Long-Term Sealing Performance of La-Co Plasto-Joint?

Kengar · 05/19/2019, 02:50 PM

So yesterday I found a bunch of crystallized salt all around a fitting where other components (including a double-union ball valve) are joined to it using Plasto-Joint to seal the threaded connections. When I cleared off the salt build-up, I could feel/see water trickling around the fitting. I closed valves to isolate the section of plumbing and swapped out the ball valve, using a whole bunch more Plasto-Joint around the new threaded nipple. It seems to be dry today.

Additionally, I saw salt crystallized around another section of plumbing, which is, unfortunately, in a location that prevents full/clear access. I was able to reach up from under the tank and knock away the salt build-up, then pack plumber's putty all around the connection the best I could, but I am concerned about longevity of this "patch." (The joint is at a union in the Bean Animal siphon line, just below the overflow box -- which is sandwiched between the 7-foot, 250 gallon tank and the wall. Worst case scenario is that I cut out a section of the wall from the other side to access it if I need to, but I DON"T want to go there.....)

The system has been running for maybe seven or eight months by now, and was test run for several weeks before I started to add substrate, rock, live stock, etc., to make sure the plumbing was solid.

Which brings me to my question: what is the long-term sealing performance of Plasto-Joint? I applied LIBERALLY to all joints that were threaded, and I hand-tightened then gave just a little extra to seat the parts. Does water -- saltwater, in particular -- ultimately channel its way through the Plasto-Joint?

The first joint referenced above is maybe three feet from the return pump (Sicce ADV 9.0, rated for 2500 gph at no head), downstream of a 90 degree turn (large radius) in a line that is branched off from the main return "manifold" (another large-radius turn), so it is under SOME pressure. But the other joint (in the Bean Animal siphon line) isn't under pressure beyond that of the falling-water suction.

Thanks for input.

Question.

mcgyvr · 05/20/2019, 04:45 AM

Unlikely to be a problem caused by just the sealant..

I'd lean more towards under tightening being the culprit but you would really need to contact the manufacturer if you want any real answers on the sealants saltwater compatibility..

05/19/2019, 02:50 PM	#1
Kengar Registered Member Join Date: Sep 2000 Location: Gaithersburg, MD (D.C. Metro Area) Posts: 1,970	Long-Term Sealing Performance of La-Co Plasto-Joint? So yesterday I found a bunch of crystallized salt all around a fitting where other components (including a double-union ball valve) are joined to it using Plasto-Joint to seal the threaded connections. When I cleared off the salt build-up, I could feel/see water trickling around the fitting. I closed valves to isolate the section of plumbing and swapped out the ball valve, using a whole bunch more Plasto-Joint around the new threaded nipple. It seems to be dry today. Additionally, I saw salt crystallized around another section of plumbing, which is, unfortunately, in a location that prevents full/clear access. I was able to reach up from under the tank and knock away the salt build-up, then pack plumber's putty all around the connection the best I could, but I am concerned about longevity of this "patch." (The joint is at a union in the Bean Animal siphon line, just below the overflow box -- which is sandwiched between the 7-foot, 250 gallon tank and the wall. Worst case scenario is that I cut out a section of the wall from the other side to access it if I need to, but I DON"T want to go there.....) The system has been running for maybe seven or eight months by now, and was test run for several weeks before I started to add substrate, rock, live stock, etc., to make sure the plumbing was solid. Which brings me to my question: what is the long-term sealing performance of Plasto-Joint? I applied LIBERALLY to all joints that were threaded, and I hand-tightened then gave just a little extra to seat the parts. Does water -- saltwater, in particular -- ultimately channel its way through the Plasto-Joint? The first joint referenced above is maybe three feet from the return pump (Sicce ADV 9.0, rated for 2500 gph at no head), downstream of a 90 degree turn (large radius) in a line that is branched off from the main return "manifold" (another large-radius turn), so it is under SOME pressure. But the other joint (in the Bean Animal siphon line) isn't under pressure beyond that of the falling-water suction. Thanks for input. Question. __________________ Resident Patent Attorney

05/20/2019, 04:45 AM	#2
mcgyvr Registered Member Join Date: Sep 2003 Location: North Carolina Posts: 20,050	Unlikely to be a problem caused by just the sealant.. I'd lean more towards under tightening being the culprit but you would really need to contact the manufacturer if you want any real answers on the sealants saltwater compatibility.. __________________ Who me?