Glue for Dado Joints in Prefinished Ply

Yellow glue is effective for dado construction using prefinished panels. August 29, 2006

Question
I'm going to try some prefinished plywood on an upcoming job and was wondering which glue works best in the dadoes.

Forum Responses
(Cabinetmaking Forum)
From contributor A:
Your question is confusing. If you use dado construction then your glue joint is wood on wood and not any different than it would be if the plywood was unfinished. You should be able to use whatever you have been using. In our case that is yellow glue.



From the original questioner:
I've always sprayed the insides after they were together, so I've never had finish on the face side(s), or the edges in the dado. My logic always told me that I had slightly more holding power since I had an edge and two faces without finish, since in a tight dado some of the glue squeezed out onto the faces in that dado. Maybe my question should have been is glue just on the edge and the bottom of the dado good enough?


From contributor B:
Considering that the vast majority of people don't use dados or glue, you are pretty safe to go with both. I use a 46 tooth Amana dado set on Columbia prefinished plywood, then a little yellow glue here and there, and a few 1-1/2" 15 gauge nails to hold everything together until the glue dries. I like the dados for alignment, but most guys just screw with no glue. By the way, gluing the prefinished is a waste of time.


From contributor C:
Polyurethane glues will bond to prefinished surfaces if they are scuffed with sandpaper (100-180 grit). Note that this is not nearly as strong as a wood-to-wood glue-up but I've used poly glues for the occasional glue joint. We make our drawer boxes with a lock-shoulder dado, and the material is prefinished. But the joint is mostly wood-to-wood, and yellow glue does the job just fine.


From contributor D:
The yellow glue should work fine in the dadoes it does for us, as they are wood to wood. On the UV prefinished, when we have to glue something to it, we scuff with a used piece of 100-120 grit paper and then glue with 2P10 CA glue that we use on mouldings. It seems to be very strong - we have not had any issues yet and we've been using the prefinished for about a year now.