On Dec 24, 2016, wrote
(in ):

On Sat, 24 Dec 2016 17:45:47 -0500, Joseph Gwinn
wrote:

On Dec 24, 2016, whit3rd wrote
(in ):

On Saturday, December 24, 2016 at 11:59:38 AM UTC-8, Joseph Gwinn wrote:
On Dec 24, 2016, wrote

I have two heavy wooden doors bought 10 or 15 years ago that quickly
sagged
trapezoidal in the summer heat - the Sun hits them in the afternoon. The
original doors were ratty, but never sagged. The problem is that the door
manufacturer used some kind of plastic based glue (Titebond?) that
creeps...

If the joints were tight, there wouldn't be creep at any reasonable
temperatures.

The joints appear to be cope and stick,which depends entirely on the glue,
even if the glue line is tight.

Even mortise and tenon will rack unless the tenons fit the sockets perfectly
on all four faces; this is unlikely in US production - too fiddly.


Methinks the manufacturer didn't use good construction OR good glue.

It looks to be the glue, but I did not take the door apart.

While Titebond is a very good general-purpose glue, Im betting it will
creep quickly at 150 F.

"Polyvinyl Acetate (PVA) Glue: Any glue consisting primarily of polyvinyl
acetate polymer. This category includes most traditional white glues and
more
advanced yellow aliphatic resin glues. Although PVA glues can vary in
strength, flexibility, water-resistance and sandability, they offer good
performance, cleanup with water and are non-toxic. Because PVA glues tend to
€œcreep€�, or slowly stretch under long-term loads, they are not
recommended for structural applications.€�
.http://www.titebond.com/Libraries/Li...uideTB.sflb.as
hx

Elsewhere on the Titebond website, it says that their hide glue offers
superior creep resistance. As do epoxy and resorcinol.


Did the rail/stile joints open and show a crack?

Yes. The cracks are tapered exactly as one would expect if the jamb side
stile dropped down, but stayed parallel to the hinge side stile. The
turnbuckles prevented further creep.

Joe Gwinn
Easy to fix. Drill and pin with good hardwood dowels, the way the old
doors were made - -

Its a good idea, although the old-timers used hide glue as well.

Joe Gwinn