Yesterday and today were spent on trying to get the copper pipes soldered to the copper sheet. But it was proving to be quite difficult with several factors playing against success! Like for example the flux was drying up during the heating up process and leaving “dirt” to stop the solder sticking to the copper. Pre-tinning the surfaces was tried but the heat required to melt the solder was also causing the already soldered joints of the U bends to come apart or at least breaking the joint and allowing potential leaks. We put on our thinking caps again!

The next trick to try is copper powder mixed with a binding agent (like polyester resin) and putting the copper pipes on a bed of this “paste” of copper and fixing everything down with silicone sealant. We await for the delivery of the copper powder!

In the meantime, we bent up the sides of the copper sheet to form the tray, cut two holes in the required places for letting the waste pipe water in and out. We also sliced up the soffit board (10mm thick foamed PVC plastic) into 45mm wide strips and “glued” them into the copper tray (using PU sealant) to form the maze like long winding path for the waste water to flow over the copper sheet while transferring the heat down into the copper pipes containing the fresh cold water (hopefully getting warmer!) running underneath the copper sheet!

We have also ordered a half dozen temperature sensors to monitor the performance of the heat exchanger and the “system” efficiency of the Shower as a whole.

By Shaun

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