Crucial for an invisible weldseam is a perfect congruence. I achieve such a perfect fit by pressing the bars ends into two prisms simultaneously. Here it is amazing how much better the fingers feel an excessing projection as the eyes can see it. Finally when my fingers "say" that the fit is satisfactory I come to welding and - believe it or not - this is the point when say I love to work:
The welding process is an unexpected smooth operation - you may even call it ruminant or meditative. You try to move smooth and continuous and watch the melting metall. Yet the melting of the solid is a continuous process. That means you don't have just the discrete states "fluid" and "solid", but all in between. Like when you drive your bike at a certain point you stop thinking about that - you just watch how you channel the seam by mastering the ductile.
Max Longin is a German mathematician living and working in northern Denmark. He designed the float bed in 2004 and the stream chair in 2006. A blow-by-blow presentation of his products can be found on his website at www.max-longin.com. Feel free to contact him.