I have been asked to make a necklace with beads with a barrel of purple, wrapped around once with a thin stringer of white, then encased into a lentil. The client wanted CIM Plum. Every one I have tried has cracked. So far I have used Plum and encased with 006, Zephyr, and CIM clear. So, I then tried Grape Ape with Zephyr. They all look OK when they come out of the kiln, but crack within 24 hours.
In order to keep the barrel of purple in a crisp shape I have to have it cool when I encase or it squishes out of shape in the lentil press. I make sure that the whole bead is heated well before putting in kiln. The crack is always down the mandrel, suggesting thermal shock, but the bead is hot when I put it to anneal. Is the problem that the barrel of purple is cool when I encase?
Any suggestions?
Carolyn
There are certain CIM colours that don't like to be encased at all. I don't know if plum is one as I've not tried encasing it. Can you try layering Effetre colours for your core to try and get something similar to plum? Perhaps periwinkle with one of the amethysts over it?
I find some CIM colours can be problematic with encasing - I think there's a compatibility issue going on with it, especially since it is an opal colour. All opals are prone to misbehaving when encased (at least - in my experience). May be wiser to substitute a different colour?
What does opal colour mean Sally? I have used opal yellow but never worked out why it is 'opal'. What are the charecteristics to look out for.
Mari
The Opals are from a group of glass called Opalines. It's essentially a different sort of formulation - although of course it's still soft glass and is the same (more or less) COE as the others.
CIM Kryptonite is one. The glass has a sort of "alabaster" type, or translucent look to it and is often quite "brittle" and very often shocky. I've noticed that Martin does'nt sell many of the Effetre opalines - presumably because of this very problem. CIM do seem to have quite a few. They can be a bit of a b**** to work with and in my experience they're really not keen on being encased.
Quote from: Redhotsal on June 27, 2012, 02:23:09 PM
The Opals are from a group of glass called Opalines. It's essentially a different sort of formulation - although of course it's still soft glass and is the same (more or less) COE as the others.
CIM Kryptonite is one. The glass has a sort of "alabaster" type, or translucent look to it and is often quite "brittle" and very often shocky. I've noticed that Martin does'nt sell many of the Effetre opalines - presumably because of this very problem. CIM do seem to have quite a few. They can be a bit of a b**** to work with and in my experience they're really not keen on being encased.
Well, I've just learned something new, so thanks for that info Sal!
I've had problems with cracked encasing in the past and am thinking now it may have been some of the CIM glasses.
You really should do a little tips and hints book you know Sal, you are a mine of useful and valuable information! ;D
Well I've made four DVDs on beadmaking. I think people have probably had enough of me by now ;) :D
Quote from: marijane on June 27, 2012, 12:12:02 PM
What does opal colour mean Sally? I have used opal yellow but never worked out why it is 'opal'. What are the charecteristics to look out for.
Mari
Opal yellow isn't an opalino, confusingly. Sometimes 'opal' gets added to glass names just to mean opaque. (See Reichenbach colours, for example).
CiM plum is one of their opalinos and yeah, I have problems encasing those too. Though I seem to recall someone had some luck using CiM cirrus to encase instead of clear when they had those problems? Cirrus strikes from clear to milky white, so if you're trying that it might take a bit of experimenting to get it to stay clearer.
Did they want the translucent look of the plum, or just the colour? If it was the colour, I'd go for one of the properly opaque CiM purples instead.
Quote from: Redhotsal on June 27, 2012, 03:27:55 PM
Well I've made four DVDs on beadmaking. I think people have probably had enough of me by now ;) :D
Not at all ;D
But you know, I can see room for a little A-Z of Sal's Tips. A handy little booklet to pick up and quickly find out what Sal would do!
Every lampworker would have one by their torch, it would be a best-seller ........ ;D
Quote from: Redhotsal on June 27, 2012, 03:27:55 PM
Well I've made four DVDs on beadmaking. I think people have probably had enough of me by now ;) :D
Gertcha! No way!
I'm still waiting on Sal Carver Does Venice!
(or at the very least Volume 5)
Linda x
Quote from: Madam Steph on June 27, 2012, 03:39:18 PM
I'm still waiting on Sal Carver Does Venice!
(or at the very least Volume 5)
Linda x
Like Debbie does Dallas :o ;D
Well, she is RedhotSal! ;D
"What Sal would do" isn't actually always the right thing!
BTW - the Sal does Venice title is available but has a 18 rating. ;) ;D
:) :) :) :) :) ;D
Quote from: Kalorlo on June 27, 2012, 03:31:18 PM
Did they want the translucent look of the plum, or just the colour? If it was the colour, I'd go for one of the properly opaque CiM purples instead.
Yes, it was the colour she wanted. Tried Grape Ape but that cracked too.
I've been making encased beads using CIM Lapis and Thai Orchid, not had any crack yet but they are round beads about 15mm diameter.
Just a thought...what size mandrel are you using? Could it be that the glass either side of the mandrel is cracking because it is thin there? I'm no expert by any means, but had that happen once or twice with certain press shapes.
I have a personal rule never to encase CIM. Even with CIM clear!
Kazx
I agree with Kaz. It's just asking for trouble. I was on a course once when I had an urgent commission. I stayed up late making encased florals with one of the CIM colours. By the time I got home the next day to make up the necklace every single one had cracked. I just don't even consider it now.
Its good lo learn more about glass. This is an interesting thread you started Carolyn. Thanks for sharing info posters. I now know a little more about encasing, and what is and isn't an opal glass. Hope you manage to get the glass to do what you want now.
Mari
I agree with Josephine and Kaz - one of the reasons why I avoid any CIM glass if I can (and it is such a shame, because they have wonderful colours!)
Quote from: Redhotsal on June 27, 2012, 03:27:55 PM
Well I've made four DVDs on beadmaking. I think people have probably had enough of me by now ;) :D
I am hopimg that DVD 5 AND 6 are in the pipeline
Ruth
sewnthings
Thanks to all for the info and suggestions. Think I will suggest another design for her that doesn't involve encasing!
Carolyn
There are some problem colours for sure, escpecially CiM purples .... But some are ok Freman being one.
Sometimes during a session I'll enase a colour and keep it for reference!