Viscous finishes like typical oil varnishes don’t flow easily, so brush marks can result. It … How to Spray Polyurethane Rather Than Brush – DIY Tips Read More » Clean the surfaces with a damp rag and blow out the corners and crevasses with an air gun. It is very frustrating when one spends hours and hours building a project, making sure This will keep the finish from It dries fast so you can apply three coats in a day. This is no help. When I apply a polyurethane top coat to a project, I always get brush streaks even when I use a foam brush and when I thin the material. It gives me great results, quickly and painlessly. Do not re-load the brush. I cut the poly by feel. When brushing on the finish, make sure to load the brush enough so you can apply a Once the whole surface Apply more varnish on those areas. Water-base finishes must be applied with synthetic bristles. that all the joints fit properly, the wood grain matches from board to board, removing any is required here. business, I do not recommend buying these finishes in large cans like gallon sizes. 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. Some areas will be shiny and some will be dull. Wipe on a very heavy first coat on the bare wood. When it stops soaking in, but not more than about 15 minutes, wipe off as much as you can. article in the attempt to both help the readers who are having problems with this and new and it's the first time you have opened it, but each time you use the finish, it will They can spontaneously combust. The final level of finish gloss depends on the final grit used in the wet sanding. Wipe contoured surfaces with a clean cloth, going with the grain. Five days to a really nice finish is worth the effort. Sand down the brush marks lightly with the fine-grit sandpaper. Clean your workspace. obtain. Brush flat surfaces with a thin coat using a bristle brush. First, make sure the When brushing on the finish, make sure to load the brush enough so you can apply a liberal amount of finish without having to press down on the brush to get more out. Thinning the varnish is also important. I try to finish my work before final assembly if possible to be finishing horizontal surfaces. But instead of one or two or three coats, I generally need 8, 9 or 10 coats to achieve the same build. The third coat is the tricky one. Six hundred grit yields a nice satin look. In truth, the problems are not with the Apply the polyurethane finish lightly to the brush… The goal is to remove the brush marks. This should burst the majority of bubbles. Rub the excess off quickly with a dry rag. Polyurethane is a finish coating that can make any wooden surface more durable and more beautiful. You will waste a bit here but will make it up in future steps. Whether it be brush-on or wipe-on, I really love a good polyurethane finish. If it is a large surface I sand it with a power sander that has a small orbit. Fabulon is a very good finish also. And don’t drag the brush on the edge of the can. if you do, you will wind up with drips or too much material on the surface. You only put on a very thin coat so you’re not wiping off much. excellent results if you know how to properly brush on that finish and a little about how It keeps moisture from damaging the wood. It's best to apply polyurethane to flat (as in level) surfaces so the finish can self-level and is less likely to drip. Lightly touch the surface with the loaded brush and then start to move the brush across I tend to use brush-on polyurethane for table tops, and surfaces I want to build up a thicker finish. Repeat step 3 three to four more times. My experience with painting has not always been great. An above average finish brush is very dense and soft. You don’t need several different types of finish for satin or semi-gloss. Using the very tips of the brush, take light passes just If you are using a varnish that has a flattening agent in it that is meant to give a semi-gloss or satin sheen, make sure you stir the vanish well to evenly distribute the flattening agents. Brushing a rounded, contoured or vertical surface is more likely to create drips. You will need at least three coats, but it dries fast. Do not leave rags with oil base finishes in your shop. I generally also sweep the entire area also. brush marks will not have enough time to flow out. If you thin oil-based quick-dry urethane with naptha, it will dry fast enough so that you can get two coats on in a day. I soak them in water and lay them flat out side. Even though I’ve built dozens of cabinets and furniture pieces, I don’t consider myself a high-end finisher. When the brush marks don't resolve themselves, try a few corrective techniques. Most oil based varnishes can be thinned with pure gum Add more mineral spirts if necessary testing the results on a scrap before using it on your project. Usually 6-12 hours later, start the process of applying the next five coats. Tipping off is done by wiping the excess varnish on your brush on the side of the small container then lightly drawing the brush, held perpendicular to the surface, and then removing the excess back into the can or to areas not yet varnished. Reduce the number of particles that might end up sticking to your coats of polyurethane. Vacuum, mop, and/or wipe every surface clean. creating air bubbles. has dried. I rag on thinned urethanes. Thick coats of finish also have a tendency to retain brush marks. Another point is the temperature of the air where you are varnishing. It will run somewhere around $20 but with proper care will last years. Richard Oedel replies: You aren’t doing anything wrong. problems readers e-mail me about is how to eliminate the bubbles in a finish that they Purchase in smaller sizes or when first purchased, transfer the finish from the larger can If you cut through the finish, repeat third coat process. This is a skip-the-brush system. get thicker because as the amount of finish gets lower in the can, the more air stays in swear never to use that inferior product again. Applying polyurethane (and most other finishes) in heavy coats creates bubbles, puddles and runs and becomes a defect in and of itself. If you are not in the method). finishes flow out and their set up time. I use a badger tail brush 2˝ available at Dick Blick (dickblick.com). Let dry 24 hrs. Besides having a great name right out of the 1950s, this is tough stuff and is used on floors. I cut my poly with high quality mineral spirits, 2/3 poly and 1/3 mineral spirits for the first two coats. will have to apply a few more coats than you would have if you used the finish without When you apply a finish by brush, you are basically Natural bristles will absorb the water and swell up. I slowly apply the finish and finish each pass with the airplane technique. At about coat 5, it starts to take on that satin sheen your are looking for. Many people assume that if they brush out the finish well, it will level and stay Bob LaCivita replies: Applying a brush finish is difficult with polyurethane or varnish. Clean your brushes well after each coat. to smaller ones and make sure the lid is placed on tightly. You should only find an occasional dust bump. That is the art in the word artisan. You need to keep moving along the wet edge—don’t re-brush if at all possible. To avoid being wasteful of that wiped off varnish, use this technique. I’ve been happy with everything from pure poly at Home Depot (ok), Rockler’s General Finishes with some linseed oil, (wonderful) or Daly’s Profin, similar oil base (fantastic). bubbles will have enough time to burst before the finish sets up. Therefore, you Remember to occasionally stir this smaller container as well. Start by adding 1/8 part ordorless mineral spirits into the can you are brushing from. turpentine or a good quality mineral spirits, but it is always a good idea to check the Allow at least a week for the finish to cure. label on the can to make sure. Sand down the brush marks lightly with the fine-grit sandpaper. thickening too quickly. Wipe on a thin coat over the whole project. I've never done polyurethane before. Micro-Mesh sanding pads with grits from 1500 to 12,000 will take you to a wet look finish. the surface. A light coating of finish after sanding disguises the area. It gives me great results, quickly and painlessly. Polyurethane typically leaves brush marks from a paintbrush whenever it is first applied, but if it is the right consistency and if the proper procedures are applied, the ridges resolve themselves and the polyurethane settles to a smooth finish. finish has enough solvent in it. the can and this will make the solvent evaporate much quicker. At this point I look for areas that have absorbed the finish more then others. The second coat is a repeat of the first. I believe this is well worth the extra time, considering the results you will An above average finish brush is very dense and soft. Thinning this much may not be necessary when the can is brand