The top of the tank shouldn’t see much loading other than slosh loads unless it is overfilled, so perhaps an external scab patch would be good enough. A thin sheet metal patch with a 2 inch overlap, held on with stainless steel sheet metal screws and sealed with food grade silicone acting as a gasket.
If you put a washer at each fastener hole between the tank and the patch then you can control the thickness of the silicone and ensure there are no areas without sealant due to squeeze out. Glue the washers to the patch to ease installation and dip the screws in silicone when you install them.
The silicone won’t stick to the tank, but that is OK; a gasket installed dry in a car doesn’t necessarily stick to the mating surfaces either.
I did this when I installed Tornado Rotary Rinsers in my fresh and waste tanks. They are much smaller, but they are mounted lower so they have higher water loads per square inch, and I’ve never had a leak.
It is possible to install an inner patch as well, but it is more difficult. Cut the inner patch in two, and feed the two halves into the hole. Hold the inner patch in place with wire through the fastener holes the tank. Practice a couple times then remove and re-install the inner patches with silicone and put the cut-out piece of the tank with silicone onto the inner patch to act as a spacer and to cover the seam between the two halves of the inner patch. Feed the wires through the outer patch holes. Install the fasteners wet with silicone and tighten evenly in increments until firm. You can add fasteners to the cut-out area as well to directly tie the inner and outer patches and the cut-out spacer. If the inner patch is thick enough, you can make the fastener holes in the tank a little oversized so the sheet metal screws grab the inner patch better and pull it up tight to the inside of the tank.
We used the same concept on F/A-18 wing fuel tanks except we used nut plates on the inner patch with bolts and structural adhesives. It shouldn’t matter much if your tank leaks a bit due to slosh while driving and while parked it shouldn’t leak at all unless you overfill.
If you put a washer at each fastener hole between the tank and the patch then you can control the thickness of the silicone and ensure there are no areas without sealant due to squeeze out. Glue the washers to the patch to ease installation and dip the screws in silicone when you install them.
The silicone won’t stick to the tank, but that is OK; a gasket installed dry in a car doesn’t necessarily stick to the mating surfaces either.
I did this when I installed Tornado Rotary Rinsers in my fresh and waste tanks. They are much smaller, but they are mounted lower so they have higher water loads per square inch, and I’ve never had a leak.
It is possible to install an inner patch as well, but it is more difficult. Cut the inner patch in two, and feed the two halves into the hole. Hold the inner patch in place with wire through the fastener holes the tank. Practice a couple times then remove and re-install the inner patches with silicone and put the cut-out piece of the tank with silicone onto the inner patch to act as a spacer and to cover the seam between the two halves of the inner patch. Feed the wires through the outer patch holes. Install the fasteners wet with silicone and tighten evenly in increments until firm. You can add fasteners to the cut-out area as well to directly tie the inner and outer patches and the cut-out spacer. If the inner patch is thick enough, you can make the fastener holes in the tank a little oversized so the sheet metal screws grab the inner patch better and pull it up tight to the inside of the tank.
We used the same concept on F/A-18 wing fuel tanks except we used nut plates on the inner patch with bolts and structural adhesives. It shouldn’t matter much if your tank leaks a bit due to slosh while driving and while parked it shouldn’t leak at all unless you overfill.
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dstreight
Senior Member
Thank you Thane, et al, for all advice!
I've sent an e-mail to Armstrong; hopefully will hear from them tomorrow. I was initially concerned about the relatively thin wall thickness and associated flex of the tank top especially when its full. But Armstrong assured me it would work and be 100% water tight before I placed my order.
Curious Thane, thinking of installing the Tornado Rinser...
I've sent an e-mail to Armstrong; hopefully will hear from them tomorrow. I was initially concerned about the relatively thin wall thickness and associated flex of the tank top especially when its full. But Armstrong assured me it would work and be 100% water tight before I placed my order.
Curious Thane, thinking of installing the Tornado Rinser...
I like that the Tornado Rinser sprays the top, bottom and sides. I use it with a fertilizer injector (using bleach instead of fertilizer) when I sterilize the tank. This sprays a bleach/water mix into the tank and mixes the water a bit when the Tornado Rinser is submerged. Silly perhaps, but my 18 year old tank is very clean.
