After a lengthy repair process to get my white oak floors laced together after tearing down a wall, I've run into a new problem. I plan to use a dewaxed shellac (Zinsser SealCoat) as my sanding sealer under a waterbased poly. After leveling and sanding the floors I applied the shellac, however I have run into several problems shown in the photos below. First, I have lots of places in which the shellac is blotchy - the coloration is not uniform. There is no ridge or bump, just a visible color difference. I also have a few scenarios where there was clearly pooled shellac where is there is a bump. I've attempted to even out the bumps with denatured alcohol which seems to work, but I'm wondering how to fix the uneven coloration that I am observing throughout the floor? Any input is greatly appreciated!

Discoloration




Visible humps

s uneven application...high and low from heavy to lgiht..try putting some more shellac in the light areas to see if it fills in..it should..if not..hand sand the areas and if small enough area, the whole floor..

forget buffing..near impossible..

this will be better for adhesion anyway even though they state it isn't necessary( and it isn't)..but not that the sealer has dried more than one day..i would rough it up..

after you get first coat waterbase on ..buff it well...this will smooth things out..then you can do 2 more coats.

the floor should turn ok for you..

Well, I spent the day working with the suggestions here. Specifically, I went around and scrubbed down the lap marks and drips and that took care of that problem. Then I used diluted sealcoat and went over the spot that looked lighter to improve the blotchy -ness. I'm not sure this really helped much. The floor does look better, but the blotchy-ness remains.

Here are some pictures:




I'm beginning to think I should sand and start over which leads me to two questions.

1 - Is a drum sander too aggressive, and if not, what's the highest grit I can get away with (Area is 450 sqft)
2 - Should I try sealcoat again or is there an alternative that might be easier to use. When re-applying the dilute SC I used a 1/4 roller which seemed easier to control and lay down a thin coat, so I don't believe I will repeat the horror show of the first coat but you never know. Keep in mind the plan in to follow whatever goes down with 2 coats of Traffic.

how did you apply the first coat?

the markings can be in the sanding..but its too difficult to tell from a foto..

start with whatever grit will work...you can probably get away starting with 50 or even a 60 grit..


when applying..try less stop and go points.

start in middle and run in full columns one way, then turn and fill in the other way(if that makes sense to you)

lambswool will be your best method of application.

Rollers are great for some products but if I use shellac, I generally cut in with a brush and use a lambswool ( 10 inch ) to coat the field.That being said, you have to do everything James said, mainly work out the darker areas and then touch up.

As for your other questions, you could drum sand with a 100 grit belt and easily get the shellac off the floor .But the shellac needs to dry obviously.

Also, if you want to seal with a better product, I recommend Bona Dri Fast sealer. It is a bit easier to work with and if done carefully, can be rolled without issues.Dri Fast buffs out easily where Shellac melts and gums up your buffer media.And traffic is hard as heck so you will spend unnecessary time trying to get the traffic smooth.Not an easy task.

Shellacs are okay but have some issues .Drying super fast is not always good because it gives you less forgiveness and less work time.You have to haul ass when you coat with shellac and not make mistakes