Recommendations, or lack of, for water tank inspection ports.

[Peggie Hall HeadMistress]

We have one that looks like that except the screw in part is clear plastic. The problem is it needs a doubler inside the tank. As it is, it leaks if we completely fill the tank. The leak is between the tank and the ring portion of the assembly. Proper sealant could also be the problem.

Do not use any sealant...there should be no need for any. Replace the rubber gasket under the flange, or install if the one that should be there if it's not. You can get one from Beckson. It wouldn't hurt to replace the o-ring on the cap too...they sonly last 5-6 years before they start to dry out and crack.

 

[genec]

Do not use any sealant...there should be no need for any. Replace the rubber gasket under the flange, or install if the one that should be there if it's not. You can get one from Beckson. It wouldn't hurt to replace the o-ring on the cap too...they sonly last 5-6 years before they start to dry out and crack.

Proper sealant is required when first installing these... A "proper silicon" sealant is recommended.

But indeed, once in place, there should be little need for further sealant, and the o-ring should do the trick.

 

[Peggie Hall HeadMistress]

I've installed a few and the instructions didn't call for any sealant. However, I can see a need for it if the screws are over-tightened--something many people are prone to do in the mistaken belief that it's the way to insure against leaks, when in fact it'll cause a rubber gasket to leak because it puts puckers in the gasket around every screw (applies to joker valves in toilets too). Mfrs may have decided it's easier to recommend sealant than rely on customers to know how tight is enough.

 

[Hagar]

Hi Peggie,
Good to hear from you! How are things with the Doyenne of Discharge? I have used butyl tape as a sealant with good results on a lot of applications but have not been able to find if it would be a good or bad idea for the sealant around the ports in the water tanks we are talking about. Do you have any information about suitability? Thanks.

 

[pfaffk]

A year or 2 ago I had to replace my Water Tank fill meter and had to install one, here are a couple of pictures of what I did.

 

[Peggie Hall HeadMistress]

Because sealants are rarely if ever needed in sanitation systems--in fact, recommended against in most applications--I'm not as knowledgeable about which to use in what application as perhaps I should be. The only thing I know for certain is, using 5200 for anything on a boat should be a hanging offense!

Years ago (1995!) Practical Sailor published a an adhesives guide chart that I saved to my files and still have it. 22 years have passed since during which there have surely been many advances in sealant chemistry...but y'all might still find some value in it.
(And btw, it would make scrolling through posts so much easier if y'all would also learn to post photos as thumbnails instead full size. Anyone who wants to see the full size only has to click on the thumbnail.)

 

[Al Schober]

I did my water tank a few years ago, and found a proper NSF coating for the interior as well as an NSF approved sealant for the lid and fittings. Coating used is 3M Scotchkote 323 - a 2 part epoxy. Sealant used is Sika 1a. You'll find numerous NSF tank coatings, but few are rated for small tanks.

 

[genec]

I did my water tank a few years ago, and found a proper NSF coating for the interior as well as an NSF approved sealant for the lid and fittings. Coating used is 3M Scotchkote 323 - a 2 part epoxy. Sealant used is Sika 1a. You'll find numerous NSF tank coatings, but few are rated for small tanks.

Whoa that scotchkote 323 doesn't look right...
http://solutions.3m.com/wps/portal/...Epoxy-Coating-323?N=8694383+3293812268&rt=rud

I found some stuff called Liquatile 1172.
http://www.epoxyusa.com/coat_tar_p/ep34.htm

I have not ordered it yet. But it appears to be the right stuff.