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gnidnu
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I'm having trouble with this partly double sided infusion. This was the most recent try. Layup: (Mould Side) 200 g/m² Glass Twill Weave 300 g/m² Carbon Biaxial +-45° 300 g/m² Glass Biaxial +-45° 400 g/m² Glass Unidirectional 0° 10 mm Gurit Corecell M80 Foam, Perforation Grid 2mm / 20 mm 300 g/m² Glass Biaxial +-45° 200 g/m² Carbon Unidirectional 0° 200 g/m² Carbon Unidirectional 0° 300 g/m² Carbon Biaxial +-45° 160 g/m² Carbon Twill Weave 78 g/m² Glass Twill Weave MTI hose on left side, feed line on the right. Can't measure absolute pressure, but relative pressure was -0,93 Bar. Resin was degassed until no more bubbles were visible. Didn't turn out well. It looks like the flow front on the A side was significantly slower than on top, which resulted in complete dry spots. |
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Hanaldo
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Yeh that's a hugely thick laminate for infusion, especially when it is 95% uni. You would need to slow the infusion right down, and I would probably double up on the infusion mesh.
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ajb100
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As above, that's a large stack to be working with, slow the resin right down and give it a chance to soak through. Resin doesn't flow vertically through ud/borax as well as woven fabrics so that won't be helping
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ChrisR
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As mentioned, that's quite a thick stack, slow that sucker down. Do a test infusion, the same stack, the same length but less width, lay up on a sheet of glass so you can see the mould side during the infusion. During the infusion mark the top and bottom with a marker pen every few seconds, that way you can see how the resin is flowing afterwards. For a stack that thick with so many layers I'd think you'd need to keep the vac on before infusing for at least an hour to make sure all the air is fully removed. I've not used MTI but have read loads about it, I think in your case you need to loose it and work on the inlet/outlet positions using regular methods i.e. stopping the mesh before the outlet, just having peelply. I have seen at a demonstration a 25thk solid layup laminate infused without MTI. edit: just looked at the attachment, sorry but WOW thats a really massive waste of materials for such as small finished product! I thought the whole mould was the finished item!
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Warren (Staff)
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As already said, UD and the overall thickness is slowing things down. The core will also slow things down. Therefore you must slow your resin down and if necessary use a slower hardener to give you a usable pot life.
Biaxial cloth infuses ok when done slowly as there are still some gaps, pure UD is very hard to infuse.
Cutting down the excess fabric will save you a lot of material waste and resin waste. Also it means the resin has less distance to travel which is always a good thing.
Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant
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gnidnu
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Thank you all so much for your replies, really appreciate your advice. 
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Hanaldo
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Jeez, and here I am tossing up between cutting my fabric at 600mm and risking not covering the entire part or cutting it at 610mm and wasting excess 
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deagrateful
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Maybe I can help as I've just been infusing a chair core which is a 7mm hit in one go (650 gms CF either side of several layers of quadaxial e-glass). Use a slow mesh and make sure you allow the resin to continue into the part for a while after it's reached the MTI hose. For me (on a 1.5 m2 360 degrees shape) the part wet's out in around 45 mins but isn't at a reasonable VF for a cosmetic part until about the 3 hour mark. This is with a very slow mesh/ silicone peel combination (Compoflex SB RF3). This seems to work every time now but the first time I was having issues like yourself. Let me know if I can help at all! Kris
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Hanaldo
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3 hours!? How long is your pot life??
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deagrateful
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Nearly 10 KG of resin goes into the part. 2/3 of this is infused fairly quickly and then a second batch is mixed up and lasts until the end of the infusion. Pot life in my workshop (18 degrees) is around 2 hours (xtra slow) assuming I don't heat the resin. If the resin is warmed and the viscosity reduced then the infusion is sped up, but at the cost of a shorter pot life. I also use 2 seperate large containers to feed the resin which obviously helps to avoid any sort of exothermic reaction.
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