Moisture marks (wet spots) under the protector
On some pinball machines, so-called ‘wet spots’ may become visible after installation. These are areas between the playfield and the protector that appear damp, dark or slightly streaky.
Such phenomena can occur particularly with newer pinball machines. They are usually caused by components in the clear coat that are still outgassing or by tiny air pockets between the playfield and the protector. The term ‘wet spot’ has become established in the pinball community, although these areas are not caused by water ingress.
Depending on the pinball machine model, these may be barely noticeable or clearly visible. Important to note: wet spots are not a defect in the playfield protector or the playfield itself. The protective function remains fully intact. Nevertheless, you should try to remove these areas.
Removing wet spots
In many cases, wet spots can be reduced or completely removed by carefully blowing air between the playfield and the protector. To do this, air is gently blown between the protector and the playfield so that trapped air or moisture can escape. Compressed air is best suited for this; alternatively, a hairdryer (on the cool setting only!) or a small electric dust blower can be used.
As long as the clear coat has not yet fully cured, the damp spots may reappear later. In this case, the process can simply be repeated. Once the playfield has fully cured, the spots usually do not reappear.
Our experience shows that wet spots occur more frequently on some pinball machines than on others. They are a well-known and technically harmless side effect.