What it the 1st step to do when I want to apply oil base primer on top of semi-transparent stain + solid stain (both oil base)? Homeowner wanted to paint instead of stain. Started getting blistering in different locations of the house, when I applied Cover Stain, oil base primer. Its usually where the sun hits it. I think existing oil base stain was not completely dry, but it felt dry. I popped a bubble and it still feels sticky, but the outside of the stain felt dry.