WAX
would not settel to the bottom it will rise to the top
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| Shellac Question http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10102&t=12928 |
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| Author: | Brock Poling [ Mon Jul 23, 2007 1:50 am ] |
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I have a question for all you guys who mix your own shellac. In mixing my own I used to end up with undisolved flakes. I usually mix a 1# or 2# cut with hardware store DA. I try to shake/stir the mixture several times per day. I then tried grinding the flakes in a coffee grinder before weighing them. That seemed to help somewhat, but I still end up with a lot of sludge that needs to be filtered out. I have been wondering if a magnetic stirrer would help get a better dissolve... Is this just the norm or am I doing something wrong? I am just using it for a sealer so it isn't critical to my operation, but I can't help but think this isn't right. |
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| Author: | Kim [ Mon Jul 23, 2007 1:55 am ] |
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Brock, If shellac flakes are not fresh, they will not dissolve. The less fresh, the less soluble. Also it is normal for some sludge to form at the bottom of the jar, most of this is wax and you should decant the mix away from this muck into a fresh jar. Cheers Kim |
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| Author: | Brock Poling [ Mon Jul 23, 2007 1:59 am ] |
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Interesting... I had just assumed in flake form they were good "forever". Good to know. Thanks. I do decant and strain the remainder a few times into a clean jar before use. Is one brand of shellac better than another? I have been buying them from Stewmac or Woodcraft mostly. |
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| Author: | Pwoolson [ Mon Jul 23, 2007 2:08 am ] |
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I've always heard that dried flakes are good forever too. You might try another brand of DA. Some are more "denatured" than others leaving less solvant in the mix. Try a mix with everclear sometime. See how that disolves your existing flakes. |
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| Author: | letseatpaste [ Mon Jul 23, 2007 2:09 am ] |
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I just mixed up some shellac flakes that were about 2 years old. I don't remember where I read this, but it was recommended to only put in half of the alcohol for about a day, and then add in the rest. I did this by accident as I had quickly done the math wrong in my head and did a 2# cut when I wanted 1#. After about 3 or 4 days, it was all mixed up with no sludge at all. Mine was super blonde from shellac.net mixed in Everclear. |
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| Author: | Michael Dale Payne [ Mon Jul 23, 2007 2:21 am ] |
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Way would not settel to the bottom it will rise to the top |
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| Author: | Michael Dale Payne [ Mon Jul 23, 2007 2:22 am ] |
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WAX would not settel to the bottom it will rise to the top
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| Author: | Kim [ Mon Jul 23, 2007 2:36 am ] |
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Stale flakes won't dissolve, that is the best indicator of how old the flakes are. Wax is more dense than alcohol and it sinks to the bottom of the jar. THIS is not water and oil we are talking about here. Cheers Kim |
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| Author: | Kim [ Mon Jul 23, 2007 2:46 am ] |
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Given enough time, especially under hot, wet conditions, dry shellac reacts with itself to form polymers that are insoluble in alcohol. Shellacs that have been dewaxed are more prone to this. You can extend the usable life of dry shellac flakes by storing them after purchase in a cool, dry area -- a refrigerator is best. A test for suspected old shellac is easy -- simply dissolve the flakes in alcohol. Most shellacs should be totally dissolved within three days. If you see a gelatinous mass after this time, the shellac is past its usable life and should be discarded (don't confuse natural wax with this). If you just purchased it, return it to the company you bought it from. Sometimes in summer months, shellac will cake together. This is known in the industry as "blocking" and is not a sign of bad shellac. Break up the shellac with a hammer and dissolve it in alcohol as usual. |
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| Author: | Kim [ Mon Jul 23, 2007 2:48 am ] |
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Oh, buy the way, that last post was a cut and paste if you did not guess. Cheers Kim |
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| Author: | Burton LeGeyt [ Mon Jul 23, 2007 3:15 am ] |
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I had the same problem with some shellac I bought from Kremer. I tried grain alcohol and DA just to be sure but it was the flakes. The stuff from LMI has never given me any problems. It has never taken more than 24 hours to fully dissolve with some shaking and stirring every couple hours. |
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| Author: | LuthierSupplier [ Mon Jul 23, 2007 3:23 am ] |
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Brock, I had the same problem before with some shellac I got from Woodcraft. It would not dissolve period! I took it back and got a different brand, and all was well. I think the LMI brand would be safest. The thinner the flakes, the faster they break down. By the way, was it super blonde, or the garnet? The darker garnet and other unrefined shellac will have a lot more sludge than super blonde. I think it takes longer to break down for the unrefined stuff. Good luck! Tracy |
