Are Your Glue Joints Repairable?

[SolarYellow]

Came across this when googling with regard to epoxy fillets over Titebond fin attachment. Thought I'd share it, since we do tend to break things and then want to glue them back together around here.

https://sawmillcreek.org//showthread.php?21822-Are-Your-Glue-Joints-Repairable

Bob Smalser
2/7/23, 12:55 PM Are Your Glue Joints Repairable?

The results offered no surprises.
The epoxy thoroughly adhered to the strongest of the off-the-shelf glues, the 2-part resorcinol, breaking
completely at the wood rather than the glue line. Attempts to slip the chisel between the glue lines
revealed a thorough and unified bond between all three layers of glue.
Epoxy on epoxy showed similar results……and so did liquid polyurethane (Elmer’s Ultimate)…
…and powdered urea formaldehyde plastic resin glue.
Titebond, a Poly Vinyl Acetate glue, however, broke some wood but failed the chisel test…. the chisel easily
separated the two layers of Titebond, indicating poor adherence of the epoxy in between.
Titebond II broke even less wood, with poor adherence…
…and Titebond III, while a much stronger glue, still did not adhere to the epoxy.

He doesn't address it, but there is discussion here and elsewhere about PVA glues not sticking to PVA glues after the first layer is dry.

I was thinking about epoxy fillets over PVA because I hate doing fillets multiple times with shrinking PVA to get a buildup. I want to be one and done on that task.

 

[neil_w]

Is anyone surprised that Titebond didn’t adhere to epoxy?

 

[Alan15578]

Is anyone surprised that Titebond didn’t adhere to epoxy?

No, but then you also need to ask about PVA bonding to sanding sealer, primer/filler, paint, etc.

 

[JimByrne]

I use only epoxy for fin attachment and fillets