VHB tape and PVC not holding

[filteredsoul]

So this week, I've had 2 signs fall off painted cinder block walls. These were smallish signs (4ft long x 1ft tall) and just printed/laminated vinyl mounted to 3ml pvc. Pretty light weight. They are both indoors in a climate controlled building. The tape is still firmly attached to the painted block. but it completely let go of the pvc. I asked around and 1 person told me to never use vhb on pvc or poly-metal. For some reason it won't hold. So far, he's right. What (besides a mechanical fastener) could I use to hang these? Is there another kind of tape that pvc likes?

 

[boxerbay]

we found that out when we had a few facemounted acrylics fall off clients walls. we moved away from VHB tape and now use 3M4000 adhesive to affix the backframe hanger on facemounted acrylics. takes longer to dry but more secure.

 

[IslandSignWorks]

PVC is a low surface energy substrate. Nothing likes to stick to it well. A Komatex will be even worse because it's got the bumpy texture. 3M's foam tape will stick better than most.

We use VHB tape on acrylic all the time and have no issues. You could also use an Omegabond/Dibond although you might have to paint the edges (unless you want them black). VHB sticks to the powdercoated aluminum face on Dibond like crazy.

 

[Billct2]

We usually use cheap foam tape for interior installs, with a dab or two of silicone or Lexel if we're worried.
Our tape supplier will spec the correct tape and I know we have a VHB that is made for plastics.

 

[ams]

VHB doesn't like PVC for some reason. However there are many different types of VHB, you may have used one that is made for metals or glass.

 

[Bly]

I think we have had better luck with banner tape since it's designed to stick to PVC.

 

[Chuck Peterson]

I always add a few dabs of silicone or Lexel along with VHB. It takes little time and you'll have fewer problems.

 

[visual800]

VHB is great for interior AND for holding an exterior sign up till the silicone sets. We prefer to prime our PVC with 2 part epoxy as so the silicone hangs on to it. Silicone does not care for bare PVC. You could do this in place of mechanical fastening OR just drill thru it and tap it