Replies

1. 
   ted | Jul 08, 2007 06:36am | #1

   yes

2. 
   Roger99 | Jul 08, 2007 06:38am | #2

   Hi Don; Oil based or water based polyurethane goes great over DEWAXED shellac! I am redoing all my kitchen cabinets and have had very good results with dewaxed shellac and oil based poly. We use water based poly over dewaxed shellac all the time when making children's toys. We made over 3500 toys for donation last year! If you can only find waxed shellac you can decant it by not stiring it and taking the shellac off the top. The wax will settle to the bottom. If you get wax in your finish the poly will not stick well. Use a 1 or 2 pound cut and wipe or spray a thin layer over the item and let it dry well, at least 3 or 4 hours before you apply the poly. The poly needs something to stick to. Either lightly sand the surface, to scrach it up, or use shellac to get a good bond. Good luck, Roger.

1. 
   Joe | Jul 08, 2007 03:40pm | #3

   And this debate will continue . . . .http://www.josephfusco.org/Articles/shellac_test/dewaxed_shellac.html
   http://joes-stuff1960.blogspot.com/
   http://www.josephfusco.org

1. 
   Tansu | Jul 09, 2007 10:02pm | #8

   Well, Joe, I guess your "Duct Tape" test is right up there with Matt Berger's "How strong is your Glue" article. A little bit of knowledge can be dangerous...http://www.pbase.com/ishmael1/waters

1. 
   Joe | Jul 10, 2007 12:57am | #9

   No knowledge is even worse, as is the case with you. In almost 30 years using that very procedure. . . never a failure. I guess I was just lucky all 2234 times.http://joes-stuff1960.blogspot.com/

1. 
   Tansu | Jul 10, 2007 09:11am | #10

   “Not having any knowledge…”, would have been a more correct usage of language, in your response to me Joe.The thesis of your article, http://www.josephfusco.org/Articles/Blotch_Stain/Blotch_Stain.html , appears to be:“As many of you may know, there is always this "debate" that goes on about using or not using shellac as an undercoating for polyurethanes and now most recently, waterbornes.”Please correct me if this synopsis is wrong, JoeYou then go on to say:“To me there is a very small risk associated with using straight shellac and that the need to either dewax or purchase dewaxed shellac is sulfurous.”From: http://dictionary.reference.com/browse/sulfurous sulfurous
   adjective1. of or related to or containing sulfur or derived from sulfur 2. harsh or corrosive in tone; "an acerbic tone piercing otherwise flowery prose"; "a barrage of acid comments"; "her acrid remarks make her many enemies"; "bitter words"; "blistering criticism"; "caustic jokes about political assassination, talk-show hosts and medical ethics"; "a sulfurous denunciation"; "a vitriolic critique" 3. characterized by oppressive heat and humidity; "the summer was sultry and oppressive"; "the stifling atmosphere"; "the sulfurous atmosphere preceding a thunderstorm" In any event, Joe, I am sure that you meant to say “superfluous.”After stating the finish schedule used on the sample, you go on to say:“ The only thing that may cause one to raise an eyebrow here is that the stain was applied over the shellac and then the polyurethane was applied over the stain. The ideal test would have been to apply another coat of shellac over the stain once it had dried. All in all I think that this will serve the purpose. In the future I'll do something more involved.”You seem to contradict yourself here, Joe. Wasn’t the idea of your article to show that polyurethane would successfully adhere to waxed shellac? No? You showed that the polyurethane used will adhere successfully to the stain used. But, alas, polyurethane sticks well to most stains that have been allowed to dry properly. That is common knowledge.You say:“I'm sure that there are more scienfitic tests that shows that dewaxed shellac preforms better then straight shellac, but in my practical experience I just haven't found it to be so.”Let me put it this way, Joe, I have never heard of or seen a finishing schedule that mentioned the word “wax” in it. Except at the beginning (dewaxed shellac to seal out any remaining contaminants, such as wax before refiishing) or at the end of the schedule (paste wax for tactile and appearance qualities).You state in your response to me: “In almost 30 years using that very procedure. . . never a failure. I guess I was just lucky all 2234 times.”That would work out to about 75 finish jobs a year for the last 30 years straight.!!! And no failures, to boot! Are you a professional finisher? Or are you more of a jack of all trades contractor as seems to be the case. I skulked around that ghost town of a web website / construction forums of yours and couldn’t find much of a knowledge base about finishing. I did find some foul language and expletives you posted, behind the backs of some people from JLC, that would get you banned here “in a New York second” Here is what the manufacturer of Zinsser products has to say on the subject, Joe:From: http://www.zinsser.com/PDF/TDB/BE_SHLLAC.pdf “Bulls Eye Shellac is not recommended under polyurethane
   finishes. To seal wood before finishing with polyurethane use
   Bulls Eye¯ SealCoat™ Universal Sanding Sealer.”However, as correctly stated by forest girl,From: http://www.zinsser.com/product_detail.asp?ProductID=72 “SealCoat offers the timesaving versatility of refined shellac in a pre-mixed 2 lb. cut 100% wax-free formula. It’s the perfect sanding sealer because it penetrates the surface, dries quickly, gives a rich tone to wood surfaces and since it contains no waxes or stearates, SealCoat is guaranteed to be compatible with oil-base polyurethanes, acrylic finishes, lacquers, catalyzed finishes and varnishes.”But, it would appear they are not aware of the “Duct Tape Test”, eh Joe?Oh, by the way, I really liked your "Crappy Biscuit" jig:
   http://www.josephfusco.org/Tips/tip0017.htmlThink I'll go out in the shop and make me one right now... Cheers!http://www.pbase.com/ishmael1/waters

