Glued edge separating.

[mds2]

I need some advice to fix a problem. I have a table top where I have some walnut and paduk edge glued together. This has been sitting in my garage for a while and last night I brought it in the house to get the boss's opinion. Tonight when i got home I noticed that part of the joint had separated. How can I fix this? The top has been sanded but not finished yet. I would almost imagine that I need some sort of syringe to get glue back into the joint but maybe there is another way.

I'd post some pictures but I have no idea how to do that from my phone.

[rmac]

Without seeing a picture, it's kind of hard to guess what you're up against. That said, maybe this will help:

http://thewoodwhisperer.com/cutting-board-disaster/

I've also had good luck getting glue into cracks by kind of shoving it into the crack with a piece of aluminized mylar ... that's the stuff that some candy wrappers are made of. Looks like plastic on one side (usually the outer, printed side) and aluminum foil on the other. It's really thin, but strong enough that you can put some glue on it and then wrangle it into the crack without tearing the material.

Post a picture if you can.

-- Russ

[mds2]

Here is a picture:

[PaulMarcel]

Looks like you went cross grain on the glue-up; the Walnut grain goes left to right while the Padauk goes vertically in the photo. The step between the Padauk and Walnut on the split side indicates that the Walnut dried and shrank; that's a lot of sheer force to fight off especially for an end-grain joint like that. In a way, it could have been worse as it could have cracked down the Walnut. This you can at least cut the joint and do the attachment in a way that compensates for the inevitable wood movement.

[rmac]

Uh, oh.

I hate to be the bearer of bad news, but based on your picture it looks like there are two things wrong with this joint.

1. With changes in humidity, the walnut is going to want to expand and contract across the grain. In the picture, that means that the distance between point A and point B (see my picture) is going to vary with the seasons. The padauk, because the grain is running the other way is not going to expand and contract as much in that direction. In other words, the distance between point C and point D isn't going to change very much. So what you have is a joint that's going to try to tear itself apart every time the humidity changes. From what you describe, it has done exactly that for the first time already, maybe because your house is more or less humid than your shop right now. In fact, it looks from the picture like the walnut has shrunk a little bit, which would say that the air is drier in your house than in your shop. Is that a good guess?

2. The other problem is that it's generally not a good idea to try to glue to an end grain surface. In this case, you're gluing the long grain of the padauk (which is fine) to the end grain of the walnut (not so good).

So, unfortunatey, I don't think that regluing the joint is a good long-term solution. Can you post a picture of the entire top so we can get an overall view of what you want it to look like? That might make it easier to come up with a more useful suggestion than, "Don't do it the way you did it."

-- Russ

PS: I don't know if padauk is one of those exotic oily woods or not. If it is, then you may need to take some extra precautions to get a good glue joint with it, even after you have solved the wood movement problem.

PPS: How did Paul-Marcel manage to say the exact same thing in about 1/4 the words?

[mds2]

Wow, that is a lot of very good information. Thanks! I guess I'll chalk this one up as a rookie mistake. This morning I noticed the same sort of cracking on the other side. So I guess this will give me some more experience making another top. Lesson learned and now I know what to do and not to do in this situation in the future.

Here is a picture of the full top. I had some scrap pieces that I wanted to do something with so I tried to make this table top a little more interesting

.

[jsiard]

I think the best way to achieve the look you're after with the opposing grain/species patterns would be to create the look with veneers. Route 1/8"-1/16" deep dado then glue the veneers in place, the thinner the better. The veneers should move far less but will still move. Once the piece is glued up I would try to saturate the top with finish to try and slow the movement as much as possible. My $.02 worth.

[Bobby Slack]

If I would do this table top from scratch when I do the crossgrain joint, probably a sliding dovetail joing will allow both species to move and not crack ... what say you guys?

[dwacker]

The only way I'd do this is with all veneer on a stable substraight.

Don