If I need to use aluminum sheeting as form for pouring concrete or another cement product, such as mortar/stucco, is there something (chemical) I can coat the sheet metal with so the cement doesn't stick to it?
I know this is late, but I'm pretty sure you could get away with PAM or grease for releasing aluminum from concrete. Commercial release products are an assortment of commonly used items like mineral oil, or silicon lube, or graphite; less common are metal stearates (like zinc stearate in a can). I have played around with zinc stearate. I still have some that I should proably throw away, since I don't really have a serious need for it.
Check with one of your local building supply stores that cater to concrete contractors and see if they have release agents. They do sell release agents that you can spray on any type of concrete form to help the concrete release from the form. I've heard of using powdery substances on your form before pouring the concrete can help the concrete to release as well.