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| Author: | Blain [ Mon Jul 23, 2007 3:26 am ] |
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I had the same "issue" when using Shellac from Woodcraft mixed with Everclear. After 1 day there was still some build up at the bottom. No stiring, just shaking, but after another day maybe 2 it all dissolved just fine. This was a 2# cut. I would assume that a 1# cut would be much faster. |
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| Author: | JohnAbercrombie [ Mon Jul 23, 2007 3:33 am ] |
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You can also use heat (in a water bath, no flames, well-watched)to help things along. I've seen a couple of recipes from experienced builders/French polishers that involved gentle boiling of the shellac mixture. Of course, you should add solvent to bring the volume back up after any boiling. A lot of this stuff seems to be somewhere in the area between witchcraft (eye of newt, etc) and organic chem lab. Cheers John |
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| Author: | Michael Dale Payne [ Mon Jul 23, 2007 3:59 am ] |
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 (laughing at myself) I had a daa! moment. The reason is I store my mixed shellac upside down (lid side down) for three days then carfully spoon off as much wax as possible This puts the wax at the top when I open the jar but you are right the wax does sink  
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| Author: | Dave-SKG [ Mon Jul 23, 2007 4:17 am ] |
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Brock, I too have had several batches of dried flake that were bad. If you keep them stored in an air tight dark place they are supposed to last very long. I also had issues with the dissolving medium. Stay far away from DA it's poison. I use Everclear 190. If you try using any grain alcohol less than 190 you won't get a good/full disolve. I was also told that the alcohol itself can begin to degrade once the bottle is open. So the idea is to use/mix only what you think you will need. |
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| Author: | bolix [ Mon Jul 23, 2007 4:56 am ] |
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hi, we use fresh dewaxed shellac (no more than 6 months) dissolved in denaturated alcohol <95°. stired very frequently in a hermetic jar, left in a warm place. (sometimes in a hot water bath). sure, the magnetic stirrer would give a big help! in less than 24 hours the flakes are completely dissolved, with very little sludge on the bottom. we generally prepare the right amount that we need or we store the shellac in the fridge and we use it asap. (no more than 6 months)! |
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| Author: | Rick Turner [ Mon Jul 23, 2007 5:25 am ] |
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Alcohol is hydrophilic...it absorbs water from the atmosphere and then stabilizes at 95% alky and 5% water which just happens to be the definition of 190 proof. You can get lab grade anhydrous alcohol, but as soon as you open it, it starts to absorb water. |
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| Author: | Tim McKnight [ Mon Jul 23, 2007 11:25 am ] |
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Broc, In case you were not aware of it, you can't purchase Everclear in OH but you can order it from out of state and have it shipped to you. Whomever signs for the box must be over 21. I bought mine in NJ and had it shipped here. |
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| Author: | PaulB [ Mon Jul 23, 2007 11:43 am ] |
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[QUOTE=Rick Turner] Alcohol is hydrophilic...it absorbs water from the atmosphere and then stabilizes at 95% alky and 5% water which just happens to be the definition of 190 proof. You can get lab grade anhydrous alcohol, but as soon as you open it, it starts to absorb water.[/QUOTE] And you wouldn't beleive the headaches this is causing me in the lab at work - bloody azeotropes! Anhydrous Ethanol (200 proof) is available, but is a lot more expensive, in this neck of the woods at least. A magnetic stirrer is what I used before I switched to the premixed hard shellac, but that was only 'cause I had one available at work. Ours has a heating element in it as well and heating a solvent speeds up the dissolution process, but you really need to be careful heating flammable solvent mixtures. I was only heating to 35 - 40 deg C in a safe environment. I could make up a two pound cut in a couple of hours and have all the shellac completely dissolved in that time ready to take home at the end of the day. |
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| Author: | jhowell [ Mon Jul 23, 2007 12:04 pm ] |
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Todd-- I use Hock flakes and am happy with them -- usually purchased at Woodcraft. I keep the unused flakes in a set of glass kitchen (coffee) storage cannisters which keeps them fairly well sealed. I haven't really noticed if there is an expiration date on the Hock packages -- I'll try to remember to look next time I'm at Woodcraft. I use denatured alcohol from Ace Hardware. What I do a little differently is place the flakes in a cheesecloth 'sack' as though I were putting a group of spices together for a sauce. The sack of flakes is suspended at the top of the container of alcohol as the dissolved shellac tends to move toward the bottom. I feel that this keeps the flakes in the highest concentration of alcohol possible and it speeds up the dissolving. |
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