This link discusses the injector.
https://www.escapeforum.org/forums/f8/fresh-water-tank-bleach-injection-system-7427.html
This is the Tornado Rinser.
https://www.amazon.com/Camco-40126-...245-4235-90cd-177e98a2ef7f&pd_rd_i=B000BUU5TU
This link discusses the injector.
https://www.escapeforum.org/forums/f8/fresh-water-tank-bleach-injection-system-7427.html
This is the Tornado Rinser.
https://www.amazon.com/Camco-40126-...245-4235-90cd-177e98a2ef7f&pd_rd_i=B000BUU5TU
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dstreight
Senior Member
Update umpteenth 
: Sorry to those that wanted a video of me doing the spin/friction weld of the new fittings onto my fresh water tank. If you've used a router then the process of spin/friction welding is easy. But, they're not quite as clean looking as the fittings that Alcaro installed at the factory. Maybe after I do a couple dozen more...
The one big mistake I made though: Instead of wearing a long sleeve shirt...yeah, plastic burns on my arm from the spin-cast of molten plastic made me wonder why, given its "welding", I chose to wear a short sleeve t-shirt...other than it was a hot day when I did the welding. I keep liv'n and learn'n.
And, I never heard back from Armstrong Nautical about their ill advice... So, to cover the hole I drilled for their deck plate, I got a $3 poly cutting board from Walmart and used Loctite Premium Construction adhesive along with a bunch of SS screws to hold it tight to the top of the tank. I've used this same construction adhesive for quite a few years on more projects than I can count/remember and its the 'bees-knees' for bonding challenging /problematic materials like HDPE, PVC, etc.
'While I was in there'...I drilled out the 1-1/4" barbed fitting that serves as the filler port and upped it to 1-1/2" which eliminated the adapter barb I had to use to bridge 1-1/4" fitting on the tank to the 1-1/2" Tern Overland fill port. I also added another 1-1/2" spin weld fitting on the sidewall of the tank on the driver's side to speed up draining of the tank. The 1/2" NPT port the tank comes with tests my patience, er impatience especially when its more than 1/2 full...and when I'm in a hurry (which is most of the time).
I also added this fitting at fill port at the top of the tank to make removal of the tank if/when: Amazon.com
Per Thane-ESC recommendation, I added the Camco Rotary Tank Cleaner assembly to further aid in scrubbing the inside of the tank. Trying to leave 'no stone unturned'...
This weekend I'll finish up the entire project, fill the tank and verify everything works again. Another 'while I was in there' I decided to fill the Isotemp water heater with white vinegar to rinse out any scale that might have accumulated on the heating element.
: Sorry to those that wanted a video of me doing the spin/friction weld of the new fittings onto my fresh water tank. If you've used a router then the process of spin/friction welding is easy. But, they're not quite as clean looking as the fittings that Alcaro installed at the factory. Maybe after I do a couple dozen more...The one big mistake I made though: Instead of wearing a long sleeve shirt...yeah, plastic burns on my arm from the spin-cast of molten plastic made me wonder why, given its "welding", I chose to wear a short sleeve t-shirt...other than it was a hot day when I did the welding. I keep liv'n and learn'n.
And, I never heard back from Armstrong Nautical about their ill advice... So, to cover the hole I drilled for their deck plate, I got a $3 poly cutting board from Walmart and used Loctite Premium Construction adhesive along with a bunch of SS screws to hold it tight to the top of the tank. I've used this same construction adhesive for quite a few years on more projects than I can count/remember and its the 'bees-knees' for bonding challenging /problematic materials like HDPE, PVC, etc.
'While I was in there'...I drilled out the 1-1/4" barbed fitting that serves as the filler port and upped it to 1-1/2" which eliminated the adapter barb I had to use to bridge 1-1/4" fitting on the tank to the 1-1/2" Tern Overland fill port. I also added another 1-1/2" spin weld fitting on the sidewall of the tank on the driver's side to speed up draining of the tank. The 1/2" NPT port the tank comes with tests my patience, er impatience
especially when its more than 1/2 full...and when I'm in a hurry (which is most of the time).I also added this fitting at fill port at the top of the tank to make removal of the tank if/when: Amazon.com
Per Thane-ESC recommendation, I added the Camco Rotary Tank Cleaner assembly to further aid in scrubbing the inside of the tank. Trying to leave 'no stone unturned'...
