I've just published our latest video tutorial. This is the third and final part of the latest series which now covers the making of a carbon fibre engine cover from CAD model to prepreg carbon fibre part.



In this final video we're using our new XC110 prepreg which replaces the Easy-Preg that we've used and sold for many years. The decision to move away from the Easy-Preg system was a very big one and is something that we've been working towards for a very long time. Easy-Preg worked fantastically and was a great product but there were a number of drawbacks which we hope to have overcome with the new XC110 system. Namely, these were that the Easy-Preg system was limited to a specific surface ply (a 240g 3k) which could not be substituted for any other weight or weave (so finely balanced was a the behaviour of the material) and, to be perfectly honest, the very high price of the material (owing to the difficult manufacturing process).

Therefore, we hope to have achieved a number of things with the new XC110 prepreg:

Firstly, we now have a range of out-of-autoclave materials, including a 3k 210g, a 12k 450g (both of which could be used as the surface ply), as well as compatible unidirectional (UD) material and  an adhesive film. Having such a comprehensive offering means that even the most complex structural projects can be undertaken 'out-of-autoclave'. 

Secondly, by controlling the production of these materials from creel-set to freezer we have been able to significantly reduce the price of these materials so that they now compete with just about any prepreg system, let alone a high performance out-of-autoclave system. Of course, due to the extra admin and overheads of handling prepregs there is still quite a bit extra to pay on very short rolls (1m, 2m etc.) but, as an indication, a 25m roll of either the surface or backing is available from us at around £30 (34 euro, $40 usd) with further discounts available for larger orders. Download our full prepreg price list here.

There are however some significant differences between the Easy-Preg system and the new XC110 system so I thought this topic might be a good place to discuss them and take any questions people have. The most significant differences are:

1. XC110 is far more sensitive on the cure cycle. To get good results it's really important to follow a two-stage post cure with carefully controlled temperature. Full details of the recommended cure cycle can be found in the XC110 Out-of-Autoclave Complete Processing Guide PDF.
2. XC110 doesn't really seem to like vinylester mould surfaces (such as Uni-Mould). Obviously this is a huge disappointment to us because we have previously stated that Uni-Mould moulds can be used to for relatively low curing of prepregs. Although - at a push - the XC110 system can be cured in a vinylester mould it does seem to increase the chances of surface imperfections (pin holes) due to a combination of reaction with the vinylester and the fact that the preferred cure cycle for the XC110 (which finishes at 120'C) cannot be used because the Uni-Mould tools cannot take this temperature. Therefore we now suggest moulds made using either epoxy tooling prepreg or moulds made using high temperature epoxy gelcoat backed up with either high temp epoxy paste or high temp epoxy resin.
3. Bagging method: Better results are achieved with this prepreg system by not putting breather on the back of the release film where it is over the laminate (as can be seen in this video).

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

I have been doing a bit of experimenting with the XC110 in the last couple of weeks, so I'll do a little 'first impressions' write up along with some pictures later today. 

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

In the video you recommend debulking to reduce the likelyhood for pinholes and bridging. The part in your video gets debulked before the second prepreg layer is applied. Would you have done a debulk for the part in your video when the part only would have consisted of one prepreg layer?
I assume that when the geometry of a part is very complex, debulking can be necessary even though one is only using one prepreg layer (with the exception of course being, that there will be many small overlaps in a part with complex geometry).

If there's only one layer then then debulk is done when you bag it anyway... From there there's no reason to remove it from the bag and it can go straight into the oven.

Not very often that you would only do one layer though. Even one layer of the 450g would be very lightweight, let alone one layer of 200g. If you had a very complex mould with only one layer of 200 I'd be concerned about getting it out of the mould without any damage. 

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

I am! But I decided that for the purpose of the post, I should really play around with the material a bit more.

My first impression is that it is super easy to use, and actually more forgiving with vinyl ester moulds than I had expected. All of my current moulds are vinyl, so I'm in the process of remaking them in epoxy, which is the cause for the delay. First few results out of epoxy moulds have been extremely pleasing, but I just want to tinker a bit to get perfect results.

In all honesty, having used the material I can see why Easy Composites made the switch, it's great stuff. I still sort of prefer the tighter pics-per-inch of the EasyPreg, but the slightly bigger weave is growing on me. Otherwise, I like everything about the X-Preg more than the EasyPreg. 

Would it be advisable to construct a sailboat using aluminum to form the female mold? In this scenario a hull would be constructed, including some welds and grinding, then acid cleaned etc. I suppose a wet expoxy would have to be applied to the aluminum surface.  My ideal would be to place a layer of amid honeycomb and then prepeg.

The finished project would have the aluminium exposed to the elements.

We still see frequent delamination of carbon fiber parts on sailboats. Do you think for normal crusing this would not be a worry over a 20 year period?

I find it sad the easypreg is gone after finaly finding the perfect cure for pinhole free parts , and arround 20 moulds of unimold system everyting is now gone to wasted looks .

All big complex moulds some of them 7 part split moulds .
Did  anybody tried it on the unimould and what do parts look like out them ?

And also the  prepreg  mould  mould system looks nice but show us  a complex split mould to see how u work with barriers .
Also how wil u make these moulds from normal glassfibre parts that cant stand the high temps of the prepreg mould system ?