Pinning is a technique used when assembling large or heavy model kits (such as metal wargaming miniatures) that involves drilling a hole in two pieces of the model to be joined, and using a "pin" to strengthen the bond when they are glued. Pinning is a useful technique for reinforcing joints and is essential when making models from parts that were not designed to go together, such as a miniature conversion. Some modellers also use Blu Tack or another temporary adhesive as an aid when pinning.