I used a hot glue gun to glue together two pieces of material to machine one side, but I can't figure out how to release the bond without using heat, for fear of warping one of the pieces. Anyone have any ideas?
The hot-melt I've got is polyethylene-based, not many solvents will attack that. Aside from freezing it, how about using oil, dunk the whole assembly and heat it up? Another use for that french fryer and used fat/oil that's been floating around recently in another couple of threads. Stick it in the fry basket cold, let the oil warm up the whole thing evenly. I'm assuming your project is small enough to fit in a fry basket.
Brownells had a kink in their newsletter where a guy had hidden his new Beretta in an oven and the plastic case had melted around it when the oven was heated up for pizza. The case remains were removed by using a french fryer and hot oil. No damage to the gun, even the grips were still good.