I'm starting to like the idea of using this stuff a bit more - and it DOES seem to be the stuff I used in the Army (although the FR4 compliance is apparently less important than G10). I do have glass & west-epoxy for areas where wet-work will be required, but it seems to be just the ticket for small patches, access holes, backing plates, and so on...
http://www.professionalplastics.com/G10FR4SHEET If the boat-makers can use it for this sort of stuff, seems useful in my applications: http://www.aquidneckcustom.com/custom_boat_builder/composite_fabrication_methods.php On Tue, Jun 26, 2012 at 9:42 AM, Dave Acklam <dave.a.kr...@gmail.com> wrote: > I'vw found a few suppliers for that cured panel and various other pre > cured glass panels... It appears that the g10/fr4 precured sheet may well > be what was used in the aforementioned helicopter repairs, so I am > considering getting some very thin sheets to use for patching skin > punctures and similar (my plane has a good deal of minor dings and such, > from mishandling by previous owners... > > The question of using it for elevator skins vs wet layup, is another > issue.... > On Jun 26, 2012 8:46 AM, "Mark" <markweg...@charter.net> wrote: > >> FR-4 can be purchased in various thicknesses in the fully cured state; >> Google 'printed circuit laminates' or just 'FR-4 laminate'. Or you might >> check "printed circuit boards" or "multilayer printed circuits" to see if >> there is a fabricator near you and they can tell you where you can get it. >> (They might even be nice and give you a couple of panels after etching the >> copper foil off. Some of the suppliers used to be GE, Norplex, and Oak >> laminates. >> >> -----Original Message----- >> From: krnet-boun...@mylist.net [mailto:krnet-boun...@mylist.net] On >> Behalf >> Of Dave_A >> Sent: Monday, June 25, 2012 11:16 PM >> To: KRnet >> Subject: Re: KR> Anyone use FR4 for construction or repairs? >> >> Ahh... >> >> What I'm looking for (thought this might be it, but I guess it's not) is a >> pre-laminated fiberglass sheet that can be epoxied in place in leiu of >> wet-layup... >> >> When I first joined the Army, I was an airframe mechanic, and we had this >> stuff in the shop that we called card-stock or fiberglass laminate. >> It was used for repair of flat or nearly-flat sandwich-construction panels >> (essentially similar to most of what the KR's made of) in leiu of >> wet-layup... Adhesive was put between this stuff & whatever sort of >> core-patch had been applied, the end result was a nice clean/eaven, very >> quick patch.... >> >> I can't quite put a name on it, and the FR-4 substance seemed right... >> Guess it's not... >> >> If all else fails, I *can* do it the traditional peel-ply way... Will >> have >> to come up with a suitably rigid backing board for the underside of the >> elevator, because this plane is not 'flippable'... One of many times I >> wish >> I had access to my old shop on base (and all the whiz-bang composite >> repair >> gadgetry - especially the hot-vaccum-bonder)... 'course I'm much happier >> as >> a tanker than a REMF, but enough Army talk, anyhow... >> >> - Dave >> >> On 6/25/2012 7:23 PM, Mark wrote: >> > More properly FR-4 (fire retardant (e-glass) glass reinforced epoxy >> > typically used in the manufacture of printed circuit boards (I did >> > that for about 25 years). The epoxy resin is formulated with a >> > brominated fire retardant and can be purchased as a "b-staged" >> > material (partially cured and used to construct rigid PCB's and >> > Multi-layered PCB's) in 1080 (.0025" cured and pressed thickness) to >> > 7628 (~0.008" cured and pressed) layed up to produce laminates anywhere >> from 0.005" thick up to and including 0.125" >> > thick (typically). Typical lamination pressures are 250 psi at about >> > 350 degrees F. 25,000 pound shear is common when properly laminated >> > and cured - post bake is optional. Other resin systems have different >> > mechanical properties, although the reinforcing material is a >> > significant contributor to the laminate. >> > >> > The b-staged laminate needs to be driven to 300F (minimum to get the >> > epoxy to flow). You would be better off buying the woven class and >> > performing the normal epoxy flood/squeegee/peel ply method to get your >> repairs done. JMHO. >> > >> > Vacuum can reduce the net pressure of the process. T sub G's (glass >> > transition) is typically in excess of 275 degrees F. >> > >> > Hope this helps. >> > >> > Mark W. >> > N952MW (res) >> > >> > -----Original Message----- >> > From: krnet-boun...@mylist.net [mailto:krnet-boun...@mylist.net] On >> > Behalf Of Tony Wright >> > Sent: Monday, June 25, 2012 7:23 PM >> > To: KRnet >> > Subject: Re: KR> Anyone use FR4 for construction or repairs? >> > >> > Dave, >> > >> > I have never heard of fr4, but I have used FRP (fibreglass reinforced >> > plywood) in trailer repairs. think this could be used in >> > non-structural uses. >> > >> > Tony >> > >> > -------------------------------------------------- >> > From: "Dave Acklam"<dave.a.kr...@gmail.com> >> > Sent: Monday, June 25, 2012 5:51 PM >> > To: "KRnet"<kr...@mylist.net> >> > Subject: KR> Anyone use FR4 for construction or repairs? >> > >> >> Fr4 is pre-cured fiberglass sheet made with epoxy resin..... Kind of >> >> like a composite version of 1/16 ply..... It's available in :005in >> >> and up.... >> >> >> >> I'm thinking of using this for some of my larger flat repairs; in >> >> leiu of laying up glass (eg replacing the pilot side elevator skin)... >> >> >> >> Essentially, like an unmoulded version of prefab wingskins.... >> >> _______________________________________ >> >> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. >> >> To UNsubscribe from KRnet, send a message to krnet-le...@mylist.net >> >> please see other KRnet info at http://www.krnet.org/info.html >> >> >> > _______________________________________ >> > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. >> > To UNsubscribe from KRnet, send a message to krnet-le...@mylist.net >> > please see other KRnet info at http://www.krnet.org/info.html >> > >> > >> > _______________________________________ >> > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. >> > To UNsubscribe from KRnet, send a message to krnet-le...@mylist.net >> > please see other KRnet info at http://www.krnet.org/info.html >> >> >> _______________________________________ >> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. >> To UNsubscribe from KRnet, send a message to KRnet-leave@mylist.netplease >> see other KRnet info at http://www.krnet.org/info.html >> >> >> _______________________________________ >> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. >> To UNsubscribe from KRnet, send a message to krnet-le...@mylist.net >> please see other KRnet info at http://www.krnet.org/info.html >> >
