Pressure testing old solar hot water panels - Page 2

Daox · 09-17-12, 01:20 PM

That is a great idea. I had thought about using silicon but worried it might not be enough. What did you use exactly?

randen · 09-17-12, 08:09 PM

For mounting the glass we used a premium grade silicone caulking (black). First we placed 3/8" x 3/16 foam weather stripping as a dam to prevent the silicone from migrating into the panel. This provided a nice uniform OEM looking job. The weatherstripping kept the glass raised up about 1/8" to fill with the silicone. We also used several small sand bags to keep the glass down from floating with the silicone being squeezed in. Another little tip was to use a piece of 1/4" dia copper tube with the end squeezed in the vice to make a narrow tip to force into the cut end of the silicone tube nozzle. Clean-up is with varsol and lots of paper towel. We had tried cleaning up after the cure with a razor blade but it was a lot of extra work. Let it cure for two-three days with the sand bags in a warm shop. We had taken one outside to hurry the process (not good idea) but the extra heat made gas bubbles between the glass/silicone. Its been two years the glass is still hanging. Aquariums are made with the same tech and they stay together withall the weight of the water.

Randen

Ryland · 09-19-12, 09:41 AM

Silicone works well for glass but keep it away from copper! the acidic acid in the silicone will eat way at copper, it might do the same with aluminum, not sure, you can buy more expensive silicone II caulk that does not have acidic acid in it but it's close to the same price as polyurethane caulk, a much better, stronger caulk, I like to use the black roofing polyurethane caulk for stuff that is in the sun or gets hot, it will hold and never let go, 50 year life span.

randen · 09-19-12, 10:50 AM

Ryland

Don't mention to GaryGary and some others that are fabricating their solar collectors with silicone between the copper risers and aluminum fin. Don't tell Solcan who have been manufacturing panels for 30 years that the silicone will eat away their aluminum frames and the glass will fall off.

Randen

Mikesolar · 09-27-12, 09:43 PM

I would test with water at 20 psi. I never liked testing with air as sometimes you cannot tell where the leak is if it is small. Too bad you are so far away as I have 6- 2.2m2 panels for sale, already pressure tested.

solar1 · 10-11-12, 05:21 PM

I have also just completed a repair test job like you , I welded (suflos) extensions onto where like your rubber hose clamp extension is and 75mm long (mine were OD 25.4mm and the new ID 25.4 ) fitted perfectly and simple to weld up. It must of been old copper in the pipes as its OD measurements.!?? The Absorber plate was removed from the casing to do this of course. I did this to each Header and crox nutted them so i could easily do a Pressure test without any Money wasted on plugs , however i had to hire a small Welding set to do it , I had everthing ready to go before i picked the set up. I pressure tested it on the mains water supply here before it goes through a Pressure reducing valve in our plumbing system. It passed perfectly . It was probably a slight over kill on pressure but its 100%.

Daox · 10-23-12, 01:32 PM

I just got back from the local welding supply store. I had to get a welding tank refilled with gas. But, while I was there I also wanted to ask about repairing these panels. The guy there said you could braze it or use silver solder for maximum strength, but they've just used normal solder for sweating copper pipe and it has held up to hundreds of PSI. So, that is what I will be doing. He said the key is just to get the joint as clean as possible.

randen · 10-23-12, 01:43 PM

Seeing that the one tube is split I would suggest silphos. This brazing is used in refrigeration it requires the heat of oxy-acetelene but its magic. It fills voids and is a little easier than solder. Solder dosen't fill voids like a cracked tube. Solder works well with fittings but for something like a riser tube in a hole just poked in a header tube silphos is the one to use.

Randen

Daox · 10-23-12, 02:03 PM

Unfortuantely I do not have, nor do I have access to an acetylene torch. I'll have to give the solder a try. The guy seemed very confident this would work just fine. He did say the joints they made were tested up to 600 psi, more than plenty for these panels.

I also do plan on retesting the panels with mains water and pressure once I get all the pex fittings sweat on. I found that testing with air pressure was not the way to go. Not only did my plugs not hold up to anywhere near the pressure they're rated for, which lead to a couple plugs flying out of their pipes on several occasions, but every panel slowly leaked pressure which I doubt is the panel's fault.

Mikesolar · 10-23-12, 06:52 PM

I braze smaller stuff withSilphos, a Turbotorch and MAPP gas. Anything up to 1" is not too hard to do.

