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PackardV8 posted:

"The problem with reproducing any part from scratch is the ability to monitor or maintane quality control requirements."

We have manufactured thousands of different parts, some to the tolerance of .0005 and have no quality control problems in that no "bad" parts reach customers. Yes, some received items do not meet our specs and are rejected as happens with most companies

I would guess that in the collector car industry there are well over 100,000 differnt parts manufactured and all companies monitor or maintain some level of quality control.
If lots and lots of "bad" parts were being shipped to customers then the word would spread and the company would suffer. Capitalism has a wonderful way of self regulation in that area.

As far as going to a parts store and looking at a photo and getting specs to find a "best fit" item and put the data into a "magic machine", I don't think it will work for a piston, engine bearing, oil pump, manifold gasket ,king pin etc etc. Those are all precision items with multiple critical dimensions and .003 can make a difference. A Chevy king pin and a Packard king pin are both .866", lengths are different, notch is in a different place.

and the Packard king pins have a grease hole drilled from end to end.

HH,

Could it be used to make a "suitable" replacement for the A/C vents for the V8 Packards?

Yes, that is possible but I have no idea of the heat/ultraviolet stability of the material. Also must have mechanical strength to open/close, hinge the vanes etc etc.
This machine is good for making prototypes for looks, not for precision. It might be used for a first step to make a temporary mold for a part from pourable plastic.

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That is a tremendous idea. Those are complex yet open enough so the scanner should have no problem getting the inner or hidden information. Wish I knew someone who had the equipment willing to experiment for a small fee.

As Fred said, some things to be concerned about and would need info on is the materials the machines use in the reproductions. I know nothing of how stable they would be when exposed to the sun or the high inner car temp after sitting exposed on a hot day. How it holds paint is another. Both are problems I've run into when making mine. Fred is also right about the mechanical properties. Those hinges and the surrounding material thickness is nil. The original phenolic or bakelite stuff is not very strong and was broken on both my originals. Am trying to reinforce my current project vents with a metal sleeve arrangement on both sides.

One of the first acrylic compounds I used was beautiful to look at, long pot life, easy to pour and paint but after being in the dash exposed to the sun, flipped it up and all the louvers had softened and deformed. Tried other materials but did finally find an epoxy that was so-so which is what I made the first set out of years ago. Of course, while it did have drawbacks, was nowhere to be found & apparently discontinued when I wanted to make more. The urethane stuff I'm playing with now says it won't deform up to about 265 & so far has been OK for pressure casting. It's negative is that it is being a challenge to get paint to stick. Have read up on some procedures to try for the next batch but have kind of set the vents aside for now while I work on the other components.

polyurethane is normally very easy to paint - it has a surface energy of 38 dynes/cm2 or so (high), and not surprisingly is compatible with urethane paint. I suspect your problem is a residual accelerant or a mold release. Silicone is terrible for paint adhesion

I suspect you are right with the mold release. Haven't tried them yet but there are a couple that claim to be paint friendly and have bought some for the next set. The silicone molds may be another issue but haven't found a way around that. The undercuts on the louvers almost require the flex that silicone offers with the single pour method. Sure wish I had the 3D or spacial recognition capability to figure out how many pieces and how the original injection process was done with hard molds. My few remaining brain cells only work in 2D.

undercuts in a hard part/hard mold are normally handled by "slides" - parts of the mold retract to demold. as to the silicone, try cleaning your part with IPOH (ordinary stuff from the drug store is fine).

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And how about the polymer-degradation of polyurethane? I don't know when and where but once I read (but perhaps misread) that PU isn't gas-tight and therefore not suitable for human ventilation systems as it tends to fungal infestation.

Good question. I know a lot of plastic type materials are not UV stable--have a backyard full of them-- but was thinking since in this piece all is painted, that might not be as big an issue.

I don't know about the other issue either and whether the paint would negate it. I do remember a controversy a few years ago about the outgassing of various vinyl and plastic materials in closed environments -aka new cars- but don't know if this was one of them and what the ultimate recommendation was. They're still making new cars that seem to smell the same and develop a film on the inside of the glass.

Unfortunately, not a whole lot of options in the pourable/castable category without megabucks processes.