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Thread: Yet another shellac problem

  1. #1
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    Yet another shellac problem

    Using Zinsser Bullseye clear on a kids table. I refinished it with Sherwin Williams BAC wiping stain. Then I shot a coat of aerosol Zinsser Bullseye on it since the BAC stain doesn't like to be wiped or brushed, it's mainly for spraying a topcoat over but I wasn't wanting to spray on this project.

    I think the aerosol is where the problem starts. It was very orange peely no matter how heavy a coat I put on it and sanding it doesn't seem to help. It's also quite easy to get into the stain with the sanding. After one coat of aerosol I put on a coat of the Bullseye cut with DNA to about a 2lb cut. It seems that no matter how many coats I put on I just can't get the stuff to level out at all whether sanding between coats or not. I've cut it back to a 1.5lb cut in an effort to get a nice smooth finish. I'm using a Purdy natural bristle brush and getting decent results on a piece of bare scrap wood with it, at least better than the actual project.

    I'm at the point of starting over because it looks terrible. As a last ditch effort would shooting a coat (or five) of straight DNA with my small HVLP gun get it to level any? I'm about to break out the sander again...

  2. #2
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    If you are applying the shellac like varnish, you're going to have issues. Shellac is an entirely different animal than varnish. With the latter, the goal is to build up the finish to a certain thickness to provide the protective properties and so forth. With shellac, the goal is to apply as little finish as possible to make it look nice. Shellac doesn't like "thick" and too much thickness leads to problems like cracking, crazing, uneven surfaces, etc. You also cannot work the finish like you can with varnish...it gets tacky really quickly. Put it on with a quick stroke and move on with the wet edge. Do not go back over where you already applied the finish and "tip off". Working shellac is an art-form, but once you develop a feel for it, it's a wonderful finish to use.

    BTW, with the Zinsser shellac in the spray can, the same thing applies...very light coats. Never heavy with any pooling of the finish. It's better to spray on 2 or three really light applications than one heavy one.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  3. #3
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    I mostly agree with what Jim said. Your problems started by spraying too heavy a coat. You should spray light coats, just enough to seal the BAC stain. Your approach for brushing additional coats on should work fine once you resolve the initial problem. If you need more open time use Behlkol instead of DNA.

    At this point I don't see a good alternative other than sanding/stripping everything off and starting over.

    John

  4. #4
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    Thanks guys. This is my first foray into shellac. I can sure see why some still like it as it imparts a very nice visual to the underlying grain and the dry time is awesome. I'm going to go back to what I know and spray some Endura-Var after restaining. I'll go to shellac for smaller projects.

  5. #5
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    Scott....practice applying shellac (or any other new-to-you finish) on less important things than your special project. It's not an expensive finish and it really does take a bit of time "in the trenches" to get comfortable with applying it and breaking the "varnish habits".
    --

    The most expensive tool is the one you buy "cheaply" and often...

  6. #6
    Agree. Forget any similitude with painting ,you have to put on like the house is on fire. And it's not unusual to thin it
    more than what you have now.

  7. #7
    I too have had all the same problems with shellac, and agree with everything I have read here so far. Thankfully, I only had to use it once when I had no choice. I was matching a finish and there was just no other substitute. I used it to match something, but my question is, other than to match something because you have to, what is the reason {or maybe advantage is the right wording} anyone would use shellac??? Maybe I am wrong, but it sure seems like to me that it is difficult to use, compared to many other finishes it's not particularly beautiful, it doesn't necessarily hold up and cant really be considered "superior" in this regard...why does anyone bother to use it???? I have to be missing something.

  8. #8
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    Martin I like shellac for a number of reasons. Its easy to fix, seals in problems, dries quickly, and I think it can provide a nicer less plastic-looking surface than poly. Its hard enough for most purposes. Others may provide other advantages. But its not always the best choice.

    Jim,

    "With shellac, the goal is to apply as little finish as possible to make it look nice. Shellac doesn't like "thick" and too much thickness leads to problems like cracking, crazing, uneven surfaces, etc."

    I've never heard a better and more useful explanation than that. Thanks.

  9. #9
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    Quote Originally Posted by Scott Hearn View Post
    Thanks guys. This is my first foray into shellac. I can sure see why some still like it as it imparts a very nice visual to the underlying grain and the dry time is awesome. I'm going to go back to what I know and spray some Endura-Var after restaining. I'll go to shellac for smaller projects.
    Scott, I've used quite a bit of BAC + EnduroVar, but I always spray a light coat of Sealcoat shellac over the BAC first. Unless you already know that EnduroVar is OK directly over BAC, you should make a test panel to confirm it will bond OK.

    John

  10. #10
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    Quote Originally Posted by John TenEyck View Post
    Scott, I've used quite a bit of BAC + EnduroVar, but I always spray a light coat of Sealcoat shellac over the BAC first. Unless you already know that EnduroVar is OK directly over BAC, you should make a test panel to confirm it will bond OK.

    John
    Thanks!

    And I have used EV over BAC on my kitchen cabinets. No problem in 6 years. The key is letting the BAC dry totally and completely. ETA: I gave it a full 24 hours or more when other things were going on.

  11. #11
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    That's good to know, Scott. Six years, no problems; proof enough for me. Thanks.

    JOhn

  12. Quote Originally Posted by Stan Calow View Post
    Martin I like shellac for a number of reasons. Its easy to fix, seals in problems, dries quickly, and I think it can provide a nicer less plastic-looking surface than poly. Its hard enough for most purposes. Others may provide other advantages. But its not always the best choice.
    Thank you sir for the reply. I have to admit to having to use it a little differently. I had to match a particular finish that required it to be put on multiple times {thin, because I quickly realized this was the best way} to get the end color right. I used Zinnser and I think the color was amber. It was nice that it dried so quick and you can go ahead and fix a run or bad spot, but it was still a pain until I got finished.
    I have always wondered if there was some specific wood working projects in which shellac was the "traditional" correct thing to use.

  13. #13
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    Quote Originally Posted by Martin Siebert View Post
    ... I have always wondered if there was some specific wood working projects in which shellac was the "traditional" correct thing to use.
    I think (very) old furniture is the iconic example, but classical guitars are another example. E.g:

    Hill Guitar: About French Polish

    (PS- Kenny Hill isn't a chemist. I'm not sure shellac is generally considered a varnish.)

  14. #14
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    Quote Originally Posted by David Bassett View Post
    I think (very) old furniture is the iconic example, but classical guitars are another example. E.g:

    Hill Guitar: About French Polish

    (PS- Kenny Hill isn't a chemist. I'm not sure shellac is generally considered a varnish.)
    I didn't look at the link, but your comment about shellac not being considered a varnish caused me to remember that long ago "spirit varnish" was used on musical intruments and furniture. Spirit varnish has many iterations, but AFAIK all are shellac based plus additives. Today, varnish has a different meaning - an oil and resin that are cooked to form a new compound, but that was not always the case.

    John

  15. Quote Originally Posted by David Bassett View Post
    I think (very) old furniture is the iconic example, but classical guitars are another example. E.g:

    Hill Guitar: About French Polish

    (PS- Kenny Hill isn't a chemist. I'm not sure shellac is generally considered a varnish.)
    Thank you sir, I kind of thought it might have been used for old furniture or new stuff trying to be traditional. I never knew or thought it was used on instruments. Makes me wonder if it was used on old violins and if it might have attributed something to the sound quality.

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