Using bathroom silicone sealant...

[andyoxon]

OK, having spent ages prepping the shower cubicle I had a go at sealing the base with Bathroom sealant inna trad spring 'gun' and a spreading tool.  I still managed to make a semi horlicks of it...  Laying out too much, pulling too much off with the tool, not getting the corners neat, trying to smooth bits that had dried too much...  It's OK but doesn't look pretty. 

What's the secret in general for a good job?   Can I go over with another layer once it's dried off?  I still have to do the bath, so want to do better next time.

[ScumOfTheRoad]

I still managed to make a semi horlicks of it...  Laying out too much, pulling too much off with the tool,

Oh Dear God - rapidly heading for NSFW.

Seriously though - I wouldn't mind some tips on this myself.

[mrcharly-YHT]

Don't put much in - you only need a small bead to be able to smooth it to a rounded U seal. Use a wetted finger to smooth it in place.

[geraldc]

Cut nozzle at an angle and as said before, use wet finger to smooth it out.

[Jaded]

Wetted fingers are exceptionally useful.

Never underestimate them.

[Woofage]

Wet finger, yes, but wet with liquid detergent not water. Wash it off when the SS has skinned over.

[Jurek]

Lighter  fuel.

There's your answer.

The sort which keeps Zippo's running.

Put it on cotton buds or whatever.

It does the business before the silicone goes off, really.

[YahudaMoon]

Cellulose thinners and lots of rags if you make a cock of it while its wet gives a good finish

The correct way to apply it is with the nozzle. The nozzle gives the required finish. Its best to have very small gaps. So you cut the nozzle to what size gap you have to fill. Large gaps usually look unsightly.
Takes practice and patience,  fingers tools to get a finished result is the incorrect way

If you start sticking your fingers / tools in the stuff to smooth it out this usually ends up loooking like a dogs dinner though cellulose thinners and a rag can  give a good result

Not sure if turps or white spirit would do the job ?

[Andrew Br]

Lighter  fuel.

There's your answer.

The sort which keeps Zippo's running.

Put it on cotton buds or whatever.

It does the business before the silicone goes off, really.

I'm surprised that you're not recommending a Gold card 

   
 
 

... and after all that, I still have to wear them under my 3/4's for them to stay up 

That, of course, is Rapha masking tape. Nothing else will do. 

That's why he's using a gold card to spread the silicone 

FWIW Andy, my answer for all DIY is GSI.

[mmmmartin]

masking .tape on the sides of the area
spread sealant using nozzle
back of wet teasppon to smooth it off.
remove masking tape to provide a smooth edge.
er, that's it

[andyoxon]

Ok thanks, some good tips.  Re. my shower base effort, would it be a very bad idea (before using the shower) to put masking tape slightly wider that the new silicone and then seal over again, using a soapy spoon to smooth over..?

[fred the great]

I would be inclined to remove the mess and start again. Run a  small continuous bead and forget the smoothing or practice first before doing it again. If you make any mistakes, wait until it has dried and cut off any excesses with a paper cutter.

[tiermat]

One thing I learnt when doing baths is to put the plug in and fill it with water, then seal it, otherwise it will crack the first time you use the bath.

HTH

[henshaw11]

>paper cutter.

Or a razor blade.

If you use the masking tape approach you may still need to go over with your moistened finger to get a smooth edge, but hopefully there'll be the right amount of silicone in the joint.
If you've got some areas that need at lot more filling than others you could fill those first, then go over the whole lot when it's gone off. Or mebbe do the lot in two passes - one to fill (could use that as some practive), one for finish - but you'd still be safer masking off in each case, and trying to get the first pass to a reasonable (recessed) finish.

I'd start again, if you start messing with tape now and trying to build it up at best it may look a bit excessive, but I suspect more likely, a bit of a botch 'cos the thicker/wider layer will be harder to get even. A combination of a razor blade to cut out as much as possible, then the proper silicone removal stuff should do the trick, it doesn't dissolve it that cleanly so much as loosen it's grip but it will help get it off with a bit of persistence.

[fred the great]

Cutters are always safer to use 'cos they have a handle to hold.

Don't ask me why I know?

[Tom M]

I find with the traditional 'guns' that the flow rate is more difficult to manage as you need to keep pumping, and when you need to pause for a second  the flow of silicone doesn't necessarily do likewise. I've had more sucess with the pressurised cans of sealant where you can start and stop a lot more easily and the flow is more consistant.

