Topic: Glue as a manufacturing process on old glass?

[Lapimano]

Hi, I just recently purchased an item online. On the pictures, and in reality after receiving it the style of the design also looked high quality, hand crafted, and just like the authentical ones, but it was in particularly good condition, barely any scratch to the gilding, and what stood out the most: there was a separate pontil mark not just on the bottom of the foot, but on the inner side of the "bowl" (this is a drinking glass), or the upper part of the glass.
After closer inspection, I noticed a slight variation in color between the material which is connecting the stem and the bowl. I was curious, and with a pointy iron I scratched the surface of this material, and it was something softer than glass. It was some kind of glue, whether it was epoxy based, or some other glue I dont know. I dont think this is a repair, as there is no other indication that the glass was dropped at some point, it looks more like part of the intended manufacturing process to connect the bowl and the stem.

My question is could it be an authentical piece from the late 19s or early 20 century up to 1930 as the style suggests, or more like a modern replica?

Also sorry for the lack of pictures, it is hard to upload here as there is an editing process for each picture to fit into the recommended sizes, so I decided to skip on this one, but if you think the above description of the problem is not enough, I can post some, but I hope the glue part could identify this on its own. I would also like to highlight that otherwise the glass looks authentic, it is/could be a high quality replica, not necessarily of bad intent.

[Ekimp]

Hi, I think any glue or resin good enough to be mistaken for glass would be very recent (last 20 or 30 years maybe?), there wouldn’t have been anything approaching it in the 1930’s. Even if it was clear at the time the work was done, it would have to maintain its clarity over time. There is some information about adhesives that have been used for glass (restoration) in the introduction here: http://resources.culturalheritage.org/wp-content/uploads/sites/8/2015/02/osg010-14.pdf

There is an interesting topic on glass restoration using resin etc. here: https://www.glassmessages.com/index.php/topic,70185.msg390857.html#msg390857
I see that work is guaranteed for 50 years not to discolour or to go yellow, but that was in 2020.

[Lapimano]

Actually the glass is red, and the glue is orange-ish. Hm, I knew I should have posted some pictures too, but I was too lazy. Sorry for that, the pictures are on their way now, and will probably arrive tomorrow.

[Lapimano]

I'm fairly certain now, that this is modern, but here are the pictures if you are interested (not very good ones):

One shows the pontil mark inside the goblet part, one is for the glue, and one shows the details of the decoration.

[Ekimp]

Thanks for adding the pictures, it didn’t occur to me that it might be coloured

I’m sure that’s modern repair, it looks a good quality glass and can’t believe it was glued like that at manufacture.

It’s hard to see from the pictures, but I wonder if what you say is like a pontil scar in the base of the bowl is actually where the stem broke off, but it was the bowl that failed, rather than the stem, especially if the bowl is only thin. So after the breakage there would’ve been a hole in the bottom of the bowl and bits of the bowl still attached to the stem?

[Lapimano]

The problem with the broken stem theory, is the pontil scar is on the inside part of the bowl, so it couldt be a remnant from the stem breaking down from the bottom side of it.
There are no cracks or repair in the inside, apart from the rough surface of the scar, so there is no indication that the integrity of the bowl was compromised at some point. Also in this case the glue would be also in the inside of the bowl, where the cracks would have appeared.
I don't see how it could be a remnant of the stem breaking off.

I also looked at the gold decoration with a magnifying glass, and I think it is hand carved into a pre applied gold base, but the gold is more like a gold color paint rather than actual high quality gold gilding what I would expect from an authentic glass of this magnitude.

Also what I'm missing here is the color changing phenomenon I usually find with old red (and yellow) glasses, and what was discussed here earlier:

https://www.glassmessages.com/index.php/topic,73512.msg408283.html#msg408283

[glassobsessed]

A pontil mark in the bowl is not unusual in these thinly blown glasses from Murano, these two examples are the same:

https://www.glassmessages.com/index.php/topic,73200.msg406687.html#msg406687

https://www.glassmessages.com/index.php/topic,73616.0.html

Yours does look 20th rather than 19th century, many traditional designs are still be made today on Murano, some faithfully while others can be given a contemporary twist. A jewellers loupe should allow you to see the difference between the glass and any other material in some detail.

John