Reply by Lovegasoline

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Posted on Sanding Before and After Zinsser Sealcoat Shellac ( topcoat is General Finishes H20 Poly)

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176 posts in 1053 days

#1 posted 08-30-2020 10:25 PM

Here’s the results.

The Zinsser Sealcoat has completely transformed a moderately handsome wooden object into a dull, washed-out, drab looking, piece of nothing. It has obscured and reversed all of my efforts. Ugh.


I sanded to 150 on my ROS. I had no 180 ROS sanding discs left, so I sanded by hand at 180 grit. Figured that would be enough for a waterborne poly film finish.

I have a great spray gun but it’s been a decade since I’ve used it … much has been forgotten (like the fan adjustment. The documentation – Anest/Iwata – is so sparse as to be useless) so during set up I was getting a heavy center weighted pattern without a broad fan … “are the orifices obstructed?”. No. Finally got that figured out and got refamilarized wi the controls (!)... I was under extreme time pressure and rushed so working frantically.

Got one Sealcoat sprayed.
I was thinking I’d only need one, but it looks like it will need two. maybe I should have thinned the Sealcoat to a one pound cut(?) and done two coats of that?

There’s a few areas where it needs to be gone over: a coupe areas a little heavy with thick edge and one of these which boarders on a dry spot that didn’t get finish.
It left the wood grain raised/rougher than I though it would with an alcohol base so I’ll do light 220-320 sanding to smooth the nibs. I’ll need to do a second application and I’m hoping the 2nd coat of shellac will just melt in with the 1st coat for a seamless look.

I have drawers for another cabinet (not posted about) that are going to be finished just with shellac, likely two applications of Sealcoat. The case for that cabinet gets a Sealcoat of shellac inside and out, then General Finishes Waterbase Poly topcoat for the exterior only.


Back to the drawers in question kitchen drawers that will be top coated with General Finishes Waterbase Poly/Flat.

Regardless of the above minor spraying issues – which I’m sure are easily correctable (I’m actually very good with spray guns but it’s been a very long time): unfortunately to my eyes the Sealcoat on these two drawers looks like completely terrible. It looks like crap to me.

Instead of popping the grain, deepening the tone of the dovetails, and enhancing the wood, it looks to have done the opposite: washed out the entire drawer and equalized all the wood. It looks to me like early era water base finishes would look. Uninteresting. Dull.

I’ve gone through all this trouble to do hand cut dovetails for a sightly dramatic look, accentuated and with some decent contrast. Instead, the Sealcoat seems to have obscured them. The reports I’d read online suggested the opposite. Again it looks like a nice, crisp, pristine drawer with uninteresting wood and partly obscured washed out looking joinery.

Not sure what to do at this point but I’m unhappy with the look, esp. with all the work, time, and struggle put into to these.

Do I need to sand the Sealcoat off? Not looking forward to that … maybe just sand the sides of the drawers since the fronts will get false fronts and no one will see the backs?
Would this benefit from boiled linseed oil first to pop the grain and deepen the end grain on the DTs, then Sealcoat, then the topcoat of water base poly? I didn’t do that because the reports I’d read suggested Sealcoat would do a decent job of that. It didn’t.

For comparison the pics attached show what the raw maple drawers look like before finishing, wiped wet with denatured alcohol. They look great.
The next pics show one of the drawers with Sealcoat next to another hand cut dovetail item which was recently finished with 3 coats of an oil/varnish blend (1 part BLO/1 part satin polyurethane/1 part OMS).The wood on the latter is different and is a softwood (I assume pine, I scavenged it). But still, and even though the pic is blurry, and disregarding the hue imposed by the oil/poly… the joinery is more accentuated.

I thought the Sealcoat would pop the grain and deepen the contrast but it’s failed completely to do that.

-- “It is the beginning of wisdom to recognize that most men are fools and knaves, but it is the end of wisdom to embrace that vision.” -Arthur Kleps

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