Spiral Wound gaskets can be fabricated of any metal which is available in thin strip and which can be welded; therefore they can be used against virtually any corrosive medium dependent upon the choice of the metal and filler.
Theoretically, it is no longer contagious when there is no more fluid leaking from the sore, and no new blisters are forming. However, I always assume that a cold sore is contagious until it is completely healed, and to the best of my knowledge I've never transmitted the virus to anyone else. Abreva is a very good remedy. If applied when you first feel the tingle you can actually prevent the cold sore from erupting into blisters.
Most of the time you become contagious about One to three days after contracting the flu and stay contagious for up to 5 days after onset of symptoms. However, children and adults with weakened immune symptoms can be contagious to those around them up to 14 days. For colds, most people are contagious for a day before symptoms appear and remain contagious for up to 5-7 days. In rare cases, children can pass a cold for up 14 days. A cold is also known as an upper respiratory infection.