You asked me, so here it is.
I have only four (4) things to say about finishing, whether it is pens or anything else made from wood. I know that none of this is what anyone wants to hear because making pens is all about FAST.
1. Quick and durable ARE NOT mutually inclusive properties of a finish on a piece of wood. Finishing takes time, and the better the finish, the more time it takes.
2. The surface finish can be no better than that of the wood under it.
3. There is no one finish that will do everything we want from a finish. Everything we do is a compromise to accent the properties we want, and hopefully minimize those we don't.
For this discussion, there is a 4th one:
4. The lesser the finish, the more it will have the look and feel of wood. When taken to the same level of polish, bare wood looks and feels more like wood than a CA glue.
Explanation:
Number 2, the wood surface is the most important ingredient of the finish. The wood should be polished to where it doesn't need a finish before we put anything on it. That means sanding to AT LEAST 1000-grit, and I recommend nothing less than 12,000 Micro-Mesh, or the equivalent grocery-bag paper that I use.
The finish that will wear the longest is the one that puts a surface film with the most abrasion resistance on the surface. Wax is the fastest, but least durable. Plastics such as acrylics (CA glue), epoxies, melamines, etc. are the most durable. They are also the hardest and most brittle, (brittle and hard go together) and the most subject to impact damage or cracking due to wood movement. They can be the most difficult to apply. They also have the least feel of the wood, are the most difficult to repair, and have a wear pattern that results in fine surface scratches that dull the finish with time.
If you want fast, there is nothing faster than stopping at the highly polished bare wood and then adding the protection of a good wax. Carnauba is the hardest, but Microcrystalline (Renaissance) is the least damaged by the acids in our body oils. It looks good when new, but it is the least durable finish we can put on a piece of wood. Fortunately, wax is easy to repair.
In our rush to put something ON the wood, we too often forget that wood itself can provide us with a good finish. I would suggest that everyone try a bare wood finish ONE TIME before telling me it is not a viable finish for a piece of wood. A lot will depend on the hardness of the wood itself, but left to itself, the no-finish will polish the wood and keep it oiled from use. It may not look as good as the high gloss of the plastic when it is new, but in the end it will probably look better because used wood looks a lot better than a used plastic.
Varnish resins may be the best compromise available. They will take a high gloss, look like wood, have the warm feel of wood. To use Lou's analogy to the automotive industry, there is nothing that looks better than the wood dash and trim in an old Jaguar or Rolls, and that is varnished wood. Depending on the resin, it can have excellent wear resistance over time.
Penturners have almost totally ignored the varnish resins as a finish because they ARE NOT fast. In fact, they may take the longest to apply of anything that we can put on the wood. Twelve (12) coats of Waterlox will give an unbelievable gloss, and it will have the durability of the phenolic resins; but it is going to take at least 12 days to put it on the wood. Add another month to that for the finish to fully cure before we start using the pen, and we are talking about a long time to finish a pen.
We use a lot of lacquer and shellac because they are high gloss clear finishes that are easy to apply. And some of us are dipping with the lacquer because that is even faster. What all of the instructions fail to mention is that it will take at least a week (2 is better) for a lacquer to even get close to its full hardness; and that it will take several months for shellac. Ask a custom car painter how long they wait before buffing and polishing a lacquer finish. I guarantee that they are not driving it on the street that same afternoon; and that is just what we are trying to do with a pen.
As for the durability of shellac, just remember that the classic violin finish is a spirit varnish, and that means a shellac. Durability?? These folks are talking about a 300-year finish on a musical instrument that is to be used. Yes, they use other resins to make the shellac harder, more durable, and more resistant to wear. They do not add waxes and oils to make them fast, and these shellac finishes take months to years to apply.
In conclusion - Finishing takes TIME, and the better the finish, the longer it takes. Until we are ready to invest the require time, we will never be happy with anything we put on a pen. So, we continue to use our FAST finishes, remove the pen barrels and start handling them before they have a chance to cool, and then complain about there not being a durable finish for a pen.
Yes, pens can be fast, but better pens take longer, and the best pen will take a long time.