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
