The velcro itself is very strong, and it adheres to each other pretty well. The weak point is the adhesive. I shipped a pelican case in the mail with a MOLLE panel attached to the inside of the lid via the velcro. When the case arrived, the MOLLE panel had detached from the velcro tape, so the velcro tape was still attached to the lid, and the panel had fallen off. Still trying to find a better way to attach the panel.
We are testing 3M Primer 94 liquid adhesive primer that can be wiped on prior to sticking the adhesive backed tape onto the panel or lid to promote a stronger bond. HDPE (Rigid MOLLE Panel) and Polyethylene (Pelican Case) are very difficult to get a good bond to because they are such slick materials. The 3M Primer 94 testing should be done soon and will be available for purchase on our site. In the meantime it can be found elsewhere on the web for purchase.