Besides having an abiding interest in popular science, Deziel has been active in the building and home design trades since 1975. 90% of users apply polyurethane incorrectly. Oil-based polyurethane was the first polyurethane to come to the market, and dominated as a hardwood floor finish until the last 10 years or so. Finish Both Sides at Once. This can be very important in some projects and it’s often a strong reason for choosing polyurethane … Warning: Skip this step and the top can twist, cup or warp. As far as solving your problem goes, if the finish has stopped bleeding oil and feels like it has dried hard, you might be able to even out the gloss by wiping the cabinets down with a rag dampened with mineral spirits (assuming it was oil-based polyurethane) followed by a dry cloth. Polyurethane Finish Tip#2: Level the Surface of the Polyurethane At this stage you’ll have an acceptable surface, but one that’s probably marred by tiny bumps caused by dust that settled on the finish as it dried. Homeowners often wish to show the beauty of quality wood on exterior doors and trim with a clear finish. The next day we looked at the floors and were not happy. Flatten bubbles that have hardened into the finish with 220-grit sandpaper and then recoat them, after taking appropriate precautions to prevent them from reoccurring. © Copyright 2020 Hearst Communications, Inc. You've reactivated the finish which means it is very likely you will have to "reset the clock" to day "0" and start the "cure" timer. However, it is now January and all around the floor you can start to see separation between the polyurethane and each plank joint. Most every painter has experienced the problems of bubbles in polyurethane finishes. However, brushing spar urethane is a hardworking job because it tends to harden faster, and will produce as result visible brush lines But during this time all the flowing and settling and the setting of the flattener to create certain level of shine have long since finished. This ensures adhesion and improves the overall finish. So I had it buffed and recoated with the polyurethane and still the spots are popping up everywhere, where the polyurethane did not stick.…, Q: I oil rubbed a hand scraped oak floor. Problems are difficult to predict, but there are three measures you can take to minimize your risk: Make sure the surface is clean. finish before it has a chance to evaporate. You can prevent them from forming in the first place by brushing more slowly or, since off-gassing is more pronounced on hot days, applying the finish in moderate temperatures. As Paint Source notes, polyurethane floor finishes are prone to visible scratches and other blemishes, which could require that you add more layers. If the poly is water-based and too thick, thin it … I called the guy who did my floors and he wants to charge me another $300 to fix the problem. Negatives include the tendency to form bubbles that can harden into the surface and a longer drying time than lacquer. Other than this, polyurethane has a peculiar problem associated with its hardener - the hardener being isocynate, it reacts with moisture and forms carbon dioxide as byproduct. I guess that tells you what you need to do. Minimize this problem by applying thinner coats or by switching from standard brush-on poly to a wipe-on or spray finish, both of which can be applied in very thin coats. I have never seen this happen before. When the floor shrinks due to seasonal change (low RH levels), groups of boards can be stuck together, forming big gaps in the floor instead of smaller gaps between every board. If it goes on fine, use it. https://www.popularwoodworking.com/editors-blog/the_7_myths_of Learn how to make your polyurethane topcoat look perfect with this tutorial on how to spray polyurethane.. Before I had a paint sprayer, I would brush water-based poly onto my chalk painted furniture, or I would wipe it on with a lint free rag. It’s more likely that the wood you’re finishing contains a natural oil or you have applied an oil to the wood and the oil hasn’t dried. The finish will not hold up to … Remove the finish with an oscillating tool, a sanding accessory and 100-grit sandpaper if it turns cloudy after it hardens. I am a flooring contractor, so I do have the equipment. In both cases we’re talking only about the first coat of polyurethane. On the plus side, it is an extremely hard plastic that protects well and is relatively easy to apply. With a solid wood top like this one, finish both the top and the bottom surfaces, even if the bottom won’t show. Two axioms for furniture finishers are that you shouldn't shake the can before applying polyurethane and you shouldn't wipe the brush along the side of the can. Besides bubbles, possible problems include checks, cracks, runs or separation and blushing. Then try brushing it on scrap wood. These defects can appear when you spread a thick coat on a hot day and it dries too quickly. For more related content, subscribe to … How to Waterproof a Water Fountain With Spar Marine Varnish, How to Paint Metal Doors With Oil-Based Paints, How to Do Thompson's WaterSeal on Fresh Concrete, The Family Handyman: How to Apply Polyurethane, Popular