Low water alcohol for shellac

[Dengue]

Our beloved Benign Dictator is forever warning us to use very low water level alcohol with shellac flakes and dewaxed solutions etc, not the metho stuff that you can find in hardware stores with up to 20% water.

I finally found some Ethanol with < 0.81% water from Sydney Solvents.

No connections with this company for me, just letting everyone know that low water alcohol can be purchased. My 5 litre bottle arrived today by Aust Post, free postage

[justonething]

I just checked. It's free postage to my place. Thanks for the heads up

[Skew ChiDAMN!!]

Now added to my shed post-it note, listing suppliers.

[pach]

Now added to my shed post-it note, listing suppliers.

Good Idea! Pity there isn't a list of suppliers we can all share on this forum.... maybe we should start one ;-)

[Chesand]

Any decent paint shop should stock 100% Methylated Spirits. It is available at Paint Spot stores here in Melb in 1 litre bottles and possibly larger containers.

[woodPixel]

I use Sydney Solvents for IPA.

They are an excellent company. Thanks for the tip on IMS!

For 100% IMS you can also get it from The Paint Place on special order (1, 5, 20L). They sometimes have it on the shelf. Price will nowhere be as good as SS however....

Agreed we need some sort of shared Google Spreadsheet of products and suppliers!!!!

[woodPixel]

Edit! I was going to mention they usually have highly refined versions of most of their chemicals for a few more $$.

Here is the 99.9% IMS: https://www.sydneysolvents.com.au/me...-grade-5-litre

[Mobyturns]

Only one small issue - alcohol is hydroscopic. It will readily absorb moisture from the air, so once the bottle is opened the ongoing purity of the alcohol is highly dependent upon the moisture content in the air that replaces used product.

[taz01]

Only one small issue - alcohol is hydroscopic. It will readily absorb moisture from the air, so once the bottle is opened the ongoing purity of the alcohol is highly dependent upon the moisture content in the air that replaces used product.

Would something like bloxygen work to stop this, or is the cost not worth the effort?

[Robson Valley]

What you do is to decant say 750ml into a "working bottle" and seal the original.
We needed anyhdrous ethanol at LaTrobe in the lab. Did it with molecular sieve,
cheaper than buying it. Beer bottles with crown seals. Kept very nicely.
The molecular sieve can be recycled in an oven.

[Skew ChiDAMN!!]

For a long time I used to inflate a balloon in the air-space of various bottles, using a straw down one side to let air out as the balloon inflates, and then plug with a cork. But modern balloons are so cheaply made that the volatiles tend to perish them way to quickly.

Would something like bloxygen work to stop this, or is the cost not worth the effort?

That'd work,we use it for our iced wines and botyris, but I don't think it's really practical for the "working" bottle.

IMO you're better off using one of the concertina style squirt bottles with which you can slowly "collapse" the bottle as contents are used and keep air out. Does need an air-tight cap of course... and to be made from a material that doesn't consider the contents a solvent.

Now, the original bottle you decant from... that's a different story. I see no reason to not argon that... the price is affordable. The stuff we use is around $25 inc. shipping from the US and gives about 120x 750ml uses. That's... what...? 20cents for each 750ml "empty" when topping up a bottle?

I should mention that our stuff is not 100% argon. I believe it also contains Nitrogen and CO2... but the original Bloxygen recipe was pretty much the same mix.

It is sold as a wine preserver, not a paint preserver and may react with certain finishes. I haven't tried.

[Mobyturns]

I treat any product that can suffer from evaporation of thinners, or absorption of water by decanting into smaller containers pretty much on first opening if possible.

For say 4lt of lacquer I usually stir thoroughly then decant into 2 x 1lt cans plus 3 x 500ml cans then 2 x 250 ml cans as this best suits my usage needs. The size range means that product exposure to air can be limited. Something like DNA I use a storage and a working bottle to minimize exposure to air for the storage bottle. It is only ever opened to decant some product that will keep me going for a few jobs, then I immediately close the storage bottle tightly.

[Dengue]

When decanting into 750ml empty wine bottles, does anyone use the vacuum wine stoppers to extract the air and keep the stuff fresh? I do it with oil, no problems, but worried I might be creating a bomb with the ethanol or lacquer thinners under vacuum

Just found on the Internet:

The boiling point of ethanol is 79*C and under vacuum (28 inHg) it drops to around 34*C. We typically use a rule of an additional op-temp of 50 degrees Celsius above the boiling point of the solvent is enough to boil the solvent and maintain that boil.

so, at 34 degC and higher, can I assume the ethanol liquid under vacuum becomes a gas. Does this mean that the bottle will be filled with high pressure gas, ready to explode?

I wish I had paid more attention in my Chemistry classes

[woodPixel]

Couldn't you just use a bottle of welding gas? Argon or CO2? Helium in a pinch?

[Robson Valley]

Welding gases? Sure you could. The concept is the issue of water/humidity/H2O in the ambient air.
To be anhydrous, nothing else matters, agreed? As long as you get a bottle of dry gas, you're done.

Look into ceramic "molecular sieve." You can regenerate it and it has been doing a dandy job
of dehydrating alcohols for decades. Even as far back as I go.