yes, PVAc glues creep. It is not a fairie tale.
In the 60ies, I stored a leftover piece of spruce, glued up from two very dissimilar boards, upstairs in the woodshed. they were glued either with Mowicoll (a german brand long since gone) or Rakoll. One of the two pieces was what we call Druckholz, i.e. from trees grown with very one-sided load from wind or steep terrain. This wood shrinks in ALL directions. Good only for kindling. Anyway, much later, mid 70ies, I stumbled across this leftover. 
The Druckholz had shrunk about 5mm, leaving a sharp-edged step on one end.
BUT the glue joint was intact. Time period: 10 years.
That is creep.
Apart from that, in the last 50years I have seen to many pieces glued with PVAc that have literally fallen apart, probably due to creep, maybe also to temperatures.
 Martin and I were just looking through photos of different modern instruments - no names 👎) with wretched out hitchpin rails, crept laminations etc etc etc one particularly crummy example by a would-be continental "professional" from 1986.
like I said, it is not hearsay or fairie tale.


Bill



> On 05 Mar 2016, at 8:13 AM, Andrew Seemann <[log in to unmask]> wrote:
> 
> OK, now that the glue bottle has come uncorked, I have a question that has bothered me in reading glue discussions on this and other forums.  I keep hearing that PVA glue "creeps".  While I do not deny that this is can happen, due to the chemistry of the glue, and that it will creep and fail under high heat, the amount of "creep" in actual application seems to never be qualified, just that it creeps.
> 
> So far as I can tell, based on extensive searching on the internet (watching computer code run at work for hours on end gets pretty boring fast) and the main people that seem to concern themselves with this creep are on instrument forums for guitar, banjo, violin, mandolin, and harpsichord making.  Again the amount of creep is never qualified, just that it creeps.  Well, continents creep too, and other than earthquake faults, the amount of creep doesn't affect everyday life.  Do these PVA glues (as in Titebond 1, not elmers white glue) actually creep enough to be relevant to the construction of a harpsichord or guitar?  It seems that there are many instruments that have been made with PVA which have lasted decades and will likely last many more.
> 
> I know the bottle says "not for structural applications" but that really has to do with applications like laminated roof beams in a bowling alley and failure in a fire, not the construction of a dreadnought or flemish single.
> 
> So has anyone actually experienced creep from PVA and how much was it over what time period and in what application? (this isn't a sarcastic question, I really am curious about the how, whats, and when of it).
> 
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Note:  opinions  expressed on HPSCHD-L are those of the  individual con-
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versity of Iowa.  For a brief  summary of list  commands, send mail to
[log in to unmask]  saying  HELP .
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