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  1. #1
    DrewV
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    Default Shellac drying time

    I'm just about finished with my first case refinishing job in shellac, but it does seem to be taking a bit longer than I expected for the final coat to dry and harden up. Been drying for over 24 hours now and the shellac still seems "soft" in some areas. I padded on the shellac using around a 2 lb. cut under Craig's expert direction.

    I read in a number of articles (including Craig's posts here) that a drop of shellac placed onto a piece of glass should be dry within a few hours to the extent that you cannot put a dent in it with your fingernail. Now, I just purchased my shellac flakes from a reliable source, so I know it's fresh, and I used a new can of denatured alcohol to dissolve the flakes, so I know there's no excess water.

    But when I put a small drop (maybe half the size of a dime) onto a piece of glass, I can easily put a dent in it with my fingernail even after 12 hours of drying time. Environmental conditions are: indoors, 40% humidity, 70 degrees F.

    Should I be concerned, or is this normal and I just need to wait a few more days for everything to harden up? While the case definitely seems "dry", it's clearly not fully hardened up yet, and I don't want to start sanding if the finish isn't ready.

  2. #2
    DrewV
    Guest

    Default Shellac drying time (RE: DrewV)

    I'm just about finished with my first case refinishing job in shellac, but it does seem to be taking a bit longer than I expected for the final coat to dry and harden up. Been drying for over 24 hours now and the shellac still seems "soft" in some areas. I padded on the shellac using around a 2 lb. cut under Craig's expert direction.

    I read in a number of articles (including Craig's posts here) that a drop of shellac placed onto a piece of glass should be dry within a few hours to the extent that you cannot put a dent in it with your fingernail. Now, I just purchased my shellac flakes from a reliable source, so I know it's fresh, and I used a new can of denatured alcohol to dissolve the flakes, so I know there's no excess water.

    But when I put a small drop (maybe half the size of a dime) onto a piece of glass, I can easily put a dent in it with my fingernail even after 12 hours of drying time. Environmental conditions are: indoors, 40% humidity, 70 degrees F.

    Should I be concerned, or is this normal and I just need to wait a few more days for everything to harden up? While the case definitely seems "dry", it's clearly not fully hardened up yet, and I don't want to start sanding if the finish isn't ready.

  3. #3

    Default Shellac drying time (RE: DrewV)

    Drew,

    I just wanted to compliment you on a lot of the detailed questions you hav easked on this process of refinishing your case. It has brought out a lot of detail that is really helpful.

    The thnig that makes the questions particularly good is that you have done some phase of the project and asked about something you are observing that has you stumped rather than thinking up a series of hypothetical questions.

    You get good answers and we all benefit...

    Thanks
    David Robertson - Kingsland, TX

  4. #4
    Registered user. Sooth's Avatar
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    Default Shellac drying time (RE: DrewV)

    Hi, I don't know how much help I can be, but I want to try anyways.

    I make my shellac with Methyl Hydrate (Methylated spirits) which is not as good as denatured alcohol, but it's not available easily here.

    My shellac dries almost instantly because this alcohol dries much faster. I can usually recoat within 10 minutes!

    I am wondering now about two things. Is it possible that you have a low quality alcohol? Craig had mentionned getting a better alcohol that is more expensive than the regular stuff because of the lower water content.

    Secondly, when you shellac, did you leave the container open a lot, or for extended periods? If you did, some, or a lot of the alcohol may have evaporated from the mix.

    Also, how old is your mixed shellac? It will only stay good for about 2 weeks if left at room temperature (give or take). I'm not 100% sure how it's supposed to be stored, but I usually make only small batches.

    Old shellac will take much longer to dry, and will give you more trouble to work with.

    How many coats have you done? With my mix, I usually end up doing about 7-10 thin coats (brushed on).

    Hopefully Craig or Tom can also give you input on this.

  5. #5
    DrewV
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    Default Shellac drying time (RE: DrewV)

    I've spoken with Craig a few times over the phone along the way, so I'm sure I did everything the way I was supposed to. Fresh new flake shellac, Kleen Strip brand denatured alcohol, never left the jars open, padded on the shellac in many thin coats, etc. All the work was done indoors in an air-conditioned environment.

    All told, I probably ended up with around 20-25 "layers" of shellac, with about 3 or 4 layers applied in each session before allowing to dry, with the entire project having been done over the course of 2 or 3 days.

    I actually tried sanding down one small area with 400 grit and ended up sanding through the finish, I believe. I reapplied a few coats in that area to even things out. So, I'm fairly sure that I don't have an excessively thick finish so far. But I think I've got enough applied, so I want to begin sanding it down, but as I said, I'm just not sure that it's fully hardened, or whether it will EVER fully harden?

    I assume that it will dry eventually, but I guess I've never heard that you needed to wait longer than "overnight" before sanding.

  6. #6

    Default Shellac drying time (RE: DrewV)

    Drew,

    I wish I could help, but sooth pretty well hit the important points and it sounds like you did them all correctly.

    Normally, I mix a small batch (4oz alcohol with 1oz flakes). It mixes down in a few hours. I use it within two weeks or toss it.

