Reply To: Workbench Top Delaminating
No. I thought you had separated the top and planed off the glue as I suggested in my first post. Just putting glue in the joint is not a good repair. PVA (poly VINYL acetate) glue when cured is a plastic. When it dries and the polymer chains cross link not much sticks to it well, including more glue. You have to get down to bare wood before you reglue for a full strength joint. So on the worst joint I see, saw it apart, plane it so there is no glue left and the joint is air tight, then reglue and clamp.
The joint that only has a little separation can be clamped and the keys inserted to prevent further separation. You can squirt some glue in there, but it won’t do much. Most of the holding power will come from the keys.
Also PVA is not gap filling. It works best with air tight joints and good clamping pressure. And although it is common practice to clamp for a couple hours, titebond really suggests clamping until the glue has completely cured. When I worked in a shop that usually meant overnight cure at temperatures above 50° F.. You can go a little cooler with titebond III (45°F) but I’ve never tried it.
With overnight clamping we never had a joint failure. Ever. My bench was laminated with Titebond II when it was still in the field trial phase 40+ years ago. Every joint is as tight as the day I put it in clamps. We used my bench because we didn’t want to risk failure with a client’s product..
I noticed in your first post you were concerned you clamped too tight (you can’t clamp too tight with PVA.) the way to tell you have enough glue in a joint it that a small amount will bead evenly along the whole joint. If some parts don’t bead out, the joint could be glue starved. If you get the amount right, you get a bead that can be cleaned off with a putty knife or cabinet scraper when it is partially cured- say a couple of hours. Don’t try to scrape or wash wet glue off, it just forces glue in the pores of the wood which will lead to finishing problems later.
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This reply was modified 2 years, 7 months ago by
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This reply was modified 2 years, 7 months ago by
