Dissolving Shellac in Meths
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- This topic has 16 replies, 9 voices, and was last updated 7 years, 7 months ago by Reno.
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Hi,
I just mixed up my first ever batch of Shellac from flakes.
I followed an article online to get the mix of flakes to meths.
The article suggested it would all dissolve in 24 hours. However, it took about 5 days.
Am I supposed to crush / break up the flakes before mixing?
Thanks
Darren.
14 September 2016 at 5:32 pm #140158The shellac flakes were either old, or it is something with the denatured alcohol you used. I will shake the jar up but it only takes a day or less for me.
Hi,
I shook the jar up every day, some times several times a day.
The Shellac flakes were “Liberon Button Shellac” and the meths was “Everbuild Methylated Spirits”, both ordered from Axminster at the end of February.
I know Meths has a shelf life. Could it be too old now? What about the Shellac?
Regards
Darren.
This is probably totally wrong by me but I just kind of wing it when I mix my shellac. And per the recommendation of one of the guys at Highland Hardware, I bought a bottle of Golden Grain (or Everclear) at the liquor store to use as the solvent because, in his words, denatured alcohol is “heavy shit”! (i.e. the fumes are poisonous).
But I just didn’t really understand some of the terms–4 lb cut, etc. I just mixed what I thought was a reasonable viscosity and have more or less done it that way. Call me an idiot, showcasing my inexperience but I’ve been happy enough with the results. And I’m not exactly building fine furniture so I’m probably rationalizing but that’s just how I’ve done it so far. I basically just dissolve as much as I think I need for a given project so that I don’t waste the flakes since they have a shelf life once dissolved. After all (I tell myself), the alcohol is just a solvent that evaporates and I can always put on additional coats if I think I need more (but so far I’ve been happy with 2 coats of my own batch with a wax finish). I bet my mix is usually dissolved and ready within a few hours. I’ve also been known to experiment and mix a few colors together (I imagine I’m not unique in that regard though).
To your question, Tenjin, I think it is probably fairly common to crush the flakes into a finer grist to make the dissolving process go faster. Especially considering that the shellac flakes can sometimes clump up into a mighty mass that then takes even longer to break down…
- This reply was modified 7 years, 7 months ago by David B.
15 September 2016 at 2:07 am #140178I found somewhere online a guide to small patches but I just eyeball it….like I do for much of my woodworking. Thats just my nature. I recently saw someone who said make a very strong blend, then just dilute it to what you need. I think everclear is more expensive though then denature alcohol. Here (in the U.S.) I use clean strip green its 190 proof. I have a feeling Tenjin’s was a lower proof.
Denatured alcohol has additives to discourage consumption; therefore it is not taxed at the high rate of consumable spirits. It is used in numerous personal care products such as perfumes, aftershaves, and other applications where consumption is not involved (i.e. SDA 39c and 40 are common denatured alcohol variants). While to ingest high quantities of denatured alcohol (depending on the denaturant) may be a heath issue I am not aware of any issues from normal inhalation.
@narrs , I’ve seen people claim that methanol is a cumulative neurotoxin so that, even at exposures below what is deemed safe to avoid poisoning, there could be long term outcomes that aren’t captured in exposure guidelines. Just to be clear- I’ve read things by nonexperts saying this (which I can’t seem to find now), but that doesn’t make it true.
@tenjin, if I put about 1cm to 2 cm of flakes loosely at the bottom of a glass jelly jar, note the vertical height, and add alcohol to about twice that height, more or less, the flakes will dissolve by the next day. Just after adding the alcohol, I give it a good long shake. I’ll give it additional shakes whenever I walk past it during the day. Next day, it’s good to go.15 September 2016 at 12:42 pm #140201What proportion of flakes to meths are you using. I mix up small amounts (a little seems to go a long way) when I need it and have never had to wait more than 12 – 24 hours.
So for example, to make a quarter litre of a 1 1/2 lb cut would be (in metric) 45g of flakes with 250ml meths. This takes 24 hours depending on temperature
I just use ordinary methylated spirits from b&q or somewhere like that and it seems to work ok. I’m not aware that the meths has a shelf life if kept sealed. Not sure about the flakes though
Cheers
Bill
Hi,
Thanks for all your replies.
Taking some of the points in turn:
Clumping – the Shellac flakes did clump together and stick to the bottom of the jar. I shook the jar every day, and prised the clumps off the bottom of the jar.
Mix ratio: will have a look when I get home as I wrote it on the jar lid.
Is room temperature a factor? I kept the mix in my workshop (garage), which is not consistently warm.
Thanks again,
Darren.
16 September 2016 at 2:34 pm #140283Yes the ratio sounds right for a 2 pound cut. Also temperature is factor and has a significant effect on speed of dissolving – I try and leave mine indoors if practical.
I also tend to shake the container regularly during the day. This prevents clumping and increases the surface area of flakes exposed to the meths whic makes for quicker dissolving.
Paul has a piece on this subject on his blog which may be of interest.
https://paulsellers.com/2014/03/making-shellac-scratch/
Cheers
Bill
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