Shellac isn?t the poop of the lac bug rather the ?caccoon? it forms when it is metamorphisizing into its final stage of life. Shellac does hold up very well to water it isn?t a high gloss finish per se rather it can be if buffed out properly or if frenchpolished which I think would be overkill on a fish stand. Shellac holds up very well to water it can withstand standing water for several hours without being affected it can even withstand alcohol for a few minutes before it starts to burn. Maybe you?ve had bad results with it before but to my experience shellac is amazing and extremely water resistant.
Actually it is a resin secreted by the female lac. It is not a cocoon. More like a tunnel as they traverse the tree branches. The insects suck the sap of the tree and excrete "sticklac" almost constantly.
The information about water resistance is from noted woodworkers, not from my experiences. And the links were provided. In all honesty I haven't used shellac as a top coat in over 30 years. There are way better, longer lasting finishes out there that are fairly easy to use and are more resistant to water and chemicals.
Polys would be the better choice at any rate and the water based polys are easy to use. But they do give a stark finish unlike the amber tint of an oil poly. I am able to do three coats in one day with water base. I normally do a total of 6. If you're looking for a satin or matte finish do the first coats with the gloss. Let your last coat or two be the satin or matte and you won't have the flattening agents clouding the finish.
To the OP. Yes, I would use poly on all of the stand to keep the same sheen so it looks right.
As an aside. Shellac is food safe once dried. In fact it is used as a coating for many medicines.
Originally Posted by Maryland Guppy
Sorry all, I though this was under the tank to be only used as a sealant.
Shellac really isn't a sealer in this regard. It is used as a sealer between dissimilar top coats and also as a sealer for resins from woods like pine that are sappy. Also for odors. Not for water however.