I don't think dope will freeze. I have never heard of this happening before so I really cannot give you the answer. Dope usually dries to the touch in minutes. I would guess that what you have is by some mistake not dope. Sounds more like polyurethane but could be anything. Maybe someone else has had this problem.

Generally, when something won't dry (dopes) it's usually either a contaminant or the temp. I've had dope take days to dry when it's either humid or very, very cold. I left a plane I shot in the winter when I lived in Idaho in the garage overnight. I had shot the plane in sub-zero weather (outside) then put the plane into the garage to dry. Next day, it was still tacky. I took the plane in the house and it still took 3 hours to dry (probably because the airframe had to warm up).

Steve:

Let us know how this comes out.  I have never, ever had dope not dry in the cold -- but January "cold" in Oregon's Willamette Valley is usually a pretty wimpy, ice barely frozen in the puddles sort of "cold".

   Steve , I had this problem 10 years ago with some dope. After 2days I put it close to the heat register & it finally cured.  It's10 years old & looks nice today.
   John