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carboncactus
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Breather tows are not necessary with VTF, and probably not with the easypreg surface layer, as this surfacing system actually has black glass threaded into it. Any other material, and I always use them:  Me and Wozza will agree to disagree on this one though: I do believe prepreg is more advanced than resin infusion. Mainly because the resins in prepreg are more advanced in their nature. The fact that they cure at a higher Tg and are therefore more viscous, means the curing cycle is that much further ahead and mechanical properties are better. Going further in terms of resin performance, there's a high temp structural epoxy prepreg that Im gonna sample soon which has a Tg of 320C (  ) For it to have those characteristics means the resin in the prepreg is so viscous, its actually in a B stage form. It cant even be handled by hand, it has to be pressed. On the other end of the scale, resin infusion in its nature uses watery, much weaker resins. To get equally performing parts, you have to use more material with infusion, making it heavier. That along with the fact that you can choose any carbon cloth to make your part. With prepreg, the standard modulus for fabrics used are much higher. I do agree that you can probably control the resin ratio used (apart from what lands in the catch pot and what is left in the feed pot, but with prepreg if you want to lower your resin content, you can use a peel ply. You wouldn't want to lower it anymore than that though. An interesting trial was made by Gurit. They made some blades by infusion and prepreg. Conclusion: prepreg blades outperformed infused blades in mechanical properties and production value (20% more blades produced in the same amount of time). Infused blades cost less in materials, although prepreg cost less in labour. Not to diss infusion though. I think its got its place (bonnets, boat hulls etc). Just because I don't do it day to day doesn't mean I wouldn't chose it for a particular job if it called for it.
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morepower
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carboncactus (20/08/2013)
Breather tows are not necessary with VTF, and probably not with the easypreg surface layer, as this surfacing system actually has black glass threaded into it. Any other material, and I always use them: Me and Wozza will agree to disagree on this one though: I do believe prepreg is more advanced than resin infusion. Mainly because the resins in prepreg are more advanced in their nature. The fact that they cure at a higher Tg and are therefore more viscous, means the curing cycle is that much further ahead and mechanical properties are better. Going further in terms of resin performance, there's a high temp structural epoxy prepreg that Im gonna sample soon which has a Tg of 320C ( ) For it to have those characteristics means the resin in the prepreg is so viscous, its actually in a B stage form. It cant even be handled by hand, it has to be pressed. On the other end of the scale, resin infusion in its nature uses watery, much weaker resins. To get equally performing parts, you have to use more material with infusion, making it heavier. That along with the fact that you can choose any carbon cloth to make your part. With prepreg, the standard modulus for fabrics used are much higher. I do agree that you can probably control the resin ratio used (apart from what lands in the catch pot and what is left in the feed pot, but with prepreg if you want to lower your resin content, you can use a peel ply. You wouldn't want to lower it anymore than that though. An interesting trial was made by Gurit. They made some blades by infusion and prepreg. Conclusion: prepreg blades outperformed infused blades in mechanical properties and production value (20% more blades produced in the same amount of time). Infused blades cost less in materials, although prepreg cost less in labour. Not to diss infusion though. I think its got its place (bonnets, boat hulls etc). Just because I don't do it day to day doesn't mean I wouldn't chose it for a particular job if it called for it. . What he said...
Lets face it F1 chassis are not infused and Pr-preg is the material of choice for the highest spec parts.. I wouldn't think I could get my seat/fuel tank down to less than 3Kg and be structural any other way....
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compositepro
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320c TG are you sure its not from Tencate your description of no tack sounds very familiar and we use it at the AMRC If it is you they do BMI's that can go as high as 400c TG
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wozza
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morepower (20/08/2013)
carboncactus (20/08/2013)
Breather tows are not necessary with VTF, and probably not with the easypreg surface layer, as this surfacing system actually has black glass threaded into it. Any other material, and I always use them: Me and Wozza will agree to disagree on this one though: I do believe prepreg is more advanced than resin infusion. Mainly because the resins in prepreg are more advanced in their nature. The fact that they cure at a higher Tg and are therefore more viscous, means the curing cycle is that much further ahead and mechanical properties are better. Going further in terms of resin performance, there's a high temp structural epoxy prepreg that Im gonna sample soon which has a Tg of 320C ( ) For it to have those characteristics means the resin in the prepreg is so viscous, its actually in a B stage form. It cant even be handled by hand, it has to be pressed. On the other end of the scale, resin infusion in its nature uses watery, much weaker resins. To get equally performing parts, you have to use more material with infusion, making it heavier. That along with the fact that you can choose any carbon cloth to make your part. With prepreg, the standard modulus for fabrics used are much higher. I do agree that you can probably control the resin ratio used (apart from what lands in the catch pot and what is left in the feed pot, but with prepreg if you want to lower your resin content, you can use a peel ply. You wouldn't want to lower it anymore than that though. An interesting trial was made by Gurit. They made some blades by infusion and prepreg. Conclusion: prepreg blades outperformed infused blades in mechanical properties and production value (20% more blades produced in the same amount of time). Infused blades cost less in materials, although prepreg cost less in labour. Not to diss infusion though. I think its got its place (bonnets, boat hulls etc). Just because I don't do it day to day doesn't mean I wouldn't chose it for a particular job if it called for it. . What he said...
