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RE: drying coil forms/acrylic fab techniques
Malcolm,
snip
Tubing seems to be particularly
susceptible to this. I've often welded sheet acrylic like this with no
problems. Perhaps tubing is stressed for some reason associated
with its manufacture or perhaps it has something to do with the
different ROCs inside and out. Anyone know?
snip
Acrylic tube is can be purchased in either cast or extruded. Cast
acrylic tube is made
by pour the raw monomer into a mold,curing. then grinding,polishing to
size. optical,mechanical.and chemical properties are superior to
extruded.the latter method is cheaper but has extrusion lines,residual
plasticiziers,and residual stress from the process.
lower chemical resistance + residual stress=crazing. Also,when solvent
cementing tube(ie cementing a bottom on) the easy way is to apply the
solvent from the inside. unfortunately this also makes it likely that
solvent fumes will build up inside and cause the tube wall to craze and not
appear till minutes or hours.
sorry for the long winded reply,bottom line cast tube with good fabrication
methods should do the trick.
if you are interested can forward a copy of a series of booklets I will
forward a copy from the Rohm&Haas company on
sawing,cementing,forming,machining,painting,ect. of Plexiglas.They are all
old (circa 1970) but good from the heyday of Plexigals GM......... (ie
cell cast acrylic )
hope this helps
Robert Cressler
(a.k.a. ex Plexiglas salesman from the seventies)
PS this will no doubt make me look dumb but what does "ROC" stand for??