paul34 said:So, why are gelcoats used on boats and "automotive" paint used on cars?
Why isn't car paint used on boats, or by the same token, gelcoat used on cars?
From my knowledge, on a brand new boat, the gel coat is not sprayed on, unlike cars.
When a fiberglass or carbon fiber part is being made, a MOLD is need.
The first layer to go into the mold (to line the mold) is the Gel-Coat, since GC is the outermost layer of a boat or carbon fiber items, or any gel-coated items.
The interior surface of the mold determines how smooth and shiny the finished product is.
Therefore, it is common for the mold's interior surface to be micro-polished to varying degrees of smoothness and reflectivenes.
If the mftr wants the final product (boat, fiber glass items etc) to hv a highly refined, ultra smooth, super glossy look, he'll need to perform extensive micro-polishing of the mold's interior...and then apply that 1st layer of gel coat. It's like a cake baking tray, and then lining that tray with butter etc !LOL!
So, when you look at a boat's surface, how flat and refined the finish is, depends greatly on the quality of the mold.
Example: The mold used to make budget plastic, matte-look toolboxes does not need to be micro-polished.
The transparent, super clear HDPE or PET bottles used for shower gels wil require a mold that has been micro-polished.