My shellac looks like gravy

Talk about musical instrument construction, setup and repair.

Moderators: kiwigeo, Jeremy D

Post Reply
TrevorMag
Wandoo
Posts: 14
Joined: Sun May 10, 2015 4:53 pm

My shellac looks like gravy

Post by TrevorMag » Sun Dec 26, 2021 7:54 pm

All the YouTubers' mixes look like super transparent golden syrup or cognac or some other delicious foodlike substance.
Could be a dud batch, but the smart money says it's because I used Bunnings Meths.
All the online advice says "denatured alcohold 96 or 98" - can't seem to find that in Hobart.
Look online perhaps?

User avatar
ozziebluesman
Blackwood
Posts: 1529
Joined: Wed Oct 10, 2007 9:12 am
Location: Townsville
Contact:

Re: My shellac looks like gravy

Post by ozziebluesman » Sun Dec 26, 2021 8:09 pm

Sounds to be like you shellac flakes, granuals, beads or what ever dry form you used is old stock or it have been subjected to moisture so your brew has not dissolved correctly. If it is a milky colour that's your problem for sure.
Good luck.
Merry Christmas
Alan
"Play to express, not to impress"

Alan Hamley

http://www.hamleyfineguitars.com/

User avatar
kiwigeo
Admin
Posts: 10582
Joined: Sat Sep 29, 2007 5:57 pm
Location: Adelaide, Sth Australia

Re: My shellac looks like gravy

Post by kiwigeo » Sun Dec 26, 2021 8:09 pm

The meths you get from Bunnings will contain a certain amount of water as well as a denaturing agent. What you're after is Industrial Methylated Spirits or IMS meths. Carbatec carry the stuff and there are a few other sources. https://www.carbatec.com.au/metholated- ... industrial

If your made up shellac is going gooey also check the flakes you're using are fresh...the stuff does have a shelf life.
Martin

User avatar
ozziebluesman
Blackwood
Posts: 1529
Joined: Wed Oct 10, 2007 9:12 am
Location: Townsville
Contact:

Re: My shellac looks like gravy

Post by ozziebluesman » Sun Dec 26, 2021 8:15 pm

Thanks Martin you are right as well.
Is it ok if I make a suggestion where to buy the shellac?
https://www.thewoodworks.com.au/shop/co ... gms-detail
This is what I have use for a while now and it is great, Store the dry shellac in the fridge.
Cheers
Al
"Play to express, not to impress"

Alan Hamley

http://www.hamleyfineguitars.com/

User avatar
kiwigeo
Admin
Posts: 10582
Joined: Sat Sep 29, 2007 5:57 pm
Location: Adelaide, Sth Australia

Re: My shellac looks like gravy

Post by kiwigeo » Sun Dec 26, 2021 8:33 pm

ozziebluesman wrote:
Sun Dec 26, 2021 8:15 pm

Is it ok if I make a suggestion where to buy the shellac?
https://www.thewoodworks.com.au/shop/co ... gms-detail
This is what I have use for a while now and it is great, Store the dry shellac in the fridge.
Cheers
Al
Yes of course no problem with suggestions for sources of materials. Thanks Al.
Martin

User avatar
56nortondomy
Blackwood
Posts: 674
Joined: Sat Jan 14, 2012 11:56 pm
Location: Melbourne western suburbs

Re: My shellac looks like gravy

Post by 56nortondomy » Mon Dec 27, 2021 4:17 pm

I bought 100% metho from paint spot, i don't think they all stock it but some do.
Wayne

User avatar
joel
Blackwood
Posts: 280
Joined: Thu Oct 11, 2007 7:55 pm
Location: Brisbane, Australia

Re: My shellac looks like gravy

Post by joel » Tue Dec 28, 2021 9:01 am

I did a bit of research into shellac this year.

Problem:
Shellac flakes that won't dissolve, or dissolves into gloopy mess, or won't dry hard.

Cause:
Oxidised shellac flakes. This is especially a problem for de-waxed shellac, it appears the natural wax in shellac slows the rate of oxidation.

Solution:
Store flakes in Nitrogen or CO2. You can buy Nitrogen in a can to spray into polyurethane and lacquer cans to stop them filming over and drying out. I'm a homebrewer I have plenty of CO2 and use that.
If you have old large flakes, you can crush or pulverise them to expose un-oxidised shellac. That will help dissolve the old flakes, but it depends how far gone they are.


Problem:
Milky or botchy finish

Cause:
Water in the mix

Solution:
Use new alcohol (or metho). Now, some of the old books I've read say that a good finish can be achieved with anything higher than 80% alcohol!!! I don't know about that, but I do know that modern manufacturing means that our regular metho is of pretty darned high purity to begin with. All alcohols are hydroscopic - they absorb moisture from the atmosphere until they hit their aziotropic equilibrium. For ethanol and methanol that's approx 95% alcohol / 5% water. This is unavoidable with out chemical drying agents. You can spend the extra to buy "100%" pure ethanol, but the moment you open it up it's going to dilute itself to 95% rather quickly.


If you really want to chemically dry your alcohol at home, you're in luck! Epsom salt is a "hydrous" salt in its normal form - it's one Magnesium Sulphate ion with seven H2O's. Yep 7 - heptahydrate. You can bake Epsom salt in your oven at 150 degrees C for a few hours to drive off 6 water molecules to create monohydrate Epsom Salt https://en.wikipedia.org/wiki/Magnesium ... onohydrate. The result is a chalky white powdery substance. Chuck this into your metho. It will absorb the water, but not the alcohol. Result = 100% pure alcohol, no water. Of course the problem is now filtering out the very fine powder you've got in your alcohol. Personally, I'll just buy a new 1L metho from the hardware store and use that, secure in the knowledge that its 95% pure alcohol with only just enough adulterant added to meet the legal requirements to stop idiots from drinking it.
- If God had intended us to drink beer, He would have given us stomachs. - David Daye.

- The mouth of a happy man is filled with beer. -

User avatar
kiwigeo
Admin
Posts: 10582
Joined: Sat Sep 29, 2007 5:57 pm
Location: Adelaide, Sth Australia

Re: My shellac looks like gravy

Post by kiwigeo » Tue Dec 28, 2021 2:38 pm

Some good information being posted...thanks.
Martin

TrevorMag
Wandoo
Posts: 14
Joined: Sun May 10, 2015 4:53 pm

Re: My shellac looks like gravy

Post by TrevorMag » Wed Dec 29, 2021 3:38 pm

Thanks to all, some good suggestions here I'll follow up on

Jim watts
Blackwood
Posts: 103
Joined: Thu Oct 10, 2013 3:37 pm

Re: My shellac looks like gravy

Post by Jim watts » Sat Jan 01, 2022 6:24 am

Are you sure your shellac is dewaxed?
I tend to use Kusmi buttons which are not dewaxed, it looks like a milky caramel color until I separate the wax out by filtering it though coffee filters a few times after it's dissolved.
You might try filtering it and see what it looks like.

Post Reply

Who is online

Users browsing this forum: No registered users and 114 guests