Why did the finish on my piece has become cloudy

The term for a cloudy, milky appearance in the finish is Blush. There are three causes:

1. The most common reason is an incompatible stain. For example, using a water-based topcoat over an oil-based based stain. When the top coat is applied, the oil in the stain seeps up through the finish and reacts with the acrylic causing a chemical blush.

To prevent this, either use a quick-drying water-based stain or allow the oil-based stain to dry for 72 hours. You can also seal an oil-based stain with a coat of shellac or lacquer sealer to provide a barrier between the oil and the acrylic.

2. Another cause for blushing is high humidity. Applying a water-based finish in humidities of over 75% may cause blushing because moisture becomes trapped beneath the finish and cannot evaporate.

You can prevent this condition by increasing air movement in the finishing area with a fan. All water needs to evaporate is sufficient air movement. You can also improve drying conditions by increasing the temperature in the drying area.

3. Another common cause is a wet object or a water spill left two long on the surface. In most cases, the white mark will recover and fade within an hour if the spill is cleaned up in a timely manner. If the water has been sitting on that area for an extended period of time then it might not be able to bounce back.

To fix this, the surface needs to be scuffed and sanded first. Second, we recommend applying a sanding sealer to protect the top. Sanding sealer has a larger resin particle, so it will provide a better build for the next sanding step. Then finish with your topcoat.