Joe Barry replies: You want something that is easily cleaned and won’t allow glue and finish to stick. When you redo the bench top (which you will eventually have to do with use) you want something that is easy on your tools. You don’t want to tear up the blade of your Lie-Nielson plane or gum up the coarse belt on your belt sander.
My choices in the past have been – mineral oil, Watco Danish Oil or bowling alley paste wax. Watco was the most durable and attracted the least dirt of the three.
Al Breed replies: I just use oil and thinner and rub it down after it sinks in. What you want is something that resists glue but that can be easily planed when you go to level up the bench from time to time.
Bruce Hamilton replies: The best finish for a bench top in my opinion is no finish at all. If you must, it would be an oil-linseed product like Watco so it is totally absorbed into the wood with no surface film. The only purpose is to seal the wood from staining.
Water based finishes are faster drying than oil varnish (which include the urethanes) but they still stay open longer than lacquers and shellac particularly on humid days.
The principles for a clean finish is the same for all finish. You need a clean environment – a clean room with filtration of the incoming air if you are using a fan, vacuum the floor and yourself and wet the floor down with a garden sprayer and wipe your clothing with a damp rag. And don’t forget to strain your finish material when loading your gun (use the finest filters you can get) and use a filter on the pickup tube in the pot on the gun. Dust off the surfaces to be finished with a tack cloth just before you spray.