Hope you can help. Yesterday I lightly sanded our cast iron fireplace surround (eg not the part next to the fire that gets hot), then primed it with Dulux oil based metal Primer. This went on fine and covered well. This morning I started applying Dulux Water based satinwood paint on top but it is like painting with slightly sticky milk - it is giving almost no coverage at all. What have I done wrong? Please help.
Thank you