shelf life of spar varnish

[Diggin Jiggin]

I haven't turned birch before but I will try some next winter. Until this season I really hadn't had any splitting issues with the soft maple and I really enjoy working with & turning it.

[Rockfish9]

I've found that if you heat maple or birch in a toaster oven prior to dropping them in the sealer they seem to seal better...

.. place some clean brick or stone in the sealer can to take up as much space as possible.to displace the air. then put a piece of plastic film on then hammer the lid down.. I use the same sealing oil for a few seasons... and strain periodically... ...but I use Tung oil

[basswipe]

Spar varnish or any varnish/poly for that matter is not meant for submersion.This is why the finish is failing and the plugs are splitting.