Hello folks,
This is my first post after lurking for a while and really enjoying the site.
I was just wondering if anyone here has used lightweight (like under an ounce/ sq. yd)nylon or other nonwovens in between the plies of their laminate to improve resin flow through the laminate when infusing. I read about it somewhere, but was interested in hearing your experience?
Thank you,
Andrew
The only thing I’ve seen done is on VERY thick laminates, they used distro media inside the part. Otherwise, a nylon non-woven won’t have nearly enough flow as a fabric itself, especially if you are going light weight areal density. Else, you have to be sure that the nylon matieral isn’t coated, and won’t act as a release layer! 
If you want to improve flow, use a flow mesh, or a CFM mat. In specific cases you can use alternatives (Soric, Rovicore, etc)
Nylon can be used for its release properties. Cover cracks in concrete with strips of peelply, and laminate them over with glass fabric. Now apply your flooring compound. Presto, a crack-bridging epoxy floor.
Thank you, guys, for your thoughts. I got thinking about this after receiving some samples of Cerex N-Fusion non-woven and then reading this in the April 2013 issue of Composites World magazine:
(Begin Quote)
Glass vs. carbon
Permeability issues also vary based on fiber type. “The space between the 5- to 7-micron diameter filaments of carbon fiber is almost nonexistent compared to that between the 20-micron diameter glass fiber filaments, especially when compacted under a vacuum,” Steggall illustrates. “Glass is easier to infuse because of the bigger diameter bundles.” He also notes that carbon fabrics use stitch yarns that are half the size of those used in most glass fabrics, so the vertical openings are much smaller. “There is no such thing as a fast infusion of carbon fiber,” Steggall contends. “It is very difficult to achieve the same speed of flow through the depth as across the area.”
Steggall’s own search for a way to speed vertical flow led to a mesh made from randomly oriented continuous nylon 6 monofilament. “At a very small amount of weight — 6 g/m2 (0.02 oz/yd2) or about the weight of two paper clips,” he reports, “the mesh induces flow in almost any type of carbon fabric.” The flow improves regardless of fiber angles (e.g., 0°/90°, ±60°, etc.). When the mesh is attached to each ply of a 300 g/m2 (8.8 oz/yd2) stitched carbon fabric, it creates a channeling effect like that from a 0° oriented uni fabric and the stitching. For heavier 400 g/m2 (12 oz/yd2) fabrics, he uses a 12 g/m2 (0.4 oz/yd2) mesh. “For me, this is the way to achieve permeability in carbon fabric because it provides good strength and toughness properties with only marginally more resin in the laminate.”
The material is now used by Gunboat International (Wanchese, N.C.) in its 55-ft/17m all-carbon-fiber production sailing catamaran. The company infuses the complex hull in one piece, with the nylon mesh layered between each ply of woven and stitched multiaxial carbon fiber fabric. Most impressive, it aids flow in the chine (transition from the hull bottom to the hull side), where 83 plies of carbon fiber unidirectional fabric and 10 plies of carbon fiber biaxial fabric provide resistance to deflection along the inner side of each hull. Steggall says the nylon web provided what the project needed: “consistency in the infusion and wet out at low risk plus 18 percent more energy absorption in impact testing.”
(End quote.)
I’m still in the researching and slowly-acquiring-materials phase of infusion, so I haven’t gotten to try it myself.
Oh yeah, as the owner of a home with some serious floor cracks, I may just try that one day.
Thanks,
Andrew
I’ve drank with him at SAMPE, and know his daughter well. Awesome to see him being quoted here!
note: glass fiber in cement is not good. The cement breaks down the glass. There are certain types of glass used for reinforcements, not your standard E or S. Carbon on the other hand, should work
Vectorply makes a product called micromesh. It does improve permeability between plies and definitely has good applications.