Greetings all,
I’ve been reading about the wonders of shellac and love the pieces I’ve seen finished with it so I’ve decided to play with it a bit.
Question; Is there any big or noticeable difference between shellac you mix yourself and the pre-mixed in a can such as Zinsser?
I’m making a small dining table with spalted sycamore and want something that will pop out the figure and grain. I know I’ll have to top it with varnish or do you have other suggestions for that as well?
Thanks!
Raymond
Replies
Ray,
There is a difference between pre-mixed shellac and shellac you mixed fresh from flakes. With Zinsser's shellac you can only get three grades (colors) and only one of these are dewaxed (sealcoat). Dewaxed shellac can be top coated with any finish. Shellac with the wax still in it shouldn't be top coated with waterborne finish or finish with poly in it. Dewaxed shellac is also one of the best barriers against moisture vapor penetration of any finish, while waxy shellac is not as good. On top of that fresh shellac dries faster, harder and is more effective as a moisture barrier. If you are in a pinch I would use Zinsser shellac but if you have time use the flakes.
Wether or not you use varnish depends on were your priorities fall on the protection vs. reparability scale. Shellac is a lot tougher than most people think, but varnish is more scratch resistant and more impervious to certain household chemicals. If you do decide to use varnish may I suggest that you use something besides poly. Pratt & Lambert #38, Waterlox and Behlens Rockhard are all superior to poly in many ways for use on furniture. All also have their pluses and minuses compared to one another depending on the look you want.
Rob
Rob,I must have been typing as you posted.We have a little difference in opinion about the Zinser product.Rich
Rich,
Not really too much of a difference of opinion. I have used, and will probably use in the future Zinsser shellac. In fact I told the OP that if he was in a time crunch to go ahead and use it. I just think that the fresher shellac is the better it is.
Rob
Ray,
I mix my own shellac from flakes. I always have, always will. I like doing it. I think I get as much satisfaction from the preparation as from the final finish. I grind the flakes to a powder in a coffee grinder reserved for that purpose, and they dissolve in 15 minutes. No sweat, always fresh.
That said, the Zinser products are excellent. They are of the very highest quality. You'll experience no difference using premixed Zinser compared to freshly-mixed flakes.
Zinser uses proprietary chemistry to prolong the "shelf life" of the dissolved shellac. If it's not out of date, and it's been stored as specified, you can use it with confidence (and a lot longer). Whereas, I've had to throw away whole batches of stored, dry flakes that I found had gone bad when I tried to mix up a brew.
Rich
Rich
I clearly don't have your experinace with flakes but I am forced to ask how fresh was the denatured alcohol?
The reason I ask is I've pulled 70 year old shellac off and added fresh denatured alcohol and been able to get a good shellac from it.
I do know the light ends of alcohol evaporate quickly and also alcohol will draw moisture from the air. Both which have messed up my shellacing in the past..
I've opened a can of denatured alcohol and maybe they weren't really completely sealed at the factory or whatever but one can will give me a problem while another can won't. (same shellac)
Frenchy,I am very sure the alcohol was "fresh" as the very first thing I did when that batch of flakes failed was to buy new alcohol and try again. Obtaining new flakes took over a week, while trying several sources of alcohol was only a short trip to some local stores, including getting some reagent grade ethanol from a research chemist friend.I estimate 25-30% of the flakes dissolved. The rest just stayed as a soft mass at the bottom of the solution."I've pulled 70 year old shellac off and added fresh denatured alcohol and been able to get a good shellac from it."I have expressed very serious doubts about your claim to be able to use old shellac as a successful finish. I don't know if you read it, but I posted a long response in a thread several weeks ago.Rich
Rich
I am like you it seems: I have always mixed my own shellac brews. After reading Teri Masaschi's FWW article, I think the Zinser stuff might be worth a try. She has some other really good tips. Take a look its here in the finishing section.
Dan
After reading your post I did just that. Thanks! Some great articles there.
Mike D
Dan,Thanks, but I have no desire to pay Taunton to view their membership-only site.Rich
By the way I see you are out in N.Arizona. Are you near Flagstaff? I lived in Albuquerque NM back in the early 80's while I was a flying instructor at Kirtland AFB. I used to get over to Arizona and loved it up in the north end.
I'm back in NC and takin' advantage of all of the hardwoods around me here.
later
Dan
Dan,I didn't realize my profile still listed N. Arizone. I was in Prescott, 100 miles from Flagstaff.I moved to central Florida last May.Rich
Ray-
An in-between option is premixed concentrated shellac in a 5-pound cut. You can dilute the concentrate to whatever mix you want for coating; the advantage is that you can mix small quantities. Homestead Finishing Products
http://www.homesteadfinishing.com/
sells the concentrate in pint and quart volumes. They have it in dewaxed pale and dewaxed dark colors.
