Topic: Stylish Jade Green Uranium Glass Vase Frosted Outside

[flying free]

Dr Fischer auctions have this one in white and Chrysopraslas (uranium opaline) in a similar basic shape to op's:
https://www.the-saleroom.com/de-de/auction-catalogues/dr-fischer/catalogue-id-fischer10005/lot-ced36f67-575a-4fd2-ac9a-a44500b56d15

c.1860

Not matt glass.

[Ekimp]

Hi, i was wondering how the frosting has been achieved in the examples shown in this tread, maybe there is a clue there?

I have an onion shaped vase in similar very bright uranium colour and ‘frosted’ finish (it also has some gilding). On my vase the frosting looks like it was achieved by mechanically abrading the surface of the vase with some sort of grinding wheel. I had previously thought this finish would be achieved by acid etching. Is this the usual technique? In KevinH’s example, if the surface was mechanically abraded, it would explain why the frosting isn’t also under the rim as it would have been inaccessible to the grinding wheel.

[Lustrousstone]

The frosting was most likely done using fluoric acid - there was no need to do under the rim. I  also doubt your vase was frosted using a wheel (it's not a large area technique); sandblasted seems much more likely

[LEGSY]

Sorry for delay in reply had daughter over 
My vase has an applied foot for sure i think the finish must be a sort of acid dip
technique i would think very precise and smooth as a babies bottom the top of the vase has been left
also the inside. When held to a strong bulb it has a cloudy clarity with specks of dark in there also.
I will try for better pictures Sunday although my camera is not the best i really didn't think this £1
vase that had been on a shelf at local skip yard for weeks would get so many replies
Thank you for commenting

[Ekimp]

It’s great what can be found isn’t it 

Not sure if it is any use, but thought examination of the treatment might help in comparison of the different vases shown in the thread. I had thought my vase would have been acid etched and it feels smooth...but:

On my vase, when examined under magnification (x10 loupe), you can clearly see fine horizontal marks all over the frosted surface (second photograph, not as clear as life. The pale vertical dashes I think are stretched bubbles).

In the neck, there is a manufacturing defect where there is a small pale lump with a shallow depression on each side (third photograph). You can see the surface in the depressions hasn’t been frosted as the wheel, or whatever tool used, didn’t reach to the bottom of the depression. If this had been acid etched or sand blasted, then these shallow depressions would surely have been frosted the same as surrounding treated areas?

Where the frosted area transitions to the untreated area you can see fine horizontal marks where there has been some overlap (fourth photograph). In this transition area you can also clearly feel a smooth ridge as though a significant amount of the surface has been removed from the frosted areas.

I’m not particularly familiar with the acid or sand etching treatments but they don’t seem consistent with the observations of my vase, which made me wonder about others.

[Ekimp]

...fourth photo.

[flying free]

Christine would sand-blasted apply to something from 1860?
Acid etched I think is possible. 
I'm just looking at my blue vase and the feel of it is very different to say a large uranium Murano satin glass lady I own.  That feels like silk, like I could absolutely drop it if I wasn't careful.  Very slippery as it is so smooth.  Whereas my blue vase feel as though it has a texture to the surface.  It's also matt but feels very different.

m

[Lustrousstone]

Sandblasting was patented in 1870 by Benjamin Chew Tilghman apparently.

Acid etching was done manually using a brush. You can often find tiny spots that have been missed.

Grinding such large areas would be too time consuming (time was money and workers were on piecework) and expensive for what is a "middle to upper" class piece of glass.. And it would be difficult to achieve consistency and such smoothness. It is more likely that the marks are tiny cooling marks in the glass. Look at at any piece of glass under a lens and you can see tiny directional lines. I suspect yours show up because of the opaque(ish) nature of the glass or because it got a little bit too cool during blowing.

[Ekimp]

Um...there are several other small lumps surrounded by depressions where the depression hasn’t been treated (two different examples shown in the photos). If a wet acid was brushed on, then I can’t see how it was possible to miss all these areas - and only these areas. I can see what you are saying, but being able to examine the vase in hand, I still think this was frosted mechanically. I have a similar blue vase that shows the same surface texture and imperfections etc. The finish looks very like a metal component polished in a lathe by emery paper.

I was thinking it is feasible that the vase was mounted in a lathe similar to this one: http://www.vintagemachinery.org/photoindex/images/9121-A.jpg

This type of machine could be fitted with soft headstock and tailstock mounts, the work held in place by friction, possibly by a sprung tailstock. The tailstock would be fitted with a quick release mechanism for quick change of the work piece. When spun up, the vase surface could be abraded with fine emery paper (or the antique equivalent) either by hand or maybe by a rotating belt, wheel or brush. Such a process may possibly be safer, cleaner and even quicker than using acid. This method is still used today in production of metal components.

[keith]

Thought I'd add mine to the mix.....