Excuse the broad terms.

What type of material/metal are the rear outer fenders (visible) made of?

What type of material/metal are the rear inner fender (not visible and attached to the outer panel) made of?

How are they held together? I can see there is some type of white colored glue/caulk/epoxy that seals them together. Is this just some type of waterproof sealant? Can I buy this at home depot?

In order to make my wheels fit, I needed to cut my fenders (i did not want to roll them.) I needed to go so close that the inner and outer fender panels separated in one spot. Im thinking I need some type of sealant/glue and a few rubber clamps and im good to go. What do you guys think?