WHAT ARE ALDAX GARDEN MOULDS MADE FROM?

All our garden moulds are vacuum formed from High Impact Virgin ABS Plastic. This is the finest plastic for use with concrete. We use two coloured plastics, black and white ABS, both with a haircell design on the back of the mould. The thickness varies according to the mould size and desired end use.

For the DIY gardener wanting a limited number of castings at an economical price we provide moulds made from 1 and 2mm ABS. For the manufacturer we use 3 and 4mm ABS for additional strength and long service.

WHAT SIZE MOULDS ARE MADE?

We provide stock paver moulds with a diameter of 300, 400 and 600mm The depth varies from 2.5mm 3.75mm to 5mm. Mould sizes may vary slightly from the stated dimensions.

DO YOU MAKE CUSTOM MOULDS?

Yes, we are happy to quote for custom moulds of any size.

HOW MUCH USE CAN YOU EXPECT FROM ALDAX MOULDS?

Your 1 and 2mm moulds should give you 10 to 20 pours, even more if you are careful in your handling.
All moulds will have a much longer life if supported. This particularly applies to the professional heavy duty moulds subject to daily stress.

The rim of all moulds takes the most strain. Even on the lighter weight moulds you can expect much longer life if you reinforce the mould edges and area underneath the mould where the cavity meets the flat rim area with duct tape. This is the area most prone to splitting in the event of incorrect handling.

The heavy duty moulds should be supported with timber framing. To get maximum life from these moulds it is essential that the strain of supporting the weight of the heavy concrete be taken off the moulds themselves with this type of additional back up support.Care in this area will effectively double the life of the moulds.

The simple frames can be made from 5cm DAR pine timber with a 1.25cm plywood base. Drill 3mm holes at intervals in the rim of the mould and nail or screw the mould in the frame making sure that the base of the mould is resting firmly on the plywood base.

WHAT TYPE OF RELEASE AGENT SHOULD I USE?

For those used to using metal or aluminium garden moulds, we have to issue a special warning! DO NOT USE MACHINE OIL OR OTHER PETROLEUM BASED OILS ON PLASTIC MOULDS. This will cause deterioration in the plastic and ultimate destruction. Use only vegetable oils, such as Castor Oil, which may be dissolved in Methylated Spirits for spray on application using a cheap garden type hand sprayer.

HOW TO RELEASE AIR BUBBLES

To avoid adding unecessary strain to your plastic concrete mould do not lift it when filled with concrete and tap it on a bench, as you would do with a hobby mould filled with plaster. The considerable weight of a concrete filled mould is enough to crack it when used in this fashion.

If you have not mounted your mould in a wooden back -up simply place a board under the mould before pouring and vibrate the board by tapping. This method places no stress on either you or your mould.

Professional casters are advised to use vibrating tables.

MOVING MOULDS WHEN FILLED WITH CONCRETE.

Lifting moulds filled with concrete seriously weakens the plastic rim, so simply slide a wooden plywood board under the mould to take the weight and to make moving much easier.

CAN I COLOUR THE CONCRETE?

Concrete is easily coloured by adding metallic iron oxides to the concrete mix before pouring. 10 to 20 ml of oxide pigment is usually sufficient for a paver. The colour is pale when wet and intensifies as it dries.

Before doing large batch pours, do a trial casting and allow the sample to dry to avoid having your pavers darker or lighter than you intended. Best of all iron oxides are UV stable. And do not require sealers.

WHAT CONCRETE MIX SHOULD I USE?

For garden moulds requiring strength such as steps, garden seats, tables or foundations a STRUCTURAL CONCRETE is required. This is what we generally call concrete in building terminology. To make structural concrete, mix:
1 part Portlane Cement
2 parts Sand
3 parts gravel
water to suit.

These quantities are by volume. For instance 1 shovel of cement 2 shovels of sand and 3 shovels of gravel. After mixing the dry ingredients together commence adding water a little at a time until the mix is just pourable.

