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" <[email protected]> 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: [email protected] [mailto:[email protected]] 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: [email protected] [mailto:[email protected]] 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"<[email protected]> > > Sent: Monday, June 25, 2012 5:51 PM > > To: "KRnet"<[email protected]> > > 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 [email protected] > >> 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 [email protected] > > 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 [email protected] > > 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 [email protected] 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 [email protected] > please see other KRnet info at http://www.krnet.org/info.html >
