This is my first shot at stripping the paint off of a corvette and prepping the body. I have a 68 Big Block vette that I am in the process of restoring. Most of my experience has been with steel body restorations so please excuse my naivity relating to fiberglass bodied cars. Anyway I have razor bladed about a third of the shell and thought I would try a spot in regards to sanding. My question ultimately is how far should one go when sanding? Do you take it all the way to the fiberglass? After razor blading I have a reddish brown layer in some areas with a brown layer beneath it and just a brown layer in other spots. None of these two appear to be paint but rather a primer or sealer of some kind. Any and all help that anyone can provide is greatly appreciated!

Thanks!

Try to get all of the previous paint & primer off. Take it right down to the fiberglass. Then gelcoat it or at least seal it with PPG DPxx epoxy primer or equivalent.