Simple Mold Making

Mike Privett

Prop master for Horrortrail.com

Disclaimers

� Copyright is a legal concept, enacted by most governments, giving the creator of an original work exclusive rights to it, usually for a limited time. Generally, it is "the right to copy", but also gives the copyright holder the right to be credited for the work, to determine who may adapt the work to other forms, who may perform the work, who may financially benefit from it, and other related rights. It is an intellectual property form (like the patent, the trademark, and the trade secret) applicable to any expressible form of an idea or information that is substantive and discrete.

� In short, don’t copy copyrighted materials.

Disclaimers

� These materials will deface, destroy or permanently alter clothing, jewelry, skin and possibly internal organs

� Use appropriate safety measures whenever using these materials

� Read and follow all manufacturers guidelines and directions

� I am not responsible for any damage to property or health as a result of using these products by you or any other party

Safety Equipment

� Nitrile or vinyl gloves

� Eye protection

� Clothing

� Respirator

Mold Compatibility

� Use solid molds to cast flexible casts

� Use flexible molds to cast solid casts

� Latex and platinum cure silicone will inhibit curing

Examples

� Plaster Mold� Latex casting, Silicone casting, Neoprene casting

� Silicone Mold� Plaster casting, Casting resin, Foam

� Latex Mold� Plaster casting, Casting resin, Foam

� Alginate Mold� Plaster casting, Silicone casting, Cement casting

Sculpture

� Any medium will work

� Some don’t play well with others

� Sulfur clay and silicone

� Watch for mechanical locking

� Watch for undercuts

� Armature issues

Material suppliers

� Professional grade material

� Excellent materials to create long term and production level molds

� Not what this presentation is about

Our materials

� Plaster

� RTV Silicone

� Latex

� Alginate

� Most are interchangeable as a casting compound

Plaster

� All kinds

� Advantages� Cost

� Detail Capture

� Disadvantages� Weight

� Breakability

� Of the mold and you!

� Useable as a casting medium

Danger!!!

� Never life cast in plaster

� The chemical reaction that cures plaster results in heat

� Heat can be intense enough to cause 2nd

and 3rd degree burns

Types of mold making plaster

� Ultracal 30

� Hydrocal 30

� Denscal White

� Plaster of Paris

� Pottery plaster

� Porousness is key for making absorption molds

Mixing plaster

� Clean Water

� Sift plaster into water

� Look for “dry riverbed”

� Allow to soak undisturbed

� Mix by hand till all lumps are gone

� Plaster strength is proportional to energy input

Plaster – making a plate mold

� For casting smaller items (Generally)

� Item must be flexible and preferably clay

� Seal with fine coat of Crystal Clear or spray paint

� Pour plaster into mold from height so a ribbon of plaster forms

� Allow to flow over item

� Watch for the item to float

Plate mold continued

� Allow plaster to cure

� Some recommend to cover the mold to add strength by increasing humidity

� Plaster will heat, then cool

� Once done, remove clay

� Do not use metal tools, which scratch plaster

� Allow to dry and mold is ready to cast

Two Part Plaster Mold

� Used for larger items and masks

� Again, item must be flexible enough to allow it to be removed from an inflexible mold

� Watch for mechanical lock of armature

� Seal with Crystal Clear or spray paint

Two Part Plaster Mold – Mold wall

� Mentally split model

� Make a mold wall along line, 2-2.5 inches

� Keep the wall perpendicular to the model

� Support the mold wall on the second side

� Add mold keys to wall to help alignment

� Spray with Crystal Clear or spray paint

Two Part Plaster Mold

� Add a detail coat of plaster

� Use a brush

� As plaster begins to cure and thicken, add by hand

� Additional coats added to get to mold wall thickness

� Burlap or hemp may be added for strength

� Smooth final coat with burlap so you can handle the mold

� Flatten the top so mold will sit securely while inverted

Two Part Plaster Mold

� Once cured, remove mold wall

� Repair any issues

� Put mold release on plaster wall

� Put mold release at least 2 inches

� Add pry points

� Repeat mold on second side

� Once plaster cures, use pry points to separate

� Remove original and clean mold

Things to note on plaster

� Impurities can speed cure time

� Second layer can be mixed in previous container so already kicking plaster will speed cure

� Impurities can weaken final plaster

� Green strength is considerably less than final strength

Oh Mother

� Mother molds are a hard outer shell that prevents over expansion of your cast

� Recommended for flexible molds

� Critical for expanding casting materials

� Plaster bandage is most common

� Must not mechanically lock� Two or more sections

� Overlap must be released

Mother Mold Materials

� Plaster Bandages� $9 for 8”X15’

