Don Pearce wrote:
On Mon, 07 Jan 2008 06:28:10 +1100, Trevor Wilson
wrote:

Don Pearce wrote:
On Sun, 06 Jan 2008 19:04:41 +1100, Trevor Wilson
wrote:

tony sayer wrote:
Enjoy....

http://dailymotion.alice.it/video/x3...pe-triode_tech
**Outstanding! Those whacky Frogs.

One question:

Why the yellow flame, before the blue flame on the glass?

So as not to crack the glass through too-intense local heating. Much
less risk if you bring it all up to a fairly high temperature before
getting serious with one bit.
**OK, that makes sense. Wouldn't holding the blue flame further away
achieve the same thing?

I remember glass-blowing classes in school chemistry. We always used
the yellow flame for annealing. I think the gradients are just too
severe in the blue.

**'K. Thanks Don. The only other thing which stood out, was that the guy
had a superbly fitted out workshop, but used a Swiss Army Knife to cut
the plates. I'd have thought he would use a small guillotine.

Trevor Wilson

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