After that I did waxing on the surface. It helps to come off from the matrix which I will finally make. Normally, we need to do waxing around four times to six times. (I did six times for my half model) Also, we need to wait awhile for drying before spreading next wax. Actually, there were two kinds of wax in our workshop. 'TR 108 Basic Mould Release Wax' is that I used for coating my plug. 'Honey wax' is another one http://www.specialtyproductsco.com/specialty/Paste-Wax/Honey-Wax%C2%AE/flypage.tpl.html.
Two of other students who used honey wax, did not use PVA film liquid. It has a silicon additive so it prevents PVA
We have to make one more layer with PVA (Polyvinyl acetate). I put the PVA liquid thinly with an edge of sponge. It needs 30minutes to an hour to dry. 
The next step was gel coating. For progressing this job, we need M.E.K.P as a hardener. The ratio of M.E.K.P to resin is between 1.5 to 2%. I used 700g of gel coat and I put 11ml (approximately 1.5%) of MEKP.
Once mix these two liquids, we should start working immediately. It does not take long time to be solid.
With an air brush, spay on the surface gently. Put sufficient amount of gel coat (between 0.75 to 0.5mm) especially the edge part because it might be cracked during the demolding proceesing.
I waited around three more hours for letting then dry.
The final stage was making the matrix with 'fiber stitchted rovings' and 'chopped strand mats'. I prepared 500g of Polyester and 2% of M.E.K.P (10ml). My group and I had to work quickly because the resin also becomes hard in a little while. At the first, filled all of edge part with fiber stitched rovings to make a clean out line. Then tore the chopped strand mats and pasted them onto the plug. Once the chopped strand mat is wetted by Plyester, it becomes limp. With a brush, sticked them nicely and get rid of all air bump with a compression roller. 
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