Chilled, not Frozen Polyurethane Resin

Here’s a handy tip I recently verified experimentally with $60nz worth of fresh two part polyurethane ‘Supercast’ casting resin from TopMark: it freezes!

Yeah ok, I’m not recommending anybody actually freeze their casting resin, but chilling polyurethane resins is quite a common trick used to extend their working times. SuperCast is a fine product in itself that has many desirable working properties for me…bar one: it sets quite quickly, in around two minutes. This can be problematic, particularly if you’re pouring several detailed molds, then you’ve got to work fast.

It’s also a problem in summer when your garage is an oven and the working time of SuperCast goes down considerably. Hence I usually chill my resins in the household fridge (in a sealed plastic bag, on the top shelf), however then it’s a fairly long trek to fetch them. Our garage has a cabinet deep freeze so I thought: I’ll just pop the resin in there for 30 minutes before pouring this next batch of molds. Of course I promptly got distracted by some other project and left the bottles in overnight!

End result: Frozen polyurethane resin, or rather half frozen as Part B seemed to freeze while Part A remained a sluggish brown liquid. Fortunately resin has no water content (air moisture degrades it after all) so evidently freezing it has no ill effect, which I tested by promptly pouring a set of molds which set just fine.


Leave a Reply

Your email address will not be published. Required fields are marked *