A Guide to Concrete Casting

A General Guide to Concrete Casting for Garden Moulds
 

Concrete garden ornaments can be made from the comfort of your own garage, shed or workshop and made in your own time with very little start-up costs involved. No previous experience is needed and very little tools can be used when you first up start which makes this an ideal home business which can easily be built up as you progress.

Whilst the initial set up costs can be quite small, there is a tremendous amount of money to made in  concrete casting. And with internet sites like e-bay around selling your items has never been easier. Items can cost you less than a dollar to produce and you can sell your ornament for 10 times that amount, it can quickly become a business that can grow rapidly, if you want it to.

The basic skills needed are mainly being able to mix materials together with water like sand and cement or plaster these materials are readily available and cheap to purchase at most DIY or hardware shops.

Tools needed are very simple and cheap to purchase like buckets and trowel you may already have these available, now all you need are some moulds to fill, there are many popular and easy to use moulds available stepping stones, plaques, signs, and pavers to name just a few and at very reasonable prices, it won’t take long before you will be able to produce beautiful low cost garden ornaments.

Look in most peoples gardens the next time you go for a walk and see how many gardens have a garden ornament or statue or a piece of concrete somewhere in their garden, you will be amazed at how many people have something to brighten up their garden, it could soon be one of the ornaments you have produced and made.

Once you have started to produce your ornaments you will no doubt want to start adding cement dye colours to your mix which can give you a wider selection, your ornaments may be painted if you wish to command higher prices, at the end of the day it is up to you it’s your business and can be done in your own time.

Your garden ornaments can be sold elsewhere as well as on-line, such as markets, boot sales, family and friends, see if you can supply your local garden centre and shops, ask people to hold a garden party and give them a commission to sell your ornaments, this can be a very rewarding experience that can not only bring you extra income, the making of the ornaments can be a very enjoyable and relaxing experience.

Garden Ornaments are often brought and given as gifts for birthdays, anniversaries, and Christmas presents as well as throughout the summer by garden lovers everywhere making this type of business lucrative to most.

It is easy to increase your sales by just adding to your selection of moulds as and when you want to, making it enjoyable and a stress free operation. As you grow you may want to produce garden ornaments faster and easier with the aid of a cement mixer to mix larger quantities of sand and cement. A vibrating table or vibrating poker will help to shake the mix in to the mould and removes the air out of the mix at the same time, saving you time money and giving you professional results. Both vibrating tables and vibrating pokers can run-off a normal household electric supply.

Moulds or molds spelt differently depending on where you are in the world can be made up of different materials, but in the main they are plastic, rubber, latex, fibreglass, metal, polyurethane and even wood can be used.

Frequently Asked Questions

What Do I Have To Use On The Inside Of The Moulds Before I Fill Them?

Latex moulds are self-releasing and do not require a release agent although it is best to rinse them with water and allow to drain for a few minutes before filling.

Plastic, Metal and Fibreglass moulds will require a release oil, usually a mineral based one, you can spray or brush the oil on, if you want to spray on, use a small hand sprayer i.e. a used window cleaner type container, these can give a very fine spray.  It is best to give the corners a slight brush, as the corners are the most important.

Do not use compressed air to spray, it is also best to leave the mould upside down for ten minutes or so, so that any excess oil will drain off.


What Concrete Mix Ratio Should Be Used?

The best mix we have found to use on slab moulds and path edging moulds is a 3-2-1 mix, being 3 x 10mm pebble, 2 x sharp sand and 1 x cement.  Sometimes this is referred to as a builders mix or concrete mix, and already has the pebble and sand mixed together.

Mix ratio’s needed for garden ornament moulds are also a 3-2-1 mix, but the sand content is higher i.e. 3 x sharp sand, 2 x 10mm pebble or chippings and 1 x cement.  Add water to bind ingredients together to obtain a wet mix.

The amount of water that you need to add will vary, dependant on the moisture content of the sand.  Add water slowly, preferably with a spray attachment fitted onto a hose until the mixture turns to a wet mix.  The best way of being consistent is to use a bucket to measure each of the materials; this proves to be much more accurate than by the shovelful.

It can sometimes be best, to tip the wet mix out of the cement mixer into a barrow first, so that you can ensure that it has been mixed thoroughly before filling the moulds.


How Can I Achieve A Different Colour Mix For My Casts?

Cement Dye Powder or Oxide Pigment can be added to the mix to produce a different colour cast, there is a fair range of different colours available. The more dye used, the deeper the finished colour will be, white cement can also be used instead of the standard grey, can also be used to give an additional range of colours.

You may well find that there are many different shades of sand which vary from quarry to quarry and will also play a part in the colour of your finished product.


How Do I Use Latex Moulds Without A Fibreglass Case?

With regards to latex only moulds, these are best placed in a piece of hardboard with a hole cut out that same shape as the bottom of the mould and the latex secured around the edges with bulldog clips, then place in a wooden box, large can or pipe, anything sturdy that the mould will fit into.

Always fill the smaller moulds last as this is an ideal way of using up any leftover cement mix and saving any wastage.


What Are Latex Moulds with Fibreglass Cases?

These consist of a latex liner with a fibreglass jacket/case which holds the shape of the ornament whilst curing.  The fibreglass case is usually secured together using either bolts and wing nuts or cable/zip ties. The latter being much quicker when de-moulding.

If your mould is an awkward shape i.e. a statue, which will not stand level on the floor, place in a bucket which has been filled with three quarters of dry sand, this will then keep it standing in an upright position whilst curing.


What Is The Easiest Way To Turn Out Latex Moulds?

To prevent latex sticking to it-self when de-moulding, you can smear the outside of the latex with a soap paste made from natural soap flakes. Add some warm water to a container and then add the flakes leave them for approximately an hour, this will make a soft paste to use.

Do not use washing up liquid as this is a detergent and will weaken the latex considerably.


What Is The Best Way To Look After My Moulds?

To keep the moulds in good condition, it is best to keep them out of direct sunlight and store them in a dark cool area when not in use.


How Long Do I Have To Leave The Mould Before Turning Out?

Make sure the cast is left to dry out completely before removing the mould otherwise particles of damp cement will be left behind on the latex or fibreglass.

The drying time depends on the atmospheric conditions and this will depend on the area on which you are situated.  During the summer months, once the evening temperature is warmer, slab moulds can usually be turned out after 24 hours.

Then leave stacked for approximately 7 days before laying.  When stacking, place wooden or plastic spacers between the slabs, the air can then circulate around them aiding them to dry.


Should I Use A Vibrating/Shaker Table or Vibrating Poker?

The purpose of a vibrating table is to shake the mix down into the mould removing the air bubbles out of the wet cement as it does so, although this can be done manually, it can be time consuming and a vibrating table will save lots of time and effort especially if you are making large batches.

The vibrating table is turned on the mould is then placed on the table and then filled when you have the correct mix you will observe the mix spreading to the corners of the mould and the air bubbles escaping to the top of the concrete.

A 300mm x 300mm x 38mm slab mould for example would usually take about 30 to 45 seconds to vibrate

A vibrating poker can also be used to shake down the mix and remove air pockets,these are best suited to deeper type moulds such as statues, bird baths and most moulds that are over 300mm deep.

The mould is semi filled with a wet mix the poker is then inserted into the wet mix and vibrated then slowly removed and more mix added and the process continued until the mould if full.

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What Can I Paint My Ornaments With?

If you wish to paint your ornaments water based acrylic paint is usually used, these are readily available from most craft shops, make sure that your ornament is thoroughly dry before painting.  After your ornament has been painted, a sealer or semi-gloss finish can be applied to fully protect your ornament.