Glass type used in CRM121 - UK Vintage Radio Repair and Restoration Discussion Forum

Panrock · 14th Jul 2011, 9:03 pm

As per the title really. I presume the Mazda CRM121/3 tubes were made of hard glass. But does anyone have more detailed information about the type or spec. of glass used?

Thank you.

Steve

murphyv310 · 14th Jul 2011, 9:24 pm

Pyrex is a hard glass many EMI crts used this type of glass. The glass used in Mullard & Mazda tubes and many others is a soft glass.

Panrock · 14th Jul 2011, 9:37 pm

Thanks for clearing that point up Trevor!

What would be great to know would be a ballpark COE (coefficient of expansion) figure on the sort of glass that's used on these Mazda tubes. A lot to ask I know - but this board has come up with wonders before!

ppppenguin · 14th Jul 2011, 9:42 pm

GIYF There's a table about halfway down this page. http://www.oldham-optical.co.uk/Glass.htm I would assume that "plate glass" is an ordinary soft glass. Also here: http://www.warmglass.com/COESummary.htm

Peter.N. · 14th Jul 2011, 10:02 pm

Thet were initially dreadful tubes many failing within the first 12 months.

Peter

14th Jul 2011, 9:03 pm	#1
Panrock Nonode Join Date: Feb 2005 Location: Worcestershire, UK. Posts: 2,533	Glass type used in CRM121 As per the title really. I presume the Mazda CRM121/3 tubes were made of hard glass. But does anyone have more detailed information about the type or spec. of glass used? Thank you. Steve __________________ https://www.radiocraft.co.uk

14th Jul 2011, 9:24 pm	#2
murphyv310 Dekatron Join Date: Sep 2006 Location: Kilmarnock, Ayrshire, UK. Posts: 5,422	Re: Glass type used in CRM121 Pyrex is a hard glass many EMI crts used this type of glass. The glass used in Mullard & Mazda tubes and many others is a soft glass. __________________ Cheers, Trevor. MM0KJJ. RSGB, GQRP, WACRAL, K&LARC. Member

14th Jul 2011, 9:37 pm	#3
Panrock Nonode Join Date: Feb 2005 Location: Worcestershire, UK. Posts: 2,533	Re: Glass type used in CRM121 Thanks for clearing that point up Trevor! What would be great to know would be a ballpark COE (coefficient of expansion) figure on the sort of glass that's used on these Mazda tubes. A lot to ask I know - but this board has come up with wonders before! __________________ https://www.radiocraft.co.uk

14th Jul 2011, 9:42 pm	#4
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: Glass type used in CRM121 GIYF There's a table about halfway down this page. http://www.oldham-optical.co.uk/Glass.htm I would assume that "plate glass" is an ordinary soft glass. Also here: http://www.warmglass.com/COESummary.htm

14th Jul 2011, 10:02 pm	#5
Peter.N. Dekatron Join Date: Jul 2008 Location: Charmouth, Dorset, UK. Posts: 3,601	Re: Glass type used in CRM121 Thet were initially dreadful tubes many failing within the first 12 months. Peter