I was planning to make those crucial breaking parts from Carbon Fiber myself, but I was such a poster-boy for PUR that they sended me free PUR-35 ($5000). It ma

I was planning to make those crucial breaking parts from Carbon Fiber myself, but I was such a poster-boy for PUR that they sended me free PUR-35 ($5000). It makes 3 liters per hour and if you replace the solid-iron pumping shaft it weighs about a kilo. Except one crucial high-pressure valve cannot be made of plastic. I made better one from fiber glass. Thereafter it been running ok for 20 years.