how to divide this head sculpt for molding

[giedrius]

What type of clay is the sculpture done in? If it's a water based clay you'll need to fully seal it prior to molding with fiberglass of the resin will not set. The same with your dividing walls if you use water clay they need to be sealed with spray laquer then sealed again with PVA release. You will also need to do a gelcoat layer first because the laminating resin is not used for the first layer contacting the sculpture itself.

My suggestion is to take the advice of seasoned members and use a stone product. Fiberglassing a mold of 3 parts takes more work than I believe you're estimating.

Thanks for advice, i will be making gellcoat first and seal it. as for 3 part mold i have time. i know it will take it a lot of it. as for stone products i just cant afford them. in my country is weird that fiberglass and resign is cheaper then plaster

 

[Dr Know]

The three pice idea that you have will work fine....
Be careful with keys on the flanges of your walls... Some times the keys may end up giving you undercuts that prevent you from opening the mold in an order of preference...

Gel coat works fine... Just be sure to seal your sculpture well...
Personally... I use shellac for water based clay...
Then release it with a few layers PVA ...

Another thing to consider as well... Water based clay sculptures dry and shrink... So if your sculpture is pretty old and dry when you are finished... And then seal it up and start your mold?
It can still shrink a little bit... Especially if heated up. So even with it sealed, mind direct sunlight... And keep the MEK-P for your gels and resins within reason. try not to cook it...
It can shrink after one side of the mold is done... Then when the second side.. Or third side is eventually done.... If it has shrank up a bit it can give you a step on your seam which can be more difficult to get rid of than a wide seam.

If you have no gel coat, you can add pigment and thickeners to the resin it self and use this mud as a gel coat. You do not need gel coat, though I prefer to use it.... And put on some music... Enjoy the process...