Today I tried pressure moulding some Harriette rudder shafts. I learnt: that carbon cloth is a lot more difficult to handle than glass cloth; after setting up the pressure bag it is not a good idea to try and unseal it to let out a bit of air when one's hands have got some talcum powder from the gloves as it makes it very hard to reseal; also if things get sticky with resin the tacky tape doesnt stick as well; when taking apart the mould to re-seal the bag and then putting it together again, it is important to make sure the end plates are put back in before repressuring. I managed to hold about two atmospheres for a while before the bag blew, so hopefully it will be good enough for a Harriette rudder shaft. If not, it was worth it for learning the mistakes before the Harry shaft.
Things that went well: the wet out machine worked a treat, though only a couple of pieces of tow at a time to be able to pull through the guides with enough pressure to keep the resin ratio down ; the kitchen scales made it easy to get accurate mixing; the mould worked well and with different inserts can be used for a number of different sections including Harry rudder shafts, beam corner rods, and mini beams. Larger sections would probably be easier as there would be a better match between the pressure bag and the mould and there would be more space to work. In the larger sections I am thinking that the outside and inside cross fibres in glass would make it easier to control and just have the inner cross fibres in carbon.