There’s a tip on the Fine Woodworking* website at the moment about preserving finishes. Peter Limon suggests using a vacuum pump on mason jars to remove the air to prevent oxidation. Because I use quite a bit of varnish, stain and oil on boats I’ve often opened a can of last year’s finish to be disappointed with the contents so I hunted around for ideas:
- Keep a set of jars in graduating sizes. I have a large, tall jar that originally held passata (I think) and various other food jars going right down to a mustard jar. Because it’s not a good idea to use finish straight from the original can I pour out what I plan to use and decant the remainder into a clean jar. The less space in the top, the less oxygen to spoil your finish.
- Cut out a piece of grease proof paper and lay it on the surface.
- Fill the jar up with clean, glass marbles to displace the air.
- Spray an inert gas into the top and put the lid on swiftly. Search online for “wine preserving spray”.
I favour 1 and 3. Cheap, easy and effective.
*You’ll need membership to find it. I tried to post this on their forum but the spam filter got it!