It's a 1,000 sqft, 50-year-old greenhouse. I am replacing the missing and broken annealed glass. Each aluminum brace/upright has a gap for caulking. It appears they used some kind of rope caulk (which I can't find in stores).
QUESTION: What kind of caulk should I use in the aluminum braces as I layer caulk, the glass, and the aluminum holding strap?