So I am doing my first real pre-preg tool.  The mould I had made for me has had issues........ loads of stress cracks appeared after only a couple of pulls.. Not looking for answers or reasons why that mould has had issues. I got so pissed off that I looked into a dozen different things and all I got was dizzy with each person giving me a different reason.  So I took one I had made and lacquered it to get a good finish and to remove some of the raised areas where the original stickers got left on the tank when it was moulded.  I put it back into the mould and have started to remake the mould using pre-preg carbon tooling. So far it seems to be working.. I have done the top section already and although I have not removed the section from the part the flange areas look perfect and if the rest of the mould comes out the same way I will be happy. Having had numerous quotes to remake the mould for me including a quote from the person who made it in the first place (he seems to feel it is other reasons and not his work that has caused the problem). I have bit the bullet with some Tooling from SHD. 

I will post updates as I go and hopefully in a few days will have a finished working full carbon pre-preg mould. 

1-4-1 is very lightweight 1-8-1 is industry standard 20 plus years

only ever going up I.e 1-10 or 1-12

lot of places don't bother with the last 200g on a 1-8-1 the thinking being on a fairly complicated mould the variation in thickness/overlaps its going to have more Than a 200g differance so its not worth trying to balance it

that and the fact a single ply off 200 isn't going to affect multiple plies of 650

people who sell you a matched 1-8-1 system will never tell you that thou !

Cheers.. It is thin but it is what they recommended and I agree the last 200 gram layer is not going to do much with a 1-8-1 lay up. The glass on the surface layer is to help get the air off the material and I guess help the resin flow. I did try a previous version on some flat sheet to see how it worked but there was some glass visible on the surface when it cured. The new material has not had the same issue with the moulds I have seen so far. The previous version worked perfectly in an autoclave but not so well as an oven cure. This has been developed as an oven cure tooling and looks to be working very well on all of the moulds I have seen and what I have seen so far on the flange faces.