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Thread: Can Water Based Shellac be used as Top Coat

  1. #1
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    Can Water Based Shellac be used as Top Coat

    I have a few speaker cabinets that are prep'd with alcahol dissovled shellac. All scraped and sanded back.

    I see Target has a Water base shellac. I'm curious how a couple of spray coats of this could work. It wont dissovle into my grain filling..

    Thanks

  2. #2
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    Joel,
    Target UltraSeal is not intended as a topcoat. It must be top coated with an appropriate product. Water will redissolve the UltraSeal film.

  3. #3
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    If you're going to spray it, I wouldn't think regular shellac would have any effect on your grain fill. I wouldn't try to brush it on though.

  4. #4
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    Thanks. I'll stay away from that idea..

    Love sprayed shellac so not a bad idea to spray just the top coats..

    Thanks again, Joel

  5. #5
    "Water based shellac? What is it? Why is it? Really, I've never heard of such a thing, can someone tell me what it is?

  6. #6
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    Quote Originally Posted by Kenneth Speed View Post
    "Water based shellac? What is it? Why is it? Really, I've never heard of such a thing, can someone tell me what it is?
    Actually Kenneth, aqueous shellacs have been around for around a century or more, sorry you missed them

    Needless to say, they were not used for, or as, coatings for wood at that and later times, that is of recent, as the aqueous coatings mfg. had call for some type of barrier coat for use under their main clear-coats. Unfortunately, when prepared this way, unless other additives or even other resinous materials are added, it does not have the same good properties as a alcohol solved lac has. None can stop for example the deteriorating of a finish that is acted upon by pine sap, since that is a main affect of the alcoholic portion of the normally solved shellac, neither can it block any type of color-bleed as normal lac can. As a good friend of mine who is head chemist of Mantrose Haeuser, said during a conversation on lacs, it's in all senses worthless as a replacement for true shellac as a wood coating.

    The making of the aqueous shellac originally was a combination of a PH adjuster that would allow for the polarity of the alcohol, which is less polar than the water, to then be able to dissolve the shellac. polarity and hydrogen bonding have everything to do with either associating or disassociation resinous bonds.

    A simple hat sizing solution used for many decades of such formula was:

    6 parts water [distilled]
    1/2 part sodium tetraborate
    2 parts dewaxed shellac.

    I have only used this formula several times in conservation work, it does come in handy when in-painting antiques that have their original coating of shellac and the need for more open time with the applied color mix is needed to cover larger areas of repair without having to stop and re-wet your brush near as often.. But again it still needs to be overcoated with alcohol solved lac for any real protection.
    Last edited by sheldon pettit; 05-02-2012 at 10:11 PM.
    Sincerely,

    S.Q.P - SAM - CHEMMY.......... Almost 50 years in this art and trade and counting...

  7. #7
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    Sheldon,

    Thank you for that indepth explaination... Good to know. I use dewaxed shellac all the time. I have never tried the water shellac may never try it...
    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. #8
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    Quote Originally Posted by Scott Holmes View Post
    Sheldon,

    Thank you for that indepth explaination... Good to know. I use dewaxed shellac all the time. I have never tried the water shellac may never try it...
    No doubt!

    Good, old-fashioned shellac . . . here I stay!

    Always loved ya, and, with Sheldon's explanation, never gonna leave ya!
    A creative man is motivated by the desire to achieve, not by the desire to beat others.
    Ayn Rand

  9. #9
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    Actually i would advise everyone to make up a small amount and use, as stated, it can come in handy for some things and most of all it creates a smell you just don't expect to ever smell from solvent shellac which i found interesting. you can also see for yourself what i'm talking of as to sap and bleeding as well as other ok? Keep in mind, that on-site touch up work can be done with no odor what so ever and then a coat of poly or acrylic or poly acrylic applied over it to seal in, just don't use it for normal purposes that solvent shellac is used for
    Sincerely,

    S.Q.P - SAM - CHEMMY.......... Almost 50 years in this art and trade and counting...

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