Bubbles visible in flow media

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Bubbles visible in flow media

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quinn	q quinn posted 7 Years Ago HOT Topic Details
q Group: Forum Members Posts: 155, Visits: 992	Here's a panel I infused 30 hours ago. As you can see in the pics, I have some bubbles in the flow media. Before infusing, I pulled full vacuum and left it for 20 minutes, no vacuum loss. Fully degassed my resin in vacuum before infusion. During the infusion I could see some very tiny bubbles flowing with the resin. Finished the infusion, next morning I could see all these bubbles. Looking through the glass on the finished side, it looks flawless. No voids or bubbles. Probably going to debag it in a couple hours and see how the panel looks. Hopefully bubbles are only in the flow media. So what went wrong? Is it likely I developed a leak somewhere during the infusion? Or I didn't have full vacuum in the first place? My gauge only pulls to 26 but i can boil water with vacuum so it's at least hitting over 29. If I was only getting 29.5 inches or so, would that be bad enough to end up with air like this? Or more likely that it just started leaking at some point? After 30 hours, the bag is still pulled down very tight. I'm also still using regular laminating resin, 600cps, not actual infusion resin.
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quinn	q quinn posted 7 Years Ago HOT Post Details
q Group: Forum Members Posts: 155, Visits: 992	+x oekmont - 9/1/2018 5:06:28 PM Yes, slightly. But but don't think that you might experience a difference. The biggest advantage of nonwoven cloths is a better pressure strength along the fibre. What makes a big difference is the fibre orientation. Do you need the stiffness in multiple directions, or just in one (or two perpendicular directions)? Because if you exchange a woven 0/90 layer with a 45/-45 biax cloth, you loose stiffness along 0° and 90° and gain stiffness along 45° and -45°. The difference gets smaller, the closer the layer is to the neutral fibre (usually the centre of your ply stack. This is why sandwich plates are almost as stiff and strong against bending. If you need stiffness in just one direction, a unidirectional cloth performs best I need strength at 0/90 mostly, but I assumed there should be 0/90 non woven biaxial available right? If not, alternating layers of uni at 0 and 90 should be essentially the same right?
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Hanaldo	Hanaldo posted 7 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	+x quinn - 9/1/2018 5:12:33 PM +x oekmont - 9/1/2018 5:06:28 PM Yes, slightly. But but don't think that you might experience a difference. The biggest advantage of nonwoven cloths is a better pressure strength along the fibre. What makes a big difference is the fibre orientation. Do you need the stiffness in multiple directions, or just in one (or two perpendicular directions)? Because if you exchange a woven 0/90 layer with a 45/-45 biax cloth, you loose stiffness along 0° and 90° and gain stiffness along 45° and -45°. The difference gets smaller, the closer the layer is to the neutral fibre (usually the centre of your ply stack. This is why sandwich plates are almost as stiff and strong against bending. If you need stiffness in just one direction, a unidirectional cloth performs best I need strength at 0/90 mostly, but I assumed there should be 0/90 non woven biaxial available right? If not, alternating layers of uni at 0 and 90 should be essentially the same right? Yes, biaxial fabrics are two layers of unidirectional fabric stitched together with the fibres aligned in the 0 and 90 axis. Fabrics with the fibres aligned at +45 and -45 are called double bias. Then you also get triaxials which have three layers with fibres aligned at +45/-45 and 0 or 90, and quadaxials which have 4 layers on all 4 axis.
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