More progress today. I found a panel that had two leak points in it. I haven't done much sweating of pipe, but I managed to get them sealed up.

How it was.

https://ecorenovator.org/forum/attac...1&d=1604431303



Cleaned up and ready for flux.

https://ecorenovator.org/forum/attac...1&d=1604431315



Yay, no more leaks.

https://ecorenovator.org/forum/attac...1&d=1604431336


I also had this one to fix up. Cleaning it out was a pain. I used a file and sand paper to clean the area. It took a while and two attempts, but its sealed now.

https://ecorenovator.org/forum/attac...1&d=1604431404

Today was the last day of pressure testing. Everything has now passed. Hurray!

The next step is to start assembling. Today I got the inserts all put in the cases, and all the inserts got a new thin coat of flat black paint (in the picture is still drying).

https://ecorenovator.org/forum/attac...1&d=1604622845

I have a question about the reassembly of these panels. The glass on them has a rough texture on one side of it. I assume this is to refract light and even out the distribution over the panel. My question is, should it be on the outside or inside?

A very sharp knife and a lot of care! When I have to remove PEX fittings I cut a deep slit into the pipe the length of the fitting following the line of the pipe, but not down to the fitting. At the end of the fitting I cut right into the pipe for about 1cm. Then bending the pipe at the fitting the slit should open up and you can recover your fitting. Be careful not to cut into the fitting as if the ridges are damaged it can leak - particularly the plastic fittings.

Personally I wouldn't use PEX tube for a solar installation. In the past I used a plastic pipe (not PEX) and with the combination of heat and pressure it ended up popping.

Also, if you do use PEX be aware that some (maybe all, I don't know) is very susceptible to UV and degrades and ends up leaking. In Spain the most common is a translucent white PEX and I have seen lots of instances where it has been installed outside by inexperienced people and then has started to leak - I've changed lots to copper. It seems to last about 5 years before failing. It ends up very fragile and almost crystalized, if you try to expand it it just splits so repair is impossible.

My only addition to this thread is beware of stagnation temps using PEX. I would stick with black automotive type radiator hose with stainless clamps or solder copper to join collectors. Just my 2 cents...

Personaly I've been using the automotive radiator hose on my 2 evacuated tube collectors for over 8 years now and no leaks, no issues.

Good luck! looks like a fun project for sure.