09-17-12, 01:20 PM	#11
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	That is a great idea. I had thought about using silicon but worried it might not be enough. What did you use exactly? __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

10-23-12, 01:32 PM	#17
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	I just got back from the local welding supply store. I had to get a welding tank refilled with gas. But, while I was there I also wanted to ask about repairing these panels. The guy there said you could braze it or use silver solder for maximum strength, but they've just used normal solder for sweating copper pipe and it has held up to hundreds of PSI. So, that is what I will be doing. He said the key is just to get the joint as clean as possible. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

10-23-12, 02:03 PM	#19
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Unfortuantely I do not have, nor do I have access to an acetylene torch. I'll have to give the solder a try. The guy seemed very confident this would work just fine. He did say the joints they made were tested up to 600 psi, more than plenty for these panels. I also do plan on retesting the panels with mains water and pressure once I get all the pex fittings sweat on. I found that testing with air pressure was not the way to go. Not only did my plugs not hold up to anywhere near the pressure they're rated for, which lead to a couple plugs flying out of their pipes on several occasions, but every panel slowly leaked pressure which I doubt is the panel's fault. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. Last edited by Daox; 10-23-12 at 02:07 PM..

09-17-12, 08:09 PM	#12
randen Uber EcoRenovator Join Date: Apr 2011 Location: Strathroy Ontario Canada Posts: 658 Thanks: 9 Thanked 192 Times in 130 Posts	For mounting the glass we used a premium grade silicone caulking (black). First we placed 3/8" x 3/16 foam weather stripping as a dam to prevent the silicone from migrating into the panel. This provided a nice uniform OEM looking job. The weatherstripping kept the glass raised up about 1/8" to fill with the silicone. We also used several small sand bags to keep the glass down from floating with the silicone being squeezed in. Another little tip was to use a piece of 1/4" dia copper tube with the end squeezed in the vice to make a narrow tip to force into the cut end of the silicone tube nozzle. Clean-up is with varsol and lots of paper towel. We had tried cleaning up after the cure with a razor blade but it was a lot of extra work. Let it cure for two-three days with the sand bags in a warm shop. We had taken one outside to hurry the process (not good idea) but the extra heat made gas bubbles between the glass/silicone. Its been two years the glass is still hanging. Aquariums are made with the same tech and they stay together withall the weight of the water. Randen

09-19-12, 09:41 AM	#13
Ryland Master EcoRenovator Join Date: Mar 2009 Location: Western Wisconsin. Posts: 913 Thanks: 127 Thanked 82 Times in 71 Posts	Silicone works well for glass but keep it away from copper! the acidic acid in the silicone will eat way at copper, it might do the same with aluminum, not sure, you can buy more expensive silicone II caulk that does not have acidic acid in it but it's close to the same price as polyurethane caulk, a much better, stronger caulk, I like to use the black roofing polyurethane caulk for stuff that is in the sun or gets hot, it will hold and never let go, 50 year life span.

09-19-12, 10:50 AM	#14
randen Uber EcoRenovator Join Date: Apr 2011 Location: Strathroy Ontario Canada Posts: 658 Thanks: 9 Thanked 192 Times in 130 Posts	Ryland Don't mention to GaryGary and some others that are fabricating their solar collectors with silicone between the copper risers and aluminum fin. Don't tell Solcan who have been manufacturing panels for 30 years that the silicone will eat away their aluminum frames and the glass will fall off. Randen

09-27-12, 09:43 PM	#15
Mikesolar Master EcoRenovator Join Date: Aug 2012 Location: Toronto Posts: 958 Thanks: 40 Thanked 158 Times in 150 Posts	I would test with water at 20 psi. I never liked testing with air as sometimes you cannot tell where the leak is if it is small. Too bad you are so far away as I have 6- 2.2m2 panels for sale, already pressure tested.

10-11-12, 05:21 PM	#16
solar1 Lurking Renovator Join Date: Apr 2011 Location: New Zealand Posts: 11 Thanks: 0 Thanked 0 Times in 0 Posts	I have also just completed a repair test job like you , I welded (suflos) extensions onto where like your rubber hose clamp extension is and 75mm long (mine were OD 25.4mm and the new ID 25.4 ) fitted perfectly and simple to weld up. It must of been old copper in the pipes as its OD measurements.!?? The Absorber plate was removed from the casing to do this of course. I did this to each Header and crox nutted them so i could easily do a Pressure test without any Money wasted on plugs , however i had to hire a small Welding set to do it , I had everthing ready to go before i picked the set up. I pressure tested it on the mains water supply here before it goes through a Pressure reducing valve in our plumbing system. It passed perfectly . It was probably a slight over kill on pressure but its 100%.

10-23-12, 01:43 PM	#18
randen Uber EcoRenovator Join Date: Apr 2011 Location: Strathroy Ontario Canada Posts: 658 Thanks: 9 Thanked 192 Times in 130 Posts	Seeing that the one tube is split I would suggest silphos. This brazing is used in refrigeration it requires the heat of oxy-acetelene but its magic. It fills voids and is a little easier than solder. Solder dosen't fill voids like a cracked tube. Solder works well with fittings but for something like a riser tube in a hole just poked in a header tube silphos is the one to use. Randen

10-23-12, 06:52 PM	#20
Mikesolar Master EcoRenovator Join Date: Aug 2012 Location: Toronto Posts: 958 Thanks: 40 Thanked 158 Times in 150 Posts	I braze smaller stuff withSilphos, a Turbotorch and MAPP gas. Anything up to 1" is not too hard to do.