If you’re going to restore a vintage camper trailer, you’re going to become friends with Butyl tape. OK, sounds like an odd friendship, but water is the enemy. Pretty much 100% of unrestored vintage campers out there have water damage. The old putty that was used in the 50’s and 60’s didn’t hold up to the elements over time, and eventually they leaked. Water damage and wood rot was the result. You want to remove every door, window and seam that represents a joint between metal, scrape off the old stuff and replace with black, synthetic rubber Butyl tape. I started with the alunimum edging that joins the roof and outer walls. It’s a sticky, yucky job, but unless you live in a desert, or plan on camping exclusively indoors, you’ll need to do it. Here’s a before and after on one particular seam.