It's sort of the accepted thing on instrument (guitar, etc...) making forums
(like mimf.com) that Titebond II is not suitable for instruments because of
glue creep. Hide glue (the ground stuff that you mix fresh yourself, not
the pre-bottled stuff) and original Titebond are probably the most two most
common glues used for building instruments. But when they talk about "glue
creep" it usually means that the joint is moving, not that it's really
squeezing the glue out of the joint.
Any "white" glue will creep under sustained load. The solutions are to
design your structure so that there is no shear load on the glue joints or
to use a different type of glue (plastic resin or phenol-formaldehyde for
example) that does not creep under sustained load.
Reply to jclarke at ae tee tee global dot net
I am beginning to wonder if it has something to do with clamp pressure. and
the quality of the joining of the boards. From all accounts white and yellow
glues do "creep". So if clamp excessive clamp pressure is used to ensure
squeeze out the jointed edge is in compression ,some areas more than others
. When the clamps are released the compressive load is gone but in the joint
"valleys" there will remain in fact a tension load which over time will be
allieviated by glue "creep".
I dont know the solution other than using hide glue where. most joints of
this type were "rubbed" joints requiring no clamp pressure.....mjh .
The common definition of glue creep is during the clamping process, the
pieces may tend to move on non-mechanically aided joints.
After the glue, any common wood glue, sets it will not creep. What you are
describing is seasonal wood movement. Very common. Design and construction
techniques can eliminate or hide this common problem to all woodworkers.
Me, too. Supposedly, creep is helpful for wood joints that need to flex a bit,
as in chairs.
"Political language... is designed to make lies sound truthful and murder
respectable, and to give an appearance of solidity to pure wind." George Orwell
That's not the common definition I'm aware of...creep is the gradual
shift of two pieces relative to each other under long term loading and
is a potential problem w/ any non-hard glue.
You're right that proud glue lines are not creep but the result of
differential expansion from temperature or more commonly moisture...
Thanks folks for all the help. A few answers to some of the questions
1. Wood being used is typically 5-7% moisture content. The wood is
seasoned in my garage for a few weeks.
Cut to rough dimension, sits another week or two, then I cut to final
2. Clamping pressure is pretty minimal meaning I don't crank the heck out
3. My joints are nice and even before glue up and after. In fact, some of
them, with the grain
orientation etc... you cannot even see.
I've obviously misused the term "Glue Creep" as these are pieces that have
on them in most cases. I suppose it's possible the moisture content might
swell the thickness
a bit but it just seems odd that none of the other furniture in the house
seems to have this
issue (not my construction). Using shellac as well, I wouldn't expect to
see moisture changes
at the joint although I may be wrong on that assessment. I suppose a more
accurate description is "Proud Joints".
I believe I'm jointing, gluing, clamping just like most folks so I guess my
question is now
becoming "Is this normal?".
5-7% is pretty low for equilibrium moisture...where are you located? If
it's not in a very arid climate, I'd expect that the final moisture is,
in fact, higher and is a likely cause.
Sounds like your working is ok other than I suppose it might be possible
(although unlikely if you work anything like I do on fine work--not
enough time for that :( ) you are sanding near the joint too soon after
gluing and the excess moisture has swollen the joint somewhat so that
when it subsequently dries the glue line does stand a little proud of
the surface. Some moveement is not unheard of, for it to be extremely
prevelant indicates to me there's some difference in moisture
equilibrium between the working area and the finished pieces'
I notice the piece you mentioned was cherry and built in the summer...if
your summers are humid and you now are looking at very dry, heated
indoor air after a couple of years, I could see that...
I'm in New Mexico. Humidity is negligible most of the time. Items
are being built in the garage and put inside the house approx. 20 feet
away. I do remember some pine I worked with at about 9% but generally
stuff get's pretty darned dry here.
Yep, I was guessing somewhere such as that...moutains or flatlander?
I'm in far SW KS and it's hard to get that dry here even...
Do you by any chance have a power humidifier hooked up to the central
I can only recomend perhaps waiting a little longer after you glue
before final sanding of the glue joint to see if that will help
equilibrium some. Even here I rarely have a problem.
Idea...Maybe try a couple of test pieces w/ Type I and II glues (and
maybe a couple of vendors' varieties as well) and see if you can tell
any difference between the glues and timing of various patterns of work.
OBTW, you <are> finishing both sides of the pieces, correct?
No humidifier hooked up. I do have to say however, that humidity does
tend to swing quite a bit. Usually it's dry (say 15% most of the
summer) but rains come and jack that up for a week or so to say 30%.
Winters are usually pretty dry. I am finishing all the sides of the
pieces (obviously not the mortices/tenons). Just seems odd that the
boards move on my projects but not the other furniture.
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