Edge gluing problem

[AZDude]

I just started taking a woodworking class this last week and my first project is to make an end grain cutting board. The instructor had me rip several strips of maple up on the table saw to get ready to edge glue, but told me not to run the strips through the jointer. He said that the glue "will hold better on the textured surface of the wood, than a smooth jointed edge." Is this true? His table saw left many saw marks down both sides of each board.

Secondly, when I hold the strips next to each other, they are not a perfect match with a few gaps here and there. Will the clamps overcome this, or should I go ahead and run the strips over the jointer?

Thanks,
Brent

[Black wallnut]

I'd personally question his knowledge. To a point he may be right but my glue ups are always very smooth and each successive piece exactly matches the one next to it. Requiring a clamp to close a gap may actually starve the joint for glue.

[dealweb]

I'd still run the pieces through the jointer to get a smooth and tight edge to put the glue on. If you have gaps due to the table saw blade then those gaps won't have a strong bond between the other wood piece. That and gaps show poor workmanship.

[Alex Franke]

I'd use a jointer, too. I think you want as many of the wood fibers touching each other as possible. Besides, you probably don't want any gaps in there either.

I believe the glue actually soaks into the wood a bit to create the bond. But if it turns out that a textured surface really is important, then couldn't you just make it straight with the jointer, then run sandpaper over it a couple of times to add the texture? (If you try this, then be sure to clean off all the dust.)

Here's what I don't get, though. Are you ripping the strips of maple just to edge-glue them back together? Or are you using different woods to form a pattern?

[poolhound]

Hi Brent, Its nice to see more Arizonans poping out of the woodwork (PUN INTENDED ) - where abouts are you?

While a good blade and saw setup can leave a very clean edge I would always tend to run even the best edge through the jointer for a vey light pass. If I can see any light through the two edges to be joined I would definatley joint the edges.

Yes clamps could overcome small differences but that does mean there is strain in the joint that doesnt need to be there.

[scmhogg]

Welcome Bret,

I learned that modern glues work on a molecular level and benefit by perfectly smooth matching edges. Gaps before glue up can be squeezed out with clamps. [and we all do it.] But, they will remain a stress point. With a cutting board the moisture will exacerbate the problem.

http://www.ces.ncsu.edu/nreos/wood/w...lity_panel.htm

Perhaps the instructor has not read the jointer chapter yet and. . .

[drumpriest]

I'll agree with everyone else here, the edge should be smooth. I did a cutting board recently and did not run them over the jointer, but my rips came out very smooth and there were no gaps. Clamps can overcome things like slight bows, but not really the small gaps caused by saw blade fluctuations. I would joint them if I had such gaps. Note that you should NOT joint end grain! Very dangerous, but for the long grain, go for it.

A rough surface is often referred to as haveing a mechanical tooth, but this is not good for wood glues. It is often needed to bond dissimilar materials such as metals to wood using epoxy.

[pecker]

For an application exposed to moisture, I would want the tightest joints I could get.

[LarryG]

Will the clamps overcome this, or should I go ahead and run the strips over the jointer?

Yes, you should. And while you're at it, joint enough extra material to glue-up a test section that you and your instructor can break apart and note where the failure occurs. (Hint: given proper jointing and good coverage with the glue, it won't be at the glue line.)

The photo below illustrates what a well-tuned jointer can achieve, and is example of what you are looking for prior to doing the glue-up. My thumb and forefinger are just BARELY touching the outer two pieces in the stack, applying only the slightest whisper of pressure needed to hold the various faces against each other. The goal, as seen here, is to make it hard to tell exactly how many individual pieces of wood make up the assembly:

[cabinetman]

I joint mating edges smooth to be glued. Serrations or deformities of any kind can trap air.
.

[Tom Slick]

I always thought the name "jointer" was to prep for edge glue-ups.

[AZDude]

Thanks for the info. I was pretty sure that I needed to run them through the jointer, but I just wanted to make sure. Thanks for the reassurance.