I am considering using VHB for an exterior signage project I have in Texas. Most signage ranges from .5/lb to 10/lb to be mounted on concrete, metal and wood.
I have looked at the spec sheets for certain exterior rated VHB and it appears the shear strength is and temperature ratings are well beyond my needs, but has there been any longterm testing as far durability? On a 5-10 year scale in extreme variables of heat, cold and humidity? Is there any warranty?
Furthermore, I have seen on some forums that suggest sealing the perimeter of the signs with silicone. Has this
I’ve attached a durability report that should cover the questions:
- Real-time testing out to 10 years in FL, AZ, and MN have shown >90% retention in VHB strength
- Accelerated aging out to 50 years have shown the same strength retention
- We’ve had applications that used VHB back in the 1980s that are still standing with no signs of failure (O’Hare airport mirrored panels, for example)
For the substrates:
- Concrete and wood will need some sort of sealing agent (3M Spray 80 works very well) prior to VHB application. The top layers of concrete/wood can easily flake off/splinter without sealing.
- Metal is a fantastic substrate, and just needs to be clean and above 50-60 F at the time of application. Once the bond has been created, the VHB can withstand -40F-200F, and sometimes more extreme depending on which tape
Sealing with silicone:
- Silicone or some sort of structural sealant can help create a primary weather-seal when needed, and is especially useful in corners or where the tape needs to be spliced. The liquid can also help give extra gap filling for parts that are not flat enough for the VHB tape.
- The VHB will act as the clamp or “third hand” for the sealant while it cures. VHB tapes have immediate handling strength as they are already 100% cured.