Thread: storing hard shellac

Are you cutting it back or using neat from the bottle? I think it's about a 4lb cut straight out of the bottle. Using normal flakes I french polish with 2lb cut shellac for body sessions and around 1.5lb for glaze sessions.

How long are you leaving the shellac between sessions?

I'm sure Neil will chime in shortly with some sagely advice.

Cheers Martin

I cut it 50/50 as the instructions stated and it worked fine when I first opened the bottle, did a couple of necks. The remaining shellac I left in the bottle ( about half full ) for a couple of months and when I went to use it yesterday for the first session it just would`nt work. It took a couple minutes to dry to touch, was just kind of smearing it around when trying to apply it. This is the second bottle I`ve purchased but the first one I used up in 2 weeks. I tried every application method with that first bottle to see how it performed and it went on great no matter how I put it on. Mike

Never struck this problem before, I've just been using some that's 13 mth old and has been open for all that time. No problems for me, it's working fine.

You sent an email to LMI which I will pass on to our chemical guru for his thoughts.

In the mean time here's some of my thoughts and questions:

Cross linking takes around 3 weeks and does not begin until the shellac is dry. It will not cross link in its liquid state even if the lid is left off the bottle. The alcohol may evaporate and the shellac may thicken but that would take a very, very, very long time and could be reversed by adding alcohol.

Gooey mess sounds like it hasn't been cut, although you say it was cut 50/50 with meth. Is it possible it was inadvertently contaminated with something other than alcohol, like white spirits. Not saying this is the problem but it has happened before on more than one occasion.

Also sounds like you may possibly have been using too much shellac.

You mention a vapour trail. This shouldn't be a visible vapour trail unless you're using oil.

just wasn`t drying quickly like it should

In your email to LMI and sent on to me by them, you said:
"When I used it today it took a minute or two to dry and after about 15 minutes it was hard as a rock, which led me to believe the crosslinking had already taken place. I tried to strip it off with alcohol and it was a bear to do, I really had to rub it to get it off."

That sounds about what I would expect when using pretty much any shellac.

I presume you're French polishing.
What is on the timber before you apply the shellac? (filller, oil, sealer, etc)
What oil are you using? (Should be mineral oil.)
Was it really hot weather when you applied the shellac?
What timber?
Were you using a rubber (menuca, tampon or whatever a french polisher uses in the US)? (if so was it new or used before for something else?)
What else can you tell us?

Cheers - Neil

I was french polishing, using parrafin oil, you mentioned contamination and I did use a different brand of meths this time as the hardware store changed brands. I tested it for water content the way you mentioned in another post and found none, has it been your experience there is a big difference in brands of meths and how they effect the hard shellac? I can get Everclear alcohol here in the States and don`t have to worry about what ingredients have been used to denature alcohol as it`s pure grain alcohol. Would you recommend using it with the hard shellac? Thanks for the responseMike

G'day again Mike - Brand of meth (ethanol, alcohol) shouldn't make a difference so long as it's 95% or higher.

As for Everclear alcohol I would think it a waste of money unless you want to add it to your bourbon for an extra kick. I imagine it would cost a lot more for no additional benefit.

Cheers

Thanks for the advice Neil, I went ahead and ordered some denatured alcohol from LMI to see if it makes a difference, I did have a bad experience with a green freindly alcohol I picked up once, mixed up some flakes with it and sprayed it and it made a lumpy mess. I`m going to backtrack and try again, I was using the hard shellac on Pecan which I had filled with McFaddens pore filler, let that dry two days, sanded, then put one coat of regular shellac on, let dry a day then started applying the hard shellac. It worked great on the samples I did, but doesn`t it figure that if somethings going to go wrong it will be on the finished piece. I`m going to clean house and start with new containers and ingredients in case I inadvertantly mixed some ingredients. Since the hard shellac doesn`t crosslink till dry, if it`s not the alcohol then I`ve made a blunder at some point, won`t be the first time. Thanks! Mike

Good luck Mike.