[mrcharly-YHT]

Tip: Just before you need to stop, disengage the 'tab' that locks onto the piston rod.

[drossall]

Took me two goes to get our bath right - first time leaked quite a bit.

Another vote for washing-up liquid and a finger - worked better than the special tool I bought for the first time. Also (for baths) filling them first.

[HTFB]

This looks like the right thread to resurrect.

What we have, see, is a shower with concealed pipework. So the hot and cold feeds come up behind the tiles to a fancy brass diverter unit, and from the diverter the outlet pipe stays behind the tiles up to an arm with the shower head.

All the business happens at the diverter, which has a press fit into a manifold to accept the various pipes, and the manifold is mounted in a nifty plastic box in the wall that comes up to the back of the tiles; then a front plate goes on top of the tiles for the controls.

The idea is that, if there's a leak at the diverter, the box catches the water and lets it drain out of the front, over the tiles, rather than into the fabric of the flat.

Obviously this relies on the person installing the bathroom to seal the cutouts around the inlet pipes, the odd overflow channel the manufacturer left for some reason at the back of the box, the front of the box to the tiles, any cracks he put in the box as he installed it, and so forth.

The utter moron who installed this bathroom did none of this, the bastard. So, when the diverter failed, we've had gallons of water dripping slowly down the studding, penetrating under the laid floor and over the concrete, and ruining bits of wall all over the flat.

So my problem is: how can I seal the inlet cutout? It's a D shape, in the back corner of the box, with a pipe rising though it into the manifold, so the gap is quite large---say up to a centimetre---and the back half is inaccessible.

The *last* time the diverter failed, it was dripping from the shower head, so the box wasn't tested. I tried pre-emptively to seal the cutout with a large amount of silicone, but though messy it wasn't 100% effective, as it needs to be. (There were the other places that weren't sealed either, through which most of the water has been coming, but as far as I can tell I've got those sorted this time).

I'm stripping out the last lot of silicone with a proprietary remover at this moment. So do I
(a) try again with the silicone;
(b) use something else;
(c) throw my hands up, and just call in a plumber to see what he can do?

[neilrj]

Can you line the box with something waterproof that you can silicone in place so you have a 'belt and braces' lining in the hope that lining or the 'glue' will do the job? Surprised the diverter fails so often though!

[HTFB]

Today's second, more comprehensive, swathing of the whole thing in silicone seems for the moment to be doing the trick. Or if it isn't, the escaping water is trickling silently down the back of the tiles rather than dripping into the void.

Of course all this damp has had consequences, including enough movement of the tiles that the line of grout down which the water is running, as it ought, is now cracked and the trickle goes back behind the tiles if I let it. A strategically placed J-cloth is wicking the flow away for now.

Any thoughts about whether I can just silicone over that grout, or should I try to do a proper job?

[jsabine]

How much do you want to do a proper job, and how much do you just want to stop the water seeping through?

Scraping out the grout and replacing won't take *that* long, but silicone will work as long as you can get the area, preferably including the inside of the crack, dry. (Something like CT1 or Plumber's Gold will stick to a damp surface where silicone won't.) I'd be inclined to finish it flush with the tiles rather than trying to indent it like the current grout.

ETA - if you do go for silicone, clean the surface really thoroughly before applying it, making sure there are no traces of soap. Wiping over with vinegar or IPA is a good final stage.

[T42]

Gawd, this revives horrible memories. The unutterable swine that did the plumbing in this house left a gaping hole behind the decorative flange covering the pipes to the shower taps. We found out when the ceiling downstairs bellied downwards and water ran out in a thin trickle a few inches from a bookshelf.  The tiles were mounted on a studding with an uneven 3-4" gap between it and the old half-timbered wall (this house was built in 1837). I had to build that up with aerosol cavity filler before I could engineer a silicon plug to seal it.

The same sod also concreted in a stiff PVC wastepipe at one end and took the other one into a sink mounted on aforesaid wall. In a powerful gale this house works like a timber ship: the pipe snapped and again we found out the hard way.

[drossall]

Apocryphal, but a former neighbour told me a story of another former resident who had had a problem with an overflow, and enquired whether he could solve it by bending the pipe upwards.

Must go and fix our overflow, which is dripping outside the window as I type...

[Fab Foodie]

One thing I learnt when doing baths is to put the plug in and fill it with water, then seal it, otherwise it will crack the first time you use the bath.

HTH

^^^^ This is most excellent advice.