, and just for the pleasure of using hot hide glue.

(Your reasons here)

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As you may have noticed I'm quite for new things (the CNC thread) but in this case I would certainly stick with hot hide glue and not because it is traditional. I build mandolins where modern glues are normal and HHG is acceped as extra and customers are willing to pay for it. Partly because of old valuable instruments were built with it, but also the other properties:

Generally the strength of joint tested by cabinet makers (and their typical joints) are not something I would rely on. There is number of odd joints on instruments where the strength of joint would be very different from tenon or similar. Also cabinetmakers don't test joints that are under long time stress like instruments. Also, on instruments we don't always need the strongest possible joint. We intentionally weaken the joint between top and ribs...

To me regarding the modern wood glues (Titebond, PVA and similar) the creep is not the worst thing as it only shows its bad face when the instrument is subjected to hot or humid conditions well outside of comfort zone. Reversibility of joints is also partially myth - HHG at full strength will be a nightmare to open while slight heating of Titebond will allow it to release quite easily. The waterproof glues will only hold if the wood is not subjected to bad weather - the stresses in the joined pieces will eventually tear it apart. I have 100 years old spruce board joined with HHG (side of old chest) that spend better part of it's life as siding of woodshed (on sunny side) and upper half of the joint that was sheltered by the roof overhang still holds while the lower part has partially rotten away as it was in contact with wet soil. The modern PVA glues have been around for more than 50 years already so reliability can be shown for them as well.

The most important property is that you can safely reglue the hide glue joint back together after cleaning with water (or on fresh separations no cleaning is needed) but the modern wood glues just won't stick to old dreed glue, if you try  and apply drop of Titebond over wood that was painted with thin layer of the same  and left dry, the drop will not adhere and will peel away cleanly with very little effort. I read that casein glue has similar property to HHG. Yu can certainlly make nce violins with modern glue but future restorers will frown upon you later.

Just one addition, Mr. Hargrave used Titebond (type II or III ? waterproof) for the bass top/back joints. I found out that joining bass top with HHG is for brave (I managed to do it on 2nd attempt and still can see the line n few places so perhaps I'll re-do it again) so the modern glue is safer option for him to get good joint as he uses the plasted sealer that wets the wood considerably. (Personally  I would fear that the joint will ever need repair in the future as is more than common on basses). Perhaps casein could be the optimal choice for that... but it's not generally available.

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5 hours ago, not telling said:

Also, creep is a major issue with Titebond, sometimes immediately and sometimes within months.

1. But-as devil's advocate I am very curious-is this true with the type of load and angles of the butt joint with violin plates specifically?

2. Is a hide glue center joint impossible to introduce creep into? Has anyone seen this happen on a violin?  (I once thought I would test aspects of this myself and of course I didn't. That would require making at least rough arches several times and wasting a bunch of them with a Titebond joint, which I couldn't get perfect enough to get valid results anyway,  just to partially answer something that won't even affect those who will never switch to PVA.)

1. It is. And Titebond specifically warns that their glue is not recommended for sustained high loads.

2. Hide glue can creep a little, if the moisture level becomes high enough.  But even at 95% humidity, it seems to be better than Titebond.

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8 minutes ago, Marty Kasprzyk said:

I use Gorilla glue for my center joints.  

It's waterproof which is important for violas.

Why? Unlike a bass, it's not big enough to use as a rowboat.

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4 hours ago, Marty Kasprzyk said:

I use Gorilla glue for my center joints.  

It's waterproof which is important for violas.

I got the idea of using Gorilla glue from the late violin maker Sam Compton.  He claimed the joints were indestructible and were creep resistant.  It works well and indeed most of the people trying my instruments have been very nice people.

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7 hours ago, Marty Kasprzyk said:

I got the idea of using Gorilla glue from the late violin maker Sam Compton.  He claimed the joints were indestructible and were creep resistant.  It works well and indeed most of the people trying my instruments have been very nice people.

Emphasis added :D

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