Glass Message Board
Glass Discussion & Research. NO IDENTIFICATION REQUESTS here please. => British & Irish Glass => Topic started by: AndyD on June 20, 2017, 03:35:49 PM
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Hello,
I was wondering if anybody would know if the crack in the image is the result of annealing. I recently bought an Isle of Wight Studio Michael Harris signed blue and white swirls squat bottle and stopper (from an auction). When I received it and held it up to the light I could see the fine crack but it can't be felt from either the outside or from within. It's hard to find and can't be seen when on normal display but now I know it's there it would be more acceptable if it is a possible fault from manufacture.
Many thanks,
Andy
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IoWSG is not known for having annealing cracks, their cooling ovens were not subject to temperature fluctuations in the way older manufacturers' equipment was.
The crack also seems to be on the main body, not the base, where annealing cracks tend to appear, in my limited experience of them.
I'm slightly more familiar with annealing cracks on Monart, but I cannot tell from just a photograph whether or not a crack is from annealing or not.
However, my gut feeling is that is it a normal, ordinary, damage crack and nothing to do with annealing.
Does it ring when tapped with a fingernail, or thud?
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It is on the main body and there is a slight thud when tapped. Your probably right, it is the result of a knock. Still a lovely rare thing and nice to have in my small collection.
Thanks
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It's far better to have a damaged bit of something scarce you can still enjoy, than not to have it at all. ;D
But the damage should have been reflected in the price.
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I have had a few IoWSG items with small cracks in them, pretty sure two of them were aurene, one was definitely a strapped aurene vase (another was pink and blue swirls). Each time the cracks were hard to spot and on really close inspection I could see that they were only within the inner layer of glass, the layer that in the case of aurene holds the colour.
In this case if there is no indication of damage on the surface associated with the crack then I would assume an annealing fault resulting in a stress crack.
John
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If it's only in one layer, it will still ring when tapped, will it not?
Maybe I ought to have a closer look at some of my Aurenes, especially the strapped ones!
The only thing I have with a humungous crack in the base is a massive tortoiseshell bell vase, I have assumed it came from an annealing problem originally, because of the size.
The crack in Andy's pot seems to be at two angles rather than a single line?
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Thanks John, I think you're right. It is within the glass and looks a lot worse in the image. My family couldn't find it and sometimes I can't unless the light is right.
It's the only piece of blue and white swirls I have at the moment and wasn't expensive. Definately worth having and an amazing colour. Nice that it's signed too.
It does ring a bit but not the same as a globe vase but I think it's more the shape.
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I remembered last night that white is a colour of enamel that does cause problems in annealing because of it having different cooling rates to other colours.
It cause loads of problems for wfs with the stuff they were putting a white rim on and they ended up giving up on it.
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I guess that's why then. I've had a better look and can't see any impact mark.
Thanks yet again for your help and for sharing your knowledge.
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I don't always remember the relevant stuff at the right times. :-[