before and after basics: polyurethane

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Hello everyone! I can’t believe it’s already Thursday — this week just flew by. Thank you for all of the suggestions last week. I’m going to try and tackle them one at a time, starting today with polyurethane.

Many of you have asked how to apply it, what tools work the best and whether you should use water-based or oil-based varieties. In today’s Before and After Basics, I hope to answer all of your questions about this tricky liquid! — Barb

CLICK HERE for the full how-to after the jump!

Water-Based Polyurethane (I really love a matte finish)

Materials

  • foam brushes
  • soft-bristle synthetic brush
  • fine-grit sand paper
  • foam roller

In reading lots of articles on application, you will find that some people prefer to use foam brushes and some prefer bristle brushes for application. I personally do not like foam brushes, as they get over-saturated and fall apart! It makes for a frustrating venture, so I use either a bristle brush by itself or along with a foam roller.

Instructions

1. Make sure that you never shake a can of polyurethane as it will cause air bubbles to form in your finish. Gently stir with a stir stick. If you are using just the brush, you can dip right out of the can, but if you are going to use a roller, pour the poly into a tray.

2. Roll the poly onto the surface, making sure your paint strokes are in the same direction — do not work the roller back and forth, as this will leave lines and uneven spots in its wake! When working with any type of poly, it is super important to remember this step. Over-working with a roller or brush breaks the chemical reaction in oil-based poly and causes streaks in water-based poly because of the fast drying time. So work fast and in long, even strokes.

3. If you notice air bubbles after applying with the roller, go back over the surface lightly with your brush to smooth them out. Use a very light hand in this — you just want to skim the surface and not dig into the finish. You can do the whole application with a brush if you like and skip the foam roller. It is entirely up to you and what you find works best. Try it both ways and come up with your favorite finish.

4. Allow product to dry according to directions on the can, which is normally around 1 to 2 hours.

5. Lightly sand the surface with fine sand paper before applying a second coat. Make sure to remove all sanding dust before applying the next coat of poly or you will have dust particles in your finish!

6. Apply a total of 2 to 4 coats of poly depending on the needs of the piece.

Oil-Based Polyurethane

Materials

  • china bristle brush
  • fine sand paper
  • mineral spirits
  • staining pads

Some suggest using mineral spirits to thin out the first coat of oil polyurethane, and you can totally do this. I use a product called Arm-R-Seal by General Finishes that I find doesn’t need to be thinned down. This has been the best oil product for my furniture products.

Instructions

1. Using a natural-bristle brush, apply the poly in long, smooth strokes (going with the direction of the grain) overlapping the previous stroke just a bit to ensure proper coverage. Remember again not to over-work the brush as it will disrupt the finish.

2. One thing to be careful of with oil is drips! Check for drips and go back with your brush to smooth them out.

3. Oil takes longer to dry than water-based poly, so read the instructions on the can very carefully! Let fully dry.

4. Sand very lightly over the entire surface. Again, I can’t stress enough how important it is to remove all of the dust and to have a very smooth, clean surface before applying the second coat. Many make this mistake and end up with a bumpy, uneven finish.

5. Apply 2 to 4 coats and you have a very durable surface for your furniture!

Here are my thoughts on water- versus oil-based poly: Water-based products have their advantages; they are safer for the environment and working area, they dry fast, are easy to clean up, easy to apply, will not yellow over time and are quite durable as a finish. Oil-based products are more harmful to breathe in, (please make sure to wear a mask and use all necessary safety precautions), require longer drying times and can be tricky to apply.

In my experience, I’ve found the water-based poly to be all I need for most furniture pieces, but when working on a piece that will be used for a dining room table or sink, I go with oil. Oil-based finishes are still the strongest and most durable for surfaces that get lots of wear and tear.

So, that’s my two cents in the polyurethane department and it’s based purely on my experience with furniture. I hope that clears up some of your questions surrounding this process!

See you all next week!

Note: A great source for these products and more is your local Woodcraft store.

  1. Alicia says:

    Hi there! Thank you so much for all the wonderful advice! I have recently been getting into refinishing furniture. My most recent piece is a coffee table I spray painted a plum color, then stenciled a pattern across the entire table top. I have just completed my first layer of oil-based poly. My question is this: will it ruin/affect the paint job underneath the poly when info to sand in preparation for my second coat?? The paint job is beautiful (if I do say so myself) and I would be totally bummed if all my hard word was ruined!

  2. Bill smith says:

    Alicia, as long as you wait long enough, and allow the poly to dry completely, and then sand lightly, the integrity of the paint should hold. Be patient, do things methodically, little steps at a time

  3. sandy says:

    I painted my bathroom floor and put 3 costs of polyacrylic on. It looked beautiful! I gave it a couple of days, then started sanding my bathtub. I thought the poly had plenty of time to dry, but after sanding, dust particles are in there and I can’t seem to remove them. Anyone have any ideas? I hate the thought of starting over.

  4. Craig Compton says:

    Can you use Polyurethan to harden a latex rubber mask?

  5. Natalie says:

    I used rustoleum matte poly for a coffee table and it’s easily scratched and flaking. What caused this?

  6. Amanda says:

    I just made a wooden coffee table, stained it using Minwax Walnut. What is the best way to go about protecting this table? Poly with a brush? I’m a newbie DIYer :)

  7. william says:

    When using any kind of urethane water or oil based you go through different grit of sand paper before stain or sealer or applying finish make sure you have a grit free floor make sure to vacuum it and pop the grain the vacuum again when dry the apply

  8. william says:

    For wendy was the stair case ?sanded before staining a floor make sure you have a clean surface then you stain. Then you add sealer after stain has dried but before adding finish samething drying time

  9. william says:

    To for sandy for your question mineral spirit s is your answer

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