Finishing oak stairway...bubbles in poly

[Joe Pack]

Some good friends have built their own home and are now in the process of finishing their oak stairway. The oak has been stained with Zar oil-based stain and they have started applying an oil-based poly in a couple of small areas. They are experiencing problems with bubbles in the finish and are not sure what to do. The poly was stirred, not shaken, and is being used full-strength from the can. (Sorry, don't know the brand). Application was with a generic brush, not a good quality bristle brush.

A couple of questions to help them...

1. Any ideas why the poly has so many bubbles? Suggestions to prevent this?

2. Ideas on oil vs. water based poly as to application and wearability, especially over an oil-based stain? (The stain is a given; already applied.)

I will pass on your comments. Thanks for the help.

Joe

[Scott Holmes]

Did they wipe the excess stain after they applied it to the floor?

If not they let too much stain and it is causing trouble.

If they did wipe the excess then too thick an application was probably the reason... Most Poly varnishes are too thick in the can to apply properly. They need to be thinned 10-20% with mineral spirits.

Contrary to popular MYTH shaking and getting bubbles in varnish is not a problem if the varnish is applied using the correct technique. I use a 1/4" foam roller to apply it to floors; this creates about a million bubblers per square foot, then, I tip-it-off with a quality brush.