Glueing Glass

[xavier]

SWMBO was looking at a glass storage unit for the bathroom. It consists of two side pieces approximately 1.5m in length x 170mm in depth and it has about six glass shelves which are glued to these two side pieces to form little 'boxes', these shelves are 150mm wide x

170mm in depth. In other words, it's a bit like a glass ladder with a top and bottom!

Looking at it, it's obvious that the 'shelves' are glued to the side pieces but there's no sign of any adhesive. Has anyone any idea how you could glue glass in this fashion? The glass in question is 6mm and will be toughened with, I guess, polished edges, although I'm not sure if they're polished where they're glued to the side panels.

In our case, it would also have to have brackets (probably metal) glued to each end, so as well as glass to glass glue, I'm also looking for metal to glass glue.

She wants one of course, but at £362 it does seem a tad expensive to me for what is after all only about ten pieces of toughed and polished glass and some glue. Am I missing something?

xav

[Andy Dingley]

A UV cure glue, and a very expensive UV light. This is a wondeful bit of kit to work with, because it's as instant and controllable as welding. If you can work slower and arrange to clamp it in situ, then you can use an EPROM eraser.

For small jobs, a less strong but more flexible version of this is sold in car accesory shops for attaching rear-view mirors to windscreens.

[xavier]

Tks.

What's an EPROM eraser and where do I get one (it?)

xav

[Dave Stanton]

It erases, clears the memory, of eprom chips used in computers. Where the bios of your pc is stored. They use UV light to erase the chip.

Dave

[slifkin]

You can buy a blacklight UV bulb with standard bayonet fitting for about 5 GBP. These give out a small amount of UV. If you carefully remove the outer glass case, which is in fact a UV filter, the inside which is a self-contained UV discharge tube yields a considerable amount of UV. However you must be careful not to get the UV in your eyes. You should wear a pair of googles to UV 400 standard.

[Andrew Gabriel]

Use a blacklight blue tube. The shorter wavelengths from an eprom eraser (germicidal tube) are dangerous, and won't go through ordinary glass anyway, so can't help in curing the glue.

Other sources are bright sunlight (problem at this time of year), and high power halogen lamps which have no glass cover.

[N. Thornton]

aquarium glue, its a specific grade of silicone. Probably what youre missing is profit margin.

NT

[Gordon Henderson]

Not for several years in a PC they haven't... It's all flash (electrically erasable) these days... And I think the older ones used mask programmable ROMS too (ie. program once, non erasable)

Gordon

[xavier]

err

This is all very interesting chaps and I'm sure I'm going to be eternally grateful one day. In the meantime, does anyone know of anything in a tube - you know, the kind you can squeeze at one end and out pops the magic potion at the other?

Failing that it's beginning to look like 360 dumps at the bathroom shop - down the tubes you might say (ouch, I'll get me coat)!

xav

[Andy Dingley]

Loctite 350 or 358

Any decent industrial glueshop will know of it, or there's always RS Mine was £25 for a 50ml tube (lifetime's supply)

Needs _Summer_ sunshine to cure it, or a short-wavelength UV tube. EPROM erasers probably show up on eBay, or I hope there's still the old advert in the back of E&WW for the tubes and ballasts (Electronics and Wireless World - you can get it in Smiths).

Keep it away from air - use a _tiny_ amount and let capillary action pull it between the glass. If it's exposed to air you have to really nuke the stuff to get it to cure.

Loctite also do "Glass Bond", which is similar. It's different though in that it's a 3ml tube for a couple of quid, and you'll use a few of them making furniture. It's also optimised for a long-wavelength sunshine cure, or I think it works under sunray lamps too.

The other one (probably Loctite again, although there are several) is the car-shop rear mirror glue. This has a bit more "give" to it (Loctite's ordinary Glass Bond will make your mirror fall off on a hot day)

[Rod Hewitt]

Andy Dingley wrote in news: [e-mail]:

UV torches can be found. Do they produce sufficient output to cure these substances or are they only powerful enough for banknote testing?

[Grunff]

I've got a 286 motherboard with an EPROM BIOS (has erase window).

[Andy Dingley]

Long wavelength. They won't even think about curing the glue, no matter how many or how long you used them.

I was pondering this strange behaviour of UV light, and why it has to be of a certain minimum wavelength to have any effect, when I began to invent a fascinating new theory, which this posting is sadly too small to contain...

[Grunff]

Isn;t it just a photon energy threshold? Above a certain wavelength, the photon energy isn't enough to kick the appropriate electron, below that wavelength it is?

All ears.

[Rob Morley]

't know what you would do for a UV source though - maybe a sunbed or those things they use for hardening nail polish in salons?

[Rob Morley]

How about the things they use for hardening nail polish in salons?

[Chris Hodges]

Not really. Most of the UV glues I have used have an absorption peak matched to the 365nm mercury line (they are transparent again below this). This will penetrate a thin layer of normal glass. Some also have an absorption in the deep blue which helps them to cure in sunlight ("Glass Bond" is a DIY brand which IIRC will cure with UV or blue). Dymax is one brand we use at work, Norland is another, though most of their UV glues are designed and priced for use with precision optics.

"Disco" blacklights are 365nm, but there's not much of it, and what there is is quite spread out, however that should get most of these glues to go off. Germicidal/EPROM erase lamps (as pointed out elsewhere) won't get through the glass and aren't guaranteed to set the glue off anyway.

These glues can be extremely strong and can bond metal to glass as well as glass to glass. A test we did at work was to bond a 20mm square 3mm thick mirror along one edge to a bracket inside a dead PC case. Dropping the case onto a solid concrete floor from ~1m rarely broke the bond but frequently broke the glass (cleanly).

Both surfaces should be completely clean, especially grease free.

There is one other issue I discovered when attenpting to cure UV glue with a ~370nm UV LED: If the intensity is too low you will get a partial cure (tacky with no strength) which no length of exposure will improve on.

[Asa Cannell]

Nichia just came out with a 365nm (ultraviolet), 100mw (optical power output) LED. Its probably the highest power UV led in the world right now (the claim it is on their website), and 365nm is especially exotic for a solid state ultraviolet source, most are at 390 or above, few are at this short a wavelength and next to none are at this output power, at any wavelength. This might be what you are looking for for UV curing because of its output wavelength and very high power output. They have made samples available recently at $200 a piece with a minimum quantity of 5 pieces and a lead time of 4 weeks. I bought 5 of them (yep $1000) for a project I am working on, but I only need two. I am selling the other three for $200 each plus shipping. You can download the datasheet and place an order at:

http://www.exoticelectr> > Andy D> >

[Chris Hodges]

don't think this project's got that kind of budget, but thanks for the info and the offer.

Chris