With chalk you can make, for example, wedding favors or figurines for the crib to paint, create scented chalk to hang, make small sculptures or make casts of hands.
In short, chalk is a very flexible material that is suitable for DIY work.
In this guide we see where to start to work the plaster, how to mix it and how you can get, in an easy and economical, objects really very nice to decorate and beautify the house.
Plaster of Paris
Plaster of Paris is a material used since ancient times. It was used by the ancient Egyptians as a binder in the construction of the pyramids. The name is linked to the ancient quarries of Montmartre famous for the plaster used on a large scale in the French capital.
Plaster of Paris can also be used for the preparation of plaster paint to create the Provencal or Shabby effect, by adding pigments you will get the desired shade. Using a diluted preparation will get the watercolor effect with a dense preparation is possible to obtain the effect craquelé.
What you need to begin
- Plaster powder
- Water
- A plastic bowl
- Silicone molds
- A spatula or small trowel
- Acrylic paints or pigment powder
- Scented essences
These materials can be used all together to obtain objects but can also be used only in part, it all depends on the type of object we want to create.
Preparing the plaster mixture
Plaster is used alone, mixed only with clean water.
The proportions of the mixture vary according to the type of work to be done.
For a plastering job, for example, the mixture should be firmer while for casting in a mold the plaster mixture should be quite liquid.
In general, this is the ratio in weight water/plaster:100/357 (100 ml/gr. of water every 357 gr. of plaster of Paris). To obtain good results the temperature of water and plaster must be between 16°C - 22°C.
Once you have assessed the amount of work, or rather the quantity you are likely to have to use, here is how you should proceed:
- In a perfectly clean plastic basin pour the amount of water for the desired mixture. Add the plaster powder in a fine spray
- Let the plaster absorb the water for about 15 seconds and then start mixing the mixture with a spatula or small trowel
- If the container is concave we recommend using a trowel with a rounded tip, if the container has a flat bottom we recommend using a square-tipped trowel or spatula.
Plastic or wooden spatulas are also great for mixing the plaster.
Be sure to mix well so that no lumps are produced but the mixture is perfectly smooth.
A good mixture is an essential condition to deal with the next part of the work, whatever it is.
For large quantities it is advisable to use mechanical rod stirrers at a mixing speed <500 rpm.
Pour immediately into the molds carefully and slowly enough to expel the air from the walls.
NB: once the mixture is ready, use it quickly because the setting of the plaster continues and accelerates and it is not possible to add water to dilute the mixture once it has begun to harden.
Demould after a minimum time of 25 min. and in any case when the mechanical resistance of the plaster is sufficient.
The complete drying of the plaster after the reaction takes place after at least 2 hours. It is possible to dry in an oven set at 50/60°C and ventilated.
To obtain colored and/or scented plaster
The plaster can be colored with acrylic colors once it has hardened, however we can also obtain a colored mixture in case we want to obtain a particular color.
To make a colored plaster mixture just add a colored powder pigment to the water in addition to the chalk powder.
You can also scent the mixture with scented essences whose scent will be imprisoned in the chalk that will release, for a long time, a pleasant aroma.
The scented chalks can be used to perfume drawers, cabinets, baskets, replacing, with little expense, much more expensive commercial products.
Obviously scented chalk, like any other scenting element, can do very little against the smell of mothballs and mold, to overcome these problems there are specific products to eliminate unpleasant odors from closets and trunks.
Pouring plaster into molds
To obtain decorative objects of plaster we almost always use special silicone molds, into which the plaster is poured.
In most cases, these molds allow you to obtain objects with a decorated face and a flat bottom, basically bas-reliefs. To obtain three-dimensional objects it is necessary to use bivalve molds.
Bivalve molds allow you to obtain two parts, front and back, of an object, parts that will then have to be joined together.
The part of filling the molds is perhaps the most difficult step and must be done carefully if we want to obtain an object without imperfections.
The process must be carried out with a certain speed and, at the same time, with precision. Let's see how to do it.
First we dip a brush in the plaster and carefully brush the plaster mixture inside the silicone forms.
This step serves to ensure that the surface of the object, which will then remain in view, do not generate bubbles that will eventually spoil the appearance of the object itself.
Only after having brushed the mold with plaster we can fill the mold up to the edge and then remove the excess with a spatula, so that the back of the object created is perfectly smooth.
Once dry the plaster will have acquired the same shape of the mold and thanks to the flexibility of silicone can be easily removed.
Plaster sculptures
With plaster it is also possible to create small and large sculptures, not surprisingly, sculptors first create a copy in plaster before moving on to sculpting marble.
This is because plaster is easily workable and has a low cost, so it is also suitable for those who want to practice with the art of sculpting. Similarly and for the same reasons, it is possible to make sculptures with cellular concrete.
Obviously, in order to sculpt with plaster, it is necessary to have a parallelepiped of material that will have to be made by casting a large amount of plaster in a formwork.
In order to avoid the problem of possible air bubbles inside the mixture, it will be necessary to slightly beat the formwork to try to make these bubbles come out.
The objects created with plaster can be subsequently varnished with acrylic colors, but to do this it is necessary to have good dexterity and a good knowledge of colors.
With plaster, however, you will be able to make interesting objects to be transformed into wedding favors, figurines for the crib, etc.