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morepower
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20_rc51_00 (27/01/2014)
What do you do after a debulk? Do you give everything a last once over and work all the creases/edges? Do you go right into the bake? If you have a thicker layup I'm assuming there is an interval of layers that you debulk between each time correct? Then unbag and lay the next few in there and then rebag and repeat...? At the time of the last debulk do you typically have everything in the bag ready for the oven or do you wait to put in the breather after the last debulk and then throw it all in the oven? I do go over it all again.. you can usually see/feel if it is down fully... I would de-bulk again if I am going to use a lot of layers but even when I only put the backing layers down and going to cook.. I will give it time to de-bulk some more but I dont open the bag again... Usually a couple of hours in the oven at 30 degrees and give it a final push down all over to ensure the bag is pushing down everywhere....
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20_rc51_00
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Group: Forum Members
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What do you do after a debulk? Do you give everything a last once over and work all the creases/edges? Do you go right into the bake? If you have a thicker layup I'm assuming there is an interval of layers that you debulk between each time correct? Then unbag and lay the next few in there and then rebag and repeat...? At the time of the last debulk do you typically have everything in the bag ready for the oven or do you wait to put in the breather after the last debulk and then throw it all in the oven?
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morepower
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If you want to be on the safe side with a debulk you can time your work to have all of the surface layers down just before the end of the day and debulk at ambient temp over night. If you have to debulk during the day and finish the lay up the same day I would do a warm debulk at 30 to 35 degrees for 2 hours.
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20_rc51_00
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fgayford (25/01/2014)
20_rc51_00 (22/01/2014)
http://www.ambercomposites.com/prepreg/out-of-autoclave-prepreg/anyone have any experience with this? I live in Canada and I'm having a hard time tracking down any OOA materials. Anyone have suggestions for anything in Canada or the USA? Alternatively I might have to bit the bullet and buy from somewhere in Europe.... Any other sources would be appreciated. Until now I've been doing infusions but I'm really tired of the whole infusion process and need a change. Its a PITA with the whole layup and then the trimming afterward. Prepreg might just let me cut back on the amount of post production trimming.... Hi Composites Canada in Toronto is now carrying prepreg 3k twill. I tried a sample and got no pinholes. Mind you I did put it in my autoclave at 80 psi. It is very similar to ezcomposites prepreg which I have also used. Its worth a try. They will ship directly to you. Fred Thanks Fred! I have seen your contributions to the forum and your work, thanks. Do you mind if I send you a pm occasionally to pick your brain? I will look into Compcanada Chris, got it! thanks
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ChrisR
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20_rc51_00 (24/01/2014)
Thanks Chris, appreciate the link and tips. I need a change from infusion, the thought of it is daunting to me. And I dread the trimming of mass excess material (because laying fabric perfectly matched in size is just asking for trouble imo). I also get anxiety attacks  about the reinforcement stack shifting during handling or loose fibers on the cosmetic side etc etc... I'm pretty obsessive about bridging, I wouldn't foresee that as a stumbling block for me. regarding the debulking, this is to reduce entrapped air (as much as can be before resin flow/viscosity reduction with heat anyways) and reinforcement consolidation right? How long typically for debulking? when do you know that it's "enough"/ what is the observed end goal?
