Gesso Retarder，it is a crucial additive in gypsum technology. Its main function is to extend the solidification time of gypsum slurry, providing artists, architects, and craftsmen with longer operating time to finely shape, decorate, and adjust gypsum works. Understanding the mechanism, types, and usage precautions of Gesso Retirer is crucial for achieving high-quality gypsum products.

The solidification of gypsum is a complex chemical reaction process that involves the combination of gypsum hemihydrate compounds with water to form dihydrate gypsum

This retarder of plaster is rapid and exothermic, and in the absence of a mortar, the gypsum slurry will harden in a short period of time, limiting subsequent operations. Gesso Retirers interfere with this process through various mechanisms, typically including the following: firstly, they may adsorb onto the surface of gypsum crystals, hindering their growth and polymerization, thereby slowing down the solidification rate. Secondly, certain Gesso Retirers may react with calcium ions in gypsum, reducing the activity of calcium ions and thus decreasing the rate of dihydrate gypsum formation. Finally, some Gesso Retirers may alter the surface tension of gypsum slurry, affecting the contact between water molecules and gypsum particles, thereby affecting the solidification rate.

There are various types of Gesso Retirers commonly found on the market, including citric acid, tartaric acid, borax, colloidal protein, and more

Different protein retarder have different retarding effects and applicable ranges. Citric acid is a commonly used organic protein retainer that reduces the activity of calcium ions by chelating with them, with significant effects and relatively easy control. The retarding effect of tartaric acid is slightly inferior to citric acid, but its properties are stable and not easily decomposed. Borax is an inorganic Gesso Retirer, and its retarding effect is greatly affected by pH value, which usually needs to be adjusted according to the actual situation. Colloidal proteins, such as gelatin or casein, inhibit crystal growth by adsorbing onto the surface of gypsum crystals and are suitable for gypsum products that require fine surface treatment.

When using Gesso Retirer, the following points should be noted

Firstly, it is necessary to strictly control the dosage of Gesso Retinar. Excessive amino acid retarder can cause gypsum slurry to excessively delay solidification, or even fail to solidify, seriously affecting the progress of the project. On the contrary, insufficient use of Gesso Retirer will not achieve the expected retarding effect. Secondly, it is necessary to thoroughly mix the gypsum slurry to ensure even distribution of Gesso Retirer and avoid inconsistent local solidification rates. In addition, different gypsum materials and environmental temperatures can also affect the effectiveness of Gesso Retirer, and adjustments need to be made according to the actual situation. Finally, it should be noted that certain Gesso Retirers may have an impact on the strength or durability of gypsum. Therefore, when selecting Gesso Retirers, it is necessary to consider various factors comprehensively and choose the most suitable type and dosage.

In summary, retarder for plaster is an important auxiliary material that provides greater flexibility and operability for gypsum processes by extending the solidification time of gypsum slurry. A correct understanding and mastery of the mechanism, types, and usage methods of Gesso Retirer is of great significance for creating high-quality gypsum products. Through careful selection and control, we can use Gesso Retirer to control the drying process, creating exquisite gypsum artworks and practical gypsum building materials.

Gesso Retarder FAQs

What is Gesso Retirer?

Gesso Retirer is an additive used to delay the setting time of gypsum (or gypsum based materials such as putty, gesso primer). It can extend the operable time of gypsum, facilitate construction, carving or adjustment of details, and is commonly used in artistic creation, architectural decoration and mold making.

What is the working principle of Gesso Retirer?

Delay the hydration reaction of gypsum (CaSO ₄·ݤ H ₂ O) through the following mechanism:

Adsorption effect: forming a protective film on the surface of gypsum particles, hindering the contact of water molecules.

Complex calcium ions: bind with Ca ² ⁺ in solution to reduce the rate of hydration reaction.

PH adjustment: Some Gesso Retirers affect the solidification rate by changing the acidity or alkalinity.

What are the common types of Gesso Retirers?

Organic acids: such as citric acid and tartaric acid (with significant effects but may reduce strength).

Proteins: such as bone glue and gelatin (natural and environmentally friendly, with a short retarding time).

Synthetic polymers, such as polycarboxylates (with precise time control and minimal impact on strength).

How to use Gesso Retirer correctly?

Addition ratio: usually 0.1% to 1% of the weight of gypsum, excessive amount can lead to a decrease in strength or complete non solidification.

Mixing method: It needs to be dissolved in water first, and then evenly mixed with gypsum powder.

Environmental temperature: High temperature accelerates solidification, and it is necessary to increase the amount of Gesso Retirer appropriately.

What should be noted when using Gesso Retirer?

Strength effect: Excessive addition will significantly reduce the final hardness and durability of gypsum.

Compatibility testing: The chemical composition of different brands of gypsum may affect the retarding effect and needs to be tested in advance.

Storage conditions: Gesso Retirer solution is prone to the growth of microorganisms (such as proteins), and it is recommended to prepare and use it immediately.