When to use plumbers mait/silicone sealant

[AndyP]

Probably a simple question but:

When should I be using plumbers mait and when should I use silicone sealant?

Obviously I use silicone for things like round edge of the bath etc. However, on my new bath, the instructions said to use silicone around the rim of the waste to seal it to the bath.. I thought I was supposed to use plumbers mait. The sealant I got from Wickes (their kitchen and bathroom stuff, which says it's suitable for baths, showers, etc) says it's not suitable for continual immersion in water, which seems to suggest I shouldn't use it for the bath. The bloke in Wickes recommended I use their "external leak sealer and jointing compound" round the waste.. I'm a bit confused by all this.

As per another post, I'm also about to put a new tank connector into my cw cistern in the loft. If I want to be really paranoid, would putting some plumbers mait in there make it less likely to leak, or would it be pointless?

Thanks, Andy

[tarquin]

it would probably be counter-productive IMHO,just use the washers as supplied with the tank connector fitting.

joe

[Lee]

Use Fernox LS-X it's great for these applications.

Lee

[AndyP]

Sadly no washers were supplied (tank connector bought from Wickes - they sell many different types of washer separately, although it's not obvious which sort I should use).

Cheers, Andy

[Al Reynolds]

Almost never.

Most of the time.

Whenever I've used plumber's mait in any joint, i've ended up taking it out, cleaning it all off, and using silicone or the correct washer. I reckon you'd be best to start with silicone or the correct washer.

AFAICR, Belfast sink wastes need plumber's mait, but I don't have one so I'm not sure about that.

HTH, Al

[AndyP]

So is there a brand of silicone suitable for total immersion in water - eg round bath waste? As I mentioned, the stuff I've got (from Wickes) says it's not suitable for this.

Thanks, Andy

[Grunff]

Then it's not silicone. Silicone is always suitable for immersion in water.

[Ed Sirett]

There are very few places where Mait (stay soft putty) is needed. Basin wastes is one. Useful also when ceramic is on ceramic to soften the contact, i.e. basin on pedestal, or WC pan on floor tiles.

[Al Reynolds]

I always use Unibond Sanitary Sealant. Never had any problems on wastes etc.

Al

[Pete C]

Hi,

If it's cheap stuff maybe it has fillers in. Silicone has long been used for holding glass fish tanks together so the proper stuff can be used in that way.

cheers, Pete.

[The Natural Philosopher]

Silicone sealant is not appropiate for surfaces which need to slide over one another to seal - e.g. threads.

In every other way, its better than sliced bread, except for toast.

[Andy Wade]

... a disaster. AIUI you should _never_ use linseed oil based compounds (such as plumbers' mait or boss white) on plastic fittings.

(I'm assuming you mean a plastic cistern, not an old galvanized one.)

[Dave Plowman (News)]

Fernox LS-X as already mentioned.

[Christian McArdle]

Nah. I cleaned all the plumber's mait off and replaced with silicone when I installed mine. ;-)

Christian.

[Steve Firth]

Not silicone, but Evostick Nail and Seal is suitable for prolonged immersion. It's much better than silicone, even the Fernox LS stuff which is just the usual piss-poor silicon in a small tube.

[AndyP]

Hmm. Well it definately says it's silicone on the tube. And it definately says it's not suitable for continual immersion in water. Sounds like there are different "grades" of the stuff with the Wickes variety being down the bottom end.

Cheers, Andy

[Pete C]

Does the oil affect the plastic in any way?

cheers, Pete.

[Andy Wade]

I think it can do, with some types of plastic, possibly by a reaction with any plasticiser, causing embrittlement. I first came across the advice in the instructions that came with a Ferham plastic (PVC, probably) cistern and have kept it in mind ever since.

[Rob Graham]

Ah well, in that case I'm going to have problems sometime in the future !! Firm believer in Plumber's Mait for traps and the likes. At least I might now have an idea what was the cause.

As a side question - what is the best way of getting taps to tighten properly onto the bath or basin; previously you could rely on the stiffness of the copper pipe to help with this but with flexible couplings and plastic washers I'm finding it difficult to get taps to lock properly to the bath, etc.

Rob

[AndyN]

Use what are called top hat washers. Fit tap in hole, slide top hat washer under and onto tap tail and lastly fit tap back it on to secure it all. Job done!