CASTING JACOB’S LADDER

A Carving in Jacaranda wood by Susan Woolf.Place: Tshwane University Theatrical Art studio.

Casting team Lecturer Pieter Bezuidenhout &Artist Susan Woolf. Students Joey Van Wyk and Jurgens Potgieter.

01 03 2008

This woodcarving by Woolf, was used for the edition casting in the Tshwane Theatrical studio. The snake & ladder were not included in the casting.

MATERIALS

Plastic Clay. Quantity.Silicone Mould Max 30SIL Thixotropic AgentScaleRelease Agent: Baby Powder to dust on. Wooden molding toolsMixing sticksPaper hand towel rolls.Bucket with warm water Plastic gloves

METHOD FOR MOULDS

Work in a room that has a suitable temperature.

Prepare all material and equipment and prepare table space.

Set out wooden sculpture to be cast and draw a chalk line on the sculpture demarcating the divisions of the cast.

Dust the wood surface with baby powder to act as a resistant agent.

Use plastic clay (softened in a bucket of warm water) to build a 2cm high wall along the line for the first cast. (We used cardboard under the sculpture to make a base for the mould).

MATERIALS TO MIX TOGETHER

1kg of Silicone mould.

100gms of Silicone Catalyst.

1.5 tsp Thixotropic Agent ( will add 2.5 tsp for next mix).

This pink mixture was thoroughly blended with a wooden spoon. Next it was applied inside the clay barrier for the first part of the mould. It was built up until it formed a substantial mould. This had to dry for twenty four hours.

OUTCOME

The substance we used is new on the market and we have had no experience with it before.

We soon found that the mixture was a bit too loose, this meant that we were continually scooping up the runny liquid to build up the mould. Also it meant that we had to wait much longer for it to dry.

SECOND PART OF MOULDRemove the clay around the thick wall edge of the last mould.Trim this edge to ‘clean it up’ with a blade

Apply dish wash liquid with a brush to mould wall, as a resistance agent.

Clean wooden sculpture, apply baby powder to act as a resistance agent.

Mix prepared silicone, catalyst and thixotophic.

Pour to make next mould, making sure to remove air bubbles

OUTCOME This time we used 2.5 tsp of thixotropic which made it a bit too thick, still manageable though.

Creating a wall or ‘sleeve’ in clay around the carving

Pink silicone applied to the other half of the carving

STAGE TWOFIBREGLASS CASINGMATERIALS• Resin• Brushes• Fiberglass sheets cut into small (8cm x 4 cm) squares.• Vaseline Petroleum Jelly• Paper hand towel rolls.• Bucket with warm water. • Plastic gloves• Plastic Clay

• PU CRYSTAL CLEAR 200 PART A 1.000 KG• PU CRYSTAL CLEAR 200 PART B 0.900 KG• EASE RELEASE 200 1.000 UNIT• PIGMENT SO-STRONG RED 57GM 1.000 UNIT • Made one cast only

METHOD

We prepared the pink silicone by cutting off all rough edges and filling the holes with clay to avoid any undercuts. The mould was cut into tree main sections

A 4cm clay wall in preparation for a ‘sleeve’ was created all the way around the pink silicone mould, which has been covered with powder or Vaseline. Next, we added 36 drops of catalyst into 100ml of clear cast resin.

We cut up two types of fiberglass material into 10cm x 4cm oblongs and layered them onto the pink silicone mould with a brush. The thinner material was used first and was also painted onto the clay edge which ultimately formed a sleeve around the mould. We had to wait for the resin to become tacky before adding the next layer using the thick fiberglass. All bubbles had to be dabbed out with the brush and resin and fiberglass added until it was 5mm thick.

After it had dried (overnight) the clay strip was removed from the first half of the fiberglass mould and more Vaseline applied to the pink silicone and against the ‘sleeve’.

The same process was repeated for the second half of the mould (image 22 -25).When all was dry and the fiberglass mould halves separated from each other, holes were drilled onto the resin ‘sleeve’.

This allowed both sides of the fiberglass casings to be bolted and unbolted when necessary (image 26 -29).

