I have made smaller moulds with the epoxy tooling gelcoat and epoxy putty. I have experienced that its easyest to put the hole mould in a bag and then do the infusion. 

Yup -- listen to Hanaldo ..

I always smooth off the outside of my moulds ..

then I coat them whit a layer of laminating resin - (Especially the "putty" moulds) that way they mostly become perfectly vacuum tight .. Leak free .. I have one or two that are not "leak-proof", and have too narrow flanges, and what I do to stop the resin flowing to the back, is to add gum strip all around the "too narrow" flange .. I leave the white backing tape/paper on, so the envelope bag can slide on the gum -- to avoid bridging on the part ..

"Sapere Aude"... Dare to KNOW!

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