Clear gloss without synthetics?

I am painting a staircase white. I want to add some stencilled designed to it and then apply a clear gloss varnish on top, to protect the designs below and add a gloss sheen to the surface.





I think polyurethane would work well but I want to use a natural product rather than a synthetic one. I looked at tung oil but was told that oils are only for wood whereas polyurethane can bind to anything - is this true?





Would waxes work? I know that gloss finishes are possible without synthetics because they were produced hundreds of years before synthetics were invented (e.g. french-polished floors in the Renaissance etc).Clear gloss without synthetics?
oil base poly would work, BUT it will turn the surface a golden/amber/yellow color. the best bet would be a water-based/acrylic polyurethane. benjamin moore makes a product called ';stays clear'; and minwax has polycrylic. either one would be ideal for that application. LAcquers are not recommended for floors. they do not provide adequate protection/durability on a floor. as far as the ';synthetic'; question, I would have to ask why you have an aversion to synthetic resins. in the case of water-based poly, they will be low odor, and much more gentle to use. they are the safest posible product to use in this application. you can try an oil based poly, but as I said, it will turn the surface a golden color, and since you painted it white, I don't think it would look good at all.Clear gloss without synthetics?
Lacquer is probably the material you have in mind. It is made from an insect (the lac beetle, I believe) and as such is completely natural and has been around for 100 years. Depending on how far it is refined, in can be very transparent or fairly amber in color. The color will be specified on the label. It is used in french polishing and was the finish of choice for a long time. One caveat; if the surface is subject to much wear, don't expect lacquer to hold up forever. Modern polyurethanes are much tougher.