use too much bag rather than too little.  You will spend on a mould that size probably a good hour or more getting it drawn down under vac and getting the bag in all the nooks and corners. Youll spend ages moving round the folds to move the bag where you need it and then manipulating it to ensure you dont get bridging on the corners.

A hint is to cut the bag on a soft surface or something you know is 100% free of contaminates or sharp edges as the last thing you want is to transfer the bag material to the mould and later find a hole in it!!  Its annoying having a leak on a small mould let alone a giant one.

If Matt has recommended that layup then you should be fine.  Remember its not a flat panel, its a complex shape with curves and corners, which will all add rigidity. Plus you will get loads more rigidity where the soric is used.   Some complex shaped small trim panels ive done in my car only used 2 layers of 200gsm and they were pretty stiff and plenty stiff enough for a trim piece.

An example of how a curved shape massively adds stiffness:


thats half a brake resevoir and its 3 layers of 200gsm resin infused. And im a fat knacker and it didnt break or crack in any way.

what about the peel ply... can that be baggy just making sure it covers and has no voids... or does it need to be tight like another area of carbon.

pics of progress last night

spoke to matt and he gave me the same advise... the bag is massive, I pulled a vacume yesterday but after it got close to full vacume the bag burst so I scrapped it and went over the mould rear again and found some sharp areas were it could have been pieced... it looks like it bust on a few of the bolts despite being covered (well mostly lol) so I have taken them out one at a time and fitted much shorter ones and recovered...

With the fact you have soric and mesh, you shouldnt have problems with the resin not wetting out as the soric will help it flow through the carbon.

Also its such a large mould that the infusion could well take well over an hour so plenty of time for the resin to wet out as it goes and plenty of time for you to fiddle and adjust resin flow if theres any areas of concern.

Just out of interest, how have you sealed between the mould parts? or have you envelope bagged it to avoid any leak through issues?

I've enveloped bagged... not gone well, spent all day chasing leaks, I missed a few sharp edges on the rear of the mould, had another couple of deep recesses on rear burst and after 6hrs on it and getting close I could hear a very slight leak on the inner mould in the impossible to rear area so gave up.

You could try taping some breather fabric or similar over the joins on the underside where any potential sharp edges are.

The problem you have with fibreglass moulds, is it only takes one shard poking through to burst a bag. Although one tiny glass strand alone may not cause a massive leak, as the bag pulls it can tear the hole bigger. Hence why you need to spend a bit of time after cutting the edges going over the underside of the mould as well to check for sharp bits etc.

You will get there eventually!

i had the same problem with my first split mould, i had some advice from here to say that he used silicone bathroom sealant on the joining flanges before bolting them together and got a perfect seal, it also rubs off after easily. the problem i had was where ever the bag was between the mould and the soft faced tressle it would have a hole

going well though andy watching with interest