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Thread: Given a choice, polyurethane, shellac, or lacquer, which one??

  1. #16
    Shellac is a great product, it makes a good sanding sealer for traditional topcoats. its a barrier coat as well. Dries lightning fast 9 to touch 10 min to sand 4 hrs) Been around for CENTURIES. Its a excretion from the Lac bug and harvested by hand mostly in Pakistan and that area. It is the only stain killer that really works (aside from freshly made aluminum paint which is impossible to find now).It is always soluble with alcohol which makes it easy to repair. it was the primary finish for 18th & 19th century furniture usually in the form of a french polish. Clear shellac turns white when water is left on it like a drink glass.9 but the ring goes away if you wipe it with alcohol. Its a dated product ie it goes bad (never really dries if it gets to old but a fresh coat on top will usualy fix it.) You will get drunk from the alcohol fumes if you doing a large enough piece without a booth though. Shellac is a mainstay in most shops but as a finish? well i guess its better than stain alone. P&L made the best varnish a few years back but lately it hasnt been that good from what i hear. Todays Polly's are a huge improvement over just a few years ago and most high solids varieties are a uv barrier but it takes quite a few coats for outdoor exposure but inside is no problem even on cherry. Its a good idea to familiarize your self with all these finishes as they each have their place and all have their shortcomings. It is always best to think about how a piece will get used and abused and how much time you want to spend keeping it up and that usually will determine what finish it gets.

  2. #17
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    nice post john....

    Is there a book, or reference material, that has a flow chart of "how to choose the right finish"
    I never came across such....of course, it would have to be relatively modern as things have changed so much in finishing over the past 10 yrs..

  3. #18
    Being in the Hardwood floor business, i've got my hands on a lot of diff. types of finish as well as brands as well as quality.with floors i've used water-borne urethane and oil-based urethane.I use water-borne urethanes with a high % of urethanes , and am very pleased,i am able to rub out some of these if i use it for something other than floors.I have ruined spray guns however using water-borne[they clog up your tips unless you do a very good job of cleaning].On a table top, i would use the hardest finish that could also lend itself to rubbing out.IMO that would be WOP.I have never used conv. varnish but have seen some beautiful examples.I am at the stage that i'm looking for less toxic not more.I like shellac,[that is on many guitars, violins, etc.] and can be rubbed out and spot repaired.I like lacquer only from the standpoint, that it can stay in my gun,you can put many coats on without sanding,it can be rubbed out, and it's reversible like shellac.If it's summer i'll use lacquer with the shop door open,if the door is closed, i'll use shellac and wax or high % Water-borne urethane.

  4. #19
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    I put shellac on everything. I usually put down a coat of tried and true fist, then shellac, then some kind of beeswax polish. No harmful fumes, child-safe from the start, not just after its cured. I work in my house, and the curing process for any other kind of finish puts toxins in the air long enough to be a problem.
    Paul

  5. #20
    Understanding wood finishing by bob flexner has something like this.

  6. #21
    I respect yr experience over mine. But I wil say that I find wipe on POLY to be hard to rub to a gloss. It's easy to rub down to satin. The other varnishes and shellac and lacquer are easier for me to rub to a higher sheen.

  7. #22
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    Will,

    Lacquer has lacquer thinner, very stonge stuff that evaporates very quickly. Shellac has alcohol, it too evaporates very quickly. Lacquer and shellac don't cure, they dry so after a day there is no smell.

    Varnish is a reactive finish, after the thinner (usually mineral spirits) evaporates, you have a chemical reaction that takes place. The varnish reacts with the oxygen in the air and "cures". Smells continue (off gassing) until the process is complete; ~30 days in ideal conditions, longer in less than ideal conditions...
    Scott

    Finishing is an 'Art & a Science'. Actually, it is a process. You must understand the properties and tendencies of the finish you are using. You must know the proper steps and techniques, then you must execute them properly.

  8. #23
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    Prashun, you might be right, poly is closer to satin vs. high gloss....however, wipe on poly is very thin, as per MinWax, it takes 3 coats of wipe-on poly to equal the thickness of ONE coat of their brush on poly... with steel wool, i can get a nice sheen, but it might not be quite to high gloss....never compared enough side by side to know.

    Scott, thx for the smell status. I am in Pauls camp here.... I will only use finishes that don't have a strong and/or toxic odor.... so is the only noticeable odor of the shellac the alcohol evaporating? I can live with that, hell, people drink the stuff all day, so a few breathes won't be toxic, at least I think not.

    So why use shellac over my beloved WB Poly? I assume better gloss is the most obvious?

    Paul, you mentioned using initial coat of "tried and true" first.... I googled this company, they make several products, which do you put down? I assume its the polymerized linseed oil which prob. is low odor? I use Tung oil, and it smells for weeks sometimes, but your Linseed does not smell for long? Any reason for this 1-2 punch (oil + shellac) ... did you stumble across it, or is this a common finishing technique? Do you spray the linseed oil on? Sounds like we are in the same camp, avoid toxic fumes at any cost while trying to get the best possible finish. thx for sharing your insights...

  9. #24
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    I use the varnish oil for the first coat or two, then shellac. I use a mask to put down the shellac. It disapates after a n hour or two. I use this combo because my daughter has autism, and is very sensitive to solvents, and they don't go away for a veryz long time. It has the added benefit of being pretty damn nontoxic as well.

    I kinda stumbled on this, looking for something harmless to use for finishing.
    Paul

  10. #25
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    Paul, doesn't their varnish oil have some solvents that off gas? If not, I will try some of this! How long do you wait between coats?

    Also, why the mask for the shellac, are you sensitive to the smell of the alcohol evaporating? Does a standard VOC mask filter absorb alcohol odor?

  11. #26
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    Their varnish oil has no solvents at all. You must apply it very thinly or it doesn't cure. I rub it with a cloth. I wear a mask for shellac as I am a recovering drunk, and I don't like breathing the fumes. Even after almost thirty years, it bothers me. So I wear a solvent mask.
    Last edited by paul cottingham; 12-19-2011 at 10:56 AM.
    Paul

  12. #27
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    Thx Paul....
    How long do you wait for varnish to cure before applying Shellac?

    After my experience with Tung oil odor, I would have never thought to use an oil again, (except on rare outdoor projects)..... but you have motivated me to try their varnish oil....thx

  13. #28
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    With the tried and true, I wait an hour, then rub it with a cloth. The next day, I do it again. The real issue is putting it on thin enough to begin with. You literally canot put it on too thinly. I use both the traditional and the varnish oil, basically depending on my mood. Then I put on two or three coats of shellac about one and half pound cut.
    be aware...it still smells, but nowhere near as badly as a solvent based finish. And it is much much less toxic. I would even say it is totally nontoxic, with the exception of the alcohol in the shellac, which disapates quickly. I have heard that you could drink tried and true if you were so inclined. And they coat candy with shellac. So there you go.
    Paul

  14. #29
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    thx Paul....long wait times with the oil, I figured this.... that is one area the WB poly has me spoiled..... I can put on all 3 coats in a day, with ease, in warm weather, half a day :-)

    Alcohol fumes don't bug me like solvents do, so I can handle that, but will still use a mask when applying... Anyway, thx for your non-toxic finish recipe. I will surely try it as my WB poly alternative. My guess is, the Shellac will finish with a higher sheen vs. the Poly...

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