what temp does coe 104 melt?

febgirl · September 05, 2009, 10:30:37 PM

I have spent ages reading through things on the internet with no success.

Then I thought I know people who are much more cleaver than the internet, hope you can help me.

I work in a science dept in school and am going to be demoing make beads to the general studies class, then letting them have a go. I want to scare them big time,

in the interest of safety only. So thought I would go on about how hot the glass is. Then I though as it is a school I better get my facts right.

So what temperature does coe 104 melt at???

Thanks

Hamilton Taylor · September 06, 2009, 06:01:20 AM

Hi,
Here's the spec according to Arrow Springs, so you need to translate temps:

Effetre
Coefficient of Expansion (COE): 104
Annealing range: 920 - 968º F
Strain Point: 840º F
Softening point: 1050º F
Working Temperature: 1400º F

Working temp is probably the one you want, having said that it sounds to me as if it could be a bit low, maybe?: 760C

HTH,
Cheers,

Sean

Ian R Pearson · September 06, 2009, 09:20:34 PM

Well ignoring the fact that glass doesnt "melt" the way I usually explain to kids when demoing is by making a comparrison. So glass works in a flame which is 5 or 6 times hotter than boiling water and you wouldnt put your hands in boling water would you kids??? ( oh yes they will, I bet at least one asks!!).

Ian

Redhotsal · September 06, 2009, 11:27:57 PM

yep - it's somewhere around 800c but that's just an estimate since 104 coe encompasses quite a large range of compounds that we know of as glass. There's a difference between melting points of Effetre, CIM, Lauscha, for example and there's definitely a difference between melting point of say, Effetre white and Effetre trans cobalt, for example. Also - since glass colours are largely a result of the different compounds (usually metal oxides) which are added to the generic glass base it is to be expected that there are differences in melting points of individual colours.

Also, rather like chocolate - melting point is really a range of temperatures for glass. You get molecular movement of glass even down as low as 500 degrees (that's why we can anneal glass at that point), although if you tried to poke it the glass would be stiff. Contrast this to a metal where the difference between solid and liquid is an actual temperature - e.g.silver is 961C, an absolute figure, below this it is a solid and above this it is a liquid.

If you really want to scare the kids just tell them that at the base of the minor burner the temperature of the flame is approximately 1800degrees C - which is very roughly a third of the temperature of the outer surface of the Sun.

Blimmin' heck - never mind scaring the kids - I've managed to scare myself!

Redhotsal · September 06, 2009, 11:41:11 PM

When I (used to) get asked to events where there were loads of kids present I always used to print out this, as kids are on the whole fearless and will try to dangle themselves in the flame if you don't keep them at a decent distance.
In fact - there's no difference between girls and boys in the "total disregard for their own safety" stakes.

julieHB · September 07, 2009, 07:36:23 AM

I'm impressed, Sal - I knew not that the base of the flame was that hot!! I'd have thought the sun was a bit hotter, though

Redhotsal · September 07, 2009, 10:32:24 AM

Yes, the sun itself is a lot hotter - about 15 million degrees in the centre - but at the outer visible layer, i.e. when the sun effectively "stops" to the eye, which is the photosphere, the temperature has dropped dramatically.

The temp of a minor burner is truly scary hot at the base of it. The working temperature - about 3-4cm above the base is much lower - around 1000 degrees. When you get to the top - just at the point where the flame starts to disappear it is about 500C and good for parking your bead while you are looking for bits of stringer or, of course fending off curious children.

febgirl · September 07, 2009, 02:05:09 PM

Thank you everyone I knew You wouldn't let me down.

febgirl · September 17, 2009, 09:32:44 PM

Thanks everyone again.

I had a lovely afternoon with some 16 year old girls. I explained everything to them and then demonstrated making a bead. They thought it looked really easy and rushed in. The first girl made a mess of it and was really surprised how difficult it was. After that they all listened a bit more and by the time they had made the 3rd bead were getting the hang of it. I think they might be hooked. Kept asking questions about where to get things.

It was a really successful afternoon, we will certainly repeat it.