What temperature can I apply Liquid Rubber MetalSafe Sealant? Liquid Rubber Waterproof MetalSafe should be applied above 5°C (41°F). Avoid hot, direct sunlight applications as well. Related articles What should I use to clean up? Can I build my final membrane all at once? Will sun have an effect on the Liquid Rubber MetalSafe Sealant? Comments 0 comments Please sign in to leave a comment.