Core mat infusion and print through questions

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#1

I am currently working on my first infused products, and I have found that in certain spots I need to add some thickness at mounting points, not really for strength, just due to the way the hardware mounts. Layup schedule is currently 5 layers of 5.7 oz 2.2 twill with 2 extra layers of 2" strips around the outside perimiters. Where the latches will mount to the hood is where I need to beef up the thickness. I am wondering in I use 3 layers of carbon twill, then add a layer of 2mm core mat, then 2 layers of carbon, then another layer of core mat, then the last two layers of carbon, am I likely to experience any print through issues from the core mat, and also am I likely to create any dry spots in the layup by doing this?

As a side question, if I wanted to make hoods for people not looking to spend as much, could I get away with doing one layer of 5.7 oz 2x2 twill and then multiple layers of fiberglass surfboard cloth, with a layer of core mat, and then more layers of surfboard cloth without having print through issues?

Is core mat bad to use with infusion and how much resin does in normally soak up?
Here is my first hood with straight carbon, layup schedule as described above, it weights in at about 2 pounds. I would like to stay in that general area of weight.
Thanks in advance!

#2

Coremat is not suitable for vacuum applications. (although the XM version can handle quite some vacuum).

For infusion you need Soric, the younger sister of Coremat. (both are made by Lantor)

I am not fond of Coremat or Soric at mounting points, I prefer some heavy glass.

I also wonder why you spend so much money on 5.7oz carbon fabric. For the surface, it is OK, but for the inner layers, I would suggest a multiaxial (biaxial) as this is much cheaper per sqft and also per pound.

For cheaper products indeed you could revert to 1 layer of carbon, and the rest glass. Again, multiaxials or cheap woven roving are your friends (financially). Keep in mind though that 1 layer of 5.7oz carbon will shine through, so either use black dyes glass as the first layer behind it, or another layer of carbon, or hand layup the carbon, then infuse or hand laminate the rest of your stack behind, with black dyed resin.

#3

How do you maintain the stability of an open structure with carbon front and glass back. I’ve always experienced warping when doing this…especially if the part is exposed to varying temperatures (CTE differential). I’ve done carbon/glass/core/glass/carbon though without warping.

Does the mounting of these types of parts help prevent warping or is warping not the that important?

#4

Totally depends on the part and on the backing laminate.