2. 
   Joe | Jul 10, 2007 02:17pm | #11

   Now I bet you think you’ve insulted me and put me in my place, why you were actually able to find the typo and surmise my intended use. Good for you. I will try and control my dyslexia better in the future.“”“Not having any knowledge…”, would have been a more correct usage of language, in your response to me Joe. “
   This would have been an assumption and implied you not having any knowledge in the topic at hand. After the vitriol, it’s clear the “no knowledge” was more accurate.Now for all that the article is or is not, its purpose was to give some insight to using shellac in a meaningful way. Was it a perfect test, no? Can it help, yes. If it were to just get people to go out and give it a try, it had severed its propose. They were working with wood and finish, getting better. Unlike your prose which just seems to ridicule and demean. Do you find pleasure in that?

   Now I would find it hard to believe an artisan like you with a flair for the Far East and Beverly Hills square doors has no experience in this? Not even a, hey I tried this once and the poly peeled right off. Nope, you put forth nothing in the way of proof, other than to site what the manufacture print on their labels. Have you ever read some prescription labels? Scary.Now there was one glimmer of intellect in all this. . . you were able to do the math, bravo! I thought that would get your attention! But, you digressed back into your vitriol state and “hurt my feelings” when you spoke badly of my site and my skills. Oh well. . . .Now I’m going to my shop/garage and make one of the Far East Beverly Hills square doors just to show a dolt like me can ;-)http://joes-stuff1960.blogspot.com/
   http://www.josephfusco.org

   Edited 7/10/2007 8:42 am ET by Joe

3. 
   SteveSchoene | Jul 10, 2007 03:46pm | #12

   It's pretty clear that in general, polyurethane varnish adheres better to dewaxed shellac than to shellac that still has its natural wax.  No reason for any debate over that point. 

   But there is a wide range of polyurethane varnish and I suspect some do better than others.  And, even if the adherence is less, that doesn't mean 100% chance of obvious failure.  In many cases I doubt that adhesion is ever really put to the test.  Problems may not develop in a week or even in several months so tests without a systematic procedure with multiple samples conducted over a period of time don't tell very much, and can as easily be misleading as helpful. 

   But, it is impossible for consumers to know if the adhesion of any particular polyurethane varnish is more or less sensitive to wax.   Since manufacturers seldom give directions that would sell less product, we can believe that the manufacturer's of polyurethane varnish wouldn't say not to use over shellac if there weren't a reason. 

   But, there are simple answers. 

   One is: just don't use dewaxed shellac under polyurethane varnish.  It costs almost nothing extra, especially since if you are buying liquid shellac the dewaxed Seal Coat has a longer shelf life and is more water resistant, though it may not sand quite as well. 

