I don't think it's pikey at all. I do virtually the same thing, except I only use single pack aerosol can high build primer. Then flat it back with 400, before going through the grits to 2000 and then polishing as standard, then wax and spray PVA. The high build doesn't polish up to a nice gloss, but for me it's about the surface porosity.

I dont wax it.  I go straight in with the PVA.  It does coat primer really well to give a nice smooth finish

p120 is a harsh grade to start with.  It will leave some very deep scratches which will likely be difficult to completely remove later with the finer grades.

120 harsh! No kidding, it took me ages to get rid of the scratches.

Does it matter if you use straight strokes or a circular motion when sanding? I wasn't sure how I would know when the previous grit marks were gone without changing the direction I was sanding so I used straight strokes and changed direction each time.

It's better practice to do random directions, but to be honest I think that is more for professional spray painters. When I sand, I do random strokes where I can but otherwise just sand in the direction that is comfortable, for example sanding in corners etc.

Generally try and use the least abrasive paper you can get away with.  You will quickly see if the deeper scratches are coming out or not and if not, go to something a bit coarser.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Thanks for the replies guys, I've been sanding it for a while and am happy to carry on.

Sooo, next newbie question is about PVA.
I have it sanded nice and smooth and waxed 5 or six times so it is gleaming and then coated with PVA. Unfortunately I don't have a suitable spray gun yet so had a go at wiping the PVA on with a cloth. Now my lovely smooth part is rough and bumpy with the PVA and I am concerned the roughness will transfer to the mould.
Am I right to be concerned or will the heat from the gel coat curing smooth it out?
Should I remove it and wait until I get the spray gun? If so what size nozzle do I need for PVA

Sorry for the daft questions but I don't want to make a stupid mistake at this stage and loose a lot of materials and time.

Yeh that's the curse of PVA. That roughness will be transferred to your mould and will totally undo all the work you've put into it. It is apparently possible to wipe on PVA and get a nice surface finish, but I never managed to achieve it. Spraying is the way to go, I suggest washing it off and waiting for the spray gun.

As said above.

I'd emphasise the need for the dust coats.  The fine covering gives the film coats something to grip so it doesn't run off.  This is why I spray it directly onto primer as the primer is a good substrate for it to grip too.  I use a 1.2mm nozzle, a 110 aircap and I run at 2 bar.  Spraying it this way gives me a fantastic finish on the plug and then in the mould.

I have successfully used fine-pored household sponges to apply PVA. These sponges are white and a little harder than the kind of sponges you use in your kitchen sink. Put some PVA solution onto the sponge and wipe it onto the mold. Just once, don't play around with it while the PVA dries. The PVA self levels and produces a uniform film thickness. Beginners usually overestimate the amount of PVA required, only a very thin layer is required.