enter image description hereI've been repairing the shellac finish on paneling in my home, and some spots are coming out way too flat when dried. In this photo you can see how the glossiness isn't consistent, even though I applied fresh shellac over all spots within the border. Luckily this spot is barely noticeable since it's near the floor, but I'm afraid to try anywhere else.

I'm using Zinsser Amber Bulls-eye, thinning it down with an equal part of denatured alcohol. Is the problem that I'm over-thinning it?

Or can moisture cause this? The finish in this flat spot was turning milky as it dried, which I read can be caused by excess humidity or moisture. I reapplied shellac several times until it dried without turning milky.

The original finish is around 30 years old and gets scratched very easily.

  • This just looks like it needs more shellac. An time I'm applying shellac and the surface is still dull it's because I haven't built up enough shellac yet. It does seems likely you're over thinning the Bulls-Eye, but then again at full strength it may be too difficult to apply to a consistent finish (unless you switch application method). BTW you don't mention how you're applying it, I'm presuming by brush but what kind of brush?
    – Graphus
    Jan 6, 2021 at 1:28
  • "The original finish is around 30 years old and gets scratched very easily" Kinda indicates that shellac isn't up to the requirement if you think about it (which is par for the course with shellac TBH). You can overcoat shellac with varnish to improve toughness and water resistance and this would simultaneously help with achieving a more consistent surface gloss. But odour would obviously be a big issue here given the areas you're dealing with, plus it'll take A. Long. Time.
    – Graphus
    Jan 6, 2021 at 1:30
  • Yes a brush, admittedly not an ideal one...a Purdy synthox I picked up at Lowe's. I've experienced a full surface when I'm first applying shellac too, but in this case the surface already had a built-up finish, i was just trying to touch up scratches
    – Andy
    Jan 9, 2021 at 15:50
  • I'll have to look up the Purdy brush as I'm not familiar, but actually synthetics are now considered the brush of choice for brush application of shellac. OK just looked up the Syntox and it looks like it's pretty much ideal for this, so 'cut' of shellac and brushing method will probably be the two key things to focus on.
    – Graphus
    Jan 10, 2021 at 10:40
  • Late thought: how much experience do you have with lightly sanding/scuffing shellac and then buffing/polishing it to even out surface finish? Contrary to my first impression it could be that there is enough shellac here, it just needs its surface improved. And as a general thing you should never expect that brush-applied shellac will require no further work.... at the bare minimum some rubbing with steel wool followed by a buff with a cloth. I'd suggest trying this before anything else.
    – Graphus
    Jan 10, 2021 at 10:44


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