Mr. G. Brettin's Slow Motion Leg Hump

madwi

When you get good at sanding try your hand at finishing a plastic injection mold for clear plastic part like a headlight. I never had the patience to sit there but the guys would sand with 220 and work up to a finish with Charmin toilet paper, and it had to be charmin.

gbrettin

I have a buddy that polished metal die sets for injection moulding. He said that the metal had to be absolutely mirror finish perfect and would spend weeks sanding to absurd high number using diamond paper. THAT would be terrible. He said that he would find flaws for some reason or another late in the process and need to kick the part back to milling. That meant starting over.

JLarson

Less text, more boost noises!!

Looking good man. Cool to read about a different kind of fab project than normal.

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2014 370z Touring Sport Magma Red MT // BP Single Turbo 6467 // 63mm TB's // Z1 Ported Upper Mani // RJM Pedal // Zspeed Stage 3 Clutch // 526 WHP, 451 WTQ
2006 350z (Sold) // 1990 300zx (Sold) // 1985 300zx 2+2 (Sold)

madwi

Thats exactly it what im talking about, final polish was the tp. I could never do it, about an hour in and I said f this and went back to my machine. Made me appreciate them that much more and always tried to get the best machined finish to start with to save time. Ran a few extra cycles in the EDM machines crisping up the sharp corners and blending in transitions.
We made the molds for inifinty, honda and others. If you ever notice the seatbelt latch covers in a viper; I made the electrodes and burned the snake's face into the mold.

Your mold looks awesome and that cowl doesnt seem like its gonna be fun to mess with.

gbrettin

The cowl will have its own challenges of getting the left and right side mirrored, but I know I can nail the gel coat process on it. That will cut 90% of the repair work out.

I'm really considering moulding some vents into the cowl as well, so that engine bay air pressure can get out too.

On my hood, I really need a small duckbill to divert air up over the windscreen which would take care of a high pressure area that builds up at the center base. I forgot where I saw that particular 3d rendering of pressure zones on this site. The duckbill/diverter really should have been baked into the hood mould but I guess that can be a challenge for a different day. There are too many spinning plates as is.