Woodworking is never a simple task. So, we are not surprised to find putting on coats of finish is challenging. It’s the final step, and I know that when something wrong happens, you may feel terrible like it’s all devastated. Fortunately, in the post, you can get what to do when polyurethane won’t dry and how to tackle the situation.
Sometimes, there isn’t anything wrong but your impatience. The finish coat dries in two phases. First, the thinner evaporates and you won’t feel tackiness when you touch the surface. Next, oxygen exposure triggers the curing process on the varnish. It’s the second phase that makes the woodwork’s finish completely dry and hard. In case of wooden floor, it reaches the top durability after up to 4 weeks, depending on weather condition (e.g., heat, humidity, etc.) and the thickness of the polyurethane coats.
Until you don’t smell the odor emitting from the surface, it’s still curing. I have experience using Minwax polyurethane on the wooden floor twice, using both oil-based and water-based ones. (And I did freak out because "Why the hell the Minwax polyurethane won't dry?"). If you see polyurethane not drying on hardwood floors, it’s likely you didn’t let the stain dry properly prior to adding the varnish. Below is the estimated time for the top coat to dry.
After 24 hours: you can walk on the floors without shoes. Don’t walk with bare feet, either. Instead, put on some socks if you have to step across the area.
After 48 hours: walking with shoes is allowed.
After two weeks: you can let your pets (cats and dogs) running around. If you cannot keep your animal companions away, cover their paws with doggie socks.
After one month: it’s time to move the rugs onto the surface.
After 6 hours: you can walk with socks on the floor
After 24 hours, you can walk with shoes on the surface. Keep your pets away. Otherwise, their claws may ruin the perfect coat
After 48 hours, get somebody to help you move the furniture back (don’t drag them along the way).
After one week, dogs are allowed to walk on the surface. You can spread the rugs on the surface after one month.
After staining, you have to wait for an extended enough period before applying the finishing coats. Otherwise, the surface won’t be able to dry and may look like a lizard’s skin. So how long does it take for a wood stain to dry? The waiting time can vary depending on the brands and the weather conditions.
The ideal temperature for the stain to dry is from 75 to degrees Fahrenheit. However, as long as it’s somewhere between 50 and 90 degrees Fahrenheit, it will work just fine. The cooler temperature may slow down the drying speed.
Besides, higher humidity in the air will make the period lasts longer. You can direct the fan’s wind on to the surface or open windows to boost the ventilation and speed up the drying. Most stain brands require users to wait 12 to 24 hours before adding the polyurethane finish. However, to ensure the best results, you should let the interval last from 24 to 48 hours, especially when the environmental factors are not ideal.
In short, you have to wait more than 24 hours before applying the first coat of polyurethane. Each finish coat should stay still for at least 6 hours before putting on a new one.
How long does it take for penetrating stain to dry? The waiting period shouldn’t last too long, or else you have put a too thick coat on the surface. If the stain is still sticky after 12 hours, you may have to remove it. Letting the lacquer there won’t make it dry naturally.
To get rid of the excess stain, apply another coat and let it soak for some minute, then wipe the surface. The move will leave only the penetrated stain. Now you can let it dry and apply the polyurethane. If all the stain is removed after wiping, you should consider re-sanding the surface.
Now you have done all the things above right, why won’t varnish dry? If the polyurethane still feels sticky after 48 hours, then it’s likely that the wood contains natural oil that hinders the drying. Most of the time when the situation happens, it occurs on the first coat. The second one shouldn’t have any drying problem as long as you add it on when the first has dried completely.
Apart from mahogany, exotic woods (the term that often refers to the woods from the jungle), usually has a very oily resin. You can feel the oiliness by touch the deck. Polyurethane, however, contains a mineral-spirits solvent that can dissolve the resin. So, when you apply the lacquer on the wooden board, the substances mix and prevent the finish coat from drying.
The ultimate solution to the kind of wood is using naphtha, acetone, or lacquer thinner to wipe off the oil on the surface before applying polyurethane. Or, you may use shellac to seal the resin inside the wood. The substance also assures that the surface won’t bleed oil later.
If you have made a mistake: putting the finish on without getting rid of or dealing with the oil, you can try using heat from a lamp or a fryer to speed up the drying process. The effect is modest, though, but it’s worth a try. Otherwise, you must eradicate the finish coat and apply a new one.
First, apply a coat of paint stripper on the area using an old paintbrush or roller. Make sure all the nooks and crannies are covered with the substance. Let it soak into the varnish for 10 minutes. When the surface is bubbling and wrinkling, it’s ready to be dealt with. Don’t use a water-based stripper because it will cost you much more time.
Then, grab a scraper to scrub the varnish down. You should use a plastic one if you don’t want to scratch and ruin the surface. The polyurethane will peel off easily as you move the tool along the wooden board. Just keep the moves in the same direction as the wood grain. A steel brush will come in handy if your woodwork as small details.
Next, use after-wash, a solvent used after the paint stripper, to rub down the polyurethane. You can utilize a paper towel to take the substance and wipe off the remained varnish. Unlike the stripper, this substance doesn’t need soaking before removing.
Repeat the process if needed until the sticky finish is removed entirely.
After reading the post, I hope you have figured out why your coat of lacquer won’t dry and how to fix sticky polyurethane. Just like the way we do with other tasks in woodworking, dealing with the problem need patience and a lot of care. If you still have any question, please leave it below. We are more than ready to help.