Still haven't heard from guru who's AWOL at the moment.

Cheers - Neil

Mike,

I have on occasions had a body session go gunky. Im not using hard shellac but in this case I traced the problem down to just loading a bit too much shellac or not enough alcohol on the pad. I let the gunky shellac dry and then cut back with 600 grit wet and dry and walnut oil, removed the excess oil with the stiffing pad and after letting it dry carried on with body sessions.

The above may not be your problem but worth keeping in mind.

Cheers Martin

I think I have found the problem, I picked up a can of SLX brand alcohol and compared it to the brand I had picked up at the hardware store. There was a big difference in the drying rate between the 2 brands, I`m guessing there are numerous chemicals that can be used to denature alcohol so whatever they used is retarding the drying time. I`m still waiting for some alcohol from LMI, I`ve used their brand before to dissolve shellac flakes because it dissolved them faster than SLX. It`s expensive so I didn`t use it for polishing but I`m going to try it and see how much difference there is. I`m going to order some Everclear also and compare it with the others, I don`t expect it to work any better but at least it doesn`t contain any of the poisinous chemicals that the denatured stuff has in it. I don`t drink but the wife does, if I don`t use it all I could make her a bloody mary with a real kick Mike

Great detective work Heartstrings

Though In wouldn't want to be in your shoes when 'the kick' kicksback

Finally got to speak to the guru and his immediate reply was veneering.

Veneering.... should have thought of that myself. This is when the separate parts of shellac settle out in the mix. This is most easily seen in white shellac and brown shellac when it appears the shellac has separated into two different sections.

This isn't obvious in dewaxed shellac or hard shellac because of the absence of wax, however it still happens.Our shellac is mixed and kept in 200 litre drums and it is always mixed well before decanting because I know it will be layered even after a day.

Same goes or the shellac in your bottle. It wasn't shaken before use then it woill have been veneered meaning the first lit will have been more meths than shellac and the next time you used it it would have less meths and therefore would appear thicker. If this wasn't shaken then the next lot would be thicker again.

Get the picture.

I have known about this ever since my first encounter with shellac, but never in my wildest dreams thought to pass this info on with the product. Doh!

Simple fix below









Wait for it........












It's coming
















Keep going





















you're almost there





























lookout here it comes......


















I lied















here it comes this time














SHAKE WELL BEFORE EACH USE (the bottle not you)

Cheers - Neil

Thanks for passing that on, it`s the first I`ve heard of it. I sure didn`t bother to shake the bottle before use and it had been setting for a good spell. I`ve got a new bottle on order and will make sure I give it a shake before each use.Mike

Mike and Neil,

Shaking the bottle definitely good advice but a couple of comments:

1. If the layering is happening then wouldnt the lighter fraction (the meths) be on top of the bottle and get poured out first? Mikes problem would happen if he was getting the heavier shellac component out of the bottle first.
2. Mike youre cutting the neat HS back to 2lb arent you? Surely during this process you would a)agitate the mixture and b) cut back even further a lighter product?

Just thinking aloud

Cheers Martin

Martin - That's why the first lot was fine because he used the lighter fraction the second lot was from the same bottle, quite some time later and would have been the heavier fraction as the lighter had already been poured off..... or so goes the theory.

Mike - If you use regular shellac or waxy white you will see the definite layering especially if it sits for some time as the wax drops to the bottom of the mix leaving a non cloudy, more transparent layer on the top.

You would shake these to bring the separated fractions back together. It's just the natural thing to do. But when the entire bottle is transparent it isn't something you would thing about unless it has become second nature to do it automatically.

I shake everything before I use it and even when I pick it up even if I have no intention of using it. Just a bit of a habit I guess.

Will change the labels for future bottles to include Shake bottle before use

Cheers - Neil

PS the top fraction in waxy white or brown shellac is called tops and often poured off for use because of it's clarity and properties. However doing this does degrade the rest of the shellac in the bottle.