[JoeC]

Greetings all,

I have a table repair I'd like to solicit opinions on. This is a cherry trestle table built in 2002. As you can see from the pics, one of the joints has visibly opened creating a concern the joint might fail. This has opened largely due to my moving from San Diego to Hawaii two years ago, that is, from a dry to a relatively humid environment, although it had opened a bit prior to moving. The joinery is a large mortise and floating tenon. All other joints show a bit of movement, but nothing like this one. That particular piece of flat-sawn cherry just swelled much more than the others.

So the biggest question is might this joint fail? The table support a 3/4" thick piece of glass that probably weighs the better part of 100lbs. The glue used was Titebond Original wood glue, which has some ability to tolerate this kind of movement. I am concerned about this, but after 12 years, seems to me it would have failed by now if it was going to. Thoughts?

My choices are (I think):

-Do nothing. This of course implies the joint won't fail.
-Saw the leg off and redo the joinery - which would be a little project all by itself and not easy with an assembled table.
-Do something to fill the gap - which would be for aesthetic purposes only - and then reinforce the joint with a butterfly dovetail on both sides. This would provide some reinforcement and be an interesting little detail.

Thanks very much for your thoughts and opinions,

-Joe

Sorry for the inverted images; import kept flipping them!

 

[ryan50hrl]

I think you need to repair it......as that top is heavy and the risk of it breaking is real. So if you were to flip it over.....can you coax it back into place with a clamp or ratchet strap?

 

[woodnthings]

glue failure in my opinion

While the pictures are small, no close ups, it's likely a result of the glue failing...why? dry joint? wood movement? both?

It looks like a really nice piece, so I would take the time to remove the top and then remove the leg portion. A little heat from a hair dryer will help soften the glue. This may help:
http://www.ehow.com/how_6241558_remove-titebond-glue.html

The problem is the weight of the table and anything placed on it will spread the joint further without a serious repair, it's just the way the forces are acting upon the joint. Go for it! :yes:

 

[cabinetman]

Doesn't look like glue failure to me. It appears to be an expansion due to changes in moisture content. I would remove the glass and turn the table over and physically move the wood by hand to see if there is any slop. If there is and the joint moves freely, then I would address a repair.

.

 

[woodnthings]

I' stickin' with glue failure...

Because there is no corresponding condition/failure on any of the other legs. I could be wrong, regardless, a serious repair is in order.

 

[Steve Neul]

It looks to me like expansion has caused glue failure. If at all possible I would try to take the joint apart rather than cutting it apart. You would loose the tenon if you cut it apart. I believe I would take the leg off of the table and clamp it to a work bench and work the leg back and forth and see if it will let go. Since it has been glued once I would re-assemble it with two part epoxy.

If it just won't come apart you might work some epoxy into the joint and clamp back in place. Then after that dries on the underside where it doesn't show machine a slot for a spline.

 

[warped wood]

I would be worried about it as well, if you can draw it back together i woud put in matching butterflies on all four joints in contrasting wood. Make it part of it

 

[Greg in Maryland]

How much strength does that glue joint provide anyway? It looks like an end grain joint and based on the original posters description, it is really held together via mortise and tenon.

Greg

 

[JoeC]

Thanks for all the replies,

The joint is not loose at all and seems to have plenty of strength. That is, I can't wiggle or move it at all, nor clamp it to try to close it. As best I can recall, I used a floating tenon that was 4/4 thick, 4" wide or so, and I want to say 4" long - which means it went into a 2" deep mortise on each piece. All that adds up to a lot of glue surface. It could be the joint has in fact been compromised on the open side, but is still solid where the joint is tight.

I hadn't though of a spline along the bottom - I like that idea. I could flip the trestle over, clamp two boards along the concave curve to provide a flat platform for a router, and cut a grove of my choosing. Mill a spline to fit and glue it in place and no one will ever see it, and it'll provide additional strength for all of the pieces that intersect there.

I'll see about taking a higher res closeup tomorrow,

-Joe

 

[JoeC]

Here's two close-ups:

 

[JoeC]

Two more, one of the whole table, and then the other side:

 

[JoeC]

I'm planning to get some help to take off the top, then again asses if that joint is loose at all. The last time I did that, it wouldn't budge, so I attributed its current state to that particular leg and wood movement. More to come, and thanks for your responses.

-Joe

 

[ryan50hrl]

If the loose tenon is that big.....and your unable to move it in there...I don't know that i'd cut it apart. I think if it was me at this point i'd monitor for any additional movement.

 

[Steve Neul]

Ryan50hrl may hava a point. The joint has failed but it is still too tight move by hand. You might someday be able to get it all the way apart if you let it loosen on it's own.

 

[2lim]

If you can't wiggle it, I would not disassemble. If you are worried, maybe use a syringe and some CA glue to fill that crack, as the CA will harden in the gap and lend a little support.

Simon

 

[JoeC]

So here's an update. I finally got help moving the glass and took the table into my shop, flipped it over and clamped it in my vice. I tried to move the leg back and forth by hand, but it would not budge. A few taps with my heaviest dead blow yielded a different result and the leg started to move. A few more taps moving it back and forth and it came free:



It looks like there was plenty of glue; the joint simply failed for whatever reason. The fit is good and snug, so not sure what else to say? The tenon seems solidly glued to the upper leg. I tried to get it to move with my dead blow and put a clamp on it to lever it, but no movement. That glue joint still seems solid. I lightly sanded the exposed tenon and the mortise. The pieces now go together with a bit of wiggling. What's the best glue to use for this repair? A two-part epoxy was mentioned. That suggests West Systems or System Three.

I also thought i might dowel pin the leg onto the tenon from the inside face as an extra measure, but only if I think my glue repair might fail!

-Joe

 

[cabinetman]

I would use a slow set two part epoxy.

.

 

[Steve Neul]

I agree on the two part epoxy. I don't think I would dowel the tenons. It wouldn't add enough strength to merrit doing it and would make the joint more difficult to get apart if the time comes the joint failed again.

 

[punkin611]

This IMO is a case of using the wrong glue. The glue(titebond) used has a soft glue line. If hot hide glue had been used it's hard glue line would have helped support the joint. This is one reason why period furniture makers are going back to the old tried and true methods. Plus you could repair it over and over with hide glue with no problems. The weight of the top and constant end grain stress contributed to the failure as well as the layout of the joint.

 

[Ange]

if you can pull the joint together and epoxy it, you can rout a grooove across teh bottom of the legs in the "valley" and insert a spline that is pinned especially to each leg and a couple near the middle near the joint. This would be invisible when the table is upright (preserving the aesthetic) as well as make the legs work against one another in order to fail in the manner they have. Might be a good idea to go ahead and do the other side while your set up if this is the method you choose.

-Ange