Can anyone give me ideas on how to build a box that will open after a certain amount of time, like an hour or two hours? Or buy such a box even.

-JoeJoe

Geez, this could take hours. If it's a mechanical release you can have a mechanical timer. Anthing from a wind up clock work style trigger to a sand or water timer. If it's electro mechanical, then just use a 555 Timer chip or a one shot on delay relay timer to activate a solenoid release. The rest are just details.

Or how about a pocket remote and you just pop it open on command when ever you like?

A good idea. I have hundreds of RF remotes and use expensive commercial versions for hoists in our aerial shows but I would still trust a sand timer in most cases more. The simlest answer possible is frequently the best.

What about ice? Frozen shut... not sure what you are going for, but that is the type of thing that could melt during the show to release a prediction.

It's not actually for a show, I just need it for personal use ... is there no where you can buy such a box? The only thing I'm able to find for sale are full fledged safes starting at about $800, which is out of budget.

-JoeJoe