Topic: Sun damage?

[Yvette]

Hi - I have a small but growing collection of Riihimaki vases that I absolutely love.  I keep them on a window sill as they look so good in the light, but I am worried that the sun may damage them.  The sun really is very strong on them.  Is it possible that the sun could damage or fade them?

[essi]

Hello Yvette, and welcome to the glass message board.
The subject of glass and sunshine I'm sure has been discussed on this forum before.
On the top of the page there is a search feature for previous debate about this subject.
My input is quite the opposite but may be relevant. Foolishly I left a shaped and textured Riihimaki vase(emma from the country house series)
in a shed over the winter period, where the round part of the vase met the square neck it fractured I think due different rates of contraction due to the temperature fall.
Not trying to worry you but I wonder if the same thing could happen with a rise in temperature.
I would think the more rounded vases would be ok.
Hope this is of some help.
Tim

[chopin-liszt]

I think it was the manganese declourant used in older glass that would eventually turn purple if exposed to too much bright sunshine - I don't think modern glass recipes need to use manganese decolourants - and they often use crystal anyway as it is easier to work.
I really do not think it is a problem with modern glass.

[Anne]

Hi Yvette, welcome to the board.

If the sun is strong through the window I'd be more concerned about the risk of the sun through the vases causing a fire. It can happen - members here can attest to scorched window sills and furniture.

[Paul S.]

The use of manganese as a decolourant as mentioned by Sue - goes back a long way, though I'm also ignorant of whether modern recipes include this method to clear the unwanted discolouration - purple looking shades don't seem to be apparent on modern production stuff  -  perhaps the sand is washed more thoroughly now    

Unsure of the meaning of the word crystal used in this thread - possibly lead crystal (used for most cut glass), though it may be that the Riihimaki pieces mentioned here aren't examples of cut glass, so unlikely to be lead crystal  -  unfortunately, crystal is used often simply to describe clear/uncoloured glass.
I doubt that any of the colours would fade, but in addition to the other v.g. reasons already mentioned, for not putting glass on a window sill, might be that you're advertising you have collectible glass, and this just might encourage burglary.         Perhaps put the collection in a cabinet and illuminate with strip lighting??       Glass that's unprotected and on window sills is a disaster waiting to happen - dusting, pets, partners, children - plus it needs cleaning as they simply become dust traps.