Yahoo Groups archive

Homebrew PCBs

Index last updated: 2026-04-28 23:05 UTC

Message

Re: Spray etcher

2012-08-27 by Tim Gibbs

Hi All,

 

A possible explanation for the acrylic crazing is a combination of using
H2O2 and heat. 

Benzyl peroxide is used as a initiator for the setting reaction in dental
acrylic used in dentures.

Dentures are made using a lost wax casting processes where the denture is
waxed up and then invested in plaster. The mold is warmed up and the wax is
removed. A mixture on partly processed acrylic as a fine powder is mixed
with liquid monomer to form a dough usually with benzyl peroxide as the
initiator. A little heat is applied and the dough polymerises to form the
acrylic.

Patients are advised not use bleach on their dentures.

 

Cheers

Tim


Is it a problem with peroxide then?

'Cause I had a commercial acrylic bubble
tank that was used for years without problem.
Then after switching to CuCl (regenerated
with 40 weight H2O2) it crazed and went
brittle in about 6 months.





[Non-text portions of this message have been removed]

Attachments

Move to quarantaine

This moves the raw source file on disk only. The archive index is not changed automatically, so you still need to run a manual refresh afterward.