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Shellac flakes?

Discussion in 'Woodturning Discussion Forum' started by Tom Hansen, Sep 2, 2020.

  1. Tom Hansen

    Tom Hansen

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    I've lost too much product from premixed shellac + DNA and want to move to mixing my own from flakes. I notice there are "colors" of shellac amber, orange, blonde, etc... Is it safe to assume that will effect my sealer color?

    I know I need to get dewaxed flakes. Anything else beyond that before ordering?
     
  2. Roger Wiegand

    Roger Wiegand

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    I prefer the non-dewaxed when using it as the final finish. I think it works better when French polishing. You will pay a lot more for lighter and lighter colors. Depending on your supplier some of the less refined shellac may contain bug parts-- you want to filter it. (you want to filter it in any event) Yes, the shellac will impart color to the wood, though not as much as you might think looking at it dissolved in the jar. Always make test pieces.

    To get it dissolved in non-geologic time get a cheap blade-type coffee grinder and pulverize the flakes (just what you are going to use) before you make up the shellac. That way it will dissolve in hours rather than days.

    I pay the big bucks for the Behlen/Mohawk reducer. It works well and consistently; one is never quite sure what's in the gallon cans of DNA from the Borg (it changes over time). Good shellac is expensive, treat it well with a good solvent. Use the cheap DNA for cleanup. I find the lifetime of shellac made with the proprietary solvent is longer, mine frequently is still good after 2-3 years.
     
    Dave Bunge and hockenbery like this.
  3. Russell Nugent

    Russell Nugent

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    From what I've read you only "need" dewaxed shellac flakes if you plan to use it as a wash coat or sealer before using another final finish. Some finishes will have problems apparently adhering to the regular shellac.
     
  4. Roger Wiegand

    Roger Wiegand

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    I've wondered about the necessity of using dewaxed as a sealer coat-- I used regular shellac for that purpose for decades without ever seeing a problem. It must be a problem with only some kinds of finishes, the oil-based varnishes I've used seem quite compatible.
     
  5. Ross Scott

    Ross Scott

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    I only ever bought one can of premixed shellac and vowed to never buy it again after learning about the short shelf life and no manufacture dates on the can I started buying the flakes and dissolving my own I can only get orange shellac flakes at the hardware store while it does impart some colour to me it is not overpowering, I also like the fact I can mix small amounts This applewood burl hollowform was finished with home made shine juice with orange shellac and I used a shellac based sanding sealer while finish sanding before using the shine juice.
     

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  6. Dave Bunge

    Dave Bunge

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    Thanks for the tip on this product. I like the fact that it does not contain methanol. The SDS says it's 75+% ethanol, up to 10% each of butanol and isopropyl alcohol. It should be somewhat less toxic than the denatured alcohol containing 50% methanol that's sold at the big box stores.
     
  7. Tim Connell

    Tim Connell

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    If you are looking for alternatives to big box store methanol mixes, go to your liquor store. EverClear (grain alcohol)is going to be as non toxic as anything you can use. May not be available in all states, and may not price out favorably in some areas, but it has been used for years for shellac, especially since they started using so much methanol in the DNA.
     
    Mike Adams likes this.
  8. Dave Bunge

    Dave Bunge

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    Good idea, but it would mean a road trip for me. Michigan law caps liquor at 151 proof max, (25% water) which is probably too wet for shellac.

    I still have some denatured alcohol with the old fashioned formulation, i.e. greater than 95% ethanol according to the manufacturers SDS when I bought it. I suppose by now it's picked up a fair amount of water too, but it still works well. Just looking for what to use next when that can is dry.
     
  9. John Freund

    John Freund

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    I have recently been using Isopropyl alcohol to dissolve my shellac. I found some 99% at the local home center. I have a tough time getting DNA here in Southern California. The Iso evaporates a bit quicker than denatured, making the finish harden up a lot faster. So far, I like it.

