September 11,
I was able to correct the leaks in the fresh water tank. I initially had three leaks. Two corners and one bottom seam. One corner and the bottom seam were fairly straight forward to fix. The last corner proved to be a real problem. I tried to fix it multiple times and ended up with a mess. Since I was unable to get to the problem and was now dealing with a mess, I cut out the entire corner and replaced it. Solved the issue and the tank no longer leaks. Investigating the bad corner, I noticed a void in the weld that might have been trapping water or air that prevented the new weld to seal properly. Whatever the reason, it is fixed now.
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| I cut the corner out and replaced by a solid chunk of HDPE. |
I also attached the plumbing to the second freshwater tank and performed a leak test. I have two corners leaking and the first few attempts to fix these failed. It was late and I was tired, so I needed to put the work up and think on the best way to fix these corners. Hopefully, the second tank won't be as miserable to fix as the first.
Sept 20,
Making some progress with sealing the second tank. I still have a very small leak in a few places. Every step forward seems like two steps backward sometimes but I'm making progress. I also worked on the brackets that hold the plumbing in place on the bottom of the tank. No unsupported plumbing on this boat.
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| One assembled in the background and one in pieces in the forefront. |
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| And this is how they attach. That ball valve and connection to the tank is now well supported. |
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| Both tanks being filled near full to check for leaks. Almost 200 gallons of water (1500 pounds). A 24 hour wait reveled some very small drips around some of the seams. These very slow drips can be ground down and re-welded without draining the tanks. The act of grinding the drip area down, temporarily stops the leaks and lets me get a good weld in. Unfortunately, there are occasionally underlying conditions that make these leaks pretty persistent so I keep trying until I get a 24 hour leak free period. The tanks have been filled for a week now and I've addressed most of the issues. I had a new leak show up this morning after 6 days. It is such a slow drip that the water almost evaporates before I can see it. Almost. Well, that will be easy to fix. |
Obviously, I've made a tactical error in the design of these tanks. Most importantly is the difficulty in welding the corners where three planes (two sides and the bottom) come together. If I ever make a tank again out of HDPE, I will mold the sides like I did for the black water tank connector (Vee groove half way through the thickness of the HDPE, add heat and bend to a 90 degree corner. Then weld inside.). I believe this would have eliminated 95% of all my issues with these tanks. I'm not terribly happy with the workmanship on these tanks. The re-weld work is not that pretty. At least the inside will be smooth and clean and the tanks will not leak. To prevent any nooks and crannies where dirt can collect, I've ordered some food grade silicone that is formulated for tough surfaces. I'm going to fillet all the inside corners with the silicone to make a super smooth inside to help keep the tanks sanitary. I insist that I am not using the silicone to stop any leaks. All leaks will be fixed by welding the plastic. However, if I happened to miss a very slow leak, the silicone will act as a long lasting insurance policy.
