Todays shop time.

[kenlip]

It would be a simple and interesting experiment to conduct.

Cut a sheet of ply (an off-cut will suffice) into 3 pieces. Use Titebond-3 glue to glue two of the pieces together with the grain of the outer layers parallel and the third piece with the grain at right angles. The two joints will have been made using the same wood, same glue and same clamping pressure. Once the glue has set, try to break the joints. It would be nice to be able to devise some way of quantifying the force needed to break the adhesion.

My guess is that the perpendicular pieces will give way a long time before the parallel ones.

I have neither plywood nor Titebond, otherwise I'd do the experiment myself.

Ken

 

[kenlip]

daugen,

I did a quick Google search and found this.

Plywood Edge Glue Expt - YouTube

What he says at 3:15 seems to confirm what I am suggesting.

I agree with you that the box will be fine. The triangular bracing 4570man glued into each joint is going to significantly increase the strength of the box. They provide lots of long-grain adhesion which, with modern glues will be incredibly strong, as you say.

Ken

 

[daugen]

Having built many small birdhouses and feeders from scratch, I am reminded of
a very well known quote of Aristotle:
The Whole is Greater than the Sum of its Parts.

Strength comes when it's all together, not from just one seam to the next.
I think I remember telling my wife once will you wait until I'm done....

Somewhere in my barn I have a home made weight box I built for my Gravely garden tractor years ago.
Heavy oak construction. Lots of glue and bracing and I really wondered if the bottom would fall out when I loaded
400 pounds of weights in there. Nope, though when it did fail from not being secure enough used on the front of a tractor out in the field,
it failed not at a wood joint but at the stress line. Wood snapped on the hanger part. When I rebuilt it, it was modified with steel plating
over the hangar. That's when I learned just how strong that glue was. Not from the birds in the birdhouses...

 

[kenlip]

Having built many small birdhouses and feeders from scratch, I am reminded of
a very well known quote of Aristotle:
The Whole is Greater than the Sum of its Parts.

True. However, Thomas Reid, in his Essays on the Intellectual Powers of Man, 1786, tells us that A chain is as strong as its weakest link

I guess, on the intellectual scale, Aristotle probably trumps (seems weird using that word too denote something good ) Reid, although Reid makes a pretty strong argument :thumbsup:

I agree with you about the strength of modern adhesives. I have done the test. I glued two boards (solid wood, not ply) together and then broke them apart. They separated by cohesive failure of the wood rather than adhesive failure.

 

[4570Man]

I glued it up that way because it was the only way the pieces would fit together and form a large enough panel. Really it would have worked with only 2 sides, but I wanted 4 to contain the dirt. One thing I did learn is plywood joints hold a lot more glue than a solid wood joint. I used titebond 3 for this project because again it was all I had. I prefer 1 or 2 because they'll wash out of your clothes.

 

[daugen]

sounds like we've got that quite covered.
And I just learned something new, having Titebond 1, 2 and 3 lined up in my shop.
Didn't realize the first two were more "washable". Not that I should be using any of this stuff with nice clothes
on. Titebond 3 must have some extra ingredient like epoxy in it.
Plain Elmers yellow glue for inside stuff, nicely washable.

Wish they would develop a better glue dispenser, one that sucked the air out or whatever would prevent glue hardening.
By the third or fourth time I'm in that bottle, it's beginning to get unhappy and I'm looking for wire to poke in the clog.
I know you can buy better bottles aftermarket but it would be nice if Titebond would provide something better than a ketchup bottle.

 

[4570Man]

The clear tip pulls off the lid for cleaning. I think it's pretty trouble free and works pretty good. I had some gorilla wood glue. The glue worked fine and wasn't like that other foaming crap they made. The bottles are awful though. They're too stiff to squeeze once they get more than 1/2 empty.

 

[bigtiller]

Wish they would develop a better glue dispenser, one that sucked the air out or whatever would prevent glue hardening.
By the third or fourth time I'm in that bottle, it's beginning to get unhappy and I'm looking for wire to poke in the clog.
I know you can buy better bottles aftermarket but it would be nice if Titebond would provide something better than a ketchup bottle.

I gave up on bottles for that reason. I take the cap off and pour some out now.

 

[kenlip]

One thing I did learn is plywood joints hold a lot more glue than a solid wood joint.

That makes sense, given that approximately half the surface is end-grain, which sucks up the glue. One would want to be very liberal with the glue to try to prevent glue starvation in the joint.

I think we have pretty well exhausted the plywood gluing question, but I have another question for you - how are you planning to use the box? From the size of the wheels I would assume that it's not going to be wheeled on turf or gravel. Are you going to wheel it to and from the woodshed/pile on a paved path? ; Do the outdoor carrying with pallet forks? ; Other?

 

[4570Man]

My wood shed is 2 miles from the house. I load wood on my truck and haul it to the house and stack it in the garage. From the garage to the stove is about a 30 yard trip across tile and hardwood. That 30 yard trip is all the cart will be used for. And the wood sheds a lot of dirt in the house. I hope to contain most of that. I know it's not the most efficient setup ever, but it's about the best of my options.