Physically (mechanical/structural/etc) there is no difference between G10 and FR-4. The flame retardant in FR-4 is designed so that the material is self extinguishing once the ignition source has been removed. My recollection is that the UL requirement was that it stop exhibiting evidence of flame or embers within about 30 seconds of removal of the ignition source. G10 does not need to meet the self extinguishing requirement.
On Tue, Jun 26, 2012 at 11:54 AM, Dave Acklam wrote: > 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 <[email protected]> > 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" <[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] >>> 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
