How to make LoS from plain sulphur

On rec.crafts.jewelry, this is, for the internet late-arrivals, a
newsgroup, someone asked how to make LoS from plain sulphur.

Here is what I have in my notes, and I wonder what others say:

Mix S (sulphur) and K2CO3 (potash, potassium carbonate) in equal
parts. Add water slowly over at a medium heat until you get a
viscous paste. That’s LoS. Store, hermetically closed, away in the
dark. Add water to liquefy for useage.

This works well for me. What do others say?

Hi Andreas,

Mix S (sulphur) and K2CO3 (potash, potassium carbonate) in equal
parts. Add water slowly over at a medium heat until you get a
viscous paste. That's LoS. 

Does it actually work? I responded to the owner of the group as he
asked me if I knew of any reactions which would result in LOS from
pure sulphur. The only reaction I could find was quite a lengthy and
hazardous procedure involving boiling the sulphur with potassium
hydroxide for hours on end - and even then there were no guarantees
that you would end up with the mono sulphide of potassium, which is
essentially what LOS is.

DO NOT PERFORM THE REACTION I HAVE MENTIONED ABOVE - it’s far too
hazardous and uneconomical. Maybe Andreas’s reaction is better and
safer than the one I found.

Helen
UK

Liver of Sulphur is not “mono sulphide of potassium,” but potassium
polysulphide.

However, don’t bother with trying to make it yourself; if you intend
to use it for blackening silver as it isn’t worth the bother. If you
can’t get it go to a good gardening shop and ask for lime-sulphur,
which is calcium polysulphide. This will always work if reasonably
fresh. It has the same disgusting smell as the potassium or sodium
chemical but is far cheaper as it is used to spray roses against
aphids and other insects which prey on them.

Cheers for now,
JohnB of NZ

- and even then there were no guarantees that you would end up with
the mono sulphide of potassium, which is essentially what LOS is. 

Liver of Sulphur is poly sulfide of potassium not the mono sulphide
although either one will work for blackening of silver. As John
Burgess says buy Lime Sulfur at the garden store. Works well and is
no less stable than LOS.

James Binnion
James Binnion Metal Arts

Liver of Sulphur is poly sulfide of potassium not the mono
sulphide although either one will work for blackening of silver. 

Yes, sorry, I was misinformed by someone that it was potassium
(mono)sulfide. I simply bought potassium sulfide from a chemical
supply company on that basis, and it works fine.

I think LOS is a mixture mono, di, and trisulfides of potassium.
When my potassium sulfide runs out, or more likely goes off, I will
buy the lime sulfur from the garden store. I too would not recommend
making LOS when there are plenty of equivalent products on the market
which are easy to get hold of, and without the need to perform
potentially dangerous chemical reactions.

Helen
UK

As John Burgess says buy Lime Sulfur at the garden store. Works
well and is no less stable than LOS. 

Which isn’t saying much, since once mixed with water for use, LOS
isn’t very stable at all, lasting at most a couple days before it’s
lost a lot of it’s effectiveness. I’ve seen some garden sulphur
products that work, are already in liquid form, and appear to remain
pretty stable over time. Unfortunately, that was a while ago, so I
can’t give you more precise product info…

Peter

I uses to use Lily Miller or Ortho brands of lime-sulfur: Dorman Bug
Spray Concentrate.

It’s getting harder to find and often now is oil based…

A

I would urge caution when using Lime Sulfur.

My experience is with Precious Metal Clay and I used Lime Sulfur on a
piece. I did not like the effect and as I normally do, fired it off
with a butane torch.

Close examination revealed that the sulfur had pitted the surface of
the silver.

Needless to say, I have relegated the Lime sulfur to my husbands
garden shed. Debbie

Debbie Rijns
Director of Education
PMC South Africa
http://www.pmcsouthafrica.co.za

John, what do you say about this? Myself, I would pickle the patina
off whether it was PMC or regular silver.

Did you dilute it with water?

marilyn

what do you say about this? Myself, I would pickle the patina off
whether it was PMC or regular silver. 

I’m not John, but I’ll chime in. Taking off a Liver of Sulphur
patina means removing silver or copper sulphides. These are not
particularly affected by sulphuric acid based (including sulphuric
acid salts like Sparex or similar pickles) pickles. In short, it
doesn’t work very well at all. Pickle is good at dissolving oxides,
such as what you get from heating, but it’s not good at removing
sulphides.

Thiourea based tarnish removers are a better way to go. The common
commercial one is “Tarnex”, or you can get (or at least used to be
able to get, it’s been a while since I did so…) from the Vin-Roc
corporation, their dry granular “mix with water” version intended
more for industrial use (simply because it’s sold by the pound in the
dry version, which makes a whole heck of a lot of active solution.)
Used as directed, that product is four times more concentrated than
Tarnex, which I’m told, is mixed up from exactly that product and
repackaged and sold for a lot more. The original product, mixed as
suggested, works a lot faster and better, and has a good shelf life
even once mixed. When I was in grad School (Tyler), there was always
a mixed up tub of the stuff under the undergrad studio sink for
students who’d changed their mind about a patina and wanted it off
again Without going to the shop and looking at the label, my memory
of the product name is CQ-10. But I’m not sure. Can look it up if
anyone wants… Vin-Roc corporation, last time I searched, is a bit
more old fashioned than many vendors these days. You actually have to
call them up on the phone to order stuff. No simple online ordering.
About what you’d expect from a company that’s actually an industrial
supplier, not a retail dealer. But the last time I bought this stuff
from them, they were quite easy to deal with. I think they’re in
Cleveland, or Cincinatti or something like that. If anyone wants,
I’ll dig out the bottle and check…

Peter

In short, it doesn't work very well at all. [I.e. it doesn't work
well to pickle off patina] 

First, I’ll point out that is you flux and gently heat then pickle, t
does work. But what I really want to mention is that, as has been
said here before, ionic cleaning does remove patina or tarnish from
silver. My titanium anodizer, with the polarity reversed, works great
at about 10-12 volts and 1-3 amps. You can see the tarnish float off
the silver like a wisp of smoke-- very satisfying. There are cleaners
that work better than the TSP-substitute I use for anodizing, but
it’s good enough! I’ve read you can make an ionic cleaner out of an
AC adapter. I haven’t done that because I have my anodizer, but I
really should do it for my students’ sakes…

Noel

From what I’ve read Liver of Sulpher is a sulpherated potash
containing:

25% Potassium
75% Potassium Thiosulfate Hydrated

The MSDS can be found heRe:
Avantor is setting science in motion for a better world | Avantor.

As in many other things it is possible there are a number of
compounds known by the name Liver of Sulpher, so the ingredients
shown above may only be those used in the formulation produced by
Mallinckrodt Baker, Inc.

Mike DeBurgh, GJG
Henderson, NV