    I have read that you need a minimum of 80% iso to work correctly with shellac. The water in lower percentage alcohols makes it gummy and not really cure correctly.


    To answer the OP's original question, yes the different colors will effect the color of the sealer, finish, etc. Dewaxed is a safer bet for sealer, but just like @Roger Wiegand, I used regular shellac for years (still do a lot of the time, to be honest).

    In all honesty I use canned shellac a lot of the time as well. Thin it with some additional alcohol and it dries faster and cures harder. It's ready to go. I don't have to wait (if I forgot to mix some up). It can also be more cost effective (although, prices have been going up the last few years on all finishes and stuff).
     
  10. Richard Coers

    Richard Coers

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    Flakes do not have an infinite shelf life. They will degrade and absorb some moisture. Depending on storing conditions, I've read between 2 and 3 years.
     
  11. Russell Nugent

    Russell Nugent

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    Finishing guy I was listening to on Fine woodworking podcast today said flakes ed will last basically forever if they're kept sealed and out of sunlight.
     
  12. Richard Coers

    Richard Coers

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    His shop is different than my basement shop in Peoria, IL then. I threw away 3 original screw lid plastic containers of Behlen shellac flakes that had become one big mass after about 6 years. I tried dissolving them and after days in DNA, they were still one big glob. They had never left my basement, and I can attest to there being almost zero natural light down there. I used the 2-3 years based on other reports from a Google search to be safe. https://www.shellac.net/faq.html How should I store the dry shellac flakes? Kept in a cool, dry, dark place, the shelf life in my shop is 3+ years. Your mileage may vary. Never leave your shellac in a closed car. It will melt into a brick. Of course the good news is you can always smash the brick and then melt it down. https://www.shellacfinishes.com/ufaqs/what-is-the-shelf-life-of-shellac/ Shellac flakes have a finite shelf life unknown to most users. Even if Shellac flakes are stored in a cool, dark and dry place, but older than 2 years (thumb rule), it will not dissolve completely in alcohol overnight when compared to fresh stock.
     
    Last edited: Sep 5, 2020
  13. Roger Wiegand

    Roger Wiegand

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    I recently unearthed a ~30 year old jar of Behlen shellac flakes (stored dry, in the dark, they were still loose flakes). I tried hard to get them dissolved, pulverizing them first, soaking in solvent for days, finally running the rubbery globs through a strainer and trying heat to get them to dissolve. (After it became clear they weren't going to dissolve readily I just wanted to get them in solution so I could use them to make "burnt shellac", a rather remarkable adhesive used to make reversible airtight wood/metal seals in player piano work). After two weeks of effort I gave up and dumped the mess.

    I have to assume that there is some level of polymerization that proceeds over time that eventually renders the shellac unusable. This stuff was OK ~15 years ago, the last time I remember using it, before it got lost in the move. I was surprised because I'd always thought the shelf life of dry shellac was indefinite. This was orange shellac, a second bottle of "super blonde" of similar age went into solution as usual and behaved perfectly; so perhaps the level of impurities affects the shelf life.
     
  14. Mark Jundanian

    Mark Jundanian

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    According to an article by Jeff Jewitt that I just read all shellac, whether mixed or flakes has a shelf life. Refrigeration extends the shelf life.

    Mixed up the shelf life is supposed to be 6-12 months for blonde/super blonde dewaxed, and 1-2 years for an unopened bag of flakes.

    Waxy shellac can last 1-2 years mixed and 5 or more years as unopened flakes.

    This wouldn't have predicted Roger's experience, but confirms at least that flakes don't last forever.

    The article could have been better. He explains that mixed shellac degrades over time as there is a slow chemical reaction (esterification) between the alcohol and the shellac. He also explains that shellac in any form does not react with oxygen, but doesn't then explain why flakes degrade with time or why dewaxing hastens the process.
     
  15. Mike Adams

    Mike Adams

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    PSA: Amazon is once more selling isopropyl alcohol to anyone.
     
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