Figarti had similar problems with flaking paint. The problem usually lies in the primer or the paint. Tin Plate models like Gonio-Kaden-Hendrix are made from pressed steel that is than Tin plated to prevent corrosion, like a Tin Can for food. You scratch the plating off and rust can occur. I have a Hausser 760 Long Range Gun made in 1955. The gun is like new, no rust or paint flakes. I live in the Pacific Northwest and it rains frequently with high relative humidity. Zinc Diecast can have corrosion issues if not primed and painted properly. A condition called Zinc Pest used to cause diecast toys to bubble under the paint. A contaminant in the Zinc alloy was found to be the cause. I probably have a ton of painted Zinc diecast in my house i.e. model trains, planes, cars, armor, artillery etc. No obvious problem with any of them over many years. I have old Britains diecast artillery pieces over 50 years old and again no problems. Hausser Tin Toys made in the 1930s are still in good condition. The guns fire, the vehicles wind up and run; with working headlights in some models. Neat Toys!