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oekmont
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1/4" should be enough. But you should always try to infuse the shortest possible distance. This makes life much easier. And you could have used the gained 30min for something else.
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quinn
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+x40 minutes is a very long time for such a "small" plate. Are you infusing along the shorter length? If so, your resin has to be medium viscosity. Like thin honey. A plate of that size would take me about a minute. I infused the long direction. It was 250mm wide, 650mm long. I assumed my resin was too thick and infusion resin would help with that. It went pretty quick for the first half, like 5 or 10 minutes, then went slower and slower toward the end. I was only using 1/4 inch tubing. Maybe I should use bigger? Also I'm thinking it's pretty likely I must have developed a small leak at some point since I ended up with bubbles in the flow media.
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Hanaldo
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Yeh that really makes more sense to me - it doesnt matter what axis the fibres are on, if it has the fibres going in two directions then its biaxial.
Guess it's just a regional thing. Definitely here in Aus if you order a biaxial expecting +45/-45 then you'll be disappointed.
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oekmont
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Oh, if you meant 0/90 biaxial, then its basically the same as a regular cloth of the same weight.
As far as my understanding goes, every cloth with 2 fibre directions is called biaxial. Most of them are 45/-45, which are also called (at least here in Germany) bidiagonal. There are far less 0/90 biaxials, at least in the shops I use.
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Hanaldo
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+x+xYes, 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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oekmont
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Group: Forum Members
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40 minutes is a very long time for such a "small" plate. Are you infusing along the shorter length? If so, your resin has to be medium viscosity. Like thin honey.
A plate of that size would take me about a minute.
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quinn
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+xYes, 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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oekmont
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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
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quinn
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+xYou can get a perfect resin ratio with infusion. This usually means, that you have to close the feed line before the resin front reaches the vacuum line. Ideally to the right time, that the excess resin barely can impregnate the rest of the part. Alternatively you can close the feed line, and let the vacuum line open, until no more resin enters the catch pot. Both will increase the chances of getting not a perfectly good finish. And the carbon optics are less "deep". If you decrease your resin ratio, you will get a less stiff plate, as the thickness (wich is the major factor for stiffness) decreases. To get the same thickness, you would have to compensate with additional cloth. This will lead to increased weight for the same thickness, but slightly better rigidity. Basically what I said before, but from a different perspective. Ah ok. This panel I just did, the resin was setting up right as it finished. Took about 40 minutes, probably because I'm still not using infusion resin, which i will next time. I did close the feed line a little while before vac line, but as I said the resin was already thickening so I'm sure it didn't pull much out. I think I'll get a bit better results next time with proper resin and also experimenting with other fabrics. grade A finish is not important for these parts so I will let it suck out a fair amount of resin at the end next time. Also I'm thinking when I try using some inner layers of non woven biaxial, it should not only improve stiffness a bit from the non kinked weave, but also I would assume it has the potential for lower resin content. Non woven fabric should have less voids for resin to fill, right?
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oekmont
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You can get a perfect resin ratio with infusion. This usually means, that you have to close the feed line before the resin front reaches the vacuum line. Ideally to the right time, that the excess resin barely can impregnate the rest of the part. Alternatively you can close the feed line, and let the vacuum line open, until no more resin enters the catch pot.
Both will increase the chances of getting not a perfectly good finish. And the carbon optics are less "deep".
If you decrease your resin ratio, you will get a less stiff plate, as the thickness (wich is the major factor for stiffness) decreases. To get the same thickness, you would have to compensate with additional cloth. This will lead to increased weight for the same thickness, but slightly better rigidity. Basically what I said before, but from a different perspective.
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