Glass for larger frames

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mbaister
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Glass for larger frames

Post by mbaister » Thu 25 Jul, 2019 6:15 pm

I have a few jobs that are just over A1 size, one is about 112cm x 80 cm, does standard 2mm float glass work at this size or are there any more economical products out there that are less fragile when working on a larger scale? The only thicker glass I can find, even 3mm, seems to be considerable more expensive.

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Re: Glass for larger frames

Post by Not your average framer » Thu 25 Jul, 2019 7:06 pm

My understanding is that 2mm glas is only suitable for glass sizes of 1 metre squared, I've never asked if being smaller on one dimension makes it o.k. to go up a bit more on the other dimension, but I think that may be what it means. I don't know who you would need to ask to check for sure, but my thinking is that I would contact my glass supplier to be sure. My own glass suppliers is Wessex, who have advised me during previous times, to be honest, if the customer is willing to pay the extra, I would want to go for 3mm glass to be sure.

This is not such a simple matter as you might be thinking, because in the event of an accident involving somebody being hurt, if an insurance company becomes involved you need to prove that you have kept within recognised safety standards. I'd check with an expert first and if 2mm is o.k., then I would explain the situation to the customer and let the customer decide. I the customer wants 2mm glass, I would want something confirming that decision signed by the customer.

If these frames are going to hang in a public place, laminated glass may be required, again speak to someone who knows about this.
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Re: Glass for larger frames

Post by prospero » Fri 26 Jul, 2019 2:06 am

The problem is, thicker glass is heavier glass.

2mm glass is not all that fragile. It won't shatter unless subjected to a severe blow. If the sheet isn't under stress
in the frame and has no chips in the edges, it will sit happily on the wall. But if there is a little bump under the rebate
or it's jammed into the frame too tightly it is just waiting to break.
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Re: Glass for larger frames

Post by JonathanB » Fri 26 Jul, 2019 7:40 am

Martin -
Just to add to the above, I went to a talk at Wessex last year given by David Palmer, a specialist in glass and glazing, and he confirmed that in his opinion 2mm glass should never exceed 1 metre square, and that you should also be careful with narrow frames up to and exceeding 1 metre long. If in doubt, a chat with David at Wessex Leatherhead will usually answer any questions. You might like to consider acrylic if worried about weight. I've used the Wessex cut to size service and it's excellent. If you've got access to Art and Framing Today from January 2019, a summary of David's presentation is on page 16 and is well worth a read for all issues relating to glazing.
Good luck
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Re: Glass for larger frames

Post by Steve N » Fri 26 Jul, 2019 7:42 am

I look at it this way, as long as the frame is strong enough to hold the glass, and if you put the frame together properly , not using bendy tabs on something this size, 2mm should be okay,

Another way of looking at it , why do they produce 2mm float glass in 3ftx4ft sheets :?:
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Re: Glass for larger frames

Post by Justintime » Fri 26 Jul, 2019 9:53 am

Unless its for an institution (hospital/school/carehome) where their H&S rules are law, its up to us to offer professional advice.
Personally, I always strongly advise 3mm glass, (serious face). The extra cost is preferable to the upset of damaged art/refit/reframe.
I often use a Telum diamond pad ("other brands are available") if I have any doubts, to smooth and round off the edges and corners.

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Re: Glass for larger frames

Post by Justintime » Fri 26 Jul, 2019 10:11 am

[quote="Steve N"

Another way of looking at it , why do they produce 2mm float glass in 3ftx4ft sheets :?:[/quote]
They also produce 2mm float glass in 4ftx6ft sheets but...

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Re: Glass for larger frames

Post by Steve N » Fri 26 Jul, 2019 10:29 am

Justintime wrote

"They also produce 2mm float glass in 4ftx6ft sheets but..."


Yes they do, and I'm going to be doing one which is 140x65cm next week, but I don't have problem with it, the frame is well beefy to support the glass
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Re: Glass for larger frames

Post by Not your average framer » Fri 26 Jul, 2019 10:55 am

Broadly speaking I think we are more less saying roughly the same thing, but here's a few more thoughts to consider. I sometimes get asked to frame Ordinace Survey maps, customers buy the on-line for not a lot of money and they generally don't like spending very much on framing them, so it has to be 2mm glass and the maps is touching the glass, because that what they want.

I dry mount the map onto 6mm MDF which has been coated with a very cheap polymer adhesive which after drying becomes a dry mountable adhesive in my heated press. This means that the glass is supported from behind by the 6mm MDF and the glass and the frame are given quite a bit of extra strength and stiffness, because the backing board is so stiff.

If you are an absolute stickler for sticking to following the rules, this might not be the way to do things, but this is just an unofficial way of making things a bit more solid and durable. Too many customers want the narrowest possible frame moulding as well and there are limits to what I will agree to do to accommodate this requirement.

