myredracer wrote:
Wondering if it's perfectly okay to put new Proflex over old stuff without having to remove any of the old caulk? I removed some along the top of the fender skirt a couple of seasons ago using white gas and plastic scraper. Even tried a little heat from a blow dryer. OMG, not easy... Would rather just add more even if it doesn't look as nice.
You can go over Proflex with Proflex. The trick is cleaning the old Proflex to get a good bond. The best thing I have found to prep Proflex is "Klean Strip Prep All". Find it at auto body supply places. Just use it sparingly around decals. It will clean the old Proflex and soften the surface, taking some off to some extent. When I remove Proflex I cut out as much as possible with an exacto knife. You can cut in from two directions carefully, then peel it off in a strip. Harbor freight sells a set of red plastic scrapers for a few bucks the work great that I use to scrape it off after cutting. You can sharpen them up with a slow running belt sander with 220 grit paper. Then use the Prep All to remove the remaining residue.
And you also can go over silicone with silicone. It depends on the brand. By saying that I am referring to certain commercial grades and generally not the silicone you buy at the Big Box or Ace, its done all the time on concrete parking garages and other structures. It usually requires a specific primer.
Keystone uses/used Tremco Trempro 645 Silicone for any joints that did not touch roof membrane. Not sure if they still do or not, but a friend and I successfully went over our 2013 and 2012 Keystone Passports with it after prepping with a combination of prep all and denatured alcohol. The issue with the 645 is its hard to find unless your an OEM, but its made for the transportation and RV Industries.
