Replies

1. 
   Rich14 | Nov 08, 2006 03:11am | #1

   Jeema,

   Shellac does not deteriorate, but in time the flakes becomes less soluble in alcohol and old flakes when disolved do not form the desired hard dry film, but a more rubbery consistency. This is due to chemical changes in the shellac as you mentioned.

   Shellac made from fresh flakes dries hard. The hard film also undergoes changes over time, but those changes actually enhance the film. They don't diminish its hardness and they make it somewhat more resistant to redisolving in alcohol, should some be spilled on the surface.

   Rich

2. 
   HowardAcheson | Nov 08, 2006 04:49am | #2

   Shellac flakes kept in an airtight container and out of sunlight can and do last almost forever. I used the last of some flakes this summer that were almost 10 years old. They dissolved fine and dried perfectly.

   Howie.........
3. 
   user-211435 | Nov 08, 2006 08:29am | #3

   Shellac does deteriorate as a finish over time. 

   Hal

    

1. 
   Rich14 | Nov 08, 2006 04:19pm | #4

   Hal,Do you mean on the wood, or in storage?All finishes "deteriorate." But shellac-finished pieces have survived well for centuries.Rich

1. 
   joinerswork | Nov 08, 2006 05:49pm | #5

   Rich, and all,

   It's difficult to generalise on any old finish.  To say that shellac finishes have survived for centuries is to presume knowledge of a piece's history that we almost never have.  I've read finish recipes from early 1800's that called for the addition of various resins and other additives to shellac to make "spirit (alcohol) varnish".  To look at an old surface, we can only speculate whether we're looking at a shellac film, shellac+benzoin, shellac+ sandarac+ copal, etc, etc.  So did the film deteriorate (or not) because it was adulterated, or for some other reason?

   Then, do we know that we're looking at a centuries-old finish?  Books of household hints up into the 30's recommend "freshening" a dull old finish by adding a coat of  new every few years.  Is it still centuries old if it has been reamalgamated every 5 yrs with new resin?  How can one tell if a shellac film is centuries old, or 75 years old, or 15 years old?

   I've worked on old finish films that were alcohol soluble, that reacted to alcohol in totally different ways.  One piece may be easily touched up by infilling a scratch with fresh shellac, that will blend right in.  The next piece's finish may bubble up and lift as soon as the wet brush touches it.  I've seen dark, degraded "shellac" finishes respond to a wipe with a damp alcohol pad by getting bright and clear, and by getting more opaque.  The problem is that we just don't know what is really in that "old" surface, short of having a CSI type analysis done to it.  Nor do we know in what environment the piece has been, in its lifetime, and what effect that has had.  We've probably all seen that case piece that has one end bleached and alligatored from exposure to sunlight from an adjacent window.  I restored the finish on one piece that spent the summer in a storage locker.  The "shellac" finish had almost melted, and after being levelled, remained somewhat soft and tacky.  Had it degraded from the high heat it had suffered, or from being overcoated (which it obviously had been) and contaminated, or because the resin molecules had just aged and stopped holding hands, and gone soft?

   Regards,

   Ray Pine

1. 
   Rich14 | Nov 08, 2006 06:01pm | #6

   I have several pieces of furniture that my father finished with shellac 1n 1946. The finish has not deteriorated at all to this point.

   Ask me again 1n 2046.

   Rich

1. 
   joinerswork | Nov 08, 2006 09:17pm | #7

   Rich,

   You are fortunate to have some pieces your dad built.  My brother has a desk that our granddad built sometime in the early 1900's.  Un fortunately the finish history is already lost to us, it might be shellac, and it still looks like it did in the 50's in my first memories of it.  I have an 18th century tripod table, the base of which had what may have been its original shellac finish on it when I restored it in 1971.  It was black and crusty, flaking off.  Alcohol dissolved what was left of it, when I refinished it as part of its restoration.

   Let's wait til 2146, then it'll have really been tested,  for centuries.  I don't mean to dispute your contention that shellac is a superior finish, at all.  I like shellac too.  I'm just pointing out  that after a couple hundred years, what we see may not be what we think we are looking at.

   Cheers,

   Ray

2. 
   Rich14 | Nov 08, 2006 09:24pm | #8

   "after a couple hundred years, what we see may not be what we think we are looking at."

   Heck, after a couple of minutes what I see may not be what I think I see!

   Rich

3. 
   xmike | Nov 09, 2006 01:08am | #9

   "Is it still centuries old if it has been reamalgamated every 5 yrs with new resin?  How can one tell if a shellac film is centuries old, or 75 years old, or 15 years old?"

   Ah, a Monty Python skit comes to mind regarding a family heirloom - "You see this ax?  It's as good as new, yet it's been in continuous use in our family for nearly 400 years.  Why?  Because we've maintained it!  During that time we've replaced the handle 5 times and the head twice.  It's a great ax!"

