How important is shellac age for a very thin cut?
I'm slowly working my way through an extensive panel door refurb in my house--so slowly that I'm worried I need to throw out my shellac and get more.
The doors are poplar, and to get a good finish that matches the original woodwork in the house (which is also poplar), I go through a multistep staining process that layers on the color for an even, rich finish. The first step is a washcoat. For that I use a thin cut of dewaxed shellac in denatured alcohol. A few months ago I did the master bedroom door with a 2 year old mix. It came out fine. Now it's a 2 1/2 year old mix. I'm thinking I'm really pushing it on the esterification. But, maybe for a washcoat application, the esterification isn't an issue--perhaps it only matters for a top finish? Perhaps I should thin the mix with less denatured alcohol, essentially making it a stronger cut, to compensate for the esterification?
On the one hand, I can see the virtue of buying new and starting over. Otoh, I hate to spend the $30 to buy a new gallon and throw away half a gallon of the old stuff, if it's still functioning for the particular needs of what I'm doing with it.