Re: Reproduction Rubber Parts

Posted by Pgh Ultramatic On 2024/12/19 3:25:41

Here is a behind-the-scenes look at the mold making process. I use modeling clay to support the part such that the casting will result with the seam line in a desirable location. The part number and version control number are stamped into the clay, as well as index marks.

I did some testing of A-scale Shore Durometer values on both Steele and original rubber (respectively) on selected parts. Obviously the original hardens over time but also my car is at 35F currently, so these values are more of a curiosity than directly comparable data.

Hood to Cowl: 70, 78
Front windshield: 70, >100
Rear windshield: 70, 90
Vent window: 70, 78
Taillight Lower Gasket: 70 (Steele)
Solid door weatherstripping (all): 40 (Steele)
Extruded door weatherstripping, as measured: 18, 23
Dimmer grommet: 75 (original, at room temperature)

Of particular note is the unusually high apparent hardness for the front windshield. I wouldn't be surprised if they made it harder on purpose to support the windshield. There was also a bulletin on using Sealzit to keep it from squeaking when it shifted around.

At some point I will take more data from the best original rubber I can easily get my hands on.

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