I've never used POR15, but could you purchase the gallon size for economy, then transfer to "disposable" plastic quart containers? I do this with house paints and wood finishes all the time.
Air-tightness is not an issue, although there may be some other reason not to use plastic. If you purchase the plastic containers made for paint products, the lids seal nicely. Do it all the time.
It is a moisture cured paint, water vapor is the catalyst. Unless you have a deep tub filled w/ dry nitrogen gas and ensure no normal atmosphere intrudes the moist air will start the process of turning it into a solid.
A trick my grandfather used to due with shellacs that loved to absorb water was to do the saran wrap trick under the lid and on down onto the surface of the product to kill the airspace above it. Seemed to work for a long time.
Quick Links
Say no to Lawrence Welk attitudes
Linear Mode