   An even better solution is not to use polyurethane varnish except for floors.  Traditional resin varnishes, phenolic or alkyd, adhere quite well to shellac with its wax--and look better and rub out more easily.   

    

    

4. 
   Joe | Jul 10, 2007 06:17pm | #13

   Steve,You make some good points. I agree that most traditional finishes work better with shellac , but is poly really that bad? Not everyone has the “fine” sense of being correct. Sometimes they just want to do something they can appreciate and get done in a reasonable time. Shellac and synthetic poly have worked well for me over the years, about 15 years ago I made about 60 tables for a local German restaurant and the finish schedule was a spit coat of shellac, stain, a seal coat of shellac and three coats of ploy. Two gloss and one satin. Those tables have never once showed any sign of failure due to the waxed shellac and ploy combo. They sure as hell have been beaten up though. . . and still look good.http://joes-stuff1960.blogspot.com/
   http://www.josephfusco.org

5. 
   SteveSchoene | Jul 10, 2007 07:29pm | #14

   As I said, not every combination of shellac and poly will fail.  Still, having a few examples where they don't fail is no reason to press ones luck, especially since most oil based finishes, including polyurethane varnish, have been changing formulas due to VOC regulations.  Since there is no downside to speak of with dewaxed shellac that's all I'd use under poly or not. 

   Poly isn't bad.  It's just not needed very often.  A German restaurant, especially if it hosts a boisterous Oktober fest, may well be a good place for polyurethane varnish, though now I suspect a sprayed conversion varnish might be the choice, especially if there were 60 to do.  I'd certainly not risk a call back of that magnitude by using shellac with wax under poly.  

6. 
   Joe | Jul 10, 2007 07:44pm | #15

   Steve,In lies the point. 15 years later no call back, just how are you and the family Joe, would you like your regular seat? I still stand by the fact that you can without much concern use shellac out of the can under ploy. Do you have an experience that went bad that you'd like to share? http://joes-stuff1960.blogspot.com/
   http://www.josephfusco.org

   Edited 7/10/2007 12:46 pm ET by Joe

7. 
   SteveSchoene | Jul 10, 2007 08:53pm | #16

   This is still just a sample of one--one shellac covered with one particular polyurethane.  Repeating the same test 60 times only adds information about that one combination.  Such a test doesn't tell us very much, only that this particular case, with specific products that are not available the same now as then, didn't fail. 

   But when manufacturers, who do have the facilities to do statistically significant testing, tell us not to put their product over shellac, or not to put poly over their shellac we ought to believe them. It is absolutely in their interest for users to succeed while using their products.  And, if the admonition might lead to selling less product then we can be certain they would only say it if there was a reason. 

   Besides there is no earthly reason to prefer the shellac with wax.  Dewaxed shellac is also the superior product when used alone.  The only sensible way to proceed is to use dewaxed shellac under polyurethane or under waterborne finishes.  Since there is no meaningful downside to the dewaxed shellac, there is no reason to argue in favor of a practice that, even though it may work most of the time, nonetheless has a higher probability of failure.  Use only dewaxed shellac under polyurethane varnish. 

   It's kind of like arguing that I haven't been killed yet without wearing seatbelts, therefore wearing seat belts isn't a good idea.  Buckle up. 

    

8. 
   Joe | Jul 10, 2007 10:29pm | #17

   Steve,I can only gather from your reply is that you don’t have any experiences. . . So your position on the subject comes from. . . hear say? Hey that’s good. Who do you know that has had a failure? To just kept stating that something is no good, wrong or incorrect without any practical first hand knowledge seems disingenuous to me and it borders on dogma. Now I have finished countless projects with that process and can only state emphatically that it has worked every time. Oh and please let’s not compare seatbelts and shellac, that was a ridiculous statement.http://joes-stuff1960.blogspot.com/
   http://www.josephfusco.org

   Edited 7/10/2007 3:37 pm ET by Joe

9. 
   SteveSchoene | Jul 11, 2007 02:24am | #18

   When there is good, reliable and unbiased evidence available that CLEARLY says it is unwise to use polyurethane varnish over shellac containing wax, I am totally unimpressed by someone's purported "first hand experience".  That's why science exists.  By ignoring the science you confuse people who might think you are knowledgable about this topic.  Yes, you can sometimes get away with doing things that aren't really correct, but getting away with it doesn't make it correct. Instead of defending improper practices just say, "whew I was lucky", and go forward working more soundly.  Worse, there isn't any good reason to stay with the shellac with wax.  Why would you defend that particular product so vigorously?