Woodworking: Finishing for First-Timers, How to Prevent Bubbles in Furniture Refinishing. Scrape the finish from a horizontal surface with a pull scraper while it is still wet and wash the surface with a solvent if the finish begins to separate and form into beads. Any thoughts? Jump to Latest Follow 1 - 2 of 2 Posts. Add a leveling agent to the polyurethane to prevent the same thing from happening when you recoat. After flattening the affected area with sandpaper, wait until the temperature drops and spread a thinner coat. If there is anyone who knows of something that I can do I would really appreciate the help. As a clear finish for woodwork, polyurethane has advantages over lacquer and alkyd varnish, but it also has disadvantages. I need to make it look uniform. Bubbling, puddling and running are common problems. Polyurethane finish on hardwood floors problem. Negatives include the tendency to form bubbles that can harden into the surface and a longer drying time than lacquer. Always lightly sand an existing coat before applying a fresh one over it. In all my videos on finish coating my number one rule is “LAY IT ON THIN”. Loose or Creaking Boards & Tight or Popping Boards, recommendation to hire an experienced pro. The problem usually appears as moonlike craters in the first coat of finish seconds after application, but it can also appear as ridges (sometimes called “crawling”), and it can hold off showing itself until the second or third coat. ... Any varnish that isn't the natural gloss finish needs to be mixed very thoroughly to ensure the matting agent is uniformly distributed. How to Clean Your A/C / Air Conditioner Condenser Unit – A clean air conditioner saves $! Pop bubbles that appear when painting or spraying polyurethane with the tip of a paintbrush. problem w/ sticky/gummy polyurethane finish Post by scottg » Thu Jul 03, 2008 9:54 pm I have finished a cherry project with minwax red mahogany or red … Let's start with polyurethane, a hardwood floor finish that's been popular in the US for the last 30 to 40 years. I just found out from MinWax they have a problem with their stain and polyurethane. Now the floor looks very dull and chalky. I've been a lurker for a while but I'm having an issue with a recent project. This can also be another cause of bubble. This is a problem that happens most often with waterborne finishes in which the finish glues the sides of the boards together. The floors having pooling marks with excess finish, brush marks and start/stop marks. Polyurethane finish problems? Hence it is important to check the condition of hardener. The contractor said the imperfections will all go away within 7 days and that the polyurethane will level out and not show any of the application marks. This is generally just a matter of a few hours. While there is no easy way to remove silicone from wood, you may be able to get most of it off by sanding. Both activities introduce bubbles into the mixture in the can, and it's likely that you'll transfer some of these to the surface you're finishing. How do we fix this? Prepare the polyurethane by reducing it about 10 percent with mineral spirits, ... How to get consistent stain on problem woods. As a landscape builder, he helped establish two gardening companies. Many can be corrected by sanding and recoating. So for a truly professional looking finish multiple thin coats of polyurethane is … There are two types: water-based polyurethane and oil-based polyurethane. Sand a checked or cracked finish with 220-grit sandpaper and recoat it. While layers of polyurethane can protect underlying surfaces, they cannot protect themselves. I waited 48 hours for the stain to dry before applying the 2 coats of poly. A: I don’t believe there is any truth to that. They can be caused by the turbulence of the paintbrush or by moisture released by the substrate. Polyurethane is also used in the manufacture of water vessels like the construction of inflatable boats, sealants for boat decks and outdoor marine vessels, and as foam in rigid-hulled boats because it provides buoyancy, sound proofing, and force. After application the finish has a certain amount of time, depending on the type of coating and environmental conditions in the home, to flow out and level. If you experience oil-based polyurethane not drying well, it’s not likely that it’s bad polyurethane. Minwax fast drying polyurethane problem. Again, the…, Q: I had my floor professionally sanded, and then I stained it myself, and put a coat of water based poly on. 4 steps to a perfect polyurethane finish. It's not an uncommon problem, especially when applying polyurethane as the finishing coats. Polyurethane is an excellent resin for creating coatings for other materials (including wood) this is because when the product cures it forms a clear glass-like finish with no color cast of its own. Examine the remaining finish. Q: We have Brazilian Cherry floors and had an experienced flooring guy screen/sand half of our floors. Both finish types come with a spray application. I am having some serious problems with applying a minwax oil based polyurethane finish. Use mineral spirits if applying a solvent-based product and water for a water-based one. It