Step 3: 3. Tin Foil Layer

Picture of 3. Tin Foil Layer
I have seen some tutorials do this, and some not, it is really up to you. it is an added layer of protection from the resin seeping though to your carpet, and I highly suggest it. Use squares of the foil, taping and overlapping them as you go. You should now be ready to start the glassing.

Protecting the interior is very important as this stuff will not come off. I suggest placing newspaper, or drop plastic all around your work area. Also, if you like you can also put a sheet of plastic between your trunk and cabin to prevent fumes from getting in and stinking up the car for a few days.
sensoh8su9 months ago

Newspaper will do next-to-nothing against resin. Go with a plastic layer just to be safe.

almost forgot. If you know what your shape is going to be for your box, this is a good point to draw out the outer shape with a sharpie or other permanent marker. The resin will soak up the dried ink and leave you with a nice cutting line after you have removed the box from the trunk.
The foil layer is used as a mold release instead of multiple layers of wax. Polyester(fiberglass) resins don't adhear well to the coatings on foil. It also helps reflect some of the resins curing heat back into itself to aid curing.

Great write up so far.