Homestead also has a broad range of colors in dewaxed dry shellac.
Don
Ray,
I have found that mixed shellac seems to lay down flatter than the premixed product at the same cut. The many choices of colors is also a real benefit and a good dark garnet is almost like adding instant age to a piece of furniture which is grreat for period furniture makers. Another real benefit is what it does for pieces that are top coated with waterbased finishes. It gives a great amber base color for these top coats which overcomes the cool look waterbased finishes tend to show. In fact Target USL over a couple coats of dark garent shellac looks an awful lot like a good varnish when rubbed out.
Ron
"I have found that mixed shellac seems to lay down flatter than the premixed product at the same cut."
This is probably because of differences in the solvents used. A "heavier" solvent with lower surface tension will lay down flatter. I believe the Behlen Behkol solvent has butanol in it at least partly for that reason.
-Steve
Just finished re-finishing a cherry desk. The original finish was oil then some "experts" re-finished it and applied a varnish. The varnish cracked and flaked off in many areas. I sanded it- 60 to 320 grit - applied shellac. I mix my own from flakes - by volume 1part shellac to 8 parts methyl hydrate. I cut that mix by adding 1/4 cup m.h. to 1/4 cup shellac mixture and applied 4 coats; sanding between coats. It dries quickly so the job was completed in one day. I rubbed with Rottenstone then applied carnuba wax. ( my "mother's" carnuba car wax)
I am extremely pleased with the results. If in doubt, apply your finish to scrap wood.I quit using 'off the shelf' shellac years ago. I like fresh shellac.
Edited 12/30/2007 2:51 pm ET by willy
Willy,
what is the difference in flake made and store bought?
Best,
JimI know less than half of you, half as much as I should Like;
I like less than have of you, half as much as you deserve.
Shellac has a limited shelf life. Too often I have had shellac (store bought) left over from a job and it eventually becomes gummy and has to be scrapped (actually taken to the chemical disposal centre) I mix just enough to do the job at hand - it's fresh and if there is waste, it's very limited.
Edited 12/30/2007 4:33 pm ET by willy
Hi Willy;I asked because I thought you would say that. The shellac I have bought never has become gummy.
In fact the stuff I bought still works - but according to the expiration date - it shouldn't!Aside from that point, is there another point where flakes are better than store bought?Best,
JimI know less than half of you, half as much as I should Like;
I like less than have of you, half as much as you deserve.
You're leading me on Jim - - - I'll let you answer your question !!!!!!!
Willy,
Your right!
I'm happy ; your happy; right?Best,
JimI know less than half of you, half as much as I should Like;
I like less than have of you, half as much as you deserve.
These posts should be on the cafe --- actually I like to mix my own shellac and get a lift out of the fumes.
Willy;
What can I say, you can't compare the expert's noses to the novice knows!
Happy New year!Best,
JimI know less than half of you, half as much as I should Like;
I like less than have of you, half as much as you deserve.
Raymond,
If you want something to pop the grain of your sycamore, I'd have a look at a curing oil. Have a look at what it did for my dogwood table.
http://forums.taunton.com/n/mb/message.asp?webtag=fw-knots&msg=39245.1
Chris @ flairwoodworks
- 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
Edited 12/30/2007 7:58 pm by flairwoodworks
The bullseye product is great stuff. However it is not 100% dewaxed and it takes a bit longer to get hard enough to sand. I use dewaxed flakes. Most of the time because I buy them in quantity and flakes can store indefinately, also the cure time is importaint to me.
Pardon my spelling,
Mike
Make sure that your next project is beyond your skill and requires tools you don't have. You won't regret it.
I have used the Bullseye product for a while now, I liked the idea that I could get the same stuff in the future to fix, or match what I had done in the past. But I have noticed that only two types are available locally to me, as of late, and that they have changed the product a bit. First off they no longer tell you the cut on the can, and second it is NOT the same cut it was, it is noticeably thinner. So they have done something of late that I am not sure of and do not want to even tell you what kind of cut you are getting. So at this point with the new stuff in the stores I am NOT happy with them any longer.
Doug
The amount of solid by weight for a 3 pounds cut comes to 37.5% if you make the calculations, Zinsser has been adding 29% by weight and I will not doubt if now they add less.
"The amount of solid by weight for a 3 pounds cut comes to 37.5% if you make the calculations..."
