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Discussion Starter #1
I've got a question maybe someone can answer. What is the story behind "movable molds" or such description given to JL casting molds? I figured out that must be how variations to the basic casting are made. A few examples are the 71 & 72 Plymouth, Mini Cooper & S (which I think are actually about 4?), 69-72 Novas. What is the history behind these, and is it prohibitively expensive to do these in the future? I was thinking Shelby GT500, maybe 66 Impala, etc. I know the plastic roofs on the 67 Belvedere, 2000(?) Camaro, 59 & 65 Impalas are a great way to produce more variations with little lost of accuracy. Just was curious...
 

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Brock

I just saw this.

I believe to do this they must have the idea when the mold is firast created. Once it is done, there are no changes to it due to cost.

I know there are some, like the 68-73 Vette) that have many different parts to create the different years that have not even been used yet..

Try doing a search for posts by Hot Rod Al and I think you will find the answer
 

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Traditional molds are two-piece molds: male and female. What JL has done is broken up the female part of the mold into front, back, two sides, and a top. The fronts and backs can be changed out to make different year taillights, grilles etc. Everything is engineered all at once as it is prohibitively expensive/difficult to add new "slides" once they tool is hardened and in production. The slides allow greater room for potential error.

Doing this doesn't add much to overall cost of the tool, but it ratchets up the complexity considerably. It's expensive and difficult to switch out the slide cores: it takes two guys eight hours (plus downtime) to switch out a core, get it aligned, do a test mold run, fix and adjust, etc. To my knowledge JL is the only company who does this, and who knows, with budgets being what they are, whether this will continue in the future?

I think Mac has done a good job choosing cars and tools that don't really require massive tooling changes--ie early Vega, early Maverick, Avanti, 69 Blazer, 50 Suburban et al. Compare those relatively simple ones to the nightmare of the Firebirds ... somewhere there exist incorrect samples of a '79 nose with a '78 tail, or vice-versa.

jk
 

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Discussion Starter #7
Thanks Jeff! Good info. It has always impressed me that PM/JL had went to the trouble to make various years or versions of the same car; without just using tampos. The Mini Cooper's several variations really caught my attention; then I looked at others and found there had been several.
 
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