Best joining method for end-to-edge butt on particle board shelves?

[jayrdub]

I'm building shelves using 3/4" melamine particle board. The shelves are 16" wide in an inside corner of a closet (making an L). Along all surfaces I'm able to set the shelves on 1x2 ledgers except where one shelf butts the other on the inside corner. I'm wondering what is the best method for joining it. I haven't worked with particle board much, so I don't know how well dowels, biscuits or pocket holes compare. Obviously the most important thing is withstanding sheer down-force on that inside corner, so what is going to be the strongest?

Thanks, Jeremy

forgive my use of inches, my government doesn't allow units of measurement that make sense

[silentC]

If you want to make a really good job of it, frame the whole 'L' up using 1x2 and then just sit your particle board on top.

Like this:

+------+
|......|
|......|
+------+
|......|
|......|
+------+------+------|
|......|......|......|
|......|......|......|
+------+------+------+


16" is a pretty wide shelf and I think you will get some sag in the front anyway.

[jayrdub]

If you want to make a really good job of it, frame the whole 'L' up using 1x2 and then just sit your particle board on top.

Like this:

+------+
|......|
|......|
+------+
|......|
|......|
+------+------+------|
|......|......|......|
|......|......|......|
+------+------+------+


16" is a pretty wide shelf and I think you will get some sag in the front anyway.

The shelves are for a kitchen pantry. Do you think that 16" is too deep?
The L is about 3'x3'. Even at 8' lengths the 3/4" PB seems really stiff, but does it sag over time or something?

[Papa]

3'X3' I would just make the whole thing one piece. And I would not
use PB, MDF or ply would be a much better choice.

[silentC]

OK, 3x3 is a different story. Yes I would probably do it with one piece. Melamine chipboard is OK, most kitchens here are made from it but you might heed Papa's advice on that seeing as he would know your materials over there better than I would.

Pantry shelves like that would usually be cut from a single 3' square. You can cut a curve instead of a square hole out of it to form the 'L'. But you would then need to use a flexible edge band (you can buy iron on edge bands).

Check here to calculate sag: http://www.woodbin.com/calcs/sagulator.htm

[jayrdub]

3'X3' I would just make the whole thing one piece. And I would not
use PB, MDF or ply would be a much better choice.

Why's that? I thought MDF was less rigid and more prone to sagging than PB.

The single piece sounds like a great idea though, hadn't thought of that. How would you finish it? I like the melamine on the PB for a pantry.

[Papa]

Just a nice coat of paint and some shelf paper?

As short a span as you have I don't think it will ever be a problem. Ours are 4'
supported along the back edge and have not moved in fifty years. They are ply
BTW.