Chris -

My PPP is a few years old, maybe 4 or 5, it has thickened a slight bit but is still very useable. A couple of things I do, squeeze from the back and keep the putty forward, minimizing any air that cannot be removed. Keep the cap threads and tube top as clean as possible, so it all seals well while stored.

I use water and a tiny metal spatula, for blending and softening the exposed amount in the tube, to keep the putty useable for filling. When finished, I stir a little water into the top of the putty in the tube opening, it seems that keeps the interior sealed better from air entering the tube.

Hate that you lost a tube, awful waste, but still a very good filler when in good condition.

Patrick 

Yeah, I cannot lie, it has been a pretty good product. Maybe I'll give it a shot and try some of your techniques in keeping it useable. Thanks Patrick.

--Chris

I had a similar experience with my first tube of PPP, I had used the tip included with the putty and left it in place, thinking that, if anything, the only part that would dry up would have been the extreme tip. I was wrong. I ended up chucking the tip in the garbage bin, I too found that after awhile the stuff in the tube end was drying up fairly fast as well. I recently bought a new tube of PPP and opted to not use the included tip. I instead bought a couple of syringes and needle applicators. I thin the putty down and then put it in the syringe and can apply it where needed, neatly.  I then stick the syringe needle in a cup of water, this seems to eliminate any air getting into the syringe, keeping the putty workable for the next session. Change the water periodically to keep it somewhat fresh.

I've been using the stuff for over a year now and really like it. My tube gets dried out near the tip and I have to shove a toothpick up in there and stir it around. Wow, I used to have Squadron putty dry out in the whole tube but not this so far!

Patrick, I've going to take some of your advice on keeping the end from drying out- thanks!

I have a larger pin that I use to plug the applicator. And every couple of days, I will knead the tube. So far I have not had any drying of the tube at all.

Chris;

 I am sure all of those who answered already will think I am nuts .( probably already do anyway , LOL.) .When I get ANY putty I do this . I get a jar or bottle with a good sealing lid . Then making sure there's no foriegn material in there , I empty the tube in there getting every last bit .

     Now this has worked for over forty years or more .That's since all these new products became available . I  put the two parts in seperate bottles . Since then I have lost none of the product to drying out .

         Epoxy will harden in it's individual original containers over time . The Syringe type of container is the worst about this .  Hmmm , Building a Swift Boat huh ?      Tanker - Builder           P.S. I am to the point I am using more and more SpruGlu instead of other types of fillers .

I have had the same problem, with alot of different putties.

I buy a 40 ml tube of putty and chuck half of it, if they sold 20 ml tubes for half the price that would be a good idea.

Same here, I needed some putty on the weekend, but both my Tamiya and Humbrol had dried up. Going to make my own using left over sprue and thinners. 

I put my putty tube in a snack-size ziplock bag and squeeze the air out before sealing. It seems to help preserve freshness quite a lot.