A Powder Coating Trade Coater had a quality problem with airborne dirt falling on the powder coated parts. The dirt was identified as sitting on the surface of the coating and was not evident when the parts entered the oven.
The Company had tried coating an internal oven wall with a competing coating which worked at first. The coating acting like a non-drying adhesive layer that acts like “Fly paper”. The problem came back however after 2 -3 months. It was identified that the tacky coating had dried out and lost its tackiness. Eventually it made matters worse as the oven coating started to flake off.
The solution was to strip this coating off (mechanically and with paint remover) and then hang steel panels wrapped around with aluminium foil coated with C-190 in the oven. To avoid the film drying hard, the panels had the coated foil removed and replaced weekly.
Initially four panels were used to capture the airborne contamination. Once the oven was clean of airborne dirt by using the coating of one oven panel, as part of the maintenance programme, this ensured the ovens stayed free of dirt and dust defects.
High bake systems such as powder coating means a much shorter tackiness lifespan and the coating needs frequent replacement. In a low bake oven (80C) the coating would remain tacky for much longer (several weeks).