Re: bubbles in plastic

[protek@shreve.net]

      Acrylic is poured into molds for casting.  These molds have to be 
maintained at a certain temperature and under a certain pressure or you 
will have bubbles formed inside the cast piece.  I do not know their 
composition but the way to avoid this while casting is to keep the work 
under pressure.  I think they use around 150 PSI but I am not sure about 
this figure.  Perhaps the bubbles would not form under pressure.

G. Boucher.

PS.  I have never heat formed acrylic to any extent so I am not an expert 
in this area.


At 09:24 AM 12/10/99 -0900, you wrote:
>I have read again the psub white pages and have been surfing the list
>archive for details on working with plastic and notice that the heat
>temp is 300F and water boils at 212F.
>does the fact that the sheet was formed under pressure at the factory
>account for the water not "boiuling" out when heating it to 300F??
>
>If the answers are in the archive can anyone point me to a date?
>
>Thanks!
>
>Bill