Topic: what's-'em-a-call-it? on drinking glasses.

[scavo]

Can any one please tell me proper term for the bead (?) we sometimes see on blown glass glasses etc. It's usually on fine-ish blown glass.
You get it a lot on commercial drinking glasses too (are they blown?)
Is it there for a specific purpose? To prevent chipping? I assume it gives extra strength to quite thin glass.

Also ...
How far does it go back?
How is it done?
Does it relate to a specific method of production?

As you can tell I know very little about glass so am asking lots of questions.  :wsh:

ps. pretty sure you know what I'm talking about without a photo.

[Ivo]

you may be assuming tooooo much.

[Anne]

Are you meaning that wee bump on the rim of some glasses scavo? It looks like there's a slight thickening of the rim and a bump in it as if something was trailed round then slightly overlapped to complete the circle....

[antiquerose123]

..... or are you meaning like those little glass crystal that almost look like *Salt* on the glass surface, but is small little Glass beading......as done to give some glass extra Texture?

i wonder how those are done myself...when you think about it..


??

[Frank]

It is called a safety lip/rim. It allows less metal to be used in the glass and thus reduce manufacturing costs and losses in transport to retail outlets. It is done with machine made glasses simply by them passing through a flame on a conveyor belt. I have posted pics of this process somewhere in the past. Possibly on SG. It can also be done as a finishing process to hand made glasses.

I have a strong feeling that the idea was developed in the UK and not very long ago.

[scavo]

Ivo: Assuming tooooo much in think no photo is ok? You can see it on these glasses clearer in any photo I can take:
http://beergeekshop.com/beer-glasses-pint-glasses-c-3_5.html

Antiquerose: NO, not like salt. See above link.

Frank: I think you have it with the safety rim/lip. All glasses in pub/restaurants have it in the UK. I imagine it serves to stop breakages in all events - even drunks drinking, people cutting their mouths ...

going to find another link .. back in a moment

[Anne]

Scavo, that's what I was suggesting

[scavo]

okay, referencing another of my posts:
http://www.glassmessages.com/index.php/topic,43236.msg241890.html#msg241890

the lip of this mould-blown (?), hot finished (?) (I really don't know how it has been made ... but it also has the same 'bead' or safety lip as seen on beer glasses.

[Pinkspoons]

According to Mogens Schlüter in Glass Is Life the technique - and the machinery - was invented by French firm Gerbaud some time before the late 1940s, after whom the technique, Gerbaud cracking-off, is named (at least in Denmark).

Since the end of the forties these machines have been used in Denmark with varying degrees of success, because this method also has its weaknesses. The glass is actually melted off at the right height by small, pointed and extremely hot flames. This gives a technically better glass because the glass is then cooled and does not have to be reheated. On the other hand, the glass develops a little slug by the rim. This gives a cheap appearance to very thin glasses but it more suitable for thicker glasses.

[scavo]

sorry Anne, yes, you got my drift.
sometimes there is a little 'nipple' on the rim too, which I assume is the 'off' point.

So, I assume it is an alternative to grinding off the lip on cheaper homeware /more commercially used glasses.

Is it safe to say you won't find this finish on crystal drinking glasses?

I suppose on art glass/ decorative glass it is harder to tell the intention.