    I apply it with a rubber that has been pre-dampened with alcohol. I find that within an hour, it is hard enough to sand using olive oil as a lubericant.

    Lack of hardening is normally associated with excess water content in the alcohol/shellac mix, but it sounds like you mixed then used immediately. With high humidity, I guess it could absorb a lot of water quickly, but you are doing it in an air conditioned room.

    The only thing I can think of is that you had earlier mentioned how slowly the flakes were disolving. That's pretty odd in these summer temperatures.

    One suggestion is to make a fresh batch using just one oz (by weight) of flakes that you have pre-crushed to small bits and four oz of alcohol. In normal daytime temperatures, this mix should be fully disolved in no more than 3 hours. If it takes a lot longer than this, something is wrong.

    If it disolves properly, then rub some of this new mix onto the surface and compare results.

    Sorry to hear that you are having a problem. Shellac is normally the easiest finishing product you can use.

    Regards,

  7. #7
    Registered user. Sooth's Avatar
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    Default Shellac drying time (RE: DrewV)

    I know that shellac with too much water in it can take months to dry.

    Is it possible that you applied too many coats overlapped, and didn't wait long enough in between? It should dry very hard, and smooth/shiny.

    Did you apply it to a stripped case, or overtop an old shellac finish?

    I don't see how it's possible that you sanded through the finish with the paper. When the shellac is dry and hard, it's hard to sand it down much. Vigorously rubbing with even dry 400 (non lubricated with oil) usually only removes the very top "bumps" in the finish.

    I guess the only thing you can do is one of two things: Wait until it fully hardens (which could take a long time...) or start over.

    Hopefully someone else can be of more help. It shouds like you were doing it right, but it just went wrong...

    I've only done 3 clocks in shellac so far, but haven't had any problems at all.

    I wish you some luck. If you want, I could e-mail you a photo of the sanded-down shellac to show you what it should look like, roughly (pun not intended!)

  8. #8
    Registered user. Sooth's Avatar
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    Default Shellac drying time (RE: DrewV)

    Maybe Tom is right. It shounds like you did everything right. Maybe your flakes are bad? Usually these last forever, but maybe it's a bad batch?

    I use Tom's proportions also (got them from him) 1 oz to 4oz, and with my Methyl Hydrate, the flakes dissolve in less than 15 minutes! The stuff is very strong, and seems to work fine for me. I know one other person on the message boards also uses Methyl alcohol, and hasn't had problems.

    I think it could be the flakes though. I don't know HOW, but maybe.

  9. #9
    DrewV
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    Default Shellac drying time (RE: DrewV)

    Yes, I mixed it and used it immediately. I just purchased the flakes directly from http://www.shellac.net, who claims to have fresh flakes and has gotten reasonable reviews from people on the internet.

    When I received my 1 lb. bag of shellac flakes, they were pretty well packed into a more or less solid hunk of flakes, but they broke apart fairly easily and dissolved pretty readily in the alcohol. I can't say I noticed anything that caught my eye as being a problem with the flakes, other than the fact that they were caked together when I received them.

    With regard to the sanding, well, I pretty quickly sanded through the finish with the 400 grit paper lubed with some paraffin oil. I could have easily gotten down to the bare wood in a matter of less than a minute without the need for any sort of vigorous rubbing.

    In the end, I guess it's possible that I applied too many layers, too quickly, so that the lower layers didn't fully harden. But I guess I didn't read anything that ever mentioned using caution with allowing each layer to dry first. I just waited a few hours between each coat just so that the pad didn't drag when I started the next coat.

    I guess I'll have to wait a few days and see what happens. But I'm still interested in finding out what the story is with this stuff and why it didn't harden "overnight."

    I did notice a few very small drops that must have dripped out of the squeeze bottle onto my work surface while I was padding. Those drops must have been there for a while, because they were definitely hard as a rock and chipped off of the work surface with my fingernail. I could not put a dent in those drops. I'm hoping that's a good sign, although I'm more concerned about how the shellac is hardening on my clock more so than my work surface.

  10. #10

    Default Shellac drying time (RE: DrewV)

    Drew,

    We are all very interested in figuring this out. Since, myself, Sooth and Craig have never ran into this kind of thing when prepared and applied as you did. Strange........

    Since you found some drops that did harden as expected, the final answer may be as simple as "a really humid day".

    Keep us posted.

    Regards,

  11. #11
    Registered user. Cathy in Hawaii's Avatar
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    Default Shellac drying time (RE: DrewV)

    Aloha Drew,

    It sounds as your layers aren't building up as much as expected as well as the shellac not drying completely. With that many layers, it should be thicker, shouldn't it? When applying layers do you think the new shellac has time to soften and remove some of the earlier shellac?

    If you happen to have an oven with a gas pilot light and if your clock case will fit in the oven (and if your DW will let you) perhaps you could put the clock case in the oven overnight with just the pilot light on. That works real well for rising bread and drying out sliced bananas. It would probably dry out your shellac, too. Put a sticky note on the oven knob or pull the knob off completely so nobody will "pre-heat" the oven without checking inside first.

