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Author: Subject: Testing Quartz Wool vs Borosilicate Wool
BobD1001
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[*] posted on 26-5-2021 at 13:52
Testing Quartz Wool vs Borosilicate Wool


I recently ordered some quartz wool off eBay from a Chinese supplier. It has just arrived, and now I am second guessing whether its real quartz wool or just glass wool. The listing stated the following:

"Quartz wool

Fiber diameter of 5-10um

A silica content: si02 ≧ 99.99%

2, the thermal conductivity of 0.01 - 0.029 kcal \ degree m

The following 3, temperature 1600 degrees"

(listing here for reference: https://www.ebay.com/itm/293638119168)

I did a quick test with just a candle lighter and it melted pretty quickly, which I was not expecting, but seeing that butane/air burns at over 1600C that may have been an invalid test.

Any other ideas to test if its quartz or just borosilicate?

[Edited on 26-5-2021 by BobD1001]
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unionised
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[*] posted on 26-5-2021 at 13:57


Wrap some round a piece of thin copper wire and put that in the flame.
If the glass melts but the copper doesn't then you know it melted below about 1080C
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Chemetix
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[*] posted on 26-5-2021 at 16:13


Quote: Originally posted by unionised  
Wrap some round a piece of thin copper wire and put that in the flame.
If the glass melts but the copper doesn't then you know it melted below about 1080C



I know it sounds logical to use MP differences as a distinction but the reality is that small masses will melt in a very mild flame. Quartz wool will melt in a bunsen flame the same as borosilicate. The size of the balled up material will differ and they'll behave differently such as the colour of emitted light but they will still melt.

Temperature is a statistical thing, so for a given amount of gas in a flame the molecules will have a distribution of temperatures. A very thin piece of material only has to absorb a few of the high energy molecules and it has melted. The larger the mass the more that the high energy molecules get distributed through the bonds of the material and so there needs to be higher flame temperature involved to give a greater proportion of high energy molecules to create an even distribution of energy high enough to break or weaken bonding.

This can be considered a physical manifestation of Wein's displacement law.
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yobbo II
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[*] posted on 27-5-2021 at 04:02




If you make a blob of quartz glass with some wool then you will get a better idea of its melting point.

You can melt 40 gauge (very fine) copper wire in a candle flame. It will form a knob of molten copper on the end of the wire you put into the flame. You may need a magnifying glass to see it. It's like as described above with the glass wool.

Yob
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[*] posted on 27-5-2021 at 05:57


dissolve some in NaOH solution and look if any cloudy matter . glass have CaO hence Ca(OH)2 and they don't dissolve in very basic solution and end up precipitating.



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[*] posted on 27-5-2021 at 10:37


Quote: Originally posted by Chemetix  
Quote: Originally posted by unionised  
Wrap some round a piece of thin copper wire and put that in the flame.
If the glass melts but the copper doesn't then you know it melted below about 1080C



I know it sounds logical to use MP differences as a distinction but the reality is that small masses will melt in a very mild flame. Quartz wool will melt in a bunsen flame the same as borosilicate. The size of the balled up material will differ and they'll behave differently such as the colour of emitted light but they will still melt.

Temperature is a statistical thing, so for a given amount of gas in a flame the molecules will have a distribution of temperatures. A very thin piece of material only has to absorb a few of the high energy molecules and it has melted. The larger the mass the more that the high energy molecules get distributed through the bonds of the material and so there needs to be higher flame temperature involved to give a greater proportion of high energy molecules to create an even distribution of energy high enough to break or weaken bonding.

This can be considered a physical manifestation of Wein's displacement law.


That is largely bollocks.
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[*] posted on 27-5-2021 at 15:26


Regular glass strongly attenuates ultraviolet light while quartz passes most of it. If you have a UV source and something fluorescent, you could try to make the item to fluoresce behind a sample of the wool.
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[*] posted on 27-5-2021 at 17:36


[/rquote]

That is largely bollocks.
[/rquote]

I stand by those claims. I maybe should have said temperature in flames rather than temperature in a general sense, but context should have made that clear. Wein's law and the invoking of a black body radiator is relevant here as the gasses in a flame act as radiators and radiation is the significant mode of transfer of energy within a flame.

If you have a source to explain the melting of fine fibres in an otherwise mild flame that would not measure a temperature even close to a materials' softening point, then please offer it.
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[*] posted on 28-5-2021 at 04:39


Quote: Originally posted by Chemetix  
[/rquote]


If you have a source to explain the melting of fine fibres in an otherwise mild flame that would not measure a temperature even close to a materials' softening point, then please offer it.

No. I do not need to explain a figment of your imagination.
First of all, you need to show that things melt in flames that are not hot enough to melt them.

You might want to call a candle flame "mild"- whatever that means.
Bits of the flame are at about 1200C and so it is quite capable of melting copper.
https://en.wikipedia.org/wiki/Candle#/media/File:Anatomy_of_...


That diagram more or less answers the OP's question.
No part of a candle flams should be hot enough to melt fused quartz.

[Edited on 28-5-21 by unionised]
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[*] posted on 28-5-2021 at 08:01


I have some .002th reference grade Pt wire that has a slightly higher melting point than quartz. Perhaps testing that in a flame would be telling. It's so thin you sometimes can't see it.

"The thinnest [human hair thickness] is about 2 thousandth of an inch in diameter. The thickest can be about 6 thou'. Most is around 0.004 inches."

Well no luck with a tealight candle flame or Bic lighter but a single strand did shrivel somewhat in a butane flame tiny torch. The wire is Sigmund Cohn 99.99 platinum. I wonder if balled up loosely to mimic wool how that would affect heat transfer?
A quick look at some quartz wool stated a thickness 9 to 14 um, if typical.
https://www.advaluetech.com/products/fused-quartz/quartz-woo...

[Edited on 28-5-2021 by Morgan]
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