whisky glass issues

[phoenixalpha]

Just bout half a dozen of these from BMS : http://www.printerowners.co.uk/sublimat ... -glass.htm

sub Frosted whisky glasses

So I've been preheating to 60 in the mug press then putting paper on and then to 160 degrees. So 60 degrees is fine - as soon as its in for around 20-30 seconds at 160 the whole glass just cracks and is useless. I'm using no more pressure than I would a mug, in fact a lot less - but still the whole thing just shatters. Anyone got any advice on these?

[Mattie]

Hi
I had the same problem, i used to pour in some warm water and leave for about 5 mins then do the pre-heat etc this used to do the trick.

[phoenixalpha]

empty the water out before pre-heat??

[Mattie]

empty the water out before pre-heat??

yeah empty and dry with paper towel

[John G]

What do these look like when done properly - do they look good?

Also - just thinking aloud, would it not be better if there was an insert or something to put inside while pressing to ease the pressure.

[phoenixalpha]

the ones I've made so far look smashing

[bms]

What do these look like when done properly - do they look good?

Also - just thinking aloud, would it not be better if there was an insert or something to put inside while pressing to ease the pressure.

It's not pressure that causes the problem. The base of the glass is thick and the glass itself is thin, so they need preheating to get heat into the base of the glass. As glass is a very poor conductor of heat then you need to give the base a while to get up to temp to avoid too much of a shock to the glass and therefore causing a crack.

[bms]

the ones I've made so far look smashing

No pun intended eh?

[John G]

Thanks Martin for the explanation, thought it was uneven pressure. They sound like a nice promo item, have you got any pictures of the finished article phoenixalpha

Cheers John

[mrs maggot]

try popping them on the radiator before pressing, thats what i do with my mugs - warms their bottoms up a treat - oooh errrrr mrs