Clive, I believe you are correct, E-glass is a Borosilicate glass developed for electrical applications. There is also a more chemically resistant grade is known as C-glass. Both have better resistance to water & acids than standard Sodalime-silica glass. (Known as A-glass) S-glass(or S2)is an alumino-magnesium silicate glass, which has improved mechanical & thermal properties. C-glass E-glass S-glass Young's Modulus GN m2 69 71 85 Tensile strength GN m2 2.4 2.4 3.9 Density kg m3 2490 2550 2500 Breaking Strain % 3.5 3.4 4.6 CTE(or TCE) ppm/K 7.2 5 - 6.4 2.6 - 2.9 If low CTE is your main interest, there is also a Quartz glass (pure silica) which has a CTE of 0.54. However,there are availability & processing difficulties when compared to E-glass. Have you considered aramid fibre products? For info', a further note on glass. Letter codes are also used to denote glass fibre diameters! (U.K) The letter classification runs from B to U (missing out I) 'B' has a nominal diameter of 3.19 um, with each increment being 1.27 um. i.e grade G will have a nominal diameter of 9.54 um. Hope this helps, Regards, K.J. Berry Technology Engineer Radstone Technology PLC Water Lane, Towcester, Northants, NN12 6JN. U.K Tel: +44(0)1327 359444 ext:2165 Fax: +44(0)1327 358112 E-mail: [log in to unmask] Web: http://www.radstone.co.uk http://www.radstone.com -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Clive Ffitch Sent: 26 August 1998 19:08 To: [log in to unmask] Subject: [TN] DES: "S-glass" Fibre Reinforcement Hi All, Does anyone out there have any information or specification details on "S-glass" fibre reinforcement material as used in PCB laminates, and what does the "S" stand for? There are TCE (sorry CTE for you guys!) advantages with its use, and depending on the resin system it is used with, Er advantages also, but I am looking specifically to identify and understand the differences between "S-glass" fibre material and the more conventional "E-glass" fibre material. (I understand "E" stands for "Electronics" Grade???). How many people use S-glass? What benefits do you see? Any comments appreciated. Clive ffitch Matra BAe Dynamics UK Stevenage, England E-mail [log in to unmask] ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################ ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################ ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################