I enjoy reading your “painting clinic” section of the Products Finishing Magazine. I have just received the March, 2005 issue and would like to add an alternative method for the problem of paint peeling off cast iron.
You are definitely correct in your assessment that the moisture is trapped within the pores of the iron castings. We are an OEM of dehumidification drying equipment. The porous nature and the large heat sink properties of cast iron make it an ideal application for our equipment. One such project where our system was used to dry after a wash of cast iron parts is a large pump manufacturing facility. After the castings exit the washer the parts enter a blow station where the excess water is removed. In order to achieve the dryness within the pores, the parts then enter our dehumidification chamber. Unlike an oven where it relies on the heating of the part in order to dry, the dehumidification process relies on the vapor differential between the wet surface and the surrounding environment. Water will evaporate and be absorbed by the ambient air. One of many advantages of using this system is the elimination of a cool down zone prior to painting. Parts exit the dryer at ambient temperatures.
One of our customers who installed our system prior to powder coating told us that it would have been inconceivable to install a drying oven and expect the system to fit within an existing building. If you would like more information on our systems, please visit our web site or call and I would be happy to talk to you. E. R.
The readers of Painting Clinic and I thank you for the information, E. R. I did visit your web site and found it very informative. One of the better features of your system is “No production lost in heating up and cooling down the substrate.”
Suppliers of dehumidification drying equipment are listed under Ovens, baking and drying on pages 347 to 349 of the Products Finishing 2005 Directory & Technology Guide.