   That centuries old finish has simply been maintained! 

   Mike D :)

4. 
   Rich14 | Nov 09, 2006 01:13am | #10

   "That centuries old finish has simply been maintained!  "

   Yeah? So!? That would be a problem, because?

   Seriously, there are many examples of pieces that have not been maintained that have survived well.

5. 
   joinerswork | Nov 09, 2006 02:18am | #11

   Ah Rich,

   "many examples of pieces that have not been maintained that have survived well."

   Not many, I'll wager. Depends on your definition of "not maintained", or "survived well", I suppose, but still...the finish is the first thing to suffer, and can be difficult to document as to authenticity.

   I did some work for a local collector who showed me a recent acquisition, a Phila Queen Anne chair, with a gorgeous "old" crusty finish, lovingly maintained.  He'd bought it from a nationally known dealer who, at the new owner's request, had the newly applied finish "aged", I was told, "with a blowtorch".  It looked great. 

   Ray

    

6. 
   Gretchen | Nov 15, 2006 02:47pm | #15

   Mike, that is WONderful!!!  Thanks for a really good laugh--and something to pass on to my antique loving family!!

   Gretchen

   Edited 11/15/2006 6:55 am ET by Gretchen

7. 
   jimmar | Nov 09, 2006 03:41am | #12

   Thanks, everyone. If this is the end of this threrad, it's told me what  I was looking for.  If not, then I'm looking forward to anything else that get brought in!

4. 
   DougSmith | Nov 14, 2006 03:07pm | #13

   Can we go back to shellac basics? I am facing a shellac restoration project. I need some advice. I have a large, dovetailed, mahogany trunk made and finished in 1946. It has been sitting in a basement since then. I am replacing the hardware, using the original screw holes and I want to improve the finish. It looks like shellac. I rubbed it with an alcohol wipe and the cloth turned slightly brown and the finish dulled in that spot. Rubbing with laquer thinner left it unaltered. The finish is not crazed or cracked. It is dull and missing at the corners where there has been wear. I would like to make it look better, but I am not ready to strip the trunk and put an entirely new finish on. Can I sand lightly and use spray shellac? I notice that this only comes in clear. Why is that? What is clear shellac compared to amber? I am leery of brushing. What can you advise? Thanks

1. 
   SteveSchoene | Nov 15, 2006 11:43am | #14

   Your first step should be to clean the surface with water with a just bit of a mild soap in it, such as Murphy's Oil Soap or Dawn.  Be sure to rinse.  Water is fine with shellac as long as you don't let it stay wet for long periods.  This will get basic dirt off of the surface. 

   Then you can freshen the surface with denatured alcohol on a damp cloth.  Your tests so far do suggest shellac, though some lacquer thinners will have an impact on shellac.  You may find that this gives you what you need, with finish spreading out to even out the thin areas. 

   You can then apply more shellac--with the easiest way likely to be using a pad to apply a fairly thin "cut" of shellac--about 1 lb. or 1 1/2 lb cut.  Zinnser sells two pound cut Seal Coat, and while if offers Amber and Clear in a variety of strengths you are most likely to find 3 lb. cut in stores.  Clear has been chemically bleached and is very light colored.  Unfortunately, the bleaching process reduces the protective properties, including water resistence.   You can also mix your own flake shellac.  A good source is http://www.homesteadfinishing.com which is Jeff Jewitt's company.  Lots of good information on that web site. 

   The secret to success in working with shellac is speed.  Keep the pad moving and don't go back to fill in missed areas until the shellac has dried.  Also avoid overlap when you can.  In other words, work fast but neat.  The signal that something is going wrong is drag.  If the pad, or brush, begins to drag at all you are dissolving and disturbing too much of the underlying shellac and should STOP immediately. 

2. 
   Gretchen | Nov 15, 2006 02:54pm | #16

   I rubbed it with an alcohol wipe and the cloth turned slightly brown and the finish dulled in that spot.

   I would not be as sure it is shellac yet. That could just be surface dirt coming off of a varnish or other finish.  I think the rag needs to be sticky to the touch if it is shellac.

   Steve is right--clean it up. I would use mineral spirits on a rag--very lightly moistened.  Wipe and do it again.

   Then try alcohol somewhere and see if it turns sticky.

    Gretchen

5. 
   frenchy | Nov 16, 2006 05:36am | #17

   jeema,

    If you read the can that Bullseye sells you'll note that they guarantee the shellac for 3 years from date of manufacture. My experiance has been even older than that and the finish winds up just fine.. 
     What deteriorates shellac seems to be moisture getting into the can.. If it's well sealed I haven't seen any real deterioration.

        Once on and dried humidity doesn't seem to affect the finish.. My piano nearly 70 years old suffered only from usage deterioration.  Humidity during the years we were under construction seemed to have no effect on the finish..