Lets face it F1 chassis are not infused and Pr-preg is the material of choice for the highest spec parts.. I wouldn't think I could get my seat/fuel tank down to less than 3Kg and be structural any other way.... |
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Warren (Staff)
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Its horses for courses at the end of the day.
Sure no ones doubting that pre-preg parts are the pinnacle of the industry at the moment.
But twice the material cost for something thats maybe 20% stronger and lighter.
Clearly not worth it for most people for larger panels. But it does have its place for smaller, complicated parts where material cost isnt such an issue.
Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant
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morepower
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Warren (Staff) (22/08/2013)
Its horses for courses at the end of the day.
Sure no ones doubting that pre-preg parts are the pinnacle of the industry at the moment.
But twice the material cost for something thats maybe 20% stronger and lighter.
Clearly not worth it for most people for larger panels. But it does have its place for smaller, complicated parts where material cost isnt such an issue.Twice the cost?? Dry cloth is about £20 per sq/m and resin works out about another £5 per sq/m Plus you need pipes and other consumables spiral tube and infusion mesh which is just under £6 per meter and there will be some extra resin wastage in the pipes through to the catch tank. So that is up to about £31 per sq/m plus VAT. Pre-preg can be had for between £36 and £48 per sq/m depending on which material you have and the PRF material is good enough for most people at less than £40 per sq/m.  This is using a pre-preg that cost less than £40.00 per Sq/m and a motorcycle body kit is anything but small... But I have a week to lay up the parts and can take my time getting it all done.  The equipment when laying up is no different to wet lay vac bagging so you can do both for no extra cost... My "oven" cost me £27 for the PID, Solid state relay and sealed electrical box, thermocouple and a £40 3kw fan heater... I can either use simple card board boxes for small parts or a clean garden wheelie bin for larger parts then if you have space you can use Kingspan insulation to make a large oven and only need to get a better fan and some ducting. That would cost about £400 to build and you can still use the heater and controller ect with any oven you build of varying size if you want as it will work with any box. One other thing I would use, but many dont, a remote wireless display meat thermometer to just check the temp of the actual part too... So the set up is a little more than setting up for infusion but there are less ongoing consumables needed and you have parts that are 20% lighter and stronger. The cost of materials is possibly 25% more expensive but when you look at the value of those parts if you are going to sell them many would rather have simple wet lay for cheapness or if they want the real deal only pre-preg is going to get the highest prices.
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wozza
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I regularly have customers asking for parts in pre-preg (which I also do) but when you actually ask them why they want it in pre-preg they don't actually know. They have read on some "go faster forum" that is what they need. Also you failed to add into your costings clear coating your parts against pin holes / UV. If you clear coat after the part is cured then you are only getting a mechanical bond and is more likely to chip and peel off. If you apply something like GC50 into the mould before Infusion then you get a chemical bond and the clear coat becomes integral to the part. I also doubt very much that the average home builder using pre-preg is producing parts 20% lighter and stronger than those using infusion. The real cost saving for manufacturers producing parts from pre-preg is labour cost's, they can use semi-skilled people to "assemble" pre-preg parts using pre cut layers of reinforcement etc as apposed to employing skilled laminators.
Carbon Copies Ltd
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morepower
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Either way, infusion or pre-preg needs some form of clear coat to protect from UV. The time it would take to make one of my monocoque seat and fuel tank units with infusion would make the thing a lot more effort and being a 5 piece mould sealing all the joints and getting resin feeds into the almost blind seat hump would be too awkward. Infusion has its place in really large and less complex parts but it is not half the cost of pre preg.
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carboncactus
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morepower (22/08/2013)
I like that carbon kevlar chain guard / side panel
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morepower
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carboncactus (23/08/2013)
I like that carbon kevlar chain guard / side panel
Cheers.... I did some to see what people think.... Not to popular to be honest... I like them a lot.... But people are wrapped up in wanting carbon.... lol.
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