Repair fridge door shelves

Question

Our fridge has two white plastic shelves on the door. Both are cracked in the bottom - one just around the center, and one where almost the entire bottom has cracked along the front. I'm not entirely sure what kind of plastic they are made of - I'm guessing polystyrene because they have PS stamped on the bottom, but that's just a guess. They are off white plastic.

I've looked up replacements for them, but they are more than I'm willing to pay.

What's the best way to repair them? I've seen plenty of questionable methods searching for solutions, but no good ones. I'm not sure what kind of (easily available, something I can pick up at a big box store) adhesive I can use to glue them back together, that will hold under the weight of things we put in the shelves.

I'm guessing superglue and hot glue won't work at all. I considered wrapping the whole thing in white duck tape...but the wife acceptance factor on that solution is quite low :) Perhaps JBweld epoxy?

Answer 1

Plastic models are made out of polystyrene. The cement that is used to glue model parts together melts the parts and forms a weld. It is not an adhesive and actually works much like PVC cement. Applied properly what you wind up with is a solid weld rather than a glued joint. Use sparingly.

Answer 2

You can try to glue it, but not using a glue on the edges, but use some other plastic part (made from similiar material) and glue it like a reinforcement. If Your shelves are simple horizontal-positioned ones (non-curved surfaces), You could just make it like on this site here.
If Your shelves are shaped, You can try to use something like platic straps and glue them along the shelf, reaching before and after cracks (glued, of course). How many of them and what distance - try to figure it yourself.
Every attached materials (these additional plastics) are to be glued on 'exterior' surface, so the surface that has contact with stuff has former shape.
Surfaces, that will have contact with glue, need to be clean (use detergent to remove any fat/oil stains).
Using similiar plastic material (or close to this used in original part) will ensure that it will not crack from different deflection in changing temperatures.