Transmission tunnel top, quantities used

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This is probably dull for any reader out there, but I just wanted to keep track of materials used for the tunnel top.

I mixed 300g of resin and 90g of catalyst at 40C (I put the mixing pot in a simple ban-marie), and then put it in the degassing chamber for 20 mins – it hadn’t finished but I was paying attention to the fact that I had the resin quite a bit hotter. It’s definitely like runny soup at this temp. Interestingly when you mix the resin at temperature, it degasses naturally much quicker, so there was a lot less foaming in the chamber – just some polite bubbling.

So, after the infusion, I had 45g of resin left. I’d also left the tap open for 30s after I’d closed the vacuum (a Warren tip) to make the part slightly resin rich to enable a better facing surface, and to have a slightly thicker layer in case I want to do a little polishing.

My rough calculations are that I’ve used are:

  • 300g of resin consumes a volume of 250ml
  • 0.3125 msq of 350g 2/2 twill carbon – weight 109g
  • 0.3125 msq of 200g 2/2/ twill carbon – weight 63g
  • 345g of resin comsumed – it’s not all in the part – the tube volume alone will account for 12g, and the peel-ply and flow-mesh absorb lots and lots of resin, as do the infusion spirals, etc.

    • So, crudely 550gsm (in two layers, which means more holes) consumes 1.06KG of resin, per msq. The actual weight of the remaining part will be a lot less than that. The larger the part, the smaller the ratio of resin wasted in consumables.

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