If you put polyurethane on a rough surface you will get a rough finish. Second, as @keshlam says, make sure there is no dust at all on the surface before you apply the finish. A slightly damp cloth can help pick up anything remaining (but make sure the wood is dry before you apply).

Why is my polyurethane bumpy?

Nobody wants to do all the work of refinishing and end up with bubbles in the finish. “The most common causes for bubbles are shaking the can and improper brush prep—you don’t stick a brush into the finish without first soaking the bristles in mineral spirits, for oil-based polys, or in water, for water-based polys.

Why does Polyurethane make wood rough?

Usually when varnish makes a surface rough, it’s either that it’s picked up dust during the drying process, or it was being brushed/wiped too long after application.

What happens if you don’t sand between coats of polyurethane?

The texture of polyurethane is rougher if you do not sand between coats of polyurethane. However, the difference in finish is not visible to the naked eye. Each layer of polyurethane will still adhere together whether you sand between coats or not.

How do you fix bad polyurethane?

The problem is easily fixed. Sand the uneven finish using fine-grit sandpaper. Try not to sand too hard or you may go through into the stain, requiring that you re-stain the area. Wipe away dust and debris with a clean cloth. Apply a very light coat of polyurethane to the sanded area with a brush.

How do you stop air bubbles from polyurethane?

Use mineral spirits (paint thinner) in oil-based varnish and polyurethane. Use a retarder in lacquer. And use a flow additive in water-based finish. It doesn’t take much to have a significant effect.

Do you really need 3 coats of polyurethane?

For ideal results, you should use about three or four coats. You will also have to wait quite some time between coats, as this polyurethane takes longer to dry. No matter how many coats of polyurethane you apply, it will always be quite a time-consuming process when using an oil-based finish.

How do you make polyurethane finish less shiny?

How to Get a Matte Finish With Polyurethane Topcoat with No-Shine Polyurethane. Hand Rub With Wipe-On Varnish or Oil. Rub Down the Finish With Wax or Furniture Polish.

Can you put too many coats of polyurethane?

Generally, more than 3 coats of poly doesn’t do much good. It’s really not needed nor recommended. Each additional coat needs to be buffed so you are kind of buffing off half of the previous layer. Each additional coat takes longer to try due to the added layers.

Should I sand between each coats of polyurethane?

Allow each coat to dry fully. To give the subsequent poly layers something to bond to, sand lightly between coats with 320-grit sandpaper wrapped around a hard block. Note: The first coat needs the most sanding to appear smooth; don’t worry if it doesn’t look as flawless as you’d like at first.

How many coats of polyurethane should I use?

For protection, two coats are the minimum, but floors and anything else that will see hard wear or occasional moisture should get at least three coats. Each coat also makes the finish a bit smoother.

What can I put over polyurethane?

How to Paint Over Polyurethane Clean, lint-free cloths. Mineral spirits. Wood filler. Protective face mask. Gloves. Protective eyewear. Fine-grade sandpaper. Liquid sandpaper (optional).

Can you buff a polyurethane finish?

Buffing can create a glass-smooth finish, even after polyurethane has been applied not-too-well with nothing more than a brush in an ordinary home workshop. Buffing works beautifully, even if you’ve applied a finish that’s not too smooth to begin with.

How do you smooth out brush strokes in polyurethane?

Just dip the brush in and let it drain. You can also pad it on. Finally, for a fine finish you will need to wet sand with 600 grit and water with a drop of dishwasher detergent. Allow at least a week for the finish to cure.

Can you use a torch to get bubbles out of polyurethane?

Re: bubbles in polyurethane When the bubbles show up, I use a torch and pass over quickly to get the bubbles to rise to the surface and pop. Especially useful when using the two-part pour-on poly finishes. But avoiding the bubbles in the can is most important too.

How do you remove brush marks from polyurethane?

A light coating of finish after sanding disguises the area. Sand down the brush marks lightly with the fine-grit sandpaper. Brush the sanded area off with a soft cloth to remove all traces of dirt and grit from the sanding. Apply the polyurethane finish lightly to the brush, making sure to wipe off any extra.

How long should you let polyurethane dry between coats?

Allow product to dry a minimum of 1-2 hours between coats. Sanding between coats is not required for adhesion as long as the time between coats is less than 6 hours. However, screening or sanding between coats usually produces a smoother better looking finish.

How many coats of polyurethane are waterproof?

Polyurethane does not make hardwood waterproof, but it does provide a strong protection layer to make wood water resilient and protect your floors from scratches. To give your floors the best protection, be sure to use 3 coats of a high grade polyurethane.

How long should I wait to apply a second coat of polyurethane?

Apply thin coats to avoid runs and sags. Recoat within 2 hours. If unable to do so, wait a minimum of 72 hours, then lightly sand and recoat. Apply at least three coats on unfinished wood and two coats on surfaces already finished.

What is the least shiny polyurethane?

Flat or matte polyurethane leaves the least shiny coating and conveys the look of natural, unfinished wood. Satin polyurethane has a low to medium sheen that helps conceal dirt and scratches, making it popular for flooring. Semi-gloss polyurethane and gloss polyurethane have a higher level of sheen and reflectivity.

Which is better Polycrylic or polyurethane?

The formula has an acrylic base; polyurethane is added for better adhesion and durability. Polycrylic is not as durable as polyurethane and is meant to be used only on interior surfaces such as cabinets, furniture, and trim.