gloopy resin

From:"Renton, Lousie, Mrs" <177louie@chiron.wits.ac.za>

Hi there,
this is a question for all the resin users.
I have started using polypropylene pill vials (the sort with a snap-on 
lid)  as moulds for my resin blocks (MMA). I have subsequently 
found 2 things happening:
1. If the lid is snappped on securely I get the "champagne effect" 
with millions of bubbles frozen for all eternity in the resin.(unusable 
blocks - start again)
2. If the lid is left with a little gap or a pin hole or 2 - the resin 
polymerises fantastically without bubbles, but a layer of gooey stuff 
remains at the air/resin interface - up to 0.5cm thick
Is this normal?
How do I get the gooey stuff to set? - heat it? cool it? wait for 
another day?
Do I just scrape it off and pretend it didn't happen?
BTW - the moulds are left in an incubator overnight at 24 degC 
leaving them o/n at RT results in VERY slow polymerization 
(?airconditioning)

All comments welcome

Louise Renton
Bone research unit
MRC
Johannesburg
South Africa





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