II+ in the clear

[dorkbert]

I wonder where the shell was sourced from; since AFAIK Apple did not start proto in the clear till Image Writer II time frame.
https://www.ebay.com/itm/202729852119

 

[glitch]

Says in the listing that they wanted clear cases for Apple IIs so they made their own. There seems to be a fair bit of this lately, with the cost of custom injection molds I'm surprised to see the price even that low!

 

[David_M]

I think is is done in resin and not injection molded

 

[glitch]

I think is is done in resin and not injection molded

Huh, could be! It's not clear from the description. Printing in resin would certainly be a cheaper option than having molds made up.

 

[Chuck(G)]

Depends on the guy's machining capabilities. I've seen all-clear cases fabbed from acrylic sheet. You can do a lot with a good Bridgeport mill. Said case was used as a model for the structural foam molds that were used to make the production cases.

You can also vacuum-form acrylic sheet, which is much less costly. It seems that in today's 3D printing world, some of the older techniques have been forgotten. The first industrial application of an IMSAI 8080 that I saw was to drive a vacuformer.

I'd be very surprised if the first Apple II cases weren't vacuformed.

 

[groink]

My money is on injection molding. John says he had to make multiple copies of the case. If he produced these in any other way, he could have done one-offs instead.

 

[Chuck(G)]

I'm not following--why not vacuformed cases? Cheap, fairly easy and very amenable to small production runs.

 

[glitch]

I'm not following--why not vacuformed cases? Cheap, fairly easy and very amenable to small production runs.

I'd guess the screw bosses would be pretty difficult to vacuum form, at least without making divots in the opposite side.

 

[mwillegal]

Tooling for injection molding is extremely expensive for small runs for an item of this size. I'm thinking that some kind plastic/resin casting technique was used, which is suitable for small production runs and cuts tooling costs significantly.

By the way, the first Apple II cases were cast, not injection molded.

regards,
Mike Willegal

My money is on injection molding. John says he had to make multiple copies of the case. If he produced these in any other way, he could have done one-offs instead.

 

[Chuck(G)]

If it's acrylic, solvent cement makes for invisible joints. So screw bosses are no issue. You can see some evidence of this sort of thing in the gussets near the top.