Bench repair

[zdorsch]

All of the leg assembly has come loose on this bench. It sees a lot of use at a university ministry centers.



It appears as though someone has tried a repair before and used polyurethane glue and used pocket hole screws to reinforce the leg to seat connection. The glue did nothing and scrapes off fairly easily. The pocket holes have held the legs to the seat and probably kept the entire thing from collapsing.

Would epoxy be a good choice for all of the joints? I have some 2 part epoxy leftover from replacing the tires on my band saw (Hi-speed cement). Or should I just use titebond 2/3?



Thank you for suggestions!

 

[Mike Davis]

Oh my! The terrible, horrible, nasty things people do!

By the time you clean all that poly glue off the parts will be too small for hide glue, it’s not gap filling. You could do foxed wedges but the tenons may be destroyed by those screws. A real conundrum.

 

[Wiley's Woodworks]

Step 1 is to clean off all of the old glue from every piece. Then assess what you have left. I'm with Mike: after you're down to bare wood on male and female pieces, the gaps are probably going to be too big for almost any glue to work. Wood glues are meant to absorb into the wood pieces being glued, not as filler. Slow set epoxy would be a long shot, but it has its own set of problems when you get to clamping wobbly fittings.

Perhaps you could wrap and glue veneer around the tenons and get a snug enough fit to glue the joints back together. I would reuse the pocket hole screws as reinforcement for joints that will have to endure a lot of stress over time.

Another approach might be to drill out the mortises in the seat board (make sure you don't drill all the way through), and plug them. Then redrill appropriate sized mortises. Use Titebond III all around on this approach.

 

[Rwe2156]

My approach would be first assess how much gap there is. If it's not bad an gap filling glue like epoxy or urea resin would be the choice.

If the gaps are really big, I would glue a dowel in the mortise and redrill. This may require enlarging the hole or turning a custom dowel.

Regardless of how you do it, IMO the tenons need to be cross pinned with a dowel.

 

[old and in the way]

Zach:

You might consider cleaning the tenons and the holes, and glue everything back together with epoxy (not sure if what you have is the right stuff for the job). And then after the epoxy has set, go back and drill through the seat and the legs and the stretchers with a 3/8" to 1/2" drill bit, about 1-1/2" to 2" deep into the legs, and drive 3/8" to 1/2" grooved dowels with some glue into the holes, leaving the dowel a bit proud of the surface. Trim, sand, and paint.

FWIW.
Tone

 

[JNCarr]

Suggestion to consider --
Unless the bench has to be exactly that height, I'd consider making four rounded corner square blocks drilled to fit the cleaned up tenons. Saw a wedge slot into the ends of the tenons.
Set the blocks with screws (only - no glue yet) using the dry fit legs as a guide. Put a piece of blue tape on the bench prior to screwing the blocks down so the eventual glue doesnt stick to it.
Then glue the legs into the blocks while in place (hence the tape). Unscrew the blocks and leg set and drive a wedge into the leg ends - perpendicular to the block grain.
Glue and screw the blocks back in their original position. Stain/paint to match.
I think a pocket screw does nothing but weaken the end of the tenon.

 

[zdorsch]

Thank you for all the suggestions so far! And a quick update.

I had a chance to begin taking the bench apart. For the most part the mortises are fairly clean and only one tenon is messed up.



It looks like regular wood glue was used and the joint may have been starved.