Full Version: Acrylic drinkware cracking

From: Carl (CSEWELL) [#8]
 20 Apr 2007
To: Stunt Engraver (DGL) [#7] 20 Apr 2007

Thanks. Better late(r) than never.And I'll try to remember to post my last post first in the future.
From: http://www.devicelink.com/mpb/archive/96/01/001.html

Acrylic is resistant to a wide range of chemicals including salts, bases, aliphatic hydrocarbons, fats and oils, most common gases and inorganic chemicals, dilute mineral and organic acids, and dilute and concentrated solutions of most alkalis. It is attacked by strong acids, chlorinated and aromatic hydrocarbons, ketones, alcohols, ethers, and esters. Of course, the chemicals and other materials to which a molded part will be exposed should be carefully considered before selecting any thermoplastic.

Isopropyl alcohol tends to promote crazing in acrylic, as it does in many transparent plastics. Some acrylic grades are more alcohol-resistant than others: resistance is typically a function of the molecular weight of the polymer, with higher molecular weight providing better alcohol resistance. Diluted solutions of isopropyl alcohol can be used to wipe down acrylic without adverse reaction. Acrylic copolymers, particularly those with styrene, offer improved chemical resistance but do not transmit light as well as 100% PMMA.

Consistency is the key; any changes in thickness should be gradual, and feature radiused edges. Vertical walls should be the same thickness as the rest of the part to avoid pressure variations on the flow front, which can lead to stressed areas and voids caused by trapped air. Moderate residual stress does not affect part performance, but high levels of stress can reduce impact strength and resistance to chemical or heat crazing, and can undermine the dimensional stability of the molded part.

EDITED: 20 Apr 2007 by CSEWELL

From: Dave Jones (DAVERJ) [#9]
 20 Apr 2007
To: Carl (CSEWELL) [#6] 20 Apr 2007

Very interesting. Of course something like wine is more dilute than pure alcohol, so won't damage the material as fast. But I guess that's why the plastic wine glasses and champagne flutes are normally used and thrown away.

From: PenTrophy (PENINSULATROPHY) [#10]
 20 Apr 2007
To: Carl (CSEWELL) [#1] 20 Apr 2007

Time to switch to Lexan Barware.......

From: Carl (CSEWELL) [#11]
 20 Apr 2007
To: PenTrophy (PENINSULATROPHY) [#10] 20 Apr 2007

No thank you. I've tried engraving polycarbonate.

From: PenTrophy (PENINSULATROPHY) [#12]
 20 Apr 2007
To: Carl (CSEWELL) [#11] 20 Apr 2007

AHHH with a laser i bet....How about diamond drag.........

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