Os mold release agents may be mineral, animal or vegetable based in pure oils or oils emulsified with water. For metal, plastic, wood and concrete substrate formwork. Emulsified products are used only in wood, metal or plastic and they end up being one of the best types of release agents when it comes to cost versus benefit. Smooth, waterproof shapes use a smaller amount of product.
In large works, the application must be made directly to the molds with the help of a sprayer. As for smaller works, the release agent can be applied with brushes, rollers, rags or burlap.
To place the concrete on top of the release agent, it is recommended to wait for the drying time indicated by the manufacturer of the release agent. In addition, the molds of wood or metallic ones can be reused when mold removers are used.
Because it is an important part of concreting, the application and choice of the right mold release agents make all the difference in the result of the work or the manufacture of concrete parts. In this post, I will show you the types of release agents available on the market and how to apply them. Check it out!
What is the concrete release agent for?
As its name suggests, it serves to make it easy to unmold the concrete part, from the formwork used. But its use in civil construction is much wider than it might seem at first.
It not only serves to be applied to wooden formwork in traditional buildings, but it is also widely used in the concrete artifact industries such as tiles, blocks and coatings.
In addition to extending the useful life of the formwork used, it also improves the finish of the molded concrete parts and increases productivity, since it becomes much faster to loosen the formwork from the concrete.
Application of the release agent for concrete
Some precautions must be taken when applying release agent for concrete. Residues from the product may be attached to the concrete and impair the adhesion of the coating on it.
The use of the release agent provides an excellent finish to the concreting service, but care must be taken not to allow this to affect the next stages of construction.
As debris can affect concrete hydration and adhesion to coatings, it is very important that the removal be done completely. The process can be carried out in three ways:
- mechanical: uses sandblasting, sanding, washing with high pressure water or brushing;
- chemistry: with water and detergent, and then washing;
- by application: procedure performed using hammers and nails and subsequent washing with high pressure water.
To verify that the release agent has been fully removed, pour water over the surface. If liquid is absorbed, it is a sign that the product has been removed correctly.
Otherwise, it will be necessary to continue the removal. For a better result of the work, it is important that the release agent be removed completely.
The importance of using a release agent
The use of Unmolding is essential at the time of concreting and guarantees good results. In addition to facilitating deforming, the solution preserves the natural state of the concrete and extends the useful life of the forms.
It is used to prevent concrete debris from being attached to the formwork and influencing the quality of the service.
The product must be applied by a professional in the area, following the manufacturer's guidelines and the required standards. When properly used, the release agent improves the finish, reducing the appearance of cracks on the surface.
In addition, it contributes to service agility and increases productivity. See the types of release agents offered on the market.
What to use as a concrete release agent?
There are several types of release agents that can be used, but each one has its advantages and disadvantages. The main materials used as mold release agents are pure vegetable oils, oil emulsions, solvent-based waxes and diesel oil.
In the topics below I will explain the advantages and disadvantages of each of them, but I want to discuss something right here.
Traditionally, many works and artifact industries still use diesel oil or hydraulic fluid oil as mold release agents. Although they work with some limitations, they are very aggressive materials for the health of the person being handled and also for the environment. These two points are already more than enough to understand that fuel is fuel, lubricating oil is lubricating oil and release agent is release agent. Exchanging one for the other can have very serious consequences.
Moulding agents based on pure vegetable oils
They are widely used by the concrete parts industry. Vegetable oil-based mold release agents are the most environmentally friendly because they are biodegradable. By replacing old mineral oils, the product complies with the required environmental conditions and offers more safety for those who handle them. In addition, this release agent does not contain solvents and does not pose a health risk.
Vegetable oil-based mold release agents are sold ready to use. They also offer a great surface finish and should be applied in very thin layers.
Excesses need to be avoided to facilitate warping. Use is recommended in wooden formwork, metallic, plastics and concrete substrate.
Emulsion release agents
This type of release agent needs to be diluted with water before application, making it a more cost-effective product.
