Sunday, 3 June 2012

Latex Moulds: How To Use

By Stan Alderson


PREPARATION- STARTING STEPS

You have completely read the instructions and have a clear notion of what you're just about to do. You're going to fill a mould with a casting material and then support it in order that it keeps its exact shape while it sets. The 3 steps concerned are:

(1) Mixing the casting material

(2) Filling the latex mould

(3) Supporting the mould while setting.

Take some time and have yourself perfectly prepared ahead of time and you'll have no problems.

Mould making at certain times prescribes that you carry on promptly because of the fast setting times of varied products utilized, so it is a glorious thought to prepare carefullyby having everything to hand before commencing.

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GEAR NEEDED

Grant yourself a lot of room and conceal all revealed surfaces with newspaper. You will need a bowl, preferably of a flexible plastic to do your mixing, access to water and soap.

For mixing you will need a flat bladed plastic or wood spatula or stirrer with a long handle. We exploit a kitchen plastic and rubber bowl cleaning spatula.

SUPPORTING LATEX MOULDS FOR CASTING

Next you need something to hold the mould whilst the casting is setting. We like to use firm card boxes in which we may be able to simply cut an opening for the mold to match into. For production pouring, masonite can be employed with the openings cut by jig saw to be more permanent.

To find the size hole to cut to hold the mould while casting, moisten the mold base, turn the fringe of the mold back and press the mould against a little bit of paper or card. It will leave a humid impression of the mold base that will permit you to correctly cut a hole of the proper size into the mold will sit supported by its collar.

For smaller molds the likes of chess pieces we simply use a tall drinking tumbler or a jar of the ideal size. For enormous molds we oftentimes turn to buckets of the right size anything to hold the mold steady and upright while casting.

CASTING

We'll cope with each casting material individually as each has its own individual necessities.

DOUBLE CASTING

With bigger latex moulds that do not have a back-up mold to hold the latex mould and thus yield a perfect casting, another way is by utilising the double casting system.

Double casting helps stop the distortion that results from the unsupported latex mould stretching saggy during casting and gives a professional casting.

Make a support

* Fill the mold about 1/3 full of water and tip into a mixing bowl. Add either the Moulding Powder or the StonePlast whichever you should happen to be using till you've a creamy flowing mix. It does not want to be a thin, watery mix.

* Wash the mould out with water and shake dry. Pour in the mixture you have just prepared. Squish the mold to encourage the mixture to cover all the internal surface of the mold. Tilt the mold at different angles to permit the blend to flow over the internal surfaces you have just covered with plaster mix to build up the thickness. Continue until the mixture ceases to flow.

* Fix the mould very precisely into the support in order not to hurt the coating you have built up and allow to line up fully.

* Now fill up the mold totally with a freshly prepared crop of material being cautious not to hurt the current hardened coating.

* When completely set take away the casting from the mould.

LAST CLEANING AND CARE

After completing your casting wash the mold before the plaster dries with water and soap, dry the mold and keep in a cool and dry, dark spot out of daylight.

If using flexible mixing bowls, it is better to let the plaster dry then by bending the bowl it breaks naturally away from the sides. DON'T POUR YOUR EXCESS PLASTER DOWN THE SINK UNDER ANY CIRCUMSTANCES or else you'll have a blocked drain. We store a bucket half stuffed with water to make clean our bowls, spatulas while they're in use. The plaster settles to the bottom and can be disposed of by pouring off the surplus water, allowing the plaster at the bottom partially dry and then wrapping it in paper for disposal.




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