Results 1 to 4 of 4

Thread: repairing shellac finish

  1. #1
    Join Date
    Apr 2005
    Location
    Colrain MA
    Posts
    119

    repairing shellac finish

    I've repaired for a customer a jewelry box that has a mirror finish, replacing a couple missing veneer chips and shoring up the joinery after it was damaged by house movers. I was told that the finish is shellac by the box maker --he's in England, --the client and I are in the US. I thought I could just use French polishing technique to add a little shellac to the repaired area and have it blend into the existing finish. But it didn't work well. It sort of streaked and clouded, and never seemed to blend into the existing finish, even though it was freshly mixed, and very dilute shellac.
    I suspect it's been waxed. The customer says he never applied anything over the finish. I'm waiting to hear back from the maker, but he made it 20 years ago, so I don't expect his memory to be precise on this.
    I tried lightly scraping with a very thin, flexible scraper, and I'm wondering it knowledgeable people can tell by the finish shavings what substance (shellac or wax) I've been scraping, and how to recreate a mirror finish over what I have. I'm working on the back of the box only for now, but I have some areas on the front I'd like to touch up where I replaced the veneer chips. I've created a nice smooth satin finish on the back just by carefully scraping with the flexible scraper, and lightly sanding with 1500 grit, but it doesn't match the existing mirror finish at all. The existing finish shows some of the burl texture, which my scraping job on the back eliminated, though I'm certain I never reached wood. These photos show the shavings as created, the finished satin surface, and the mirror surface on the other sides. I have limited experience with shellac so any guidance would be much appreciated.
    Attached Images Attached Images

  2. #2
    Join Date
    Dec 2010
    Location
    WNY
    Posts
    8,114
    If it's wax it will dissolve in mineral spirits; shellac will not, so that's how you can figure out if it's been waxed, whether your scrapings or on the piece itself. That sure is a shiny finish on the top. It looks more like lacquer to me than shellac but if the builder says it's shellac then it likely is. Fortunately, you can prove which it is by taking a QTip with some alcohol on it and rubbing an inconspicuous area. If it removes the finish it's shellac, if not then it isn't. Repeating that experiment with lacquer thinner will prove whether or not it's lacquer. However, lacquer thinner will remove both shellac and lacquer, so that's why you need to start with alcohol.

    If you determine there is wax on it I would wipe the whole thing repeatedly with mineral spirits or Naptha to remove it, using a fresh soft cloth each time. Once that's done you will see how shiny the underlying finish really is. Whether it turns out to be shellac or lacquer I would spray the new finish because it's easier (for me, anyway) to apply both products by spraying. With a detail gun you can spray the repaired areas separately, carefully sand them smooth with the surrounding areas, and then spray the whole thing with a larger gun. Once the finish has cured, using automotive polish compound or your favorite micro grit products, you can level, smooth, and polish the finish to any sheen desired.

    Good luck. It sure is a beautiful piece.

    John

  3. #3
    Join Date
    May 2021
    Location
    New Hampster, USA
    Posts
    53
    I am not a pro finisher but have used shellac on many furniture projects. I think you can determine the composition of the shavings by putting them into alcohol. The resin will dissolve but the wax will fall out of solution (it could take days) as the wax in waxed shellac does after sitting undisturbed for awhile. I would be surprised if there was that much wax on the surface to create so much shavings. It is difficult to color match a shellac finish because shellac is available in so many different colors and there are variations between batches of the same color. The finish on the jewelry box appears to have relatively little color so I would guess that it is a blonde. Regardless, it is probably safer to apply blonde over the existing finish to minimize the likelihood of creating noticeable color differences. The box maker may have used a French polishing technique to get that shine. I find it easier to spray shellac and then use paper up to about 1500 followed by compound (as you might with lacquer). It should have plenty of shine after the 1500 grit so that satin result is surprising. The satin finish looks like what you normally get after 0000 steel wool. I would either try French polishing with a blonde shellac (available from shellac.net) or spraying and sanding. You would probably prefer not to apply more shellac but it would be easy to sand through the finish now that you've scraped and sanded. But again, I am not a pro finisher or restorer.

    Another thought - if some moisture was drawn into the finish during the repair then blushing could be causing the finish to appear less shiny. What did you use as a solvent/lubricant when wet sanding to 1500?
    Last edited by Holmes Anderson; 01-05-2022 at 5:38 PM.

  4. #4
    Join Date
    Apr 2005
    Location
    Colrain MA
    Posts
    119
    Thanks fort these good replies.
    I solved my problem, and I think I was simply too quick to think something major was wrong, when it turned out I just needed more elbow grease and more thin coats to get new finish to meld into old.

    So now the back of the box is lacking the burl texture of the rest of the box, but I managed to get its high gloss back. I guess I'm used to the gradual build process on the few times I've French polished (which this box certainly was originally), and so putting a new coat on a finished piece is radically different, and lacks the friendly incrementalism of French polishing new work, or stripped work.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •