I haven't used PL Premium, but the marine polyurethane caulking/adhesive I use (3m 5200) is probably similar. I wrap the delivery nozzle tightly with electrician's tape, stretching several layers lengthwise over the tip, and binding them all by wrapping around the base of the nozzle with more tape. This will keep the delivery end good for quite a while, probably for a month or two. Eventually, the material in the nozzle will solidify, but I drill through it with a twist drill to get at the good stuff.

The plunger end can also be a challenge, at least it can with the 5200. It will set up enough around the piston to prevent a caulking gun from moving it. I place a couple layers of aluminium foil over the open end of the cartridge as tightly as I can, and then wrap with electrician's tape to compress the foil tightly around the steel rim around the edge of opening. If you have a small silica gel packet (an active one) to put in there before you cover the opening, so much the better.

Pl Premium, like most single component polyurethanes, uses a moisture catalyzed cure, so if you keep the moisture from it, it will probably keep reasonably well. I haven't tried putting the whole tube in a container with a good sized silica gel pack, but this might work even better than what I have done so far. I look forward to trying the golf ball trick on my next tube. :)

Best regards,

Allan Edie

: Is it possible to preserve partially used cartridges for later
: projects, or will the pu kick off in the tube regardless of
: precautions? Some kinds of tube products are better than others
: at not going off prematurely. Any experiences here with how long
: an open tube, if sealed from the air, might remain useful?

: thanks all

: Michael