Thursday, April 30, 2020

Lockdown Project: Glass animal repair


I've always loved my parents' collection of glass animals. As a child, apparently, I used to stare at the china cabinet for hours. If I was very good, I might be allowed to have the door open, but I never tried to grab anything from it. I knew these were precious and fragile.

Despite this, some of the animals have broken over time. The lamp post, bought on Brighton pier apparently, is at least 60 years old!

Sticking glass back together seems to defeat most glues, but recently, we've seen superglues that are set by UV light appear on the market. 

  
I think this stuff comes from the dental world. My dentist has set a couple of fillings with UV and I understand they have similar glues claimed to be incredibly strong. 

Revell's version arrives with two tubes and a marker pen with UV torch on it. In theory, all you do is apply the glue, fire light at it for 5 seconds and the job is done.  


In practice, I found that the 5 seconds thing is rubbish. Think nearer 30 for a workable joint. My first attempts fell apart quickly and I found that while the edges had hardened, most of the glue was still liquid. This is especially odd as the glass is transparent, although the colour may block the correct light wavelength. 


Where we had a clean joint, the glue worked well. The delay of a few years between breakage and mending meant that a few slivers of glass had long gone, but I did my best and at least all the pieces are attached. Not good as new, but good enough not to throw away. 

I've since tried the glue on a couple of other jobs and been reasonably impressed. Not cheap, but a very useful addition to the toolbox. 

7 comments:

Duncan Young said...

Huge memories of my mother's green glass faun with broken hind leg. But it still stayed balanced on her dressing table to her dying day! Repairs like this were unheard of then. It was an epoxy resin/ UHU or nothing!

Anonymous said...

UV curing adhesives have been around a long time. I had a Mk 3 2 door Cortina back in the early 70's where the rear side windows were attached with it. One day the bond broke as I went round a corner and the window fell out. Rear view mirrors mounted on the windscreen have used it for a long time.
Widely used these days

https://en.wikipedia.org/wiki/UV_curing

Brian G

Colin said...

Although glass is transparent to the range of frequencies we see, it absorbs UV light. That's why we don't get sunburn indoors.

Duncan Young said...

Brian
I'm talking '60s!

Huw Griffiths said...

Interesting point about the glass blocking this UV light.

I'm not sure that all UV would be able to pass unimpeded through most types of glass - even types that seem transparent to visible light - it's probably fair to say that a lot of types of glass, acrylic, and other "window" materials allow certain frequency or wavelength ranges through reasonably well - but block others to varying extents.

Somehow, I suspect that a number of people with expertise in photonics might put this a bit stronger than I have.

I don't pretend to know much about this stuff (well anything at all, really) - but I strongly suspect that most of the bonding you'll get with "UV cure" adhesives is likely to be very close to the edges.

It's also interesting to see an LED being used to provide the UV - if only because a number of supposedly "white" LEDs seem to be more like UV LEDs with a phosphor.

You can quite often see this with some LED torches and inspection lights - when turned off, the LEDs used appear to be coated with yellow (usually) paint. When you turn on the "juice" they glow brightly. They also seem to light up when unpowered, if you shine a banknote checker (UV) at them.

Anonymous said...

Phil

There has been a superglue 'Glass bond' around for a long time. Remember fixing an old plate glass frosted station window that I had once (Pos LNWR). Worked well and repaired varius glass ornaments. Just left it in the sunlight for a day. Last month did a glass bowl with similar from Wilcos sold as glass glue in small green tube.
Oh and yes I've also got some of those glass animals my folks had.

pete

Phil Parker said...

I've tried glass bond in the past and never had any luck with it. In my case, it should have been called "Another chance to play catch the rear view mirror 'cos there's no way it's going to stay stuck to the windscreen".