This weekend I'll finish up the entire project, fill the tank and verify everything works again. Another 'while I was in there' I decided to fill the Isotemp water heater with white vinegar to rinse out any scale that might have accumulated on the heating element.
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dstreight
Senior Member
Edit Post #45 above & yet another update: After another e-mail to Armstrong Marine they issued a pre-paid UPS call tag for return and refund of their hatch that didn't perform as they promised (leaked, no matter the tension/tightness adjustment on the hatch).
And, the quick solution I made to seal the 6-3/4" hole I cut into the top of my fresh water tank for the Armstrong hatch, using a small HDPE cutting board and Loctite Premium Construction Adhesive along with a dozen or more stainless steel screws to aid in holding & sealing the cutting board to the top of the tank.
Well, after re-installing the fresh water tank and filling it to the top/full, the patch I made per above leaks. Not a big deal as leaving the tank less than 100% full alleviates leaking through my ill-fate/attempted hatch hole patch. For the foreseeable future, i.e. "winter and/or cold weather months", I'll leave it as is and continue to use it.
BTW, the system now works properly once I removed all the bio-slime, etc. I think the solution for me is to install a carbon filter between the tank and the pump to remove chlorine. This will allow chlorinated water to reside in the tank but allow chlorine free/near chlorine free water for washing hands, dishes, showers and all non-drinking uses from the fresh water tank.
We'll see how it goes over the next 6-months or so but I think I'll end up replacing the tank, hopefully with a little larger capacity tank and also increasing the size of the drain port to at least 3/4"NPT and more than likely 1" NPT to alleviate trying to be patient each time I need to empty the fresh water tank, along with the pre-emptive measures to be able to clean out the tank periodically.
What a process and what an experience!
And, the quick solution I made to seal the 6-3/4" hole I cut into the top of my fresh water tank for the Armstrong hatch, using a small HDPE cutting board and Loctite Premium Construction Adhesive along with a dozen or more stainless steel screws to aid in holding & sealing the cutting board to the top of the tank.
Well, after re-installing the fresh water tank and filling it to the top/full, the patch I made per above leaks. Not a big deal as leaving the tank less than 100% full alleviates leaking through my ill-fate/attempted hatch hole patch. For the foreseeable future, i.e. "winter and/or cold weather months", I'll leave it as is and continue to use it.
BTW, the system now works properly once I removed all the bio-slime, etc. I think the solution for me is to install a carbon filter between the tank and the pump to remove chlorine. This will allow chlorinated water to reside in the tank but allow chlorine free/near chlorine free water for washing hands, dishes, showers and all non-drinking uses from the fresh water tank.
We'll see how it goes over the next 6-months or so but I think I'll end up replacing the tank, hopefully with a little larger capacity tank and also increasing the size of the drain port to at least 3/4"NPT and more than likely 1" NPT to alleviate trying to be patient each time I need to empty the fresh water tank, along with the pre-emptive measures to be able to clean out the tank periodically.
What a process and what an experience!
Suregrip391
Senior Member
Only in the presence of sunshine will algae produce oxygen. If the tank is kept dark……
I made a cover for my freshwater tank to block out light and hopefully prevent cooties from growing. I don’t use it very often because I usually vacuum the tank dry between campouts. Here are the details.
www.escapeforum.org
Fresh Water Tank Cover
This is the fifth of five links that address my efforts to clean, and keep clean, my 17 footer fresh water tank. This is the first link. http://www.escapeforum.org/forums/f8/fresh-water-tank-extreme-maintenance-7425.html#post134332 While scrubbing the inside of my fresh water tank as...
www.escapeforum.org
Ron in BC
Senior Member
A forum mod first I think. It should help with your situation. Time will tell.
Ron
Ron
HABBERDABBER
Senior Member
'Tis true, but a translucent plastic water tank, even exposed poorly as it is under a rig, still allows for some photons to get in there, as the previous posts have found..
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dstreight
Senior Member
Camped out for the last 6-days, with a few more to go before returning home, and happy to report the fresh water system is operating normally. Again.
What a detour!
What a detour!
We ended up bleaching the fresh tank and replacing all the clear tubing. And we put a black foam tube on the fresh water pick up tube. So far, so good!
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