how to divide this head sculpt for molding

giedrius

Active Member
Hello,
i want to make a fiberglass mold for this head sculpt and cant decide where it would be best to make separation lines (it will be for latex castings)
577149_563437097014407_1848478854_n.jpg

i was thinking making ether 2 part or 3 part mold
 
It's hard to tell without seeing all the angles of the sculpt, but I would go for something more like this (Red Line)

577149_563437097014407_1848478854_n_zps39e5ff88.jpg
 
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IMO, neither of the two pictured.

If you want a latex casting from the mold. I believe that it is best not to have a seam line running through the face. Separate the figure front to back and have the seam on the side.
 
i was thinking about making seam line on front because there is bump that i would be able to somehow sand down and on the chin and neck there are folds that would hide the seam
 
As said above your best bet is a dividing line down the middle which will leave the face as one piece and do the back as 2 pieces making a 3 piece mold. Also if it is for latex, why are you using fiberglass? Hydrocal would be an easier, more effective option for latex castings.
 
plaster is just too expensive for me, i tried once for same head skulpt making 2 part mold out of plaster and it was just too expensive for me and as a result of that i didnt use enough plaster and whole thing crumpled to pieces. as for ultracal i cant even inport it in my country.
 
I dont think your gonna have much luck with fireglass if you want latex castings, it's not pourus so you would have to pour it and empty it to build layer by layer and something that big will take forever to do until it becomes strong enough to hold it's own shape with out a foam layer added.
 
I would do side to side in the center of the sculpture. Not down the middle of his face.. That will ruin the sculpture, regardless how well your patching and sanding skills are. It will be noticeable in latex. keep it two parts by the way. It will save you sometime in molding as well as seaming.

If you do cast in latex, it will take sometime to get the casting. As stated before, you'll be building it up in layers.
If you have silicon, I would use that over latex. Cause it will be easier to cast.

Cool sculpture!

one last thing, do your dividing wall and mold the back half first. Then if you want, lay it down and do the front half. But if its fiber glass. you can do the sculpture standing upright.
 
I am a little confused: You want to do a fiberglass mold due to the expense of plaster being too high? Did I read that correctly?

Fiberglass + Resin + brushes = Expensive

Hydrocal = $10/50 lbs

If cost is an issue, plaster is the way to go. It is also easier to cast the latex into, due to its porosity. You must brush multiple layers into a fiberglass mold, and use a heatgun in between coats to dry the layers. It is very time consuming.

Your call
 
Plaster is the cheapest mold material in existence. Even No. 1 Plaster (plaster of paris) will do in a pinch if you reinforce it with burlap or something along those lines. On a BIG mold i maybe use 50lbs which isnt expensive at all. Total mold cost to me is usually 15 bucks all said and done and works sooooooo well with latex. I use hydrocal for latex molds and ultracal if I'm going to bake them.
 
whell in my country plaster used for ceramic casting, it is very fine and receives details realy good cost arount 10$/2lbs, and regular plaster that is very course and used in indoor fixing for wals and stuff like that cost 5$2lbs. as for resign it is much cheaper compared to plaster 1liter of resign (polyester) +fiberglass 30g/m^2 + bruses would be less then 15 dollars.

and i am very poor master degree student so i cant afford buying 20kg of plaster and making mold from it, but i can afford fiberglass.
 
I don't have any experience with making either type of mold, but The Mad Masker just recently made an asari head mold with fiberglass (to make latex casts) and her casts came out great. She said that the latex takes longer to cure than in an ultracal mold, but her preference for that particular mold was to have it lightweight, so the longer cure time was worth it.

http://www.facebook.com/TheMadMasker
 
Have you tried any dental supplies? All you really need is a hard plaster, which dentists use when they take an alginate mould of your teeth and cast a plaster copy. Try the phone book, or even speak to a local dentist, he/she should be able to point you in the right direction.
 
Fiberglass resin or Epoxy resin molds are great, no discounting that and they allow for a much higher number of crisp pulls, but as stated, brushing in and letting dry between layers can take days to reach the desired thickness.

The reason the industry uses these type of molds is to create a perfect latex skin on something before running foam latex behind it. That involves stippling in a layer that is super thin but guarantees you a pimple or pock free skin, never see or heard of it being done layer after layer for production pieces.


Time and Money are big factors in fiberglass and epoxy, and to assure your best possible level of detail pickup, you should always use gelcoat, which adds to the expense further.

You just can't beat stone! Its cheap, its forgiving, its easy, and you can slush in it and walk away for a couple hours, come back, pour out your latex, and let it dry, pull your mask and your ready to trim and paint, you didn't have to spend an entire day brush, heatgunning and breathing that crap .

In reference to MadMaskmaker, her sculpt was not a full head and face, so that leaves so much more room for molding than full head does. Plus I'm guessing Steve who is a god of mask masking, may have given her some good advice to follow.

The main reason she could have gone with resin molds is the option to run silicone, which would have given her piece thinner edges and a translucency that would have helped bring her piece to life.


That is the only reason I would suggest resin molds for your creature, silicone could bring it some options that latex does not, but its unnecessary, expensive and since time is of the essence for you on this, everything you need can be accomplished with stone molds and an amazing paint job.

Side note, one thing the resin molds with brushed latex does give you is less shrinkage of the latex and a little stronger crosshatching of the fibers, and the only time that could matter is in a piece like a batman cowl or facial prosthetic that will see lots of stress and reuse.


My vote is the entire face up to about the edge of the jawline/ear where the undercut begins for the first half of the mold, a second piece for the rest of the top of the head, then split the left and right sides behind the ears to the tip of the crown. This keeps the undercuts working for you and though it may add a seam or two extra to clean up, will yield you the best possible places to have those seams, so you can burnish them down or fill them in with cabopatch.

Best of Luck!! Get on it though, July is comming up fast!
 
Thanks everyone. i still think of making mold fro fiberglass with polyester resign. but decided to take on BATS's suggestion about separating lines and leave face as single piece, separate carapace as one piece and make back of head into two pieces.

i only need to make 2-3 pull (maybe sell 1) from this mold to be even on amount of money invested in it.
im currently making whole set of armor for this character so waiting till latex drys wont be wasted for nothing
 
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.
 
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