Material-Specific Temperature Effects
PVC Foam Board
PVC foam board exhibits complex thermal behaviour that makes it both versatile and challenging to work with. The material operates effectively within a temperature range of -20°C to 60°C (-4°F to 140°F), though its properties change significantly across this range. At higher temperatures, particularly above 30°C (86°F), the board becomes increasingly pliable, which can be either advantageous or problematic depending on the application.
The material's thermal expansion rate of 0.068mm/m/°C means that a 3-meter board could expand or contract by approximately 6mm across a 30°C temperature change. This movement necessitates careful installation planning, particularly for larger signs. When exposed to direct sunlight, the surface temperature can exceed ambient temperature by up to 20°C, creating additional challenges for outdoor installations.
For successful installation, expansion gaps of approximately 3mm per meter should be incorporated into the design. Bonding operations are most successful when performed between 15-25°C (59-77°F), as adhesive performance and the material's stability are optimal in this range. The choice of adhesive is particularly important - flexible adhesives that can accommodate the material's movement are essential. In environments prone to high temperatures, supplementary mechanical fastening may be necessary to ensure long-term stability.
Aluminium Composite Material (ACM)
ACM represents a significant advancement in sign material technology, offering exceptional thermal stability through its innovative sandwich construction. The aluminium faces combined with a polyethylene core create a material that maintains its structural integrity across an impressive temperature range of -50°C to 80°C (-58°F to 176°F).
The material's thermal expansion characteristics are particularly noteworthy, with a coefficient of 0.024mm/m/°C - significantly lower than many alternative materials. This translates to more predictable behaviour and simpler installation requirements. The polyethylene core acts as a thermal barrier, helping to maintain dimensional stability even under challenging conditions.
Installation of ACM benefits from this stability, requiring expansion gaps of only about 1mm per meter. The material's compatibility with most adhesive systems provides flexibility in installation methods, though careful consideration should be given when bonding to materials with different thermal expansion rates. The rigidity maintained across its operating temperature range makes it particularly suitable for large-format signage where dimensional stability is crucial.
Check out our ACM calculators that allow you to purchase sign blanks in a variety of finishes, shapes and also with drilled holes.
Acrylic
Acrylic brings unique optical properties to signage applications while presenting distinct thermal challenges. With a working temperature range of -40°C to 80°C (-40°F to 176°F), acrylic's behaviour varies significantly with temperature changes, requiring careful consideration during design and installation.
The material's thermal expansion rate of 0.07mm/m/°C is particularly significant, as it can lead to substantial movement in larger panels. This movement, combined with acrylic's rigidity at lower temperatures and increased flexibility at higher temperatures, creates complex installation requirements. The material can develop internal stress if mounted improperly, potentially leading to crazing or cracking over time.
Installation systems must accommodate this movement while maintaining the material's optical properties. This often involves the use of hanging strips in framing systems and careful attention to drilling and cutting temperatures. The material must be installed in a stress-free state, with sufficient expansion gaps of 3-4mm per meter to prevent buckling or warping.
Acrylic is often used for internal wall plaques where the temperature difference is minimal and installation using aluminium or stainless steel wall mounts is ideal. Sign Trade Supplies offer custom size acrylic plaques that come edge polished, as well as acrylic flat cut letters with suitably bonded snapfix or simplefix letter locators.
Critical Installation Factors
Temperature Management in Bonding
Temperature significantly influences adhesive performance across all sign materials, affecting both installation success and long-term durability. Ambient temperature controls are critical, with most adhesive systems performing optimally between 15-25°C (59-77°F). Surface temperature must remain above the dew point to prevent moisture interference with bonding.
Adhesive selection must account for both the immediate installation conditions and the long-term thermal environment. The chosen adhesive system should accommodate the substrate's thermal movement while maintaining adequate bond strength across the entire service temperature range. This is particularly important when bonding materials with different coefficients of thermal expansion.
The Stykra range of adhesives covers the bonding requirements of most sign materials, when bonding dissimilar materials the Stykra 700 EXT is a great choice, it can be applied in temperatures as low as 0°C and provides structural bond that can withstand weathering, UV and thermal expansion.
Managing Dissimilar Materials
The combination of different materials in signage applications requires careful consideration of their thermal behaviours. Differential movement between materials can create significant stress at joining points, potentially leading to failure if not properly accommodated. This movement must be calculated based on the maximum expected temperature range and the materials' respective expansion rates.
Successful installations typically employ a combination of approaches to manage these thermal differences. This might include the use of flexible adhesives, mechanical fixing systems with movement allowance, or thermal breaks in extreme cases. Stress points must be identified during the design phase, and appropriate solutions implemented to prevent concentration of thermal stresses.
Installation Best Practices
Temperature management begins well before installation, with proper material storage being crucial to success. Materials should be stored at installation temperature for 24-48 hours prior to use, and consistent conditions should be maintained throughout the installation process. Weather forecasts should be consulted when planning installation schedules, with contingency plans in place for adverse conditions.
Long-term considerations must account for the maximum expected temperature range in the installation location. This includes seasonal movement patterns and the potential for extreme weather events. Regular maintenance inspections should be scheduled, particularly following significant temperature fluctuations, to ensure continued performance.
Conclusion
The impact of temperature on sign materials is complex and far-reaching, affecting everything from material selection to installation methods and long-term maintenance requirements. Success in signage applications depends on understanding these thermal behaviours and implementing appropriate compensation measures. Regular monitoring and maintenance, particularly during extreme temperature conditions, will help ensure long-term performance and durability of signage installations.