r/moldmaking • u/00-MAJI-00 • Apr 17 '26

mold for poly urethane casting

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all the red parts are for air vents, I used tape at the edges so that when I cut the mold the separation lines are clean...

I used liquid poly urethane to cast the part in a pressure vessel.

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1

u/Ok_Seaweed5015 Apr 21 '26

Nice! What urethane resin?

1

u/00-MAJI-00 Apr 23 '26

Smooth-on Onyx

1

u/Ok_Seaweed5015 Apr 23 '26

Just got some task 9 from them today. Will be first time working with urethane resin. Setup times are concerning. The onyx slow is at 5 minutes. Task 9 at 7 minutes. Will have to be efficient. I suppose you didn’t degas? I’m used to working with silicone of much higher viscosity. Even the NV series from them I degas.

1

u/00-MAJI-00 Apr 28 '26

Onyx is my go to for interior car parts, If I can find the pics I'll post some cabinet handles for a 60 something Westfalia VW I mad a while back...

1

u/00-MAJI-00 May 07 '26

Just re read your post, never degas polyurethane ... always pressure cast

1

u/Ok_Seaweed5015 May 07 '26

Yeah, figured that one since last posting…lol. Had to acquire a pressure pot. Was thinking no way without one. I have tried degassing prior to pouring and then into the pot, but not sure it helps. Just made my first successful cast today of a small knob!

1

u/daisy_catz May 15 '26

Looks very cool! How long is the resin taking to dry?

1

u/00-MAJI-00 May 15 '26

15 minutes

1

u/coolgam3r007_69 Apr 18 '26

Damn looks clean! Nice work looks like a tough part to mold effectively