Replies

1. 
   dougmeyer | Jan 08, 2009 08:46pm | #1

   Have you tried getting a new can (and I mean new) and giving it another coat? Shellac will "melt" the under coats as you put the new coat on normally (this is why it gets tacky as you put on additional coats) so I would expect that if you put on a new coat it may (if the others are not to thick) fix the issue.

   Doug M

1. 
   joinerswork | Jan 08, 2009 09:19pm | #3

   Doug, and Chris,

   Have y'all actually done this?

   I agree that the poster's difficulty is probably old shellac.  I'd be surprised if adding a coat of good shellac over the bad would make it all good.  But I have no idea of the chemistry involved.

   Ray

1. 
   dougmeyer | Jan 08, 2009 10:44pm | #5

   Yes I have, on a smaller scale, I had a table that gave me some issues. It would get tacky to anything sitting on it for very long. And the finish seamed soft. But I had a pretty thin layer (and only two of them) So I did two more and the problem went away. Of course the furniture went away a few years latter when the house burnt down but I don't think that was related.

   Doug M

1. 
   joinerswork | Jan 09, 2009 12:05am | #8

   Doug,

   Interesting.  It never occurred to me to try and re-coat when I had that problem with a large corner cabinet many years ago.  I just washed it all off--inside and out-after I got past the moaning stage.   After all these years, I still grit my teeth thinking about it.

   Ray

1. 
   dougmeyer | Jan 09, 2009 04:18pm | #13

   Not saying it is the perfect answer or that it will always work, but it did for me. Then again I had a small area, and a very think coat.

   Doug M

2. 
   flairwoodworks | Jan 08, 2009 09:12pm | #2

   Your shellac has expired. I shellacked a cabinet and drawer a few years back with old shellac, unknowingly. I leave the drawer out a quarter of an inch and give it a whack back into the case to unstick it. Get new shellac and try a new coat like the previous post suggested. Hopefully you won't have to strip it off and start again.

   Chris @ www.flairwoodwork.spaces.live.com
   (soon to be www.flairwoodworks.com)

    - Success is not the key to happines.  Happiness is the key to success.  If you love what you are doing, you will be successful. - Albert Schweitzer

3. 
   SteveSchoene | Jan 08, 2009 09:43pm | #4

   I wouldn't use any film finish on a work bench top.  If I used anything it would be a oil/varnish mix with no build on the surface. 

   Consequently, I wouldn't hesitate to strip off the shellac you used, which was undoubtedly too old.  DNA will take care of it. 

   The aging of shellac takes place through a process of esterfication.  As far as I know it isn't accellerated by oxygen in the can, but can occur without air at all in an unopened can.  This is quite a bit unlike oil based finishes, which have a long shelf life in unopened cans, but very much less when they have been exposed to the air. 

   This is one of the reasons to mix your own shellac from flakes.  The flakes have a very long shelf life if kept dry, and you can mix just enough to cover what you will use in a month or two.   

4. 
   frankv | Jan 08, 2009 11:20pm | #6

   I would probably just wipe down the suspect finish off with alcohol and start new with a fresh can of finish just to be safe, that way you remove the old finish completely.
   Flakes do keep long and that is how I use it. It is very easy to mix and you can mix very small qty's as needed. I also mix the first coat very thin (1 lb cut) then a little thicker on final coats. It is a great finish and when you're done you are left with only the smell of the wood. I use it all the time to seal the wood of shop jigs too.
   -Frank

1. 
   sedna | Jan 08, 2009 11:45pm | #7

   Thanks Frank. Do you have any idea what caused the problem? I bought the shellac premixed. It is impossible to find shellac in flake form in this city.
   Sedna

1. 
   SteveSchoene | Jan 09, 2009 12:08am | #9

   Shellac flakes pretty much have to be mail ordered. 

   The problem was almost certainly age.  What is the manufactured on date on the bottom of the can?  The clock starts ticking on that date, not when you opened the can.  Zinsser may say 2 years from then is the life, but that assumes that it was always stored in ideal conditions during it's travels from factory to warehouse to distributor or retailer, and may be optimistic anyway. 

1. 
   forestgirl | Jan 09, 2009 08:30pm | #16

   Steve, I"ve found the date on the Zinsser cans to be conservative, if anything.  I've used shellac a few months after the "expiration date" calculated, and it's dried quite well.  My storage conditions aren't horrible, but they're not ideal either (e.g., there are always a few weeks in the winter when it gets cold and humid in the shop). forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-) 

2. 
   hdgis1 | Jan 09, 2009 05:00pm | #14

   Try shellac.net Nice thing about it is that you can buy quantities as small as a 1/4 lb. He has a weird ordering system but he's a super guy with some shellac you can't find anywhere else.Chris

3. 
   davcefai | Jan 09, 2009 08:45pm | #17

   "Do you have any idea what caused the problem"As another poster said, shellac "esterifies". It is both an alhohol and an acid. Alcohol + Acid -> Ester. Think of it as shellac becoming a soap. It is probably reacting with both itself and the alcohol solvent. In theory adding a little alkali like caustic soda will slow this down drastically. However there will probably be side effects.

5. 
   TomHigby | Jan 09, 2009 02:00am | #10

   I also resurfaced my bench after reading that article in FWW.  I had written a date on my shellac can, and found it to be four years old.  I dripped a few drops of the shellac on the can lid.  After three weeks the drops have not yet fully hardened.  I'm very glad that I didn't use the stuff.  Now I'm trying to figure out how to properly dispose of a nearly full can.

   Tom

1. 
   frankv | Jan 09, 2009 03:55am | #11

   Yea, I agree, just check the date that was stamped on the can to see how old it is. When I mix my shellac I always put a piece of masking tape on the outside of the bottle w/the date I mixed it. I usually keep it for no more than 3 mos but because I mix just what I need I usually do not have to throw much away.
   I have never found it locally - I mail order it as others do. There are many kinds but I mostly use orange shellac and I order it from Lee Valley where it goes for around $17 a lb. This is enough for a long time! If you use a 1 lb cut you basically have a gallons worth of finish. You can buy denatured alcohol at the local hardware store.
   -Frank

2. 
   dkellernc | Jan 09, 2009 06:23pm | #15

   "Now I'm trying to figure out how to properly dispose of a nearly full can."

   There's an easy way to do this - properly.  Pour off the can into several empty food cans, and leave the open cans outside for a couple of days to let the alcohol evaporate.  The hardened shellac is non-toxic (it's actually a food ingredient) and can be disposed of in the trash.

6. 
   sedna | Jan 09, 2009 03:58am | #12

   Thank you all for the advice. I am glad to see that I am not the only person who did not know about shellac expiring. I have thrown the can out but I think I have had it (unopened) for about two years. I rarely use it but decided to do so because of the article about resurfacing a work bench in the last issue of FWW. As a matter of (perhaps) further interest the bench is one I made over 20 years ago from a plan in a magazine. Very heavy and a fine bench but it was surprising how much "out" it was from flat when I really checked it. Took a lot of planing but it sure is nice now. Doing it inspired me to check another surface for flatness - my old Unisaw. It is not flat either but a lot harder to flatten. I am working on it with a granite surface plate (dead flat) ,. I have stuck on abrasive and am doing it by hand. Slow work but a difference can now be seen and the tool marks from the initial grinding are fading. Probably just "busywork" but it is looking nice.
   Sedna