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.
It shortens the duration of the symptoms and makes them less severe when taken within 48 hours of your first symptoms. So, the criteria for when you can consider yourself no longer contagious is the same with or without Tamiflu. But the length of time can vary from individual to individual. According to the CDC, you can consider yourself no longer contagious after 24 straight hours from your last fever (when not taking fever reducers). That will likely be sooner for someone taking tamiflu than it is for someone who is not.