The back side is not painted, the front side still is, but I used my dremel to remove the paint from the front side where I welded the front after preping the surface with some plastic prep products, sanding, then cleaning again. I've been monkeying with it and its quite strong. The two-part adhesive on the back side reinforced the already strong weld even more. I've been banging on it and flexing it to test rigidity and its as if it was never cut.