Apply gelcoat in suitable outdoor conditions

The focus of application of gelcoat is the processing temperature. It has a decisive influence on the result and can lead to later qualitative defects even with the best processing. The gelcoat has to dry out in the perfect balance between the viscosity and the viscosity of the gel, so that it contracts too much or it hardens when it dries.

Temperature is the deciding factor

If excessive temperatures occur during processing of the gelcoat, there is a risk of shrinkage. During this process, the "gelling" during the drying is not allowed enough time. Due to this lower so-called pot life, the chemical components dry out more quickly than they harden.

Especially when applying gelcoat in the summer under the open sky, so-called undercurdling can occur. In part, this effect can be compensated for in two-component gel coats by changing the dosage of the hardener, as long as the outside temperature does not exceed 25 degrees Celsius.

Similarly destabilizing temperatures below 18 degrees Celsius. Here it is often not possible to process the gelcoat properly. The increasing viscosity or viscosity makes the gelcoat less spreadable and it can not dry out completely due to too low a deaeration function.

The high reactivity of the gelcoat provides an optimal connection to the fiber-reinforced plastic that it is intended to surround or cover. The reaction process can be limited when applying even too cold tools such as rollers, brushes or spray bottles.

Humidity and draft

The application of the gel coat is also influenced by the humidity. Dry air has the same effect to a lesser extent as too low a temperature and leads to a thickening, the increase in viscosity. When drying the Gelcoats this leads to a porous drying out. The ideal value when applying the gel coat is between fifty and 75 percent relative humidity.

Drafts can indirectly lead to hypothermia of the freshly applied gel coats. Strong wind accelerates the evaporation of styrene and this process develops evaporative cold. It can also cause undercurders that can degrade the ventilation ability during the drying process.

Tips & Tricks

If you apply the gelcoat at higher outside temperatures than the specified ideal value, in addition to the possible functional deficiencies, there is an increased exhalation of the harmful styrene.

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