Narrow Obeche mouldings, don't really cut the mustard for large frames like this, so I tell them that they must be deep enough to accommodate a sub-frame behind the backing board, or alternatively it will be a narrow oak frame (which can be painted, or stained as they wish) and the picture cord also runs through two D-rings on the bottom of the the frame and one d-ring at the top, so that after stretching across in the normal position, the remainder of the cord makes up a "W" shape and the weight of the framed picture when hanging on the wall pulls all four sides inwards.

This prevents the glass edges from becoming exposed if the sides of the frame distort over the years, which I think is real possibilty because narrow frame mouldings usually feature quite narrow rebates. My preference with items this sort of size, would not normally be for a very narrow frame and I generally recomend mirror plates for fixing directly to the wall and I emphasise this particularly for families with younger children, as I don't want frames with large pieces of glass getting knocked of the wall near to young children.

I also don't like frames above a certain size and weight, being strung to hang because regardless how much you warn the customer about hand the frame from something secure a strong enough, you can tell that the are not going to listen to your advice and will try to hang the picture from something totally inadequate. Don't laugh. but I seen picture hung from drawing pins, how they expect that to take the weight is beyond me.
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Re: Glass for larger frames

Post by Not your average framer » Fri 26 Jul, 2019 11:08 am

I only stock the 3ft x 4ft 2mm sheets of glass. In such small premises, anything any larger is quite a problem. Over the years, I've tried different ways of getting round this and the easiest answer I have found is just to get it delivered cut to size.

I have in the past stocked some 3mm and 4mm glass and the local hardware shop used to send customers for glass cut to size over to me, but it's not particularly financially worth doing and I have found doing this as somewhat counter productive to do this.
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Re: Glass for larger frames

Post by prospero » Fri 26 Jul, 2019 11:16 am

I've seen people at glass companies grab 6' x 4' sheets of 2mm and literally drop them on a bench. If you know how to handle
glass you aren't going to break it. Just because it's a big sheet sheet doesn't mean it's more fragile. :D

** Just for the record, UltraVue70 AR is more like 2.5mm thick.
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Re: Glass for larger frames

Post by JFeig » Fri 26 Jul, 2019 12:00 pm

Justintime wrote:[quote="Steve N"

Another way of looking at it , why do they produce 2mm float glass in 3ftx4ft sheets :?: They also produce 2mm float glass in 4ftx6ft sheets but...
The answer is simple. The glass plants all produce produce the glass from a continuous line that may be up to 5 m wide no matter the thickness. As picture framers we are a minor player in the consumption of a companies production. On the line the glass is cut down to a manageable size for shipping and post processing by a converter (window mfg. plant, etc.). With the larger the size of the raw stock there is the potential for a greater yield (less scrap). Just because the glass comes in these larger sizes, does not mean that the finished product is safe at the full sheet size.

The following is info from a glass manufacturer re sizes:

"Item Clear Float Glass

2mm to 25mm etc.

Size
1524x2134mm,1650x2140mm,1650x2440mm,18330x2440mm,3300x1900mm,

3210x2140mm,3300x2134mm,3210x2250mm,3300x2250mm,3660x2134mm,

3660x2250mm etc or customized."



FYI in N America most picture framing glass is 2.5 mm thick. This is due to the window industry standards for strength. I carried and used single strength glass up to 40" x 60". Over that size I would never use real glass for my safety and the customers.
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Re: Glass for larger frames

Post by mbaister » Thu 08 Aug, 2019 3:58 pm

That's all brilliant information, much appreciated, especially the advice about how to approach public display. Many thanks all!

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Re: Glass for larger frames

Post by Not your average framer » Fri 09 Aug, 2019 5:58 am

Because most framers are primarily using 2mm glass and therefore since the framing suppliers are buying huge quantities of 2mm glass, the price that framers are paying for 2mm glass is a crazy amount cheaper than either 3mm, or 4mm glass. For this reason if a framer decides to stock 3mm, or 4mm glass as well as the normal 2mm there will be some important issues to consider.

Since the thicker glass is going to be needed for larger framing jobs, it is likely to be needed for jobs larger than the usual 3ft x 4ft sheets normally stocked for 2mm glass, so the next largest standard sheet size would normally be 4ft x 6ft and as this is mostly required for jobs needing larger than the 3ft x 4ft, it then suggests that the left over piece after cutting to the size required will probably be too small for the next job requiring heavier glass, because of the frame size. So this becomes quite wasteful.

This level of waste combined with the crazy price that you may be paying for the thicker glass makes stocking it quite a lot of money tied up waiting for the opportunity to use it and this is not very sensible when it can be ordered in and delivered cut to size almost immediately. In addition to this, if you decide to stock thicker sizes of glass in the large sheet sizes that you would need to stock to make any reasonable sense, then it stands to reason that these larger and thicker sheets of glass are likely to be stored separately from the normal 2mm glass and will require extra space.

This is why I don't stock thicker glass at all, but order it as and when required and get it cut to size, so that it just drops straight into the frame and I don't have to worry about what happens, if the glass does not cut correctly. It all makes sense to me!
Mark Lacey

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