As a homeowner, you can over the years have to do some casting operations. Most of these are restorations of old concrete surfaces, but there are also a lot of other jobs for those who want to do it yourself. It is no secret that the preliminary work is very important in the context of most craft and it also applies to the casting. Do you have the right conditions regarding documentation, forms, etc, it is actually not that difficult to cast in concrete.
You can buy concrete in two ways. If you need a larger amount you can order ready-mixed concrete delivered directly from a special car. The most common, however, is to buy dry concrete in bags of 25 kg and then mix yourself gradually.
Concrete consists essentially of cement paste and so called aggregates. The aggregate containing sand, gravel and stone, while the paste is a mixture of cement, water and air. To the concrete will stiffen and get good strength and other properties it is important that you mix according to the directions that are on the bag. Remember to use clean water when mixing. If the water is in any way been contaminated, it can change the chemical process since when the concrete hardens.
An old rule of thumb regarding the fresh concrete consistency is that the less water, the stronger the concrete. When molding in small or narrow shape, it is important that the concrete “floating out” so that it can not form air pockets at the edges of the mold. When you select the quality of the concrete, you should take into account what is to be cast. There is a special ytbetong for casting floors. Concrete for other works are in different classes and thicknesses. Select the quality of consultation with knowledgeable store personnel if you are unsure.
When you pour concrete into the form, it is important that the form is manufactured with accurate dimensions, you take into account the possible connections and that the shape is tight and stable. When you manufacture the mold, it is important that you have access to a well and at some works long spirit. Remember that you create when you make the mold. When it is filled with fresh concrete can now no longer influence the casting result.
A very common concrete work is the casting of pole mounts for fences, drying stand etc. You can pour directly into the ground or with a tube of cardboard or cement form. Whether casting method, it is important that the pole shoe ends up straight and in the correct position when found. You can carefully adjust this with the spirit level when the concrete has begun to stiffen, or prop up and plumb the pole shoe from the start. But do not forget to check with water so that the staging is plumb.
When the concrete is well compacted and the surface or the form completely filled, you should generally smooth surface. Use a ‘rivbräde and, if you want a very smooth surface, a board of steel. The newly cast surface must not dry too quickly because it can cause the concrete to crack. This is because concrete shrinks violently and uncontrollably. To prevent this, make sure that the concrete is kept moist for a few days during the curing. It can be done in three ways: showering the surface at regular intervals, cover the surface with plastic wrap, wet bags or the like, or syringe so-called membranes hardening of the surface.
At most major molding operations used rebar to reinforce concrete structure further. Reinforcing steel may also be warranted at some smaller molding operations. In addition to the reinforcement makes the construction more sustainable, contributing irons also reduce cracking at the example casting of stairs. Before you tackle a larger mold-work, you should be sure you can handle the work in the right way. Keep in mind that a lot of work as a rule also requires knowledge of strength, etc.