Our oil-modified polyurethane finish of choice is made by DuraSeal.

Dura Seal is the professional line manufactured by Minwax, but we’ve tried Minwax floor polyurethane from the big box stores, and it is not the same product.

We’ve been using and selling DuraSeal since 1995 because

  • its quality and color are extremely consistent from year to year and batch to batch.
  • it is extremely hard-wearing for the price.
  • its perfect viscosity makes it very easy to spread and it levels extremely well.

DuraSeal’s Quick-Dry sealer is intended as a primer coat.

A great time-saver

While there is nothing magic about using this seal coat (their straight, full-strength polyurethane will seal the wood just as well) it can save you an enormous amount of time.

Their sealer is a carefully diluted version of their polyurethane that will dry to the touch before it cures.

This allows you to get a coat of polyurethane down over the sealer after only four hours of dry time and without abrasion of any kind.

Most oil-based polyurethanes require 12 hours between coats and you must abrade between all coats. On large jobs, this is hugely time-consuming and the Quick-Dry sealer will save you time and money.

On small jobs (100sqft or so) is is more cost effective to skip the sealer and use three coats of regular DuraSeal polyurethane, but you will only apply one coat per day and you will have to abrade between each.

Read the full coating instructions for DuraSeal.

DuraSeal Quick Dry Sealer

Published coverage rate, gallon: Covers 350-400sqft

Published coverage rate, quart: Covers 75-100 sqft

VOC level: 4.27lbs per gallon

DuraSeal polyurethane

Available in three gloss levels: satin, semi-gloss and gloss.

When in doubt, we recommend the satin because glossy floors will dull down in high-traffic zones and the contrast against the unworn high gloss areas will be unsightly.

DuraSeal polyurethane

Published coverage rate, gallon: Covers 500sqft per gallon

We also carry the satin finish in quarts.

Published coverage rate, quart: Covers 75-100 sqft

VOC level: 4.09lbs per gallon.

LIMITED DELIVERY AREAS

Due to hazardous materials regulations, we can only ship DuraSeal VIA GROUND and only to the following states:
Minnesota, Wisconsin, North Dakota, South Dakota, Nebraska, Illinois, and Iowa.

It is a common misconception that oil-based finishes are the best and toughest coating for hardwood floors, but that is not necessarily the case.

Good quality oil-based finishes are still great for floors, but the the 2-part catalyzed commercial waterborne finishes have surpassed them, at least as far as abrasion resistance is concerned.

But that hasn’t made oil-based finishes obselete; they still have plenty of positive qualities that waterborne finishes don’t:

A little bit of color, the easy way

Oil-modified polyurethanes are not tinted with pigment, but they do have a pleasant, amber color that gives wood depth and richness.

Modern waterborne finishes do not have any color whatsover and so far all attempts to add pigment to waterbased finishes have fallen far short of the color that oil-based finishes give to wood.

Flow

Oil-based finishes take longer to dry because it takes longer for their solvent to evaporate.

You may find that annoying if you’re trying to get your job done quickly, but the fact that it takes longer for these finishes to skin over means that they continue to flow and find their own level for a long time.

This means that bubbles, skips, and small puddles are more likely to melt away on their own. Waterborne finishes are more weather-sensitive and can flash dry when the air is very warm and dry.

Drawbacks

The main problem with oil-modified finishes is their odor. Enormous quantities of paint thinner have to evaporate out of the finish in order for it to cure. Paint thinner is a neurotoxin and is very hard on respiratory systems.

You must coat wearing a respirator with filter cartridges designed to remove organic vapors (dust masks are not adequate) and you must have windows cracked in the affected rooms for the entire drying cycle to make sure the evaporating solvent has a place to escape.

Do not sleep in a house on the same day when an oil-based polyurethane has been recoated, and don’t let your pets stay there either.

Pete’s Bonus Tips

Heat, humidity and air exchange.

No matter what the season, both oil and waterborne polyurethanes need THREE conditions to cure quickly and thoroughly:
  • low humidity
  • warmth
  • air exchange

The air has to be DRY because heavy, moisture-laden air literally blocks oxygen from reaching the finish

It needs to be WARM because the chemical reaction that cross-links and cures the finish will not proceed below 65°.

And a constant but gentle source of FRESH, OUTSIDE AIR provides the oxygen that the finish must combine with in order to become a solid and fully cure .

Some tips for creating the perfect curing scenario:

If the interior temperature is likely to fall below 65° at any time during the coating or the first week after coating, turn on the heat!

Don't point a fan directly at the drying floor; it will force dust into the wet finish. Use a fan in an adjacent room like a bathroom or kitchen vent that is connected to the outside, and leave it on. In warm weather you can put a box fan in a window (blowing out!) in an adjacent room. In cold weather, box fans in windows will suck out too much heat - just gap the top a window in each affected room.

High humidity is the most difficult coating condition to deal with. Turning on the AC will bring the interior humidity down, but without opening windows, the evaporating solvents have no place to escape and fresh oxygen can't get in. But opening windows brings the humidity back up. Usually you simply have to resign yourself to longer times between coats and a longer overall curing time during the most humid months.

For oil-based polyurethanes, you should keep one window in the coated room gapped to 3” for two weeks.

Isn’t oil-based polyurethane the best finish?

Oil-modified polyurethane, whose solids are a mix of alkyd resins and plastic (polyurethane), is a tough, solvent-resistant finish.

It has a long, proven history which many people consider to be superior to the newer, water-based finishes. But because of increasingly stringent air pollution laws, the coating industry has been pouring their research and development dollars into improving waterbased finishes.

So today, medium quality waterbased finishes are about equal with high-quality oil-based finishes, at least as far as wear resistance is concerned. But the acrylic resins in cross-linked waterborne finishes (such as Bona’s Traffic HD) provide a even tougher, more abrasion-resistant floor.

The resin themselves are harder, but the cross-linkers or hardeners that are added “cause the resins to cross-link from droplet to droplet, making the finish totally reactive rather than a combination of reactive and evaporative.”*

This is simply a long-winded way to say that, if you are judging finish only by how many times you can walk across it wearing your golf cleats, the cross-linked waterborne will always come out on top. Oil-based finishes still have many strengths (such as color and ease of application) than can make them superior to waterborne finishes for some applications.

Big-carton retailers are not the best places from which to buy your floor finish. Most of the finish brands they carry (MinWax and Varathane we're looking at you) are from companies that mainly specialize in furniture finishing. If they have a floor-protection product, it is an add-on. Better to choose a product from a brand that focuses on higher standards required for products you walk on. Waterborne finishes have allowed for great advances in the longevity of flooring polyurethane, but that does not mean that ALL waterborne finishes are quality. 

*Bob Flexner, Understanding Wood Finishing. Reader’s Digest, Pleasantville, NY., p.168