I'm about to make headlight moulds out of concrete, but I've never used the stuff before.
I've been told by someone who has done this before to use concrete because the mould (plug actually?) will last a lot longer.
I'm making clear lenses for a car that you can't buy clear headlights for. It's for a bi-xenon HID projector retrofit.
ANYWAY, the plan is to coat the inside of the glass lens with lithium grease, pour concrete in, drop in some rope. When it hardens, use rope to pull it out, clean off the lithium grease... then cover in bondo and sand to smooth out the indents left in the concrete by the fluted lens. Then compression form new lenses out of acrylic by putting it in the oven until it sags, throw it on the concrete and use a MDF ring to compression form a new lens.
SO yeah. That was more info that you guys probably needed, but I have no idea what to use for concrete. I don't need that much. When I go look at concrete they have like sand, concrete, mixers, and a bunch of crap. It should be pretty easy to figure it out, but I look at it all and go... whaaaaaaaaat???
