Better joints for my pallet wood cold frames

I've been making stacking wooden frames from pallet wood.
So far I've used screwed butt joints,predrilled to
I want to trade the ease and simplicity of these joints for something more time consuming and complicated,  but cheaper and stronger.
My idea is to use mitered joints with screws.
The screws would be driven perpendicular to the miter.
I hope to be able to use shorter screws, fewer screws and avoid screwing into end grain.

I think might be a good trade off.
I'm already cutting the boards to length,  so cutting miters shouldn't be too much extra work.
I think I can build a jig to make driving the screws simple and easy to repeat.
I'm just not sure if the joint will be strong.

Depending what you're using the frames for, it may make more sense to put a piece of ~1"x1" material vertically in each corner. Such pieces could be ripped out of the (denailed) structural pallet boards and would probably yield more in terms of strength/rigidity than any joint you could do directly between the ends of the pallet surface boards.

Em suggested exactly what I was going to say.  Some scrap 2x2 wood or the like would hold it together nicely.  And if you wanted to stack the frames, the chunk of 2x2 could sit lower so that it can index into the frame below it.  If that's a need...

Mike Haasl wrote:Em suggested exactly what I was going to say.  Some scrap 2x2 wood or the like would hold it together nicely.  And if you wanted to stack the frames, the chunk of 2x2 could sit lower so that it can index into the frame below it.  If that's a need...

Yep, third vote for this.

If you try it and still want more strength, a pair of triangular pieces, or short braces at 45 degrees on each end, in every corner would be my vote.

A wise consensus has emerged!
Without a tablesaw,  I tend to avoid rip cuts, but the principle remains sound even if I use 2x4 chunks.
Come to think of it, I have some skid lumber with sections approximately 2x2, good enough.

I've used scraps of sheet metal (either recycled from garbage or small scraps that haven't much potential) to make simple brackets which I've screwed on. Not super strong, but avoids the "end grain" issue.
So if you run out of 2x2 sized stuff but can find free sheet metal, it's an option.

Jay Angler wrote:I've used scraps of sheet metal (either recycled from garbage or small scraps that haven't much potential) to make simple brackets which I've screwed on. Not super strong, but avoids the "end grain" issue.
So if you run out of 2x2 sized stuff but can find free sheet metal, it's an option.

Old drinks cans cut up?

Looked it up. It is called “wood welding”.

Maybe not quite right for this purpose, but still pretty neat.

Michael Cox wrote:

Old drinks cans cut up?  

I would have thought that would be too thin, and I find "tin cans" rust really quickly, whereas galvanized sheet metal has coped well in our wet climate. I went and took a picture - I'm using the full depth of the pallet, cutting it off at the first "stringer" and in-filling any gaps that dirt would fall out of on the front face. Then I fit salvaged 2x4 into the gap between the front and back of the pallet, and that's what I've screwed the bracket to. These things are heavy and solid and I can stand on the edge if I need to.  With the exception of a little hardware, they're free, but a lot of labor. I even re-use nails from the skids I take apart for the infill bits, so I've only needed to use a few new ones.