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RE: Vacuum infusion questions 11 Dec 2013 00:46 #619
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Hi Phil,
700g is correct, it may sound like a lot however due to it's more efficient wetting out of the fibre 60/40 as apposed to 45/55 the other way, and less wastage, if you have 3 layers of carbon you actually end up at break-even on a 1sqm sheet, with more layers from there infusion becomes more efficient on resin. I realise that your application only has 2 layers of cloth but the difference in consumption probably won't be that huge. Best Regards, Paul Statham. Carbon Mods/Easy Composites Unit 39 Parkhall Business Village Parkhall Road Longton Staffordshire ST3 5XA ( +44 (0) 1782 324000 | fax. +44 (0) 1782 596868 : www.carbonmods.co.uk | This email address is being protected from spambots. You need JavaScript enabled to view it. From: Philip Lardner [This email address is being protected from spambots. You need JavaScript enabled to view it.] Sent: 14 November 2011 11:33 To: Paul Statham Subject: RE: Vacuum infusion questions Hi Paul, Thanks for the reply - very useful info, and just what I was looking for. I'm a bit surprised at the estimate for the amount of extra resin taken up by the flow-mesh layer - is 700g/sqm really correct? It seems a lot - and very wasteful! Given the area I need to infuse and the resin I'll be using for much of the project (expensive stuff) I may have to rethink my plans and stick with wet lay-up vac bagging. Thanks, Phil Lardner. From: Paul Statham [This email address is being protected from spambots. You need JavaScript enabled to view it.] Sent: 11 November 2011 09:28 To: Philip Lardner Subject: RE: Vacuum infusion questions Hi Philip, Thanks for your email and sorry for the delay in getting back to you. I was checking through some old emails and noticed that I hadn’t replied to you on this. it sounds like a very interesting project you have there. you should only run the mesh of the reverse side, you will come across a few issues trying to run is against the tool as well. you will need to drill (or punch) the foam to get resin flow to the tool-side, I would recommend 2.5-3mm holes every 20mm in the foam this should allow reasonable flow-out into the fibre. you can run peel-ply against the tool no problem so your stack would look something like this: Bag Mesh Peel-ply Carbon Drilled foam Carbon Peelply Toolface Calculating thicknesses and consumtion is quite easy. Generally resin infusion (VARTM) will produce a thickness that in millimetres is 1.25 times the cloths weight in KG so a 200g cloth is 0.2kg, which means, 0.2 x 1.25 = 0.25mm in thickness. Here’s a quick outline of the approximate laminate thicknesses of the most popular carbon fabrics. 1k 90g – 0.11mm per layer 3k 200g – 0.25mm per layer 12k 650g – 0.8mm per layer Resin quantity; With Resin infusion you are normally looking to achieve a 60/40 fibre/resin ratio, this means for every, say, 100grams of cloth you will need 66 grams of resin, all of the reinforcements are listed by weight e.g. carbon fibre 2/2 twill 200gsm, the 200gsm refers to the actual weight of the fabric in grams per square meter, so 1 square meter of this cloth will need 133g of resin to achieve the 60/40 ratio. You also need to account for the amount of resin used by the mesh which is 700grams per square meter of laminate, regardless of thickness. Another 100grams of resin will be required by the feed lines and in the bottom of the feed jug. Here’s an equation that can be used for this; Quick reference chart for resin consumption in infusion; Number of plys of 200g cloth 1 2 3 4 5 6 7 8 Area Of Part In Square Metres 0.1 183 197 210 223 237 250 263 277 0.2 267 293 320 347 373 400 427 453 0.3 350 390 430 470 510 550 590 630 0.5 517 583 650 717 783 850 917 983 0.75 725 825 925 1025 1125 1225 1325 1425 1 933 1067 1200 1333 1467 1600 1733 1867 1.25 1142 1308 1475 1642 1808 1975 2142 2308 1.5 1350 1550 1750 1950 2150 2350 2550 2750 2 1767 2033 2300 2567 2833 3100 3367 3633 2.5 2183 2517 2850 3183 3517 3850 4183 4517 3 2600 3000 3400 3800 4200 4600 5000 5400 I hope this helps, Best Regards Paul Statham. Carbon Mods/Easy Composites Unit 39 Parkhall Business Village Parkhall Road Longton Staffordshire ST3 5XA ( +44 (0) 1782 324000 | fax. +44 (0) 1782 596868 : www.carbonmods.co.uk | This email address is being protected from spambots. You need JavaScript enabled to view it. From: Philip Lardner [This email address is being protected from spambots. You need JavaScript enabled to view it.] Sent: 08 November 2011 12:30 To: This email address is being protected from spambots. You need JavaScript enabled to view it. Subject: Vacuum infusion questions Hello, I need to make a number of large composite foam-cored panels using vacuum infusion rather than wet lay-up vac bagging. The panels will be made up of 5mm closed cell PVC foam board (cut to various shapes) with a single layer of carbon on either side, wrapped over at the edges. My question is - do I need to use a layer of infusion mesh on both sides of the panel/stack or just a single layer on top? It is not important that the completed panels have a polished finish - in fact a peel-ply finish is preferable as other parts will be bonded to the panels later. Stack #1: Vac-bag film Infusion mesh Peel-ply Carbon cloth 5mm Foam core Carbon cloth Work surface/table top or Stack #2: Vac-bag film Infusion mesh Peel-ply Carbon cloth 5mm Foam core Carbon cloth **Peel-ply** **Infusion mesh** Work surface/table top Second question - is there a way to calculate (or just reasonably estimate) the volume of epoxy mix required to infuse a given area of carbon cloth? Thanks, Phil Lardner. |
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