Should I replane three week old edges before glue up?

[Kenneth Moar]

I got delayed doing a bench top glue up by about three weeks, now I'm wondering if I should replane everything to get a fresh edge before glue up. I did a little water test on the old edges vs a freshly planed edge , I didn't notice much difference. What is considered a fresh edge for glue up? Thanks

[Jim Becker]

If the material is straight and flat, there's no real reason to take off more material prior to your glue-up. If the material has moved since you last milled it, then yes, correcting those issues prior to glue and clamps is a "darn good idea".

[Prashun Patel]

To test a panel joint, I slide post it notes between the joint at various points and then dry clamp them with "moderate force". If I can't pull any out, I consider it good.

[John Kananis]

Use winding sticks on the top and edges, then check those two are square.

[Jimmy Harris]

I've glued up wood that wasn't touched in years before. And it held fine. So long as it hasn't warped, and you didn't put a finish on it, leave it outside to collect dust and calcium deposits, or something else to impede the penetration of the glue, it'll be fine.

Oxidized wood still glues up just fine. I've even use potassium dichromate to simulate 100 years of oxidation before applying glue.

[Michael Schuch]

What kind of wood?

If it isn't a species that is very oily you should be fine without planning the edges again. If it is a species that is oily wipe the edges with acetone before gluing.

[Kenneth Moar]

I'm gluing hard maple, no need for acetone on the edges. In the past I had a joint fail in Osage wood. should have wiped the edges with acetone then!

[John C Cox]

If the glue joints are structurally important, re-prep and glue. There is a giant difference in glue joint strength between freshly machined and old wood, even with the same geometry.

If not, meh. Just make sure they're clean and well fitted and off you go.

[Mel Fulks]

Here’s the pitch ! Unless the material has pitch , I would ‘be sure I’m right …. then,go ahead !

[Kenneth Moar]

Following up on my post, I did the glue up without replaneing the pieces. I'm going to guess that three weeks of oxidation or case hardening on the edges is not enough to significantly affect the joint strength of the PVA glue. If I learn otherwise I'll post about it.

[John Kananis]

It's really not. As long as everything was square when you put it together, you'll be fine.


Following up on my post, I did the glue up without replaneing the pieces. I'm going to guess that three weeks of oxidation or case hardening on the edges is not enough to significantly affect the joint strength of the PVA glue. If I learn otherwise I'll post about it.

[Mel Fulks]

I’ve used acetone , but I’ve been told it has some oil in it ! Pretty sure the info was good , and MEK is probably better. But haven’t
had any failures using the acetone . Probably won’t need any more at my age .

[Jim Morgan]

I’ve used acetone , but I’ve been told it has some oil in it ! Pretty sure the info was good , and MEK is probably better. But haven’t
had any failures using the acetone . Probably won’t need any more at my age .

Paint thinner/mineral spirits, particularly of lower quality, often contains some oily substance. But acetone? Acetone dissolves oil, so this seems like misinformation.

[Mel Fulks]

Paint thinner/mineral spirits, particularly of lower quality, often contains some oily substance. But acetone? Acetone dissolves oil, so this seems like misinformation.

Just googled and it says it’s derived from oil. The guy I worked for was careful about the big jobs , he had to be extremely
careful with specifications. I think a call to an Acetone manufacturer would confirm his caution.

[Prashun Patel]

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.

[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.