sounds…, We refinished our floors in September and they came out pretty nice. Can polyurethane floor finish problems resolve themselves? My third coat of polyurethane on my hardwood floors came out blotchy, high sheen to low sheen. These are the TWO requirements needed for a polyurethane to cure. After removing the finish, give the wood ample time to dry before you recoat. Sorry. Q: After refinishing a hardwood floor hallway with coats of polyurethane, there is a white cloudiness on some parts of the floor that will not wipe away or go away. After the f The cratering is a little larger than … If the polyurethane has crud in it, try filtering it through cheesecloth. I am having problems with my water based poly "cratering". Then over several hours or overnight it dries to walk on and over several weeks continues to cure, which means it keeps getting harder. It had little round spots all over it that the polyurethane did not cover. Avoid using a finish that contains a solvent that could attack the existing coating. Q: We have Brazilian Cherry floors and had an experienced flooring guy screen/sand half of our floors. Chris Deziel has a bachelor's degree in physics and a master's degree in humanities. Check the remaining material to make sure it's clear and particle-free. A: Was this a waterborne polyurethane? I doubt there’s any problem in finishing more frustrating than fish eye. I keep my spray room about 65 degrees and the humidity is around 50%. Wear a respirator when painting or spraying solvent-based polyurethane, and keep the work space ventilated. Make sure the surface is dull. Stained with oil based minwax stain. He applied a very fast drying, oil-based polyurethane, clean satin finish. This defect, called blushing, is the result of moisture in the wood and is more likely occur when using a solvent-based product. To save drying time, coat the bottom and then immediately flip it over to finish the top. Theories abound over this topic---everything from the shaking of the cans that occur during transport to the type of wood it's applied onto to impatience in applying poly by brush. This defect is caused by silicone in the substrate which may have been left by furniture polish or wax. This is why leveling is the pre-buffing step required next. Polyurethane finish features a few downsides because it cures, sets and rises more slowly than spar urethane that could dry in a matter of minutes. Wait for drips to dry before you scrape them off with a razor blade or sand them down with 220-grit sandpaper and recoat. While a thicker coat of polyurethane affords better protection, it’s important to realize that thickness is built in layers. I did the same…, Q: I had my hardwood sanded and refinished and high-gloss put on. There are several explanations for such a happening; however, at this point, I want to look at what to do when polyurethane won’t dry. The rough grain is dull, while the closed (smoother) areas are shiny. Note: I just don’t care if there are a few fingerprints. A: Well, of course the open grain,…. If you discover a major problem after the finish skins over … The best time to recoat polyurethane is after it has dried tack-free, which can take from one to several hours, depending on the product you're using, and before it cures, which is usually between 24 and 48 hours. What can I use on it or how can I repair it? He applied a very fast drying, oil-based polyurethane, clean satin finish. Basically, the polyurethane is pulling away from the floor where each plank meets. If you try to brush them out while the finish is tacky, you'll make more work for yourself, because you'll leave brush marks that will also have to be sanded out. I had stained my fireplace, waited a few days...then put on the polyurethane and it streaked it white...as if I had let water sit on it or something. When applying polyurethane on vertical surfaces, you may experience drips or runs. Here are the details: Sugar maple boards, sanded to 120 grit. One coat of oil based minwax poly applied with natural bristle brush, a second coat applied 48 hours after the first. Polyurethane is the most durable of clear exterior finishes. Uncured polyurethane can cause breathing problems such as asthma. This can cause problems if you apply the wrong type of polyurethane. Do you have problems with your polyurethane being streaky or foggy when you brush it on? Though frustrating, it is not strange to see that your polyurethane finish does not dry several hours or days after application. The next day we looked at the floors and were not happy. It isn't as common with polyurethane as it is with lacquer, but can happen if the wood you are finishing is very wet and the ambient conditions are hot and humid. (72 F) and at Relative Humidity (RH) of 35-65%. I am using a Bink's hvlp, top of the line, spray system. Flexible plastics are also made from polyurethane. Cleanliness. Less shine. Unlike lacquer, polyurethane doesn't redissolve after it hardens, so problems should be resolved on a coat-by-coat basis. The table and the finish need to be kept at room temp. Is this true, these polyurethane floor finish problems will solve themselves, or should I be calling my bank to stop payment?