TIL my go-to shellac flakes were the reason my finish kept clouding up

I was finishing a walnut dresser for a client in Tacoma last week, and every coat kept drying with a weird haze, even though my shop humidity was fine. After three frustrating attempts, I checked the batch date on my flakes and realized they were over two years old and had absorbed moisture. Has anyone else had this happen, and what's your shelf life rule for shellac?

3 comments

3 Comments

stone.barbara2mo ago

Moisture in the flakes is one thing, but clouding can also happen if you're applying it over an oil that hasn't fully cured. I've had that happen with a tung oil base. Shellac itself can last years if it's sealed up tight with desiccant packs.

blake_thompson272mo ago

That's a good point about the oil, but shellac's shelf life is more about the alcohol than moisture. The solvent evaporates or breaks down over time, even in a sealed can. Desiccant helps, but you can't stop the chemical change. I've opened year old cans that were bone dry but the shellac was still cloudy and stringy. Once the esters start to go, it's done.

richard_mason15d ago

So basically shellac ghosts itself when it's good and ready.