Commander 147

[ebb]

another half cent.
There have been reports in forums of failures with both resorcinol and epoxy gluing white oak.
Each report does not go into full depth of what happened, Moisture, clamping pressure, actual kind of white oak, temperature, loads, weatherability (UV, shrinking, expanding).
Failures could be due to anything - lousy glue or not carefull measuring of Parts A & B. Resorcinol has a shelf life as well. There have also been many triumphs and total success.

All woodworkers agree that laminations should include redundant mechanical fastening.
Especially horizontal load bearing laminations.

It is the acid in quercus alba that the epoxy doesn't like.
One worker says he has had success rough sanding faying surfaces JUST PRIOR TO GLUING.
Not allowing the wood oils to come to the surface. As we might suppose there may be an adverse oxidation on the wood surface that acts as a debond. This rings true to me - unscientifically.

Your vertical glueup won't pop off veneers when weight is put on it - which is what happened to laminations I've done.
The glue-up pressures in curved veneer lamination can be severe and glue can be squeezed out of the joint.
If you are laminating with epoxy you might consider a layer of cloth in the glue to preserve the glue line. The horz-lam beam in A338 is done that way. The vertical mode won't require enormous pressure.

You will probably be building up a baulk and cutting it out on a bandsaw.
You be able to see the insides of your glue lines to see how well you did.
You also will be encapsulating the beam in epoxy, which will go a long way to stabiliizing it.

For resorcinol you'll want freshly milled surfaces to start and perfectly sustained temps. Lots of clamping pressure.


Why not use trenails instead of screws - expensive screws - to marry the glue-up together.
Drill holes through the completed lamination and glue in white oak DOWELS. 5/8" D comes to mind. Drill the holes thru face to face.
Ebb would skew the holes slightly in various directions so that there would be no way the laminations could come apart. You'd never be able to drive a sharp chisel into a glue-line to see if it would pop loose.
Wouldn't happen. Trenails, better than screws. whatdoyouthink?

Have to turn your own dowels probably. Or 8 side square stock and hammer through a die plate. I think the key to using epoxy successfully on white oak is freshly prepared surfaces and 100% solids epoxy. NO solvents. No solvent prep of the wood.
Since there are so many variables there is no guarantee that it will be successful.

Bronze screws will look better in those coamings!
__________________________________________________ __________________________________________________ ___________________
Have to add: I glue many pieces of wood together using laminating epoxy.
Saturate surfaces, then wipe them 'dry'. The glue is epoxy mixed with fumed silica. Use the wet out brush to apply the fairly stiff gel. You can get pretty even coverage by smooching it around.
You cover both faying surfaces. When you press them together it is impossible to squeeze out all the gel glue.
You have a glue line and successful bond. In other words you can't glue with plain jane liquid epoxy.

I have never had a failure (but never used it for curved lams) with Smith & Co's All Wood Structural Epoxy. (google this: Oak and Teak Epoxy Glue - You Can Depend On It ---smithandcompany.org) It is a 2-part viscous thick material formulated for gluing wood to wood. There is a Steve Smith style tutorial immediately available on the website telling you how to use his glue. It's probably expensive - don't know about S&H.
Won't recommend System 3 - T-88.