Only if you make the wrong calculations. You're making the common chem lab mistake of dividing by the weight of the solvent rather than by the weight of the solution. (You're also using the incorrect solvent weight--alcohol weighs less than water.)
A 3-lb. cut is defined as the addition of 3 pounds of dry shellac to 1 gallon of solvent. I don't know the exact proportions of the solvent that Zinsser uses, but let's assume for now that it's pure ethanol. Ethanol has a specific gravity of 0.78, which means that it weighs about 6.6 pounds per gallon. If we add 3 pounds of shellac to that, we end up with a solution that weights 9.6 pounds. 3 pounds / 9.6 pounds = 31% by weight. If Zinsser's solvent blend happens to be a bit more dense than ethanol, then that would account for the remaining discrepancy.
-Steve
Steve,
Thanks for that thought! I had just finished the calculations earlier and was going to rush out to see if I could buy some of the old stuff for finishing the rest of my house.. (Too bad they don't sell it in 55 gallon drums)
Lucklily I read the information you posted and saved myself the trip!
I owe you!
Noted, did it incorrectly.
Ray:
I have used both kinds of Zinsser in all colors, and also mixed my own. Both work well; however, it is hard to beat the convenience of the de-waxed ultra-blond Sealcoat. I keep a can around for first coating almost everything. Generally, if I want other colors or types for things like furniture, I just mix up a small batch of my own. However, for floors and woodwork, you can't beat Zinsser convenience. We just replaced 400 feet of white oak floor after water caused severe warping. Over bare wood, I used 3 coats of Bullseye, mixed 2 cans of blond to one of amber so as to slightly darken the floor to better match the much older floors in other rooms.
One precaution -- while Shellac dries very quickly, it does not fully cure for some time. The drying/curing time gets longer as the mil thickness increases. SO, for high use areas like floors that have significant mil thickness, the last coat should cure for three days or so before putting furniture on it. You should be gentle for a couple of months. It just keeps curing.
Joe
Joe,
I have done a few floors with shellac and because it dried I placed furniture on that same day. I was extremely careful not to roll or slide anything but carefully set it in place. Nothing was ever marked. I'll admit to walking lightly in stocking feet at first but no furniture marked my floors.
I did have a rug stick to the floor. A rug I set down after a few days.. It stuck in a few places and marred the shellac (easy fix) but I attributed it to summer sun over heating the floor. Shellac isn't a real big fan of heat ;-) Are you suggesting that it wasn't the heat but the fact that while the shellac was dry it hadn't cured?
I do use an overthinning approach to shellac. I put on three coats of a 1 Pound cut typically. If you used the directions on the can then you wound up with three coats of 2# cuts.. about twice the thickness I use..
Would you guess that my thinner coats dried quick enough to allow the furniture wihout marking?
If you put down a fairly heavy coat of shellac (or several lighter coats over a short period of time), it definitely takes a few days before it reaches full hardness. A fresh shellac film can be perfectly dry to the touch yet yield to the "fingernail test." After three or four days it will pass the test with flying colors.
-Steve
Steve
I do know that shellac hardens over time, however one of the benefits I felt I was getting is with thinner coats I don't build up as thick a coat.
When I tried the standard approach as per the can I not only noted the massively longer time it took to dry but it didn't seem to be as hard even when dry. In my case I settled on two coats rather than my normal three coats. I tried three coats but had problems with it so I wiped it off and started fresh with two coats.
Among the problems I noted was the shellac didn't flow out the way it does when it's over thinned and the resultant surface was much more lumpy. Since this went on maple I was really disappointed because in the past my shellac on maple had always been really nice and rich. Shellac on Oak or Black walnut can show a little grain (open pores) sometimes but I'd never had that issue with Maple with my over thinned approach.
I'm sure my issues are because I'm a lousy painter but I seem to share that trait with more than a few people who like my over thinned approach. I know it's not for the skilled and gifted but for us hacks it seems to work..
Frenchy:
Like you, I get quick-dry results with thinner shellac or with a thinner overall mil thickness. However, on floors, I WANT mil thickness. On floors I use two to three coats of out-of-the-can Zinsser 3# (certainly do not do that on furniture, of course). Through the school of hard knocks, I have found that the forst coat is dry in hours or less, but the later coats are not -- and I have now had enough experience at getting rid of stocking foot prints and furniture leg impressions that I just wait about three days before putting on anything heavy.
Here in Texas we have has no issues at all with shellac in summer heat, even in areas without A/C, so my guess is that your rug there in Minnesota stuck because the floor was not cured enough when it went down.
