A while back I was watching one of Enigmatic Nomadics videos where he was installing new window curtains. He mentioned that velcro did not stay stuck well to the surface of the vehicles. My professional background has had me involved in finding and using quite a few types of adhesives and finding products for solutions to specific situations.
So here is the big issue with velcro in a vehicle....it is the heat. The standard versions of sticky back Velcro sold in hardware and fabric stores are not rated for the high temperatures that can happen inside a closed vehicle that is sitting in the sun. They do have some high temperature sticky backed Velcro but it has to be special ordered and is very expensive. There is some made for automotive use that will stick to plastics but the temperature rating is still not quite high enough and I have never seen it being sold in the auto parts stores.
The black, Heavy Duty, VHB tape made by Gorilla Glue does have a high enough temperature rating. It is fairly easy to find that product in hardware stores.
You can purchase sew-on Velcro and stick the VHB tape to the backside but it will peel off as it does not stick well to the nylon the Velcro is made with. Nylon is actually a very difficult material to glue but a little research led me to a commonly available glue E6000 that does stick to nylon. The E6000 glue also has a high temperature rating. But of coarse when it is wet it does not stick well to VHB tape. So I figured out a work around. Using the side edge of a popsicle stick spread out and work into the backside of the Velcro tape a very thin, smooth coating of the E6000 adhesive. So thin that you can still feel the weave of the material. No glue lumps allowed!. Don't worry, it is not difficult to do other than making sure you don't get adhesive on the looped side of the Velcro. After it has dried for a day or two so it is fully cured you can then apply the VHB tape from Gorilla Glue to that coated side of the Velcro and it will stay stuck on it instead of peeling off.
Use that VHB tape, looped side of the Velcro to apply to the vehicle structure. Then use the hood side of Velcro to sew onto your window coverings. The looped side is less prone to having debris get captured in it which is why you put that loop surface type onto the vehicle rather than putting it on the fabric.
Just remember the Heavy Duty VHB tape is very aggressive and considered permanent. You don't need big pieces of it, it is rated for 2 inches of tape per pound of weight and your insulated windows covers don't weigh a lot. If you do need to remove VHB tape carefully slice through the foam center of the tape with a razor blade. Then carefully lift up the edge of the tape and grab onto it with needle nose pliers or hemostats and pull parallel to the surface slowly stretching it out. That will release the tape from the surface. Take your time, do not get impatient, don't try to rip it off quickly because slow and easy pulling parallel to the surface is what is required to cleanly remove VHB tape without causing any damage.
So a little experimentation, a little time, some money for shopping and the materials. I now have some high temp, sticky back Velcro to mate up with the sew on Velcro on my insulating window coverings as well as the window screen material.
So here is the big issue with velcro in a vehicle....it is the heat. The standard versions of sticky back Velcro sold in hardware and fabric stores are not rated for the high temperatures that can happen inside a closed vehicle that is sitting in the sun. They do have some high temperature sticky backed Velcro but it has to be special ordered and is very expensive. There is some made for automotive use that will stick to plastics but the temperature rating is still not quite high enough and I have never seen it being sold in the auto parts stores.
The black, Heavy Duty, VHB tape made by Gorilla Glue does have a high enough temperature rating. It is fairly easy to find that product in hardware stores.
You can purchase sew-on Velcro and stick the VHB tape to the backside but it will peel off as it does not stick well to the nylon the Velcro is made with. Nylon is actually a very difficult material to glue but a little research led me to a commonly available glue E6000 that does stick to nylon. The E6000 glue also has a high temperature rating. But of coarse when it is wet it does not stick well to VHB tape. So I figured out a work around. Using the side edge of a popsicle stick spread out and work into the backside of the Velcro tape a very thin, smooth coating of the E6000 adhesive. So thin that you can still feel the weave of the material. No glue lumps allowed!. Don't worry, it is not difficult to do other than making sure you don't get adhesive on the looped side of the Velcro. After it has dried for a day or two so it is fully cured you can then apply the VHB tape from Gorilla Glue to that coated side of the Velcro and it will stay stuck on it instead of peeling off.
Use that VHB tape, looped side of the Velcro to apply to the vehicle structure. Then use the hood side of Velcro to sew onto your window coverings. The looped side is less prone to having debris get captured in it which is why you put that loop surface type onto the vehicle rather than putting it on the fabric.
Just remember the Heavy Duty VHB tape is very aggressive and considered permanent. You don't need big pieces of it, it is rated for 2 inches of tape per pound of weight and your insulated windows covers don't weigh a lot. If you do need to remove VHB tape carefully slice through the foam center of the tape with a razor blade. Then carefully lift up the edge of the tape and grab onto it with needle nose pliers or hemostats and pull parallel to the surface slowly stretching it out. That will release the tape from the surface. Take your time, do not get impatient, don't try to rip it off quickly because slow and easy pulling parallel to the surface is what is required to cleanly remove VHB tape without causing any damage.
So a little experimentation, a little time, some money for shopping and the materials. I now have some high temp, sticky back Velcro to mate up with the sew on Velcro on my insulating window coverings as well as the window screen material.