Structural adhesives provide clear benefits over welding and mechanical fastening. They bond dissimilar materials, provide improved appearance, insulate against galvanic corrosion and offer excellent environmental resistance. Sign bonding adhesives also provide cost savings due to reduced labor and assembly time.
Yet, you may be hesitant to use adhesives in your sign assembly because you’re worried the high temperatures associated with powder coating will degrade the adhesive. Worry no more … acrylic adhesive formulas such as our Signlok adhesive series and LORD 400 adhesive series have been tested and proven to withstand the 400-degree-Fahrenheit temperatures of powder curing ovens.
However, it is important to keep in mind that at about 180 degrees Fahrenheit, the adhesive will begin to soften. This means its hot tear strength becomes very low, which could cause slippage of the bonded pieces. Three simple precautions will ensure a good outcome:
- Allow the adhesive to fully cure before powder coating.
- Clamp or fixture the assembly prior to powder coating to avoid slippage during the process. Mechanical or spot welds may be used to hold the parts in place.
- The assembly should remain fixtured until the adhesive returns to room temperature and re-hardens.
Once the assembly has cooled to room temperature, the integrity of the adhesive bond is as strong as ever. In fact, greater strength is often seen after exposure to heat and the subsequent return to ambient temperature.
Heat-resistant acrylic adhesives will provide excellent results when powder coating bonded signs. Adhesive bonding avoids the distortions that may occur with mechanical fasteners, resulting in a smooth, uniform finish that requires no rework. And there are no compromises when it comes to structural strength in the finished sign.