The old trick with solvent based paints, which can also evaporate over time, was to store them upside down.
Dave Nelson
I use MEK as well, and I have a couple of the Plastruc bottles with the brush head, and I refill as needed from a 1 gallon can of MEK, I get at the hardware store.
I don't notice any loss or evaporation from the gallon can, as sits for months.
For paints, once I open a bottle, I use a small piece of plastic, cut from a baggie, wrapped around the bottle top, and then scew on the lid. Seems to work OK.
Mike.
My You Tube
I gave up on evapouration of the contents of relatively expensive solvents. I bought a litre bottle of MEK on Amazon. I top up my little bottles with that then I don't care about evapouration at all. My bottle cost me £10 - $12.50! (with free delivery)
Long Haired DavidA.K.A. David Penningtonmain man on the Sunset and North Eastern R.R.http://www.gmrblog.co.ukfrom the UK
I've used electrical tape before. Slightly stretch it for a good bond and make 2-3 wraps.
The Silicone stuff I linked to will fuse together so you would have to cut the stuff off then re-tape it with new.
You could probably get away with reusing the vinyl tape a few times. At least it is a little cheaper and most of us already have it on hand.
Good Luck, Ed
I probably have over a dozen various brands of water-thin, solvent-type cements on hand. So far my Plastruct ones are holding up fine as is the Ambroid Pro-weld.
What I have had trouble in the past with was the Tenax 7-R. I had maybe three cases of six bottles each and after perhaps a year most of the bottles had evaporated at least 50% of their volume. Some more, some less, some not at all.
All I can offer would be to tightly wrap a good-quality electrical vinyl tape* around the lid-bottle joint and hope for the best. That way the tape can easily be removed when needed.
Trying to find a replacement lid that is "exactly" right for the Plastruct bottle and successfully reducing the evaporation would be a slim chance, IMHO.
[edit] I recently came across this stuff:
https://www.amazon.com/3M-03625-Wrap-Repair-Silicone/dp/B00G25GOCA
and wonder if that might be a better choice? I have some but haven't tried it.
Does anyone have any tips on storing Plastruct Plastic Weld? I only get it out to use once every few weeks, sometimes months. I swear everytime it looks like the bottle is more empty than it was when I put it away. I know it can evaporate fast, and I screw the top on tight. Do you seal it in a plastic baggie? Or do I just maybe have a faulty lid?