At my wifes suggestion I painted a lavender cast iron tub with porcelan tub with one part epoxy enamel. I meticulousy followed the suppliers sanding and acetone wipe down instructions, applied their bonding agent and painted the tub. However I had one small area where silicone was bleeding thru the paint si I had to remove that small area, re-clean for silicone and repaint. At the suggestion of the supplier I bridged the area which had the problem with latex paint and painted over with their epoxy. This worked well however the old paint (not the latex) wrinkled up and separated. I'm thinking the problem is the paint is not totally cured and until it does any new solvent in the paint will cause it to lift. I have backed off and will let it cure for a couple of weeks before returning, sanding out the defects, then applying the bonding agent and overcoating with latex, then spotting in the color coat. Am I on the right track?

 

I don't know about the latex idea.

I find it hard to believe that a latex primer or finish will work in a bathtub scenario. Even the very best latex primers/paints will not do well immersed under water.

If the silicone is totally cleaned off - you don't need to bridge the area with anything, just treat the area like the rest of the tub. If the silicone is not totally cleaned off, then the latex primer/paint will be repelled by the silicone and will not adhere properly.

Once the epoxy is cured, you will probably have to treat the tub as a "re-paint", and follow manufacturer's specs for recoloring/repainting over an existing coating (as opposed to porcelain).

 

Well, the latex will not be submerged and in fact is overcoated and sealed in by a coating of the epoxy. The supplyer recommended this and I too was amazed. It worked and the solvents in the epoxy did not lift the latex.

The silicone was remnants of some agressive caulk from the shower door kit. Apparently as best I can guess, the silicone got down in some minute scratches or pores in the old porcelan and was impossible to get out even with sanding or repeated assaults with acetone.

I've solved the silicone problem, its is history but now I am fighting the hot solvents in new paint affecting the old paint. I have seen this before like when someone paints a car with enamel then trys to spot in an area with laquer too soon before the paint is cured.