Sorry not the best of pictures but hopefully gives an idea of soda blasting.

Warren

Carbon Copies Ltd

Warren, luckily I have already made the full size pattern oversized on the width (by about 70mm) so hopefully that will be enough to run the lines as you've suggested and still have the desired chair width. Unfortunately there isn't a taper so I will be replying on a happy release after driving some air wedges in the gaps!

Did quite a bit of head scratching over this last night so please excuse the long reply

I would be almost making this into two infusions, top and bottom if you like. As adding flanges in the normal manner will give you release issues the only thing I could come up with (not sure why it took me so long) was to just make the full size mould 100mm or so wider than the finished chair width. That way you can keep the spiral and hose connectors off the finished laminate.
As you have done I would run the spiral a full 360 degrees around one edge, but have two resin inlets one on the top side of the chair and one on the bottom side (hope that makes sense). Then place a vac outlet directly opposite each of these. By having the wider mould. you can now place these on the laminate rather than on the sides.
This will give you a direct air path for the vacuum preventing the lock off we talked about.
If one side for some reason infuses faster than the other you can clamp that resin feed off until the other catches up. The same goes for the vac outlets.

One thing I would be worried about on the full size version would be release, that's a lot of surface area gripping the mould The thicker you go on the laminate the less flex you will have helping the release. I know this suggestion would mean more work making the mould but if you built in a very slight taper
(across the width) I doubt this would even be noticeable to the naked eye on the finished chair but would greatly help the release.

As for surface finish, soda blasting gives a rather nice matt/frosted finish to carbon. I use it to make chess boards. Mask off the squares with gaffer tape, soda blast, remove the gaffer tape and you have a contrasting gloss/matt chequer board pattern.
A bit of artistic masking and you could end up with some interesting effects.

Hope that makes sense and helps a little, Warren

Carbon Copies Ltd

My favourite thing about infusion is its possible to very accurately calculate your resin requirements. If you work out the size of your part in square metres, then you can work out how much of each material you need to cover the part. Then you know the weights of each fabric you are using, so you can multiply the fabric weight by the total area and then divide that number by 1.5 to get a 60/40 fibre to resin ratio. Then infusion mesh uses 700g of resin per square meter, or Soric uses 550g per square meter per millimetre thickness. Add 100g resin to allow waste for the hoses and bottom of the cup and you're set! 

Hi Warren, that all makes sense, I hadn't realised that it was possible to over infuse by that much (I had assumed that the resin would just stop flowing when the cloth was fully saturated for some reason).

No apologies needed its all part of the learning curve not an easy part for your first go. Soric will generally have a slower infusion rate than flow mesh. This can be a good thing, allowing the cloth to fully wet out eliminating pin holes.
The key is getting the resin front to travel evenly across the laminate. That way the resin should reach the vac outlet without leaving some parts lagging behind. If this happens you can end up leaving the feed line open whilst it catches up, result being a resin heavy laminate.
Ideally you want to be clamping off the vac line as soon as it starts to travel up the hose 50mm or so. Leave the feed line open a further 10-20 seconds depending upon the size of the part.
How/wear did you place the spiral, inlet and vac connectors? You may find you need multiple feeds and vac points to get an even infusion.
When not using flow mesh it is possible to get parts of the bag that are not under full vac, the bag can lock itself off if that makes sense.

Warren

Carbon Copies Ltd

Thanks for taking the time out to help me with this guys, your advice is absolutely invaluable.

Have to agree, looks like it's way too resin rich. So much so that the bag has gone very slack. That would account for the uneven surface, creases and the groove left by the spiral. Soric certainly doesn't collapse under vacuum. It should be perfectly possible to achieve the peel ply finish your after. I know this is a test piece but the position of the spiral won't have helped.
With the spiral on the flange the infusion should be much better, even with flow mesh without the Soric. With the flow mesh on top of the peel ply the surface finish wont be affected.
As others have said, very nice design

Warren

Carbon Copies Ltd

Missed this, nice design