Restoring Window Joints

Q: I have not restored a lot of windows but that I have done some.  I was taught to apply epoxy adhesive to the wood joints when assembling and have discovered that this stiffens the frame up a lot.  I have seen some specs that recommend this and have also seen some that are dead against it, saying that it will make disassembly impossible in the future, should the need require.  I can see it both ways and would like to hear any comments anyone may care to make.
-evergreen

A: Evergreen,
I feel it depends on the age & value of the window, the type of window joinery, budget & the Client's preference.  If the sash joints are mortise and tenon, the best quality option is to take them apart & repair the mortise and tenon separately.  When cured they get sized & pegged back together.  Exposed voids or porous end grain can then be epoxied prior to glazing & painting.  This technique should allow the sash to be pulled apart in the future.  When epoxy is used inside the sash joints prior to assembling, they will be much more difficult to disassemble.  I have been told that high heat will soften epoxy which may allow the joint to be disassembled, though I have never tried it.  If someone has attempted this, please let us know the results.
-Paul Marlowe
ConServ Epoxy LLC Owner