Q: I applied Varathane oil based stain after sanding to my oak front door. I let it dry thoroughly, overnight, then applied Varathane Spar Urethane with a brush. It’s been on 24 hours and it’s still tacky. I’m wondering if it will ever dry.The daytime temperature is 80. I would say the weather conditions are ideal, so I’m searching for an answer. I’m wishing I had used ZAR, but perhaps that is no better.
A: Right off the top of my head, I can think of several things that could be the problem. One will simply require a bit of patience, but the others may require more work.
Although the temperature is right for quick drying, there is another environmental factor that is equally important; humidity. Very high humidity can disable the driers in oil based coatings, both stain and finish. Thus, they will lose their solvent, and give the appearance of being more or less dry, but will not cure and may remain tacky for up to a week or more.
How you stained is another factor. Stains are meant to go onto raw wood, be flooded on, then wiped off, leaving only what the wood absorbed. Brushing stain on, as if it were paint, can result in not only slow cure, but a finish with weak adhesion.
Finally, there is preparation. You mentioned sanding, but did not say whether you stripped the existing finish, or whether you cleaned the surface to remove dirt, oil or grease. With woods like oak that have very large pores, sanding alone will usually not remove either the finish in the pores or the accumulated dirt and oils surfaces tend to accumulate. In fact, sanding a contaminated surface can drive oils further into the wood. Such contamination can inhibit the cure of any finish.
If the humidity is high, give it more time and hope that is the only problem, but if any of the other steps were done in error, you may have a larger problem on your hands. And for the record, none of these problems are related to the brand, so using a different one would not have mattered.