� Plaster and cloth� Gauze, Burlap, Wide weave cotton

� Plaster alone with dividing wall� Same as part plaster mold

� Urethane foam� Great stuff

� Fiberglass

Plaster as a casting material

� Casting plasters will work dependent on final need

� Statuary casting plaster

� Hydrostone is a strong plaster for casting

� In reality, Hydrostone is a cement and so is UC30, HC30 and Denscal white

� Can be cast in silicone, alginate or latex

Painting plaster

� Acrylic paint

� Wood Stain

� Paint Washes to add depth

� Seal with Polyurethane or other sealer

What you can cast in Plaster

Silicone

� RTV and Silicone Caulk

� Advantages� Cost

� Availability

� Disadvantages� Smell

� Delamination

� Tear Strength

� Useable as a casting medium

Silicone – making a mold

� Detail coat

� Successive coats

� Reinforcement

� Number of coats

� ¼ inch

� Requires a mother mold to hold shape during casting

Dry Time

� To heat or not to heat

� Use of additives

� Oil Based Paint

� Corn starch

� Baking Powder

� Baby Powder

� Plaster

Applying multiple coats

� Only one detail coat required� Is it needed?

� Feel to determine cure� Massage into work

� Fill in deep spots and undercuts� Use thickeners here

� Acetone can make successive layers more accepting and less likely to delaminate� I don’t have issues

� Alternate coat colors if possible for best coverage

I really want to make a food safe mold

� Some silicone is Food Safe

� Some silicone is resistant to high heat� Most up to 400 degrees and specialty to 600

� Verify with manufacturer

� Read MSDS

� Avoid Mold inhibitors or anything that is not 100% silicone

� Do your homework

Silicone putty

� 2 parts silicone caulk

� 1-2 parts talcum powder or cornstarch

� Mix well and roll

� Press original into putty

� Purchase putty, 8 oz for $20

� Make it, 20 oz for $5

What you can cast into silicone

� Urethane Plastic

� Urethane Foam

� Oven Bake clay

� Friendly Plastic

� Bondo

� Plaster and other Gypsum products

� Paper Mache

Casting Silicone

� Cast into most mold types

� Use strait or can dilute with naphtha or denatured alcohol

� Toxic and flammable

� Use gloves

� Remember silicone does not like latex

� Can use fiber fill as a backing for props

� Can fill with foam to hold shape

Coloring Silicone

� Tint� Use Oil Base paints – Speeds cure� Use Food Coloring� Use Pigments

� Purchase colors� Clear, Black, White, Beige, Metallic, Bronze, Bone,

Sanded

� Paint� Tint Silicone Caulk and dilute with Naphtha� Latex paint and cover with clear caulk� Stain and cover with clear caulk

Silicone Example

Latex

� Sources� Mask Making and Mold Making

� Advantages� Cost dependent on source� Availability� Tear strength – Glove mold

� Disadvantages� Time� Smell� Allergies

� Useable as a casting medium

Latex – making a mold

� Detail coat – Nothing special

� Successive coats – up to 15� Brush on and clean brush

� Reinforcement – none needed

� Use heat to speed drying time

� Once removed, use baby powder to prevent sticking

� Requires a mother mold to hold shape during casting

Cast with Latex

� Cast into plaster mold for best results

� Plaster pulls moisture from latex, creating a skin

Coloring Latex

� Tint with latex pigments� Paint with Rubber cement paints� Paint with acrylic paints� Stain with wood or leather stain� Bombay Ink

� Dilute with Alcohol and airbrush

� Exterior Latex House paint� 6 parts tinted latex house paint� 1 part latex� 1 part (or more) water (optional)

Seal your latex

� Not normally required for mold

� Clean with citric acid before adding to or repairing

� This opens the pores of the latex

� This also will help paint adhere

� Protect with Armorall

What you can cast in Latex

Alginate

� Dental or Special effects

� Advantages� Safe for skin dental capture

� Detail Capture

� Speed

� Disadvantages� One time use

� Speed

� Not useable as a casting medium

Alginate – making a mold

� Mix according to manufacturer direction

� Work quickly

� Use reinforcement or a mother mold after casting

� Remove original

� Cast quickly – Alginate will deform after 60 minutes

What you can cast in alginate

� Please note, this is not my casting

� www.accu-cast for original

Where to get supplies

� Online

� Home improvement stores

� Craft stores

� Hobby stores

� Habitat for Humanity ReStore

� Harbor Freight

Discounts

� Watch for overruns or special purchases

� Hobby Lobby, Joanne and Michaels 40% off coupons

� Harbor Freight 20% off coupons

� First Friday 50% off sale at ReStore

� EBay – good luck…

� Amazon sales

� Dental supply stores

Resources

� UTube� StiltbeastStudios

� StanWinstonSchool

� Garage of Evil� http://www.smooth-on.com

� And their UTube channel

� http://www.brickintheyard.com� And their UTube channel

Let’s make a casting!

� Foam

� Plastic

Visit us at our website

This presentation available at

� The Midwest Haunters Convention Website

� Also the silicone mold “How To”

� And the release matrix