Water tank
 |
About two years after I rebuilt the water tanks, I finally started using them again—and right away I found out the forward tank lid was leaking into the V-berth.
The funny part is, the difference came down to the sealant. The little portside tank I’d done with silicone, but on the big forward tank I decided to try butyl tape. The butyl itself wasn’t the problem. What actually happened was that in one corner, the gap between the tank lip and the lid was just too wide, so the tape never got squeezed. That left an open path, and sure enough—leak.
To find exactly where it was coming from, I hooked up my shop vac in “blow” mode to pressurize the tank, then sprayed soapy water around the seams. The bubbles gave the leak away instantly.
Now, saying “just reseal it” sounds simple—but to reseal, I had to actually get the lid off. And that turned out to be a real fight. The lid was cut so snug that there was basically no room to wedge anything under it, and butyl tape doesn’t let go without a fight. After scratching at the seam a few times with no luck, I finally came up with a trick.
I pulled all the screws, hooked up the vac again, and let it push air into the tank. The shop vac doesn’t make much pressure—maybe 3–5 psi—but the lid is about 20 by 30 inches. That’s around 600 square inches. Even at the low end, that’s a couple hundred pounds of force pressing upward. Sure enough, that was enough to “pop” the lid up just a little. Once it lifted, I could slide screwdrivers into the gap and work my way around until it finally came free.
Cleaning tape left overs was another problem. Butyl is not easy clean for the surfaces. Technically it is removable only mechanically, means - with knife with blade.
 |
| Cleaning in progress. |
One interesting thing I noticed—butyl sticks to HDPE like crazy. Cleaning it off turned into a full-hour job all by itself.
Then came another hour just cleaning up the tank lip.
I already knew butyl doesn’t really dissolve in much of anything, but I stumbled on a trick: spraying soapy water while scraping makes a big difference. Without it, the little scraps of butyl kept reattaching to the surface I had just cleaned. With a spray bottle (I mixed Dawn dish soap, hand soap, and water), the mess stopped sticking and the work went about twice as fast—and much cleaner, too.
For the final cleanup, I wiped everything down with paper towels and acetone. The acetone doesn’t dissolve butyl, but it does soften it a little, which helps.
After about two hours of cleaning, I ran a nice thick bead of silicone and carefully “dropped” the lid back in place.
When I reinstalled the screws, I tightened them just enough to see the sealant squeeze into the seam—no more than that, since I want the silicone to act like a gasket. Next week, once it’s cured a bit, I’ll snug the screws down again to really compress the seal and lock everything tight.
|
| Lid came back |
 |
| How seam looks like |
Comments
Post a Comment