Clear Cobra Polish was applied to the mould and sleeve before bolting the together. This will also help if any liquid spills into this area

Fibreglass casing

created around the

pink silicone mould

to contain and support

Both sides of the fiberglass mould seen here with sleeve and base

Holes are drilled to accommodate the bolts that hold both halves of the fiberglass casing together

STAGE THREE Casting in resin. Mould silicone.

MATERIALSBlue PigmentSilicone Mould Max 30. (Total quantity ordered 5k)Catalist STD Sil Thixotropic Agent (D 100kg)Plastic containersScale.Air ExtractorVaselineMixing sticksPaper hand towel rolls.Plastic gloves

METHOD FOR MOULDS

Work in a room that has a suitable temperature.

Take out all material and equipment and prepare table space.

Open the bolts holding the fiberglass moulds together and remove the three pink rubber moulds.

Heat the pink moulds in the oven for at least 40minutes. The moulds must be very hot.

Clean out the inside of the fiberglass mould removing all residue from the previous casting. Rub Vaseline Petroleum Jelly on the inside and on the ‘sleeve’ of the fiberglass mould. It acts as a resistant agent when the two mould sides are separated.

Fill the cups with the required amount of resin. Mix together:-Silicone Mould Mixand Catalyst STD.

Pour slowly into the container to avoid bubbles. If possible use an air extractor to take out the bubbles. Thoroughly blend with a wooden spoon. (Paul Carnall from AMT brought his extractor unit to demonstrate how to avoid possible bubbles). The mixture becomes very hot and one has to work quickly. At first a little is poured into the mould, swiveling the mould around to make sure the silicone drops into every crevasse. Add the rest of the liquid material.

This had to dry for twenty four hours.

OUTCOME

The resin we used required careful and exact measuring. None of us had cast in this resin before and thus we were fortunate to have Bezuidenhoud to oversee the operation and AMT to offer their expertise. We were surprised at how hot the mould had to be before pouring the resin in to it. The mould had to be left overnight to dry. It came out perfectly. Much work still had to be done in the finish though.

FINISHPOLISHING CRYSTAL CLEAR™ PLASTICS

To attain (or restore) a smooth, gloss finish to the surface of a casting made from a Crystal Clear urethane plastic employ a buffing technique using progressively finer grit sand papers and sanding gels to improve surface finish. For surfaces that have severe imperfections start to sand with coarse grit sandpaper prior to moving onto the finer grit grades. Use 120 grit followed by 220 grit, and then proceed to using finer grit grades. Sand the abraded surface that you wish to restore with fine grit sandpaper (320 grit) until any prominent protrusions or grooves are removed.Next, sand with finer grit sandpaper (400 grit).Follow with ultra-fine grit sandpaper (600 grit). Note: Water may be used with ultra-fine grit sandpaper to reduce particle clogging on the sandpaper and minimize heat buildup.

Next, sand with super ultra-fine grit sandpaper with water (800 grit). After this step, there should be no visible scratches and the surface should appear smooth and translucent. This step is optional. If there are still some scratches or fine imperfections present, you can polish with Novus™ # 3 Heavy Scratch Remover and rinse under water. Dry off casting to inspect surface.

Finish with a final polish using Novus™ # 2 Fine Scratch Remover, and rinse under water. Dry off casting to inspect surface. Repeat final polish until surface is perfectly clear.

For Novus™ Plastic Polish products, visit www.novuspolish.com Important; Results may vary due to a number of variables such as configuration of the casting, quality of the original casting, etc. As a result, Smooth-On can not guaranty or warrant that the above procedure will work for everyone. A small test on a non-critical area of the casting or different casting will be an indicator of whether or not this procedure will work for you

The aim is to complete seven moulds taken from the original. Each hand will symbolises a different character’s hand. Other materials will be used to complete each work in a unique and different way. Steel, aluminium, wood or other mixed media will be used.

For this project a strong mould had to be made so that as many castings as required could be done. A three part mould was completed because of the deep undercuts. Some materials were familiar to all. Other materials used for the casting were very new on the market or were different from standard materials being used. This meant a learning curve for all involved.