Topic: Show and tell - Mdina Tricorn bottle

[chopin-liszt]

  They do "match" and look absolutely stunning together. Better than my 5-cylinder line-up sculpture...

[glassobsessed]

Not the simplest items to photograph, being dark they reflect any light source like a mirror, I tried to back light them to get some light passing through and all I got were silhouettes.

They look to be made from a layer of amethyst with bubbles and presumably silver chloride worked in, then all covered with a much thicker layer of clear.

[chopin-liszt]

  I've been trying to work out what is going on in my "new" tricorn, which is also rather thick glass with loads of layers. I have concluded that silver chloride must have been added to two layers, not just one. When I can get it strongly back-lit, I get lovely greens appearing from bits of clear amber layers over the deep teal.
Some pieces of glass are just not amenable to 2D images. It's very frustrating!

The inspiration for Aurene may have started directly in your pieces here, John. And like you, I prefer yours. 

[glassobsessed]

Yes there is more than a hint of Aurene about them, you see it too.

The other short Tricorn in my first post has similar layers to yours by the sound of it, here it is backlit and the green streaks show up but there are also purple spots in there that don't.

[chopin-liszt]

Does that one have slightly concave surfaces where it has been marvered? My "new" one does, which makes me strongly suspect there might be some cooling and shrinkage of the air inside happening when the metal is in contact with the marver, meaning the object might require a tiny puff of air to expand it fully again.
I hadn't thought of that before, but it does make sense, to me.
The pale tricorn I showed here does not have concave sides - and there is very little evidence left of the marver rings. It has definitely been puffed after flattening. 

[glassobsessed]

All three tricorns here have that 'feature'. The open end would need to be sealed for cooling air to be the cause. I suspect the glass would cool more rapidly in contact with the marver than the air inside, for what it is worth.

[chopin-liszt]

Another of these split second timing things, where I have not a clue what the maker is actually doing.   
But not something I'd thought of before. The "hollow" in the walls does seem to be an earlier feature, and probably is, as you point out, more to do with the outside of the metal cooling and contracting, than the air inside. 

[glassobsessed]

Pretty sure I have seen glass blowers stick a thumb over the end of the blowing iron to seal it temporarily. What happens when a round shape is flattened?  Presumably the 'centre' is flattened before the outer edges (however short a time scale), not a clue really just thinking out loud.

As requested, the photos of your Tricorn.

[chopin-liszt]

Wonderful, thank-you! This is my "new" one, which John didn't need any more and let me have it. 

The tall u-shaped loop of silver salt ochre, which I think is the secod addition of salts, is at the bottom of the third image.

Now you mention it, yes, I've seen makers seal the end of the blowing iron with their thumb, when they take their mouth off it.
I'll have to have a think too.
The round shape would not neccessarily be held by molten metal and so wouldn't "bounce" inwards, I'd have thought. Maybe it's more to do with contraction on the outside because of temperature.

[suzygpr]

Love your new bell vase John, had my eye on it too   Glad it went to a good home. xxx