If I remember correctly, copper is not a good choice for distilling sea water into fresh water. I believe it will corrode quickly as the salt is concentrated. Also not the best choice for many of the essential oils preppers often use. Great for alcohol, though.
Also, as with the other distillation water purification articles lately, it must be remembered that simple distillation only takes out some things that can be in water, including salt water. It will take out the basic 'sea salt' content, but not necessarily everything else that is likely to be in salt water taken near a shoreline. And sometimes even in the open ocean.
I do not want to discourage people from using distillation for water, alcohol, essential oils, and a few other useful products, but I believe it is very important to do much deeper due diligence research before attempting the process(es), and not rely upon articles that do not address these other issues. Something that is a very good idea in general, if complete information is presented, can be deadly when semantics and word usage gets involved, and attempts to present compact or concise information are made, too often leaving out critical information that may not apply in even 95% of the time, but will that other 5% of the time. If a person does not know which is which, there will be problems.
I really hate appearing so negative about some things, but as was pointed out in a couple of other threads, there are new people becoming not only involved in prepping, but trying to contribute to the movement, which is good, of course, but without a strong teaching background, or technical background in the subjects they are presenting, there is information being presented that I think could hurt people. I just am not comfortable with that.
So, please do due diligence research for everything, especially for things that appear really simple. Not everything is as simple as it can be made to appear.
Just my opinion.