What sealant to use on a drinking water tank?

[NPMR]

I am just about to fit a water level 'sender' to my drinking water tank. This has a 5-hole flange at the point where it enters the tank and is simply screwed down.

Question: What 'stuff' to put in as a sealant? Normal boaty stuff such as Sika flex or 'summat' else?

 

[prv]

Rubber gasket maybe?

Pete

 

[ghostlymoron]

You need to use something with WRC approval. A neoprene gasket is probably best as it will be much easier to dis assemble in future compared with sticky sealants.

 

[kolster]

Screwfix sell 'Dow Corning 781 Acetoxy Silicone Sealant' for £6.29 for a 310mL tube which is safe to use with potable water.

edit, Google 'potable sealants'

 

[vyv_cox]

I bought a sheet of neoprene gasket and used clear silicone with it as the top of the tank is GRP without gel coat and I doubted that the neoprene alone would seal it. Don't overdo the silicone or blobs of it will fall into the tank and subsequently block the strainer or the pump. I speak from experience!

 

[alant]

I am just about to fit a water level 'sender' to my drinking water tank. This has a 5-hole flange at the point where it enters the tank and is simply screwed down.

Question: What 'stuff' to put in as a sealant? Normal boaty stuff such as Sika flex or 'summat' else?

You can get fish tank silicone sealant, which should do the job.

 

[Hydrozoan]

Rubber gasket maybe?

Pete

You need to use something with WRC approval. A neoprene gasket is probably best as it will be much easier to dis assemble in future compared with sticky sealants.

+1 to rubber gaskets. I think (but do check) that it's WRAS approval you need to look for, for materials in contact with drinking water.

 

[ghostlymoron]

Sorry, I'm not up to date with WRC/WRAS.
Much prefer gaskets to messy, sticky sealants. Although they do have their uses.

 

[Hugh Foulis]

I am just about to fit a water level 'sender' to my drinking water tank.

Could you post a link, this is something I want to look at too.

 

[Hydrozoan]

Sorry, I'm not up to date with WRC/WRAS.
Much prefer gaskets to messy, sticky sealants. Although they do have their uses.

No apology necessary - I'm not wholly up to date either, which is why I advised the OP to check for himself!

But I do believe WRc Approved is more general in scope (see http://www.wrcapproved.com/new-page-1.aspx) whereas WRAS deals with drinking water specifically (see https://www.wras.co.uk/); there is a WRAS products and materials searchable database on that site.

(There is also Regulation 31 of the Water Supply (Water Quality) Regulations which sets out conditions under which a water supplier may apply products to water, and NSF-WRc is a joint venture of NSF and WRc which performs testing under both WRAS and Regulation 31. Sealants and repair materials approved under Regulation 31 are on pp33-34 here http://dwi.defra.gov.uk/drinking-water-products/approved-products/soslistcurrent.pdf, but are I think those particularly relevant to water mains.)

 

[NPMR]

Could you post a link, this is something I want to look at too.

This is the one I'm using on a rigid tank on a Jeanneau. I will need a 30cm 'sender' and I'll use the cheaper black dial.

http://chandlery.force4.co.uk/search?p=Q&asug=&w=830693

 

[vyv_cox]

This is the one I'm using on a rigid tank on a Jeanneau. I will need a 30cm 'sender' and I'll use the cheaper black dial.

http://chandlery.force4.co.uk/search?p=Q&asug=&w=830693

I installed the same type in my fuel tank last year. Advice I received at the time was that they are very reliable. Mine was made by Osculati but I cannot see a manufacturer on the one in the link.

 

[captainboo]

I have just fitted this:

http://www.asap-supplies.com/marine.../dip-type-liquid-level-sender-euro-resistance

and this:

http://www.asap-supplies.com/marine...faria-water-tank-level-gauge-euro-black-12831

and used a small quantity of Fish Aquarium Sealant around the supplied rubber gasket as the surface of the tank isn't perfectly level (built in tank above keel).

If it is good enough for my fish it is good enough for me to drink - and you can buy it in a small tube!

 

[Hydrozoan]

Well, your exposure to it is probably a lot less than theirs - especially on a body mass basis, I assume!