Just finished putting a couple of fresh coats of varnish on my wooden boat. I have a little bit left in the quart can. Any way I can keep it from getting hard, so I could use it later for touch ups?
Yup, it works
Also, put the leftover varnish into the smallest container you have, as that will reduce the amount of air in with it.
can put the smallest covering of thinner atop the varnish -it too keeps the air out.
Take a propane torch and don’t light it, just slowly bleed propane thru it into the can, it’s heavier than air and will displace it and will prevent the varnish from oxidizing (hardening).
Someone will get upset about that suggestion. But thats what I do.
How about a clean rock inside?
Would also do the job of eliminating air space in the container.
Along those lines…
…using marbles, steel balls or other objects that you can be sure are absolutely clean and won’t contaminate your varnish is probably a better solution than a rock.
Like Cocaine, but propane… I thought it was my own idea, but others have it. I tested propane gas in my varnish cans and it worked great. Just don’t use a match to see how much varnish is in there when you open it up.