Tung oil or poly urethane?

[kelLOGg]

I will soon be finishing an ash table top and am asking if tung oil provides protection from spills. If the weather was warmer I would use poly but it is too cold to apply. (Shop is unheated).  I don't want to wait for a 70° day.

[btulloh]

Tung oil is not really good at protecting from spills. A lot of coats of a polymerized oil would be fairly good, but not perfect. You can always put the tung oil on for now and topcoat with poly later though. No problem with poly adhesion over tung oil. Do the tung oil now and topcoat later with the poly. Just don't use wax or furniture polish while you're waiting for the warmer temps. 

[Crusarius]

water base poly (polycrilic) is not very obnoxious smelling and can be done in the house with very little odor. It almost has a mild mildew smell to it. But does not last very long.

[bluthum]

Way back in the day I'd use nothing but some type penetrating oil, tung was my fav. Overtime I started incorporating various amounts of oil base poly into the mix [waterbase wasn't around then]. Eventually I swallowed my pride and started using poly film based products entirely as they last longer and offer better spill protection and the opportunity for basic cleaning over the years. The higher the gloss the thicker and slicker the film thence the easier it is to clean in theory.

I'm unsure how cold you are talking about but most oil base varnish will cure at a lower temp than advertised but it takes longer. Ditto for waterbase. Modern water base polyacrylics seem to me about benign when curing, hardly noticeable with about any ventilation at all. But that's only an opinion.

The suggestion to apply tung now and a film coat is a good option also but fresh new sanded wood is best for top coats. If you do use a penetrating oil don't neglect to scuff sand before any later film coats. 

[kelLOGg]

The atypical cold weather we are having now (~9°F low) has pushed me to tung oil.. but.. this cold snap won't last. This weekend highs will be in the upper 60s. My plan is to move the projects to the 2nd floor of the barn (via the elevator) where it will be quite warm and finish it there. Then roll it into the dry kiln set to ~70°F for curing. Then recoat. It'll be a few weeks before I get to this.