Glass Scrim Ply

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Glass Scrim Ply

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pkcomposite	pkcomposite posted 10 Years Ago HOT Topic Details
Group: Forum Members Posts: 3, Visits: 14	Hello all, I'm new to the forum and will shoot right to my question: What is the purpose and effect of glass scrim ply (106 overlay to be exact) on top of carbon laminate? The carbon laminate is a two ply 0/90 uni that is used for honeycomb sandwich panel skin. One of my need is surface resistivity to not exceed x ohms per square - this is not achievable with the presence of glass scrim. Removing that the carbon fibers are now exposed to external damage but other than that, what else? Thanks. Edited 10 Years Ago by pkcomposite
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Dravis	Dravis posted 10 Years Ago HOT Post Details
Group: Forum Members Posts: 592, Visits: 1.9K	Are you referring to a commercially purchased cured CF sheet ? Depending on the intended use, I do not think a glass "scrim" on top of the CF is needed, but to keep a very low resistivity / high conductivity of the actual surface, you will probably need to leave some of the carbon fibres exposed ... how that affects the surface properties of the sheet i do not know .. However, if I were to build with your "constraints" on the design I would incorporate Nanocyl "Epicyl" carbon nanotube additive in the top resin, this leaves the resin itself highly conductive, thoug the actual values probably will need to be tested ... This has the added benefit of a substantial increase in strenght of the laminate ... It does not work all that well with infusion resins, and only with Epoxy .. "Sapere Aude"... Dare to KNOW! The written word is the only truly efficient vehicle for transmitting a complex concept from mind to mind... 103% of all people do not understand statistics... Do not adjust our mind, theres a fault in reality :-)
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pkcomposite	pkcomposite posted 10 Years Ago HOT Post Details
Group: Forum Members Posts: 3, Visits: 14	Dravis (08/01/2015) Are you referring to a commercially purchased cured CF sheet ? Depending on the intended use, I do not think a glass "scrim" on top of the CF is needed, but to keep a very low resistivity / high conductivity of the actual surface, you will probably need to leave some of the carbon fibres exposed ... how that affects the surface properties of the sheet i do not know .. However, if I were to build with your "constraints" on the design I would incorporate Nanocyl "Epicyl" carbon nanotube additive in the top resin, this leaves the resin itself highly conductive, thoug the actual values probably will need to be tested ... This has the added benefit of a substantial increase in strenght of the laminate ... It does not work all that well with infusion resins, and only with Epoxy .. Thanks for the reply. I'm actually working with my supplier who is a HSP vendor, whom produce various HSPs using prepregs and cores they procure. Thus the carbon laminate in discussion here is actually in prepreg form which is pressed together with other materials at certain temp. This implies that use of nanotube additive is probably out of the equation since it would drive the cost way up. But it is good to know what the "scrim" does not really provide anything structural. Edit: How about galvanic corrosion? Will removal of glass cause any of this in service? Edited 10 Years Ago by pkcomposite
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Dravis	Dravis posted 10 Years Ago HOT Post Details
Group: Forum Members Posts: 592, Visits: 1.9K	Calvanic corrosion will only occur if you have conductive (uncovered) carbon fibre in contact with metals like Aluminium alloys .. This is caused by the difference in electrical potential between Aluminium and Carbon- The glass "scrim" is often employed to prevent this problem. Some metals, like pure titanium will bond directly to carbon fibre, if treated correctly . (kept from forming its normal corrosion resistant oxide surface) without causing corrosion problems .. To get an even stronger bond between epoxy resin based carbon, Pagani developed a method of coating the titanium with some exotic metals to promote an even stronger bond ... calling the end product "carbotanium" "Sapere Aude"... Dare to KNOW! The written word is the only truly efficient vehicle for transmitting a complex concept from mind to mind... 103% of all people do not understand statistics... Do not adjust our mind, theres a fault in reality :-)
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pkcomposite	pkcomposite posted 10 Years Ago HOT Post Details
Group: Forum Members Posts: 3, Visits: 14	Dravis (09/01/2015) Calvanic corrosion will only occur if you have conductive (uncovered) carbon fibre in contact with metals like Aluminium alloys .. This is caused by the difference in electrical potential between Aluminium and Carbon- The glass "scrim" is often employed to prevent this problem. Some metals, like pure titanium will bond directly to carbon fibre, if treated correctly . (kept from forming its normal corrosion resistant oxide surface) without causing corrosion problems .. To get an even stronger bond between epoxy resin based carbon, Pagani developed a method of coating the titanium with some exotic metals to promote an even stronger bond ... calling the end product "carbotanium" Panels will have inserts made of Titanium installed so no issue there with galvanic corrosion, but the sub frame may be Aluminum or Steel alloy which would cause galvanic corrosion. Do you know anything about using epoxy resins without any hydrolysable linkage such as ester bonds, which would mitigate the water penetration? Or adding sizing agent (coating) on the fiber prior to impregnating the resin?
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