GT, what are you sanding? The tiny scratches I see in the pic is nothing that a decent primer wouldn't fill in.
Just noticed this thread come back up and thought I'd follow up on where I ended up.
Started out with a hacked up narrowed stock hood that had zero support underneath, had been narrowed 16" in the front, a cowl scoop rivited to it, was paper thin and would have flapped in the breeze if I tried to run it. All I had was a shape.
So that got covered in 3 gallons of bondo and sculpted into something that didn't look like Dr Frankenstein had a hand in it.
Then the hood was pulled off the Jeep and the sanding began to get it smooth. This is where I stopped using bondo and started with glazing puddy or paste or whatever it's called.
Once the shaping was finished and the surface was smooth, it got shot with Duratec surfacing primer and sanded out to 2000 grit. The Duratec is made for mold making. It's almost like a gelcoat.
Once the surface was as smooth as I'm capable of, I added flanges around the perimeter and used molding clay to make fillets to remove the sharp edges. Also used the clay to fill in the bolt holes where the hood hinges go.
Then the hood got a final cleaning, 6 coats of parting wax, 2 thin coats of PVA release agent and the shot with 2 coats of tooling gelcoat.
Didn't get any pictures of that process............was kind of busy.
After the gelcoat was still tacky but wouldn't stick to your finger, I started to lay up the fiberglass. Total of 20 layers with polyester molding resin.
Added some pieces of 2x4 to give it some more strength and allow it to not rock around when it's upside down. When I was done, I mixed up a little resin with styrene and gave the whole thing a thin coat. The styrene floats to the surface and seals it from the air, allowing the the mold to fully cure.
Let it sit for 24 hrs to cure and then popped the hood out of the new mold. It actually popped out with no issues. Wasn't expecting that as I've never done this before.
New mold. Very happy. Very surprised.
The reason for the scoop is because it will actually be a functioning cowl induction intake. Air box will still need a bit of work to seal it off from the engine compartment once an actual hood is made.