Working on a 12" clock made out of Walnut with an epoxy inlay. Usually my go to finish is 1.5lb cut shellac i mix up myself from wax free flakes. Not sure what happened but after a few thin coats, things werent looking good. Stayed kinda tacky and not great looking. Im guessing maybe the shellac has gone bad, mixed this batch up 6 months ago or so. Anyway, i sanded it down and ready to try again. I might bail on shellac on this one and just go with a wipe on poly. Do you think ill have trouble putting the poly over the sanded shellac?
I use the Zinsser Universal Shellac from a can. The Universal Sanding Sealer is supposed to be wax free. Zinsser makes a ready mixed Traditional Shellac that may or may not be unwaxed. I have had good luck with the ready to use Zinsser product and do not have to pour the aclohol in the Shellac flakes and wait and then remove the wax if any. I dont think shellac goes bad. You might need to add more aclohol because it evaporates slowly even in a relatively sealed container.
I have used shellac under both oil and water based polyurethane. It always works. I do a lot of epoxy fill and the epoxy looks dull as dishwater before poly and comes to the shine of satin or gloss. Personally I like satin best.
How old was your poly. The air deteriorates polyurethane over time. It tends to get much darker and thicker even in its sealed can. Usually about 6 months is the shelf life of opened polyurethane but you never know how long it sat on the store shelf. If you have not started the poly application suggest you buy a new can. You can also make your own wipe on poly by buying the full strength poly for floors and the first and second coat thin it about 50% with mineral spirits. Then about 25% for the additional coats. I find that sealing the wood before applying poly usually takes 2-3 coats off the final coats. I usually put about 3 coats on of wipe on polyurethane.