FWIW, Zinsser technical told me that a complete hard cure for shellac takes 3 months. At that point, it will be at full hardness and not be as susceptible to alchohol spills. Of course, we all start using it in hours or days. I view this as being like concrete, which is usable farly quickly, but which keeps on hardening for a long time before it reaches full design strength.
Cheers and happy new year!
Joe
Joe
I've always been told that thick coats cause troubles..
Thin is in with shellac. I was told that if you hold a shellac flake up that's the maximum thickness it should ever be..
I had a piano that suffered from thick coats and it alligatored within 70 years (exactly when it alligatored I don't know, I bought it when it was 70 years old badly alligatored) I seen floors and furniture much older than that without the alligatoring issues and I know of some much younger than 70 years where alligatoring is an issue.
My theory is that the wood under shellac shrinks and swells with humidity but the shellac isn't that flexiable so it scrunches up and expands but each time it scrunches up the folds trap dust in them and even when the wood expands again those folds hold dust etc. and cause deeper alligatoring..
My floors (timbers, woodwork, etc. ) first coat dries inside of 15 minutes.. the second coat dries in 30 minutes and the final coat takes an hour. On rare occasions if the wood is extremely poreous I may add a fourth coat (2 hours to dry)
Joe don't think for a minute that my way is the only way.. heck everybody seems to have their favorite way of shellacing and you can get into some pretty violent squabbles here defending your approach.
If you want you can go on 34866.5 to see pictures of my floors..
Which if you note is black walnut.. I suspect that your floors are a lighter color? we all know dark cars are hotter in sunlight than light cars. Plus living in Texas I should imagine that your house is pretty well air conditioned in the summer.. Here except for rare periods I seldom ever use A/C (our winters are cold enough that if we don't store some warmth during the summer we turn blue like Babe the blue Ox ;-)
Frenchy,Yes, the final, hard, dry shellac film should be as thin as possible to do the job. Just thick enough, no thicker. As thick as a shellac flake? That is HUGE.A shellac film doesn't get to its thin, final beautiful appearance by being applied as an overly-dilute solution. It gets that way by level sanding as the applications proceed and by rubbing out. Almost as much material is removed by the leveling as is ultimately applied.Even a "full gloss" shellac film is thin. It just looks like more because of the "depth" of the reflective surface. And one applied to look like an oiled surface is even thinner. Very durable, but very thin.I have found that overly dilute solutions take away as much solids as they deposit. You get nowhere with them and never develop a real finish layer. Using very dilute shellac solutions on furniture is just an exercise in frustration. There's never enough of a film to rub out to the kind of appearance shellac is capable of delivering. Wiping the surface with alcohol to smooth it, is NOT the same.Successful shellac finishers have been using about a 2 lb cut as a "standard" working solution for years. There is no "problem" at all with such concentrations. The "secret" is patience, leveling and repetition until the shellac gives up and behaves, because it realizes you know how to apply it.Rich
Right , Rich, as to furniture. Some woodwork, and floors for sure need more final thickness because of the wear they undergo.J
Yes, I agree. But I think you missed my point. I have no argument with laying shellac down as thick as necessary (multiple applications) for the use of the wood surface.Frenchy has long advocated using very dilute shellac mixtures with a brush as the "secret" to applying it. I disagree with that method as it actually prevents you from EVER getting enough solid resin down as each application seems to take back as much shellac as is deposited.For some reason, it's also very hard to build an adequate film by spraying very dilute shellac.A 2# cut works well. There is no question that a little time is required to learn how to handle the stuff. That's true with any finish. But this willingness to buy into the myth that shellac is impossibly difficult is wrong. It's one of the most forgiving of materials. Once a finisher REALLY learns how to level sand between applications (of ANY film finish), the world is his. Every bit of "Fear of Finishing" disappears.I think the real problem is that people unfamiliar with wood finishes, unfortunately, try to apply everything with a brushing/scrubbing motion appropriate for latex paint on a plasterboard wall or water colors on paper. It's a technique we learn when we're introduced to paints in school, and the "technique" sticks in our muscle memory. Then they look for the "magic" answer to solve the problems that such brushing causes.None exists. None is needed.Rich
Edited 1/3/2008 6:56 am ET by Rich14
Agree.
J
Rich,
Well we do agree on all but my overly thin approach. Faced with a choice of having someone wipe on an oil or brush on my overly thinned approach I'll keep trying to get them to brush on shellac..
You described the secret and while clearly that works for you enough have been"burned" by shellac to be afraid of it and instead of doing as you suggest, gone on to simple wipe on oils with all the limitations they have, rather than patience and practice..
At least with my technique they are using shellac.
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