How do I stop pull marks?

[blind pig]

You may find that the mould release will come out as a fine translucent layer, bonded to the resin, that will need to be sanded from the surface of your clear resin.

The resin isn't really "sticking" to the surface of the mould, it is curing from the inside-out and leaving a small gap between the body of the resin and the wall of the mould, allowing the last little bit of uncured resin to cure in that small, but increasing gap next to the mould wall.

I'd suggest you have a look at the Product Disclosure Statement (if such exists) for the various clear resins you can get, and find one that has the smallest shrinkage rate when curing.

Normally when using polyester resins to make a model, additives (like fine powdered plastics) are used to decrease the shrinkage rate. You can obviously not use these to make clear objects.

[jontidy]

Yeah that seams like the way forward pig. I was also reading though that a mould release would considerably lengthen the life of the mould (can get over triple the amount of pulls). So maybe the money I would save with the extra life of the mould would outway the little bit of sanding I would need to do.
I'll get searching for a better resin with a smaller shrinkage amount first i think.