Topic: Help needed please from a Mdina collector......

[chopin-liszt]

So as mashed crystals = powder, that's the actual from used. :thup:

It's still pretty nasty stuff - personally, to handle it, I'd rather it was in a solution of something - even something very nasty - it's far easier to keep control of stuff in a solution than as a powder.
I did have to use a fair bit of sliver nitrate at work...... messy, messy, messy - the tiniest little bit, too small to see, falls off the spatula while weighing it out and a little later, your lab coat is suddenly burned full of holes! 

(I want to know how Michael Harris managed to "coat" molten straps of blue glass with it  - to make the "seaweedy" design - and how do they get the stuff into just the cracked bits on the surface of the glass, to give the crizzle effect.....)

I did know the iridescent bit was straight silver, dissociated from the chlorine - as is the cloudy, blue ephemereal effect which can appear in the final casings - but it's good to have it confirmed - I was just using logic and a very sparse knowledge of a little physical chemistry (dating back to schooldays).

Does a wee hole, poked into the glass, then a wee bit of crystalline stuff shoved in, then the whole thing cased, lead to the sort of coloured bubble that is in the Dillon Clarke bit?

I can sort of see how this method might aslo have been used by Pauline Solven in that RCA bit - there are strandy bits of glass around the inside of the piece, which could well have been created while she was manipulating the bubble shapes into the yin-yang formation.

[glassobsessed]

I was under the impression that for the manufacture of crizzle stones it would need to be in a liquid form, otherwise how else could it penetrate into the cracks?

John

[chopin-liszt]

That's exactly what I thought, John.  :thup: :huh: :huh: :huh:

[Lustrousstone]

It's nowhere as nasty as silver nitrate until you heat it; then it's the chlorine that's nasty. I really can't see how it would be in a liquid and be useful. It's too insoluble. A gob of glass rolled in a light sprinkle of powder, plunged into hot water and then blown out might leave the powder in the cracks. It's a question for Adam or one of the Harrises.

[chopin-liszt]

 

I'd already thought that - but will be interested to see if there are different replies - different folk do things different ways!
As Mike Hunter said - "There's no right or wrong ways in glassmaking. There's what works for you."

I do know Tim's (Harris) been working with some silver chloride recently.
Apparently, it's horrendously expensive.

A powder could be suspended in a colloidal form in a liquid - I still think it would be easier to control if it were.

[aa]

Studying it, I honestly still don't know if a controlled pinprick bubble mould would have been required.

I have had a look at the image and I think it is very likely that a controlled bubble "pineapple" mould was used.

I think that the turquoise would have been melted in, then the gather would have been shaped and dipped into the pineapple mould. Next some silver chloride (white crystals or powder) would have been added. When heated the silver chloride becomes liquid and runs over the surface, so as the iron was turned it would have run unevenly into the indentations. Bubbles are trapped when the outer layer is gathered.

The silver chloride gives off a noxious gas and contaminates anything with which it comes into contact. It is very expensive and difficult to find a supplier, these days.

It is also possible to use silver chloride on a trail, or series of trails, and this is probably a method that was used in making some of the pieces described in other parts of this thread.

Hope this helps. I think there is enough information here to answer most of the questions above.

[Lustrousstone]

Thank you Adam.  That makes sense for the crizzling too.

[chopin-liszt]

Ok, bear with me, I'm slow!
You've got the glass on your iron, the mould has been used on it.
You say  "next some silver chloride is added"

How is it added?
Sprinkled onto the gather? Or inside the mould? Or is it sprinkled on the marver, then the gather rolled in it?
(I wouldn't want to be around the stuff "sprinkled" anywhere if there was heat around!)

You also say it is possible to use it on a trail - but how, in purely practical terms, do you get the powder onto the great dripping blob of hot glass that is going to form the strapping/trail?

Sorry, Adam - lab tech in me needs to know these things!
Thanks very much for taking the time to pop in and help out - we all know you're very busy!

[aa]

Hi Sue 

It is difficult to be entirely precise as different people use different methods, sometimes getting similar results.

You can put a few crystals on the marver or you can introduce the SC by dropping a couple of crystals onto the gather with tweezers.

For a trail, you could use either method, then heat this up and trail it around the piece.

[chopin-liszt]

 :girlcheer: :kissy:
Thanks Adam - so much!
I feel a lot more secure about the notion of picking a couple of crystals with tweezers,  :thup: than "sprinkling it around" - which conjures up cookery-type images with a sieveful of the stuff, flying everywhere. :thud:
Now I've got a clear image of how it would work, in my head.
Again, thank you, very, very much! :rah: