Static Cling Vinyl

I have some I bought from a vendor that are on my race car. They haven't blown off and I've had it up to 110 on the drag strip...

If they are applied correctly, they shouldn't come off under normal driving.

Well my customer called me today and said they came off while driving. Though I suspect it may have been lack of prep. I told him to wash the vehicle thorougly and apply them. The one thing I suspect may have played a role is that he mentioned he applied it at night when the temperature was about 50 degrees Fahrenheit. He applied one of them on his rear glass on his vehicle. I'm kind of wondering if he applied them without cleaning the glass thoroughly. I suspect he may have just wiped it down with a towel or something since I applied a 12x24" section to my car's door and had no problems driving around town and on the highway.

static cling should not be used on a vehicle

Well he wanted it against my suggestion.. I told him interior wise yes but exterior no per the data bulletin supplied by Avery. He went against my suggestion so I'm not losing money since in the contract we signed for the order, I specifically had him sign off saying he's going against my recommendation to place the static inside or atleast use the easy removable Avery 2850 series. He had issues with magnetic signs with his last vehicle so he didn't wanna go back with magnetic.