I'm planning on infusing some sandwich panels that will be 1 outer skin of 200gsm carbon 5mm perforated PVC core and 1 inner skin of 200gsm carbon. Will it negatively influence my infusion if I only put peelply on the inner skin (bag side) where I plan on doing secondary bonding? The whole thing would have a layer of P3 film and flow medium on top of it.

are you going for an "A" surface on both sides? if not then just do the whole thing in one shot

No, only worried about the mold side being nice. I'm planning on doing the sandwich in one shot. Stack would be:

mold
200gsm carbon
5mm PVC core
200gsm carbon
peel ply in places that need secondary bonding
P3 release film
flow media
bag film


The bag side will have some areas where things will be bonded to it. I'm wondering if I only put peel ply in the areas that need it if it will negatively affect my infusion by changing the flow rates in those areas.

No not at all, it's totally fine. 

Sorry, I miss read what you intended I read it as though you were going to premake the inner and out skin and bond to the core after.

I don't think having a peel ply or not will make much or any difference to the infusion speed.

With just 200gm fibre on the mold side you need to be sure there are enough holes and/or grooves to let the mold side flow ok.

Is your core drilled or grooved in any way?

The core I'm getting is not perforated but I'll do it myself on my CNC. It seems like industry standard is 50mm centers which would add around 6gms/m2 it seems like bumping this up to 25mm centers would be a good idea as the 24gms/m2 seems like a small hit verse having wet out issues. I'll run a few test pieces later this week.

unless you are going to mill out non standard grooves, just buy the core pre-drilled. It's not worth the time on the CNC.

To some extent my core choice reflects what is easy to get in Portugal. Also, as I have the CNC machine it's not a big deal to have it drill holes.

Honestly, 50mm centres is plenty. How big is the infusion?