Water emulsion release agents must be applied uniformly to any shape with the aid of sprayers. Drying is slower compared to solvent-based release agents, as you have to wait for the water to evaporate.
Applied according to the instructions, the release agent emulsified in water provides an excellent finish, clean pans and easy demoulding.
In addition, it is not flammable and does not harm health. It normally satisfies most of a project's safety criteria. This product is suitable for parts produced in wood, plastic or metal formwork.
Solvent-based release agents
Solvent-based mold remover is a mixture of vegetable oils, waxes, and solvents that dry almost instantly. However, after applying it to the mold, it is necessary to wait about an hour for concreting. In this way, the solvent evaporates, forming a thin layer of oil. This layer guarantees a good finish and reduces or eliminates bubbles.
As it is a flammable liquid, it is important to pay extra attention when handling and storing it. In addition, it can cause health problems and be dangerous if handled in places with inadequate ventilation. Solvent-based mold removers are suitable for metal or concrete formwork on concrete, also known as runners of precast.
Diesel oil as a release agent
Unfortunately, it is still common to see companies using diesel (fuel) as a release agent for metal or plastic forms. As much as its demoulding effect is relatively efficient, its use can be very harmful in many ways, even dangerous!
From the demoulding point of view, diesel fuel ends up staining the concrete pieces and removing them is very difficult. So, if you need to finish parts that have been demoulded with diesel fuel, get ready for a lot of work when cleaning.
Environmental and health issues are the reasons you have to pay attention to the most, not to use it as a release agent. Diesel oil is regulated as a fuel, so the form of storage, transportation, and disposal must be taken into consideration when used.
Its misuse as a release agent also exposes the people who are using it to unnecessary risks, such as flammability, contact with the skin and eyes, and the emission of volatiles that, over time, can greatly harm the employee's health, if the appropriate PPE is not used.
Overall, what we should point out here is, diesel fuel is a fuel and should be used as such and should never be used as a release agent in civil construction.
What is the best release agent for concrete?
As we saw above, there are many mold release options and it ends up being difficult to choose a type, but I can summarize you in a few lines, come with me.
If your object is the best cost-benefit, without a doubt, emulsion release agents are, of all, the best alternative. Soon after, vegetable oil-based mold release agents also have the same benefits, but at a slightly higher cost per square meter.
If you have an application where a mold is required concrete on concrete, then the only alternative ends up being the solvent-based release agent specific to this application.
How to prevent concrete from sticking to the shape?
For any and all types of concrete molded into shapes, it is essential that two steps are followed so that you do not run the risk of concrete sticking to the form. The first step is very simple, but many concrete artifact manufacturers don't follow what it is, choosing the right type of release agent for the specific shape.
That is, do not use a release agent for all types of shapes. Can it be okay to use the same release agent for all of them? It can, but the performance will never be the same as that of a release agent formulated for a specific material. Wood is different from metal, which is different from plastic and concrete.
The second step to be completed is to clean the shape between the demouldings. It may take much more work, but it is the step that will guarantee uniformity in the coating of the form by the release agent and, consequently, make a perfect demoulding, with no chance of concrete sticking to the shape.
Choosing the best product
Aiming at a low cost for your work, the most suitable concrete release agents are those emulsified in water. Since it is necessary to dilute the product for the application, this option becomes the most cost-effective. Through new technologies, it was possible to develop products focusing on social issues, the environment, health and safety. This is the counterpoint with solvent-based products.
Vegetable oil-based products, on the other hand, have good performance and price. In addition, they are safer for the environment and for those who handle them. On the other hand, solvent-containing mold removers contain substances that can be toxic and harmful to health. Because of this, this product has some restrictions on usage regulations, but its use ends up being indispensable in concrete applications on concrete or precast tracks.
Therefore, when choosing the ideal concrete release agent for your construction site or industry, it is important to analyze the needs of the project, financial availability, environmental and health issues, in addition to product safety. Research the possibilities in the market and consult an expert!
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