weight of glass/acrylic

[David McCormack]

For a glass size of 102 x102cm is there much difference in weight between 2mm and 3mm glass?
And would 3mm acrylic be loads lighter but very flexible?

Thanks folks

[Otters Pool Studio]

3mm glass will be half as heavy again as 2mm glass (there being half as much glass again!), so around 7.5Kg. Acrylic would be lighter, by as much as half, but is a bit more flexible although over only a square meter wouldn't be that noticeable.

[Framemaker Richard]

Hi David

According to an old glass catalogue I have, float glass weighs approx 2.5kg per 1mm thickness per square metre.

so 102 cm x 102cm weighs:

2mm @ 5.202 kg
3mm @ 7.803 kg

Not so sure about acrylic, but quick search shows a figure of 1.2kg per 1mm per sq m

[David McCormack]

Thanks Jon and Richard.

At what size do you start recommending 3mm glass instead of 2mm and why? Is 3mm glass less likely to break if the frame gets a knock or a twist in transit?

If this job goes ahead and the customer wants to go with acrylic I'll get it cut to size but what's it like to clean? Is static a problem?

[prospero]

Best not to clean it at all David. It comes covered both sides with protective film. Don't peel it off until you have to. I even leave the front film on - just lifting the edges - during assembly. Peel off the front and get it out the door assap.

The thicker the glass the stronger (in theory) but the thicker the heavier and the stronger frame/wall fittings needed to support it.

I once did a frame about 5'x4' with 4mm glass. The customer supplied the glass as he had contacts in the double-glazing trade. The frame was custom-milled hardwood about 2x3" (with the edge rounded). He got a shock when he came to collect it. That sucker was heavy. I suggested he put legs on it and make it a coffee table.

[Roboframer]

At what size do you start recommending 3mm glass instead of 2mm and why?

I'd never recommend 3mm glass, next step up for me is acrylic and that would be over one square metre as long as it could be got out of the sizes of glass that I stock and I don't stock regular glass larger than 4ft x 3 ft so 1m x 1m for example, could not be cut out of that (and nor could 37 x 37" which is less than a sq m) but I stock AR glass that is 1100x1600mm. Some UV coated glass is 2.5mm too.

Why over 1 sq m? Just something I read somewhere years ago and went with it, you have to score a line somewhere, that's mine, but there is small print - e.g if it was over that - but not massively - and there was, say a 100mm wide mount, that would make an 'unsupported' area of less than 1 sq m. If it was juuuuuust under 1 sq m and there was only a rebate spacer, that would worry me, slightly.

[David McCormack]

.... you have to score a line somewhere, ..