If you are paranoid now, wait till you use prepreg! I really like the stuff and enjoy working with it. If you are careful then you can offset some of the additional cost of the stuff as you don't have so much waste if you nest the pattern cut outs propperly. Depending on the matrix, some require debaulking under vacuum only for x hours/mins (usually on datasheet) and others require an elevated cure during the debaulk, again see the materials datasheet. The idea is that you consolidate the ply's in stages to minimise voids, bridging and thickness change during final cure plus you can control the resin ratio a bit more closely by bleeding some out if required
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fgayford
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20_rc51_00 (22/01/2014)
http://www.ambercomposites.com/prepreg/out-of-autoclave-prepreg/anyone have any experience with this? I live in Canada and I'm having a hard time tracking down any OOA materials. Anyone have suggestions for anything in Canada or the USA? Alternatively I might have to bit the bullet and buy from somewhere in Europe.... Any other sources would be appreciated. Until now I've been doing infusions but I'm really tired of the whole infusion process and need a change. Its a PITA with the whole layup and then the trimming afterward. Prepreg might just let me cut back on the amount of post production trimming.... Hi Composites Canada in Toronto is now carrying prepreg 3k twill. I tried a sample and got no pinholes. Mind you I did put it in my autoclave at 80 psi. It is very similar to ezcomposites prepreg which I have also used. Its worth a try. They will ship directly to you. Fred
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morepower
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matthieutje65 (23/01/2014)
for me the ooa of easy composites is perfect, nice tack on the surface of the mould...by having it that way it wont lift when adding the layers on top of that...did some test with a prepreg with less tack and I got annoyed while working with it, each time I've added a layer and tried to press it down, it got away from the surface of the mouldThe problem is that is is expensive.... especially for someone in the USA... If there is a Cytec distibutor willing to do smaller quantity minimum orders then it is better if he can do that.. It is the best material but the cost from either easy composites or cytec are now not worth the extra cost if you look at how much it can cost to coat a part especially a large part.. If I used £1000 worth of VTF/Easy Preg or £350 worth of another material which is close on finish that leaves a lot of spare cash to pay to have it sprayed... I have had a full motorcycle kit lacquered for £150.00 making a total cost minus consumables and oven time of £500. It is simple math.... I would use VTF for everything if I could afford it... I cant and I have never paid more than £68.00 inc VAT for VTF but now they have upped the minimum quantity I have had to look else where.. I now pay just over £30 per meter and get great results which is more profitable for me.... I can also get plain weave which I cannot get in the VTF/easy preg materials.. If I can get finishes like this out of the mould... I would do what the OP is doing and shop round and find a material an learn how to make it work for them...  A set of these if I only used easy preg would have cost me almost £100 to make in materials and power.. Using the material I now use they cost me £35 to make.
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20_rc51_00
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Thanks Chris, appreciate the link and tips. I need a change from infusion, the thought of it is daunting to me. And I dread the trimming of mass excess material (because laying fabric perfectly matched in size is just asking for trouble imo). I also get anxiety attacks about the reinforcement stack shifting during handling or loose fibers on the cosmetic side etc etc... I'm pretty obsessive about bridging, I wouldn't foresee that as a stumbling block for me. regarding the debulking, this is to reduce entrapped air (as much as can be before resin flow/viscosity reduction with heat anyways) and reinforcement consolidation right? How long typically for debulking? when do you know that it's "enough"/ what is the observed end goal?
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ChrisR
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List of some prepreg companies supplying USA http://www.compositesworld.com/suppliers/product/294Gurit USA may be of help, it depends how much you need as most prepreg suppliers have a MOQ of 10 or 20m/yrds but also the problem with sourcing from the UK if you go that way is the uncontrolled temperature during transport and duration, if you have a prepreg with an outlife of 7 days and it takes 5/6 days to get there then there is little usable life in it. Amber composites are pretty good, played with a few but usually subject to minimum order quantities, sometimes you can get 2nds quality but "ya pays ya money and takes ya chance" sometimes its just a few inclusions or weave distorsion every so often but other times the whole thing is pretty much junk. When you use prepreg then consolidation/debaulking can make the process more labourious than infusion. You don't always have to use an OOA prepreg, a lot of the time the lower temperature ones such as ambers 8020 and E644/650 are very usable vacuum only. You will also find voids and bridging more common especially on more complex moulds as there isn't the spare resin to fill them, if you don't force each layer into every nook and cranny then you will have more problems.
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20_rc51_00
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THanks, I would assume that too high of tack might reduce the drapability/adaptability into very tight areas if the rest of the reinforcement is already laid down into the mold....too little tack and you aren't sticking to the mold just like you mentioned.
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