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Abrase surfaces with 80-120 grit sandpaper to areas
Mix and bond materials together
Consider adding creating tooling wherever-means-necessary to help bond it together together
Screws Knowledge-dump:
consider adding torque strips - that way when screws come-loose it visibly shows up on-the-part
Male versus Female Mold:
Male molds are better for when you want the out-side of your part to look nice, for example for the aero you want the outside of the car to be the “A” side to decrease drag so you use a female-mold
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