Re: ATM - The Right Stuff

[George Anderson <georgea@CAM.ORG>]

Richard
I think you hit the nail on the had but had the wrong approach.
Try some of the plastic or arts suppliers for thin sheet latex, or try a
novelty shop for one of those six foot "texas" condoms. A thin layer of
latex (not LaTeX, printer commands don't work :^o) should have enough
give and sag if it is gently pulled smooth.

George Anderson
Montreal Canada

Clear skies and good health

> Richard wrote:
> 
> When making tile tools and pitch lap foundations of dental stone, I
> have been using saran wrap to cover the bottom of the mold and permit
> easy separation.    This is OK for shallow curves like telescope
> mirrors, but when the curve gets deep, the saran wrap wrinkles and
> those wrinkles get molded into the surface of the casting.
> 
> Yesterday I tried a garbage bag, and it works MUCH better.  However,
> there are still some wrinkles.
> 
> So, what I am looking for is the right stuff-- something that will
> stretch under tension to conform to a convex mold surface, or stretch
> under the weight of the dental stone or castable refractory to conform
> to a concave surface.   Whatever it is will be cheap, commonly
> available, and come in sheets big enough to cover a mirror surface.
> (That last requirement eliminates the obvious cut up rubber condom
> which somebody is sure to suggest.)
> 
> Any good experience or ideas out there?
> 
> . . . Richard