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#1
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Shellac is perma-gelatin
I'm trying to use Shellac flakes for the second time and am having some
trouble. The first time I used it they dissovled after about three days without much fuss, but this go-round I've got a big blob of gelatin at the bottom of my bottle that I can't get to dissolve. Here are the facts of the case: * Bought blonde dewaxed shellac from Woodcraft on Thursday * About an hour later, I smashed it to smithereens with a hammer and added it to brand new alcohol (in a well sealed plastic bottle, also from Woodcraft) in a 2# cut * I tried adding it to the alcohol slowly and letting it dissolve, but it just sat at the bottom and stared at me desipte repeated stirrings, so I dumped it all in. * The bottle is a very well sealed glass jar with a rubber grommet and a metal latch - no chance of moisture getting in that I can see. * I put the bottle in a bath of warm water to speed the reaction * Come back four days later, and there's goopy shellac gelatin on the bottom, maybe about a quarter of the original volume, undissolved. I've spent the last couple hours breaking it up, warming it, shaking it, and repeating, and it's still just gelatin--the undissolved portion hasn't changed much. Is this shellac no good? Should I return it? Did I blow it in step 3 by being impatient? I still have another bottle of flakes in the fride and I don't want to screw up another batch. Thanks, George |
#2
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Go to Home Depot and buy some Bulls Eye premixed.
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#3
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buy some Bulls Eye premixed.
oh, that was very helpful |
#4
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The reason for my flippant response was I used to be a mix your own guy
myself. Once I started using the Bulls Eye from HD, I never looked back. HD wouldn't keep it on the shelf if it sat there for 6 months, they wouldn't carry it, and some locations don't. They (Zinser) claim they have a longer shelf life due to specific additives or processes. The longest I've kept 1/2 a can was a year and it was fine when I used it again. I've been through probably 10 gallon cans and have never had a bad experience with it. While mixing my own was about a 50/50 proposition. My point was, mixing is a hassle. I know it seems kinda cool and is convenient. But I haven't found it to be a better solution then grabbing a quart from HD...personally BW |
#5
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I'm steering clear of premixed because all the books agree that it goes
bad in six months, and if the flakes I'm buying are possibly bad, I can't even imagine how bad the situation is at home depot. I need help to figure out if my current batch is salvageable and what I should do differently with my next batch. |
#6
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#7
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Well, that's certainly the easiest possible answer. I'll go to Lowes
tomorrow as their web site says they carry it (no luck at HD). Now, what to do with the 4 pounds of flakes I have? |
#8
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D'oh...looks like it's not dewaxed! This furniture is too important to
take chances with so I don't think I can live with that. Argh, why must everything be flawed?! |
#9
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If your books all agree on that, you're reading the wrong books. Sorry, but
there's simply no rule that always holds, here or anywhere. In general, shellac you mix, or premixed shellac, will go bad somewhere between 6 months and about 5 years. While it varies with the specific shellac, it primarily depends on the storage temperature. When I had a cold workshop, I mixed shellac and easily kept it for years, and never saw any go bad. A friend in a warmer climate (and heated workshop) got just under a year. Further, the new Zinsser has demonstrated it will remain good for much longer than natural shellac. They sent me a test sample when it first came out, and it lived up to their claims. Only more recent books are aware of this. Further, I use different shellac colors which I mix from flakes. These are stored in sealed container, in a refrigerator, and I've used some over 15 years old. Finally, you may just have a bad batch of shellac. I don't know what cut you're trying to mix, or what type of alcohol, but if some stirring together with a pot of hot water doesn't do it then something's wrong with it. (I assume you're not trying for a 12# cut, of course.) GerryG On 28 Dec 2004 11:58:54 -0800, " wrote: I'm steering clear of premixed because all the books agree that it goes bad in six months, and if the flakes I'm buying are possibly bad, I can't even imagine how bad the situation is at home depot. I need help to figure out if my current batch is salvageable and what I should do differently with my next batch. |
#10
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wrote in message
oups.com... I'm trying to use Shellac flakes for the second time and am having some trouble. The first time I used it they dissovled after about three days without much fuss, but this go-round I've got a big blob of gelatin at the bottom of my bottle that I can't get to dissolve. Here are the facts of the case: * Bought blonde dewaxed shellac from Woodcraft on Thursday * About an hour later, I smashed it to smithereens with a hammer and added it to brand new alcohol (in a well sealed plastic bottle, also from Woodcraft) in a 2# cut * I tried adding it to the alcohol slowly and letting it dissolve, but it just sat at the bottom and stared at me desipte repeated stirrings, so I dumped it all in. * The bottle is a very well sealed glass jar with a rubber grommet and a metal latch - no chance of moisture getting in that I can see. * I put the bottle in a bath of warm water to speed the reaction * Come back four days later, and there's goopy shellac gelatin on the bottom, maybe about a quarter of the original volume, undissolved. I've spent the last couple hours breaking it up, warming it, shaking it, and repeating, and it's still just gelatin--the undissolved portion hasn't changed much. I mix my own in small batches, and I use the see it shake it method. I make in the morning, shake every time I can, and it's dissolved by afternoon. Two things you can do to hurt your chances are decrease the surface area actually exposed to alcohol by making a bunch of small grains and allowing the to clump to form, and attempting a two or three pound cut direct, rather than adding flakes to a made one-pound. Try larger pieces and one-pound, to be enriched later. |
#11
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On 28 Dec 2004 11:16:18 -0800, "
