Hi Clive, here are some properties of the different glass fabrics. It is not perfect but I hope this throws a little bit more light your way |--------+--------+--------+--------+--------+--------+--------+--------| |Fabric |CTE |Softenin|S.G |Refracti|Dk@ 1MHz|Df @1MHz|Youngs | |type | |g point | |ve index| | |Modulus | | | | | | | | |Gpa | | | | | | | | |(lb/in | | | | | | | | |(supersc| | | | | | | | |ript: 2)| | | | | | | | |X10 | | | | | | | | |(supersc| | | | | | | | |ript: 6)| |--------+--------+--------+--------+--------+--------+--------+--------| |E |60 |845 |2.605 |1.552 |6.6 |0.002 |74 | | | | | | | | |(10.5) | |--------+--------+--------+--------+--------+--------+--------+--------| |C |72 |750 |2.540 |1.541 |6.3 |0.005 |70(10.0)| |--------+--------+--------+--------+--------+--------+--------+--------| |S |34 |968 |2.510 |1.529 |4.6 |0.002 |88(12.5)| |--------+--------+--------+--------+--------+--------+--------+--------| (Data extracted from "Glass Engineering Handbook" 3rd edition by McLellan & Shand, Pub. McGraw Hill) 'E' Glass _ Used for electrical applications, the most commonly used composition for continuous filament yarns. Good resistance to water, fair to alkalies , poor resistance to acids. E-glass has been the leader of the composites industry since the late 1940s. was developed originally for use as an insulator in the Electrical industry (hence the "E" designation before the word glass) 'C' Glass_ Chemically resistant glass, primarily to water and acids. Used for battery separator mats, acid filter cloths and anode bags. 'S' Glass_ High tensile strength, high modulus glass for resin reinforcement , particularly used for ballistic absorption shields. S-glass is a different chemical formulation of glass that enhances Structural strength characteristics (so the "S" designation before the word glass). S-glass's major advantages over E-glass include slightly higher strength and stiffness on a per-weight basis, and it will also stretch further before breaking. Clive Ffitch <[log in to unmask]> on 26/08/98 19:07:53 Please respond to "TechNet E-Mail Forum." <[log in to unmask]>; Please respond to [log in to unmask] To: [log in to unmask] cc: (bcc: Frank Frimpong/HQ/CUK/Celestica) 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 ################################################################