What is the rebake procedure for arc shields or ferrules?

• A. Oven dried at 120deg C (250F) for 2 hours
• B. Oven dried at 100deg C for 1 hour
• C. Air-dried at room temperature for 4 hours
• D. Baked at 200deg C for 30 minutes

Answer: (A)

Moisture in arc shields or ferrules can release hydrogen into a weld, which can cause porosity or hydrogen-induced cracking. To prevent this, those parts are rebaked to drive out absorbed moisture. The prescribed rebake is oven drying at 120°C (250°F) for 2 hours. This temperature is high enough to remove moisture but gentle enough to avoid damaging the shield or ferrule coatings, and two hours ensures all moisture has had time to diffuse out. Shorter times or lower temperatures may not remove all moisture, while higher temperatures could risk damage, and air-drying at room temperature won’t effectively remove the absorbed moisture.