wrote: * About an hour later, I smashed it to smithereens with a hammer and added it to brand new alcohol (in a well sealed plastic bottle, also from Woodcraft) in a 2# cut Howdy, I am confused by the very last phrase above ("in a 2# cut.") How much shellac (by weight) do you have in how much alcohol (by volume)? I suspect that you may just have more shellac than you can get into solution. You may already be aware that 2# cut would mean two pounds of shellac in a gallon of alcohol. Is that the ratio you actually have? HTH, -- Kenneth If you email... Please remove the "SPAMLESS." |
#12
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I followed the directions on the bag for a 2# cut; two quarts of
alcohol for one pound of flakes. |
#13
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Why did you have to smash it with a hammer? Wasn't it flakes to begin
with? If it was clumped up, there may have been something wrong with it (moisture?) to begin with. Unheated, shellac does take a long time to dissolve, IME. Sometimes a couple days to become completely dissolved, with some intermediate shaking and stirring. But if it's still a gloppy mess after four days, that's not normal. Try heating it in a pan of hot -- not just warm but almost boiling -- water for an hour or two. I find that's the best way to dissolve it. (As I'm sure you now, alcohol fumes and an open flame are a bad combination, so you want to do the heating with a hotplate or on an electric range, or boil the water and turn off the gas before putting the shellac in the pan.) On 28 Dec 2004 11:16:18 -0800, " wrote: I'm trying to use Shellac flakes for the second time and am having some trouble. The first time I used it they dissovled after about three days without much fuss, but this go-round I've got a big blob of gelatin at the bottom of my bottle that I can't get to dissolve. Here are the facts of the case: * Bought blonde dewaxed shellac from Woodcraft on Thursday * About an hour later, I smashed it to smithereens with a hammer and added it to brand new alcohol (in a well sealed plastic bottle, also from Woodcraft) in a 2# cut * I tried adding it to the alcohol slowly and letting it dissolve, but it just sat at the bottom and stared at me desipte repeated stirrings, so I dumped it all in. * The bottle is a very well sealed glass jar with a rubber grommet and a metal latch - no chance of moisture getting in that I can see. * I put the bottle in a bath of warm water to speed the reaction * Come back four days later, and there's goopy shellac gelatin on the bottom, maybe about a quarter of the original volume, undissolved. I've spent the last couple hours breaking it up, warming it, shaking it, and repeating, and it's still just gelatin--the undissolved portion hasn't changed much. Is this shellac no good? Should I return it? Did I blow it in step 3 by being impatient? I still have another bottle of flakes in the fride and I don't want to screw up another batch. Thanks, George -- jc Published e-mail address is strictly for spam collection. If e-mailing me, please use jc631 at optonline dot net |
#14
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It was a little clumpy as flakes, which worried me, but I crushed it
because that would increase the surface area. I've been keeping it in hot water all day and it's mostly dissolved, so the situation isn't quite as grim as I thought this morning, although I certainly won't dare use it until testing it. I did see on person say that heating it up makes the final finish more brittle. But since only one person has said that, I'm choosing not to believe it for now |
#15
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I did see on person say that heating it up makes the final finish more
brittle. But since only one person has said that, I'm choosing not to believe it for now Shellac has organic acid components. Over time, the acids react with alcohol and form esters --- which won't dry properly. I'd guess that heating the mixture would just speed up the esterification recation. I'd suggest to just mix the flakes and alcohol and shake it occasionally. I'd should dissolve in a day. Also, have you considered the alcohol? Maybe it contains too much water. Try again with different alcohol and see if that works. Joel Jacobson |
#17
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#18
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I did find a dewaxed premix called Bullseye Sealcoat which I bought off
Rockler, so I'll give that a try - people seemed to think that one was close to blonde, while the non-dewaxed ones appear to be more orange (they call it "amber"). At any rate, it looks like I'll have more than enough shellac one way or another Thanks for your help, George |
#19
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You must regularly shake or stir the mixture of shellac flakes and
alcohol to get the flakes to dissolve. A temperature of 70-80° F is fine, you do not have to warm it above this. Leaving it to sit for days will do nothing for dissolution. All you will get is an softened blob at the bottom of the container. Try shaking it every hour or two. Grinding up the flakes was a good idea to increase surface area but you still must mix it regularly. As for Zinsser's Seal-Coat, it is already a two pound cut of dewaxed shellac. If you like the color, there is no reason not to use it. Good Luck. wrote in message oups.com... I'm trying to use Shellac flakes for the second time and am having some trouble. The first time I used it they dissovled after about three days without much fuss, but this go-round I've got a big blob of gelatin at the bottom of my bottle that I can't get to dissolve. Here are the facts of the case: * Bought blonde dewaxed shellac from Woodcraft on Thursday * About an hour later, I smashed it to smithereens with a hammer and added it to brand new alcohol (in a well sealed plastic bottle, also from Woodcraft) in a 2# cut * I tried adding it to the alcohol slowly and letting it dissolve, but it just sat at the bottom and stared at me desipte repeated stirrings, so I dumped it all in. * The bottle is a very well sealed glass jar with a rubber grommet and a metal latch - no chance of moisture getting in that I can see. * I put the bottle in a bath of warm water to speed the reaction * Come back four days later, and there's goopy shellac gelatin on the bottom, maybe about a quarter of the original volume, undissolved. I've spent the last couple hours breaking it up, warming it, shaking it, and repeating, and it's still just gelatin--the undissolved portion hasn't changed much. Is this shellac no good? Should I return it? Did I blow it in step 3 by being impatient? I still have another bottle of flakes in the fride and I don't want to screw up another batch. Thanks, George |
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