Quick Finishing Tip

Just because two finishes are from the same manufacturer, and just because their labels say they are "compatible" with each other, you shouldn't
assume they'll play nice together.

This is an issue with water based finishes. I have lots of successful experience with water based dye stains, and if you've read a few entries on this blog, you know how much I love water based topcoats. 

But.

Apply water based stain, let it dry thoroughly. Overnight, even. Next morning, start brushing on water based acrylic, and a minute or two into your work you'll see your brush looking like the photo above. Cherry Kool-Aid!

The dye remains water soluble, and the water in your topcoat is partially dissolving the dye. So your stain is leaching up into your topcoat. And from there, into your brush. 

This is not a "functional" problem, by which I mean, the color will not go all bananas and the topcoat will still dry hard and protect the wood. So I guess that's why manufacturers can say the two finishes are compatible. I'm not picking on General, either. Multiple manufacturers do this. It is potentially a big "aesthetic" problem, though. For two reasons:

One: instead of a clear topcoat over a stained surface, you now have a tinted topcoat over a stained surface. This can have the effect of obscuring the grain and figure in your wood, making it look muddy or out of focus. Sometimes this is fine; sometimes you can take advantage of this compatibility to create a tinted topcoat, or tinted layer over only part of the workpiece. Think of vignetting a door panel. But if you don't want this, and even worse, if you don't expect it: ARGH!

Two: dip that cherry Kool-Aid brush into your $32 can of finish many times, and you have a $32 can of very pale pink stain/topcoat. This is one good reason to decant finish into a cup or bucket instead of working straight out of the can!

How to sidestep this issue? Well, it's minimized (not quite eliminated) if you spray on the topcoat instead of brushing, padding, or rolling it. But the only way I've eliminated it is by using shellac as a sealer between the stain and topcoat. In the old days I would mix my own "super blonde" shellac from flakes, but now we have Zinsser "SealCoat" shellac for this job. SealCoat has less color than super blonde shellac. I cut it 50/50 with denatured alcohol for an easily brushable texture. One coat of this keeps the stain in the wood and out of the topcoat, and has the added benefit of cutting down on grain raising. After it dries well, I do a quick scuff sanding with 150 or 180 grit, which leaves a silky smooth surface. Good stuff. Enjoy!