Based on the previous posts in this thread, I decided to do an experiment to see how waterbased gloss poly would work as a pen finish.
Rather than using a kit, I opted to make a 'cheap' or '12 cent' pen because what I was really interested in was the finishing process rather than the pen as an end-product.
I chose to use poplar because I had a scrap lying on the bench, and because its not the most exciting wood, if the finish works on it, it should work on other woods. The particular scrap I had was a bit greenish (in color), so that also made it a good test of the color issue with waterbased poly.
I turned the blank, sanded it to 800 grit, and applied a coat of Zinsser's shellac sanding sealer thinned 1:1 with DNA. After that cured, I sanded it lightly and applied the first coat of waterbased poly using a brush and with the lathe spinning at its lowest speed (about 250 r/min). I let the lathe continue to spin until the poly set up - even with the sealer, that coat of poly soaked into the wood and raised some grain, but it dried fairly quickly.
I let the first coat cure for 3-4 hours, and sanded the blank again. Applied a second coat of the poly with a brush with the lathe spinning at 250 r/min. That coat did not soak in, and clearly formed a very wet layer on the pen so I had to leave the lathe spinning for about an hour while the poly set up to prevent drips from forming on the bottom side of the pen body.
I let the second coat cure overnight, and then wet-sanded very lightly with 800 grit abrasive - just enough to remove any roughness in the poly. Applied the third fairly heavy coat of poly - again with a brush and left the lathe spinning at its lowest speed for about an hour.
I let the third coat cure for about 7 hours before again wet-sanding very lightly, and applying a fourth coat using the same process as before.
I had intended to let the fourth coat cure overnight, and then wet-sand with micromesh, and finally use a plastic polish, but when I examined the pen this morning, I decided that the finish was good enough without that step.
Conclusions:
1. The elapsed time required to finish pens using waterborn poly is significant because it is necessary to allow each coat to cure for 4-7 hours before recoating. If I were to use this approach in a 'production mode', I think I would come up with some kind of 'finishing box' that would allow a number of pens to be finished simultaneously while providing protection from airborn dust.
2. Very light wet-sanding is helpful between coats. Trying to aggressively sand between coats can ruin the finish and require that you sand everything off and start the process over.
3. Applying the poly with a brush definitely results in a thicker finish than the usual wood-turner's approach of applying finish with a rag or paper towel. And the milky color of waterbased poly makes if emminently obvious that the application is not uniform when it is first applied.
4. But the 'rotisserie method' is really quite effective in leveling the finish, but you should plan on letting the lathe run for about an hour after each application.
5. Using shellac sanding sealer does provide a slight ambering effect that somewhatly counteracts the inherent bluishness of waterbased poly. But the sanding sealer doesn't totally seal the wood, and the first application of poly still raises grain. Obviously, the next experiment would be to apply two coats of sanding sealer to see if that changes anything.
6. Poplar is not an ideal wood for making pens because it's fairly soft, and the absence of a distinct grain pattern makes the final product rather boring.
7. The final finish using the waterbased gloss poly looks and feels about the same as a finish done with CA. And from other experiments, I know that the poly finish is just as durable as a CA finish.