    Has anyone else been shellacing in air conditioning? We usually have 80% to 100% humidity and the shellac here has dried fine. I was even shellacing a bit of wood in the carport with rain falling about four feet away and it still dried almost instantly and came out fine. (Surprisingly enough)

    A hui hou,
    Cathy

  12. #12

    Default Shellac drying time (RE: DrewV)

    OOOOh, shellac doesn't like heat. That's a good way to add 100 years to your new finish in about 5 minutes. Even the heat from a hair dryer will ruin shellac.

    Drew,
    Don't fret. Just keep going. If you sanded through with 400, then there wasn't enough build in the finish, or too much pressure applied, or the sandpaper corned up. Corns will pull the finish off if not enough lube is used. Shellac is not tricky, just takes some getting used to.

    Sometimes the environmental conditions are not well predisposed to working on clocks. Just ask Bob about hide glue taking a few days to dry in a humid environment. Even though I'm in Texas, am not experiencing the soft finish. I would say you're doing fine, though. Just add a few coats and let it dry for a day or two.

    A while back I worked on a Vienna that the shellac finish kept crinkling or distorting. I determined that the shellac was not drying enough between coats. I set it aside for a week and came back to it. No problems later.

    Now, using the same shellac mixture on another case, I was able to level (400&oil), smooth (0000&wax), and polish (rottenstone&oil) the very next day. Same shellac, different environmental conditions. Usually shellac is not testy like this. Drew, don't worry, this is the exception you're experiencing.

  13. #13
    DrewV
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    Default Shellac drying time (RE: DrewV)

    Thanks for the advice. I figured I'd just wait and see what happens in the next few days.


    In looking at the finish, however, I do wonder whether or not I had applied too much shellac on each pass with the pad. While the pad was not dripping wet, I did notice that there are a heck of a lot of lap lines and some areas where it appears that there was some bubbling of the shellac, probably due to a heavy layer being applied.

    The funny thing is that I can't possibly see how a brushed finish could be worse than what I have achieved with padding. Like I said, there are lots of areas of heavy buildup, lap lines, curves, ridges, etc. all over the case. I tried brushing shellac onto a smaller test piece and it really looks great. (Still not dry, however.)

    Can you tell me the real benefits of padding as opposed to brushing, assuming that you're using the same cut of shellac? When brushing, it seems that the shellac just flows out into a very thin layer, but when I pad it on, it seems to "curtain" easier and stay heavier. Maybe it's just my perception, who knows, but the brushed finish just looks better when I compare them side by side.

  14. #14
    Registered user. Cathy in Hawaii's Avatar
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    Default Shellac drying time (RE: DrewV)

    Aloha Drew & Craig,

    Guess the oven idea is scarey if shellac doesn't like heat. But a gas oven with just the pilot light on - not the burners - is only about eighty degrees or so. Much less than a hair dryer! Mostly the pilot light dries things out and heats it up just a wee bit.

    If you are getting lines in the shellac, it sounds like you have too much shellac on the rubbing pad, although Craig would know for sure.

    A hui hou,
    Cathy

  15. #15

    Default Shellac drying time (RE: DrewV)

    Drew I think the main advantage of padding shellac as opposed to brushing shellac is the is the quickness of the drying time when padding as opposed to brushing.Normally when you are brushing on shellac you should let it dry a minimum of four hours or longer dependent on enviromental conditions,i.e.,humidity,air temperature,etc..If you pad properly you should be able to pad a fresh coat of shellac about every fifteen minutes.During the course of a day thats a helluva lotta coats and the beauty of padding is you don't have any brush marks to contend with which in turn makes sanding a lot easier with less of a chance of sanding through your finish.I can't stress enough that padding is multiple applications of a light coat of shellac each time you pad.You have to resist the temptation to lay it on thick to accelerate the application time.thick coats require longer drying times and kind of go against the benefits of padding.Personally I like to use a pad about the size of a tangerine with the outter wrap made from an old pillow case(no lint balls)and for the pad stuffing I use cotton balls.Draw it up tightly so you don't have any creases on the pad surface and rubber band off the open end.Fill up a squeeze bottle about a quarter way with your shellac and you're ready to go.When you pad come down on your case and glide your pad along the surface and lift it off with a forward motion.Try not to overlap your previous application too much with your next stroke because this will cause streaking because the shellac dries so fast during padding.Call me Mr. Overkill but its nothing for me to put down twenty or thirty coats when I pad shellac.It gives me a nice built up shellac finish and I've never had the unpleasant experience of sanding through.Thats me though.
    I'll tell you this,I'm a disciple of Craigs' methods and If you follow his lead believe me you're going to be shocked at the quality of refinishing you'll be doing.I went through the same problems initially,cloudy shellac,streaks,abnormally long drying time,etc but like anything else you do with clocks its seems like the more you do the less frequent the problems become.Don't get frustrated,just keep tweaking your methods till it suits your needs,thats what I did.
    Best of luck with your clockcase.
    Respectfully,Bob Fullerton

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