Shellac solvent

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  • #685154
    Jeff Stuart
    Participant

    I understand ethanol is the preferred solvent for shellac. Where I live I can’t get high proof ethanol, so I’m left with “denatured alcohol”. It seems in the US you can call anything “denatured alcohol”, as long as it’s poisonous, and contains some unspecified amount of some kind of alcohol.

    Is there a US manufacturer/brand/label of denatured alcohol you can recommend for shellac?

    Thanks,
    Jeff

    #685180
    Sven-Olof Jansson
    Participant

    Hej Jeff,

    One reply often generates more, so hopefully you will get some with deeper insights.

    Being left astern in Sweden, I have the same problem. Going by the information on shellac provided by PubChem, ethanol is the preferable solvent. Whether denaturation with methanol makes any difference, I don’t know; though I believe it shouldn’t. I couldn’t find any 99% denaturated alcohol. and therefore went with 99.9% (won’t vouch for the 0.9%) iso-propyl alcohol. Used for a quite thick cut, it took its time to dissolve the shellac flakes.

    Iso-propyl alcohol is a bit less hydrophilic than ethanol. Have no idea whether that is relevant for shellac.

    Sven-Olof Jansson
    London, UK; Boston, MA

    #685181
    Roberto Fischer
    Participant

    I’ve tried 70% isopropyl alcohol and it took like an hour to dissolve shellac from the brush. That concentration is too low, and based on Sven’s reply, the substance itself might not be great for this use.

    I’ve used Kleen Strip Green denatured alcohol successfully. It dissolved shellac from the brush in a few minutes and nicely thinned the shellac from bullseye brand. It appears easy to find, from smaller hardware stores to the big boxes in the US.

    #685186
    peter marshall
    Participant

    I use the Shellac/Lacquer thinner sold by Lee Valley . It is a blend of Ethanol and Isobutyl alcohol . This has worked well for me when using shellac including dissolving shellac from the brush .. good luck

    #685265
    Jeff Stuart
    Participant

    Thanks for the replies. The Lee Valley product is not available on their US website at the moment.

    I have used 99% isopropyl to clean brushes, thin Zinser shellac. It seemed to work for a several projects. But I want to mix my own and not stray too far from the beaten path till I know more.

    Klean-Strip Green is a product I am considering. It is (minimally) 80% Ethanol, and reasonably priced.

    There is a “laboratory” on Amazon call themselves Emerson Labs who appear to be re-packaging a 95% Ethanol (4.6% n-Heptane) made by Greenfield Pharma in CT USA. Very low water content. Anyone ever tried this stuff?

    #685317
    Benoît Van Noten
    Participant

    I have used denatured alcohol without problem.

    There are really heavy taxes on drinkable ethanol here in Belgium, so it is not an option.

    #685767
    Jeff Stuart
    Participant

    Thank you Benoît. The problem here in the good ol’ USA is denatured alcohol may be less than 1/3 ethanol. Because methanol is cheaper, most brands of denatured alcohol sold here are mostly that, methanol.

    Based on what I’ve read and my own experiments, I am confident we can dissolve shellac in methanol, ethanol or isopropyl alcohol just fine — as long as there is little water in solution, and the solids aren’t allowed to settle and clump.

    When applied, methanol evaporates fastest and isopropyl slowest. This affects how the solution feels on the brush and behaves on a pad. With experience I’ll bet anyone can learn to use any mixture of alcohols.

    But, since methanol is more flammable and toxic than the others, I’d just as soon stay away from it. And since all your “classic” texts about shellac were written by people probably using plain ethanol, that would be my preferred solvent.

    I think I’m going to try the Emmerson Labs product. Only downside, I have to buy half a gallon. I need a good flux cleaner anyway, isopropyl has gotten crazy expensive what with all the COVID….

    #689599
    Jeff Stuart
    Participant

    Maybe someone might be interested how my experiment turned out. I did buy 1/2 gallon 1.9L) of Emmerson 95% ethanol and mixed a small mount of 2# cut garnet flakes from Lee Valley. I mixed an equal concentration using 99.5% isopropyl. At room temperature (75F / 24C) the ethanol solution dissolved completely in less than 3 hours with occasional stirring to unclump the flakes. The isopropyl took a lot more time & effort. Even after 24 hours there are still some undissolved solids in the mixture.

    Comparing application and finish, I brushed both solutions and some Zinser canned shellac on scrap hardwood. I don’t know the date of the Zinser (can arrived damaged, leaking with the date rubbed off the can — thank you Amazon.) They all felt the same on the brush. The ethanol dried faster and harder than the others. The Zinser was slowest and still felt sticky after 20 minutes. The isopropyl felt dry enough for a second coat after a minute or less.

    Using a pad (roughly 1# cut), the ethanol really stands out. In thin layers it seems to dry almost instantly. I could go back and pad over within seconds without drag or disturbing previous layer. The Isopropyl solution needed some rest (30 seconds) between applications. On a large surface you could probably pad continuously with the isopropyl. I didn’t try the Zinser on the pad.

    So, I’m really happy with the performance of the Emmerson product.

    #689633
    Larry Geib
    Participant

    I understand ethanol is the preferred solvent for shellac. Where I live I can’t get high proof ethanol, so I’m left with “denatured alcohol”. It seems in the US you can call anything “denatured alcohol”, as long as it’s poisonous, and contains some unspecified amount of some kind of alcohol.

    Is there a US manufacturer/brand/label of denatured alcohol you can recommend for shellac?

    Thanks,
    Jeff

    Everclear, available in liquor stores. Get the 189 or 190 proof version. but you have to pay the alcohol tax.
    It is available online if the issue isn’t a state ban.

    In the US, shellac flakes are one of the listed denaturing agents.

    https://www.law.cornell.edu/cfr/text/27/21.151

    #689655
    Sam Downs
    Participant

    I’m currently in California and ordered this medical grade Ethanol from Amazon.

    Waiting to see if it arrives and if it works ok.

    I was pretty surprised when I discovered that you couldn’t buy Metho here. I’m originally from Australia and used to mix my own shellac there.

    • This reply was modified 9 months, 2 weeks ago by Sam Downs.
    • This reply was modified 9 months, 2 weeks ago by Sam Downs.
    #689704
    Sven-Olof Jansson
    Participant

    Really helpful, Jeff!

    Many thanks

    Sven-Olof Jansson
    London, UK; Boston, MA

    #690137
    Jeff Stuart
    Participant

    Thanks Larry. Unfortunately Florida bans 190 proof Everclear. We might enjoy ourselves too much.

    #690139
    Jeff Stuart
    Participant

    Sam, that’s an interesting product. They say it’s denatured and composed of ethanol and water? I wonder how that works.

    Good price for 95% ethanol, about 25% cheaper than Emmerson. Hope it works for you.

    #690272
    Larry Geib
    Participant

    Sam, that’s an interesting product. They say it’s denatured and composed of ethanol and water? I wonder how that works.

    Good price for 95% ethanol, about 25% cheaper than Emmerson. Hope it works for you.

    This is an interesting case. The law says that a vendor must provide an sds or msds on a product .
    There is no listed sds on Amazon or the manufacturer on the label for this product.. a request for a data sheet has not been answered.

    So we have no idea what the denaturing agent is. Could be plutonium.

    #690279
    Tim Ridolfi
    Participant

    The Q&A section of the Amazon listing has an answer that states the denaturant is denatonium. From other sources, denatonium is said to be unbearably bitter at concentrations down 10 ppm. LD50 is in the neighborhood of 500 mg/kg if ingested orally. Since it’s used in hand sanitizer, I wouldn’t worry much about getting some on me.

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