[Emerald]

Very good article! Gave me plenty of information to chew on all while thinking of how to make one and how to maybe "up" the temp so that when mixed with cold water it will last longer.

If you have a permanent spot to put it in, you could put the coil of hose/black pipes into a glass topped box with the inside of the box painted black also-like the solar pumps that heat the air for inside your home or for solar dehydrators. insulate the box if possible and caulk the holes that the pipes go thru.
I have been thinking of making something similar to this but a sealed system filled with antifreeze to heat a water tank for keeping the chickens warmer in winter and keep their water supply from freezing.
Just a box with a coil of black hose/glass topped outside(painted black inside) with a coil of hose going into a tank in the shed natural hot/cold circulation will keep the antifreeze moving during the day and as long as it is not too cold the water would radiate the heat back to the chickens at night and keep water from freezing. The next day everything starts all over again. Only downside- we get stretches of sunless days here.

 

[Emerald]

Lots of guys use old sliding doors for the lids on their collector boxes. The price is right and they can stand up to small hail.

If you play your cards right you can sometimes find them on the side of the road! I would stop and pick them up the hubby would probably shoot me!
At the moment I have a stack of very heavy duty tempered glass that used to be used as shelves in old Gibson fridges.. my parents both worked at Gibson ( Frigidaire, eletrolux, white consolidated, it changed names several times ) they were going to go out in the trash, so they brought them home for something, who knows what, but too nice to toss out!. Am planning on making a solar dehydrator and maybe using some as "lites" which are smaller panes of glass for cold frames (its French, so am not sure if I spelled it right).