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Glass Identification - Post here for all ID requests => Glass Paperweights => Topic started by: marc on March 12, 2009, 01:23:07 PM

Title: Help ID weight.
Post by: marc on March 12, 2009, 01:23:07 PM
Vasart? thanks for any help. Marc
Title: Re: Help ID weight.
Post by: KevinH on March 12, 2009, 01:28:44 PM
Yes, Vasart (post 1955) is very probable. But, as I often say, without a label or other proof some of these are difficult to separate from easrly Strathearn.
Title: Re: Help ID weight.
Post by: marc on March 12, 2009, 04:47:17 PM
Thank you very much for your help, it's very appreciate for me, congratulations for your web page is very interesting, I have learnt a lot with it. Best regards Marc
Title: Re: Help ID weight.
Post by: tropdevin on March 13, 2009, 08:45:08 PM
Hi Kev

I agree that distinguishing between all late Vasart and early Strathearn is difficult, if not impossible. But from several conversations with Catherine née Ysart, who used to grind bases for Vasart, I get the impression that whilst some Vasart bases were ground on a wooden wheel with abrasive powder, giving the characteristic marks, that did not happen for early Strathearn weights.

If so, that suggests borderline weights with a ground pontil are most probably (?definitely) Vasart. Flame polished bases could indicate either. Does that fit with your understanding, or am I making too much out of scant evidence?

Regards

Alan
Title: Re: Help ID weight.
Post by: aa on March 13, 2009, 10:35:14 PM
some Vasart bases were ground on a wooden wheel with abrasive powder,
Alan

I was very interested to read this as I have never come across this use of a wooden wheel with abrasive, which seems rather unusual. Assuming the powder was carborundum (silicon carbide) I would have thought the wheel would be likely to wear down faster than the glass. Perhaps a technique peculiar to Vasart? Or was it used widely?
Title: Re: Help ID weight.
Post by: KevinH on March 14, 2009, 12:09:40 AM
On the point about ground bases of a certain style - or with certain marks - meaning "most probably (?definitely) Vasart", as opposed to early Strathearn, I do tend towards that conclusion. Especially, as you say, with the information that has been passed on by Catherine, daughter of Vincent Ysart.

But I still like to keep an open mind, hence my caution when talking about items likely to be from the transition years. It's a bit like my conclusions that all Vasart-type weights that show as blue under shortwave UV must be post-1955 and all Vasart-type weights that show as "grey" under shortwave UV must be pre-1956.

For current practical purposes, it is probably reasonable to go with those base grinding and UV criteria.

But the older I get, the more I think "never say never" is a good guide. ;D
Title: Re: Help ID weight.
Post by: tropdevin on March 14, 2009, 08:24:20 AM
Hi aa

Regarding wooden wheels not wearing away.  It is generally the case with abrasives in between two materials of differing hardness that the harder material wears more quickly than the softer! Diamonds are sometimes polished using diamond powder on a steel scaife, or cut with diamond powder and a copper disk - and it is the diamond that wears away. The effect is sometimes seen with steel axles wearing away faster than a brass bush, for example.

There is a good reason: an abrasive particle can become embedded more easily in the softer substance, whereupon it does no further damage to the soft material, but can grind away the harder material as that moves past it.  I think the general concept of soft wheels or substrates bearing hard abrasives is used quite widely. Polishing mops of cloth or felt are an extreme example of this principle.

Regards