It does appear to me that themajority of your problems are caused by bridging. What that means is that the fabric or the baggingstack is not pressed firmly into the corners and curves on the mould in someplaces. So you end up when doing the infusion having the carbon fabric liftfrom the surface meaning you end up with the resin rich corners and edges as inyour photos. In some cases you even getlarge voids in the resin.
The good news is that bridging is one of the most common issues withinfusion and bagging in general and that it can be solved with a littlepractice and improved technique.
The solution to the problem is to take lots of extra care around thesedifficult areas. When you put the carbon fabric down against the mould surfaceyou should carefully press the material into any tight corners very carefullyand thoroughly. Be careful not to distort the fabric too much as it may ruinthe cosmetic finish. Some times it maybe easier to use cut lines or more than one piece of carbon for certainprojects.
A material that may work very well for your project is our ProFinish Carbon Fibre 2/2 Twill. It has a special resin coating on the back tohelp hold it together meaning you can cut it with little or no fraying and have neat and crisp cut lines and materialedges. It is slightly stiffer than thenormal fabrics but for the shape of your part it would be a good product to use. You could make a paper template in the same way you would draw out atemplate for a cardboard box on paper. You would only need the ProFinish fabric for the surface layer and coulduse normal fabric for the rest. Just becareful to ensure the backing layers don’t have cuts all in the same place asyou don't want to create a weakness along one edge.
Next, be very careful with the peel ply, perforated release film (if used) and the infusion mesh. Create wrinkles and folds of material in thecorners which will ensure that there is no way the peel ply can cause abridging problem. The mesh can be cut up into simple to manage pieces for thesame reasons.
Finally, when you put the bagging film on, ensure that you have plentyof bag available, again, especially in the corners. You can't really have toomuch bag so if you are struggling to get it right, make the bag massivelyoversize, get the part infusing nicely, then next time you can adjust the bagsize now you know exactly how much material you need. Position wrinkles andfolds on the inside of the corners to ensure that there is plenty of bag thereand that it cannot become tight and cause a bridge. Then, when you connect thevacuum be careful to pull only a small amount of vacuum and then position thebag in the corners, pressing firmly to ensure it is pressing hard against thefabric and the mould (and not causing a bridge). Then pull a little more vacuumand again position the bag, pressing firmly and ensuring that there are nobridges or tight areas. Repeat the process several more times until you are atfull vacuum pressure. If, at any point, you suspect there may be a bridgeunderneath the film then you should stop, let more air back in and repositionthe bag before you start to increase the vacuum pressure again.
If you follow these steps then there is no reason why you can’tachieve a perfect surface finish even around some very difficult contours. It’sworth remembering though that there may come a limit, with particularly sharpcorners or really difficult shaped moulds where vacuum pressure alone is nevergoing to be sufficient to produce a perfect finish, even with the best baggingtechnique. This has only happened to us on a couple of occasions, making somevery difficult shaped parts and really the only solution is to either do someslight repair work on parts like this afterwards or to avoid themaltogether.
Warren PenalverEasy Composites / Carbon Mods - Technical Support Assistant