   Incidentally, the seatbelt example is absolutely appropriate.  It is often the case where we don't get ourselves in the situation where the benefits of using dewaxed shellac or wearing seat belts would be truely tested.  That's why things that "shouldn't" work appear to do so--they just haven't been put to the test. 

   If I were wont to use the annecdotes of personal experience I would say not to wear seat belts, since in the most serious car accident I have been in--many years ago--I would likely have been killed had I been wearing my seat belt.   It's just another example, along with thousands of quack medicines sold on TV, of where "first hand experience" isn't sufficient to answer questions that are better answered by science.   

    

10. 
    Joe | Jul 11, 2007 03:19am | #19

    Steve,Here's the plan. . . You go and believe whatever it is you'd like about waxed shellac, seat belts and global warming.I'll do the same.http://joes-stuff1960.blogspot.com/
    http://www.josephfusco.org

11. 
    peter28 | Jul 13, 2007 04:15am | #20

    Hi Steve,

    I was talking with the tech people at Zinseer today about this and it's their advice not to use a waxed shellac under a poly.

    You'd think they could sell more product stating otherwise on their can if it was considered a good idea.

    The other gentleman had a positive experience doing just that. More power to him.

    I don't use poly, but if I were to, I would use dewaxed without question. I'm well aware of it's properties and attributes. Why risk a problem?

    I liked your seat belt comparison. One I feel is even more pertinent would be cigarettes. There's a warning on them too but does it matter? How many people do you know who have smoked for fifteen years or more and "never had a problem"

    Tick Tock Tick Tock

    Peter

12. 
    BigK | Jul 16, 2007 09:31am | #21

    Yeah, but you have to remember that most smokers who have had a problem aren't around to talk about it.

3. 
   HowardAcheson | Jul 08, 2007 06:11pm | #4

   Depends what color shellac you use. If you use one of the light colored blonds or super blonds, blotching will be minimal. If you use an amber or orange shellac, you will get the same blotching as you would with an amber colored varnish.

   It's the color, not the material, that causes uneven coloring.

   Howie.........
1. 
   Joe | Jul 08, 2007 08:42pm | #5

   Howard,That's a fair point since the "colored" shellac imparts "color" a blonde shellac would be best to use.Needless to say shellac is a great way to control Blotching
   http://www.josephfusco.org/Articles/Blotch_Stain/Blotch_Stain.htmlhttp://joes-stuff1960.blogspot.com/
   http://www.josephfusco.org

1. 
   HowardAcheson | Jul 09, 2007 07:27am | #6

   I think you misunderstand what Fusco is trying to impart. While shellac is the most common finish used as a wash coat, any clear finish will work. When using shellac, it really makes no difference which color is used.One of my processes, but not my favorite, is to thin shellac to about a 1# cut, apply it to the surface and let it dry. Then I lightly sand it with 220 paper, vacuum off the dust and then apply my pigment stain. The idea is that the shellac will be absorbed more deeply into the softer wood partially sealing it. Sanding lightly will open up the harder wood where the shellac is on the surface. Done correctly--and with a little bit of luck--the pigment stain will be partially repelled from the softer wood and absorbed by the harder wood leading to a more even overall penetration.The reason shellac is most often used is that it dries faster than other finishes but any finish could be used. I've used the process with a waterborne finish and it worked fine.So, the process will work with any color shellac. You do have to keep in mind that it is best to use dewaxed shellac if you plan to use a poly varnish or a waterborne final finish. Those finishes do not adhere well to shellac containing wax.Howie.........

4. 
   forestgirl | Jul 09, 2007 04:45pm | #7

   For dewaxed shellac, many of us use Zinsser's SealCoat.  Sometimes it's hard to find in "regular" stores (big box, local hardware) but most woodworking and good paint stores carry it.  It has a much longer shelf life than most shellac and it doesn't have much color to it.

   forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)