For the decorative concrete moulds that do not need to be as strong as steps etc you can use an ORNAMENTAL CEMENT mix consisting of:
1 part of Portland cement
3 parts sand
concrete pigments if desired
water to suit

All measured by volume as previously. This mix does not need to be as strong as Structural Concrete and usually is more fluid, to pour into the moulds easily and give a good surface.

For pavers the mix can be anywhere between the structural and the ornamental. As they need reasonable strength and at the same time need to be decorative. We normally recommend the use of 1 part cement, 2 parts sand and 1 part gravel. Vary this mix to achieve the effect you are looking for. Use small pea gravel rather than blue metal or similar.

Ready mixed versions of both the Structural and Ornamental Concretes are available at all hardware stores for those who do not wish to mix their own. Ornamental is labelled sand and cement mix and Structural is usually labelled ready mixed concrete. A bag of ready mix will make approximately three 400x400x5mm stepping stones

MIXING

While for commercial production machine mixing with a cement mixer is essential, home users can mix by hand in a wheelbarrow or one of those utility plastic tubs available at any hardware store.

A garden hoe makes an ideal mixing tool if you have one, if not a small spade or shovel will suffice. Due to the alkaline and abrasive nature of cement rubber gloves are recommended and if working indoors, you should consider using a dust mask.

When starting off using garden moulds it is a good idea to work out what quantity of cement mix or concrete is necessary to fill a mould. There are several mathematical methods for obtaining the volume of mix required but to take the easy path, simply fill the mould with the aggregate being used, whether it is sand for pavers or sand and gravel for steps.Then measure the volume of the aggregate and work out the proportions of cement and water required. Neither the cement or water affects the volume required to any practical degree since they go in between the particles of aggregate.

Try and work with sufficient cement mix or concrete to give you a two hour working cycle and err on having slightly more mix than you need to fill your moulds rather than having to make another mix to top up.In our plaster work we always have a spare mould ready to take any excess mix to avoid wastage.

Start mixing by adding your dry ingredients into the mixing container starting with the aggrgate followed by the cement and oxide colour if being used. Then thoroughly mix the dry materials until the mix is uniform in colour.

Make a depression in the centre of the dry mix and pour in three quarters of the required amount of water.Mix thoroughly, making sure you incorporate all the dry material on the sides and bottom of your container.

Add the final quarter of the water while mixing, until you reach the required consistency for the job at hand. This is the tricky part, as every batch of sand has a different moisture level, every day a different himidity and temperature, so don't be in a hurry and add too much water at once.

You need the least amount of water to make your mixture the consistency required for each different type of job. Pavers should have a drier mix than a mould of a figurine containg undercuts, where additional water in the mix is required to flow into all the interstices.

FILLING YOUR MOULDS

Step 1:

Apply the mould release by brushing a light film over the entire internal surfaces of the mould. As mentioned previously vegetable oil such castor oil is the only release agent we recommend for professional and production use where long mould life is necessary. However for the short term home use almost any oil can be used . Vegetable cooking spray, mineral oil, silicone or motor oil. With long term use, motor oil will destroy a plastic mould, short term it works very well.

Step 2:

Fill the mould with about a centimetre or two of cement or concrete mix enough to cover the design pattern. To remove air bubbles from the surface lift one edge of the mould and tap gently. Rotate the mould three or four times and continue tapping. Finish filling the mould and shake gently to level the mix.

Step 3:

Cover the mould with damp towels, hessian or plastic sheeting and allow to harden for several days before demoulding.

Step 4:

Demould then place piece out of direct sunlight or strong wind for at least a week..Cover with damp hessian or keep damp by misting with water several times day.

During this period the cement paver or concrete step will continue to harden in fact this hardening process continues for the life of the object. Most strength will have been achieved at the end of the first week.

For a more complete understanding of mixing,decorating and setting up a business for making garden ornaments we have prepared a book called "How to run a Concrete Garden Ornaments Business"available from our web site www.aldaxstore.com.au

For those who would like to learn how to make latex moulds to manufacture garden ornaments we have completed a fully illustrated book showing our factory methods for making a wide variety of different moulds entitled "How to make Latex moulds" see our web site www.aldax.com.au.

By Stan Alderson