Should I replane three week old edges before glue up?

[stephen thomas]

It's been years since i read deeply on this.
The FPL found that even a day open exposure made a (negative) difference to developed bond strength.
However, that report or ones near it indicate that at the ideal level, there is some chemical bonding of wood fibers among each other, facilitated/activated by the glue & not dependent on the film strength of the glue itself. Hence the old advice to hand shoot all critical joints with a sharp single edge cutter.

OTOH, I don't believe those old reports included PVA glues. Mostly hot hide glue and Urea type resins.

Most of us don't even shoot most boards off the (machine) jointer before gluing up into widths unless it is for a "special" project.
And they hold fine.
For years, industry glues up straight off the straightline ripsaws, and most of that holds up most of the time.

Personally, i would have taken a single pass over each edge just before glue up.
But i am obsessive, and a little bit superstitious.

smt

[Jim Morgan]

We use acetone in my industry as a cleaning agent and as a solvent for the analysis of organic compounds.

Acetone contains no oil. It may be derived from petroleum, but the final, reacted product does not contain any oil - and by oil I mean any hydrocarbon that won't readily evaporate and will remain on the wood, making the finish hard to bond to the wood.

Acetone is extremely volatile (this makes it flammable, and bad to breathe, but also evaporative). It is often used to dissolve surface oil and dirt so it can be easily wiped off. It is unique in that it is a very good solvent for both "oils" and "water based products", and evaporates quick and completely at room temperatures. These things make it great for removing dirt and impurities, but damaging to your body and finishes.

Mineral spirits and acetone are both organic (carbon-based) substances. Mineral spirits are a mixture of light-weight hydrocarbons, distilled from petroleum. Acetone is a specific molecule (C3H6O), most commonly chemically derived from natural gas. As Prashun notes, acetone is an excellent solvent for preparing glue joints with oily woods because it evaporates quickly, leaving no residue.

[Mel Fulks]

Thanks for new information. Might just call that old boss and tell him to go back to school . But I do think he must have found some
archaic , or just plain nutty ‘ home-made’ info.

[James Schmidt]

I ran a glue panel press in an industrial wood processing plant for several years, we had wood that sat on pallets for weeks and sometimes months before gluing. As long as the boards remained flat and square, the 'old' boards glued just as well as the recently milled boards.

Unless there was some movement in the wood from sitting, I would not bother cleaning up the glue edges.