Got an interesting problem with a mate's shower tray where the silicone
seal keeps failing.

All proper methods of prep and application have been used (Mechanical
removal, clean down with IPA, apply with Fugenboy etc) but the seal
fails within a few months. Looking at replacing it for the third time now...

The failure mechanism seems related to the tiles; which are a large
300mm square 15mm thick travertine marble ones with a matt finish. The
seal always seems to part from the vertical surface against the tiles
while remaining stuck like **** to a blanket on the (stone resin) tray
itself.

We have tried several brands of silicone - the posh dow corning one
lasting less well than the basic screwfix sanitary.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:

The failure mechanism seems related to the tiles; which are a large
300mm square 15mm thick travertine marble ones with a matt finish. The
seal always seems to part from the vertical surface against the tiles
while remaining stuck like **** to a blanket on the (stone resin) tray
itself.

Do the faces of the matt tiles need sealing with something-or-other at
the edges, where the silicone is to be applied? Could they be porous
and are exuding some form of grease/soap?

David

Lobster wrote:
John Rumm wrote:

The failure mechanism seems related to the tiles; which are a large
300mm square 15mm thick travertine marble ones with a matt finish. The
seal always seems to part from the vertical surface against the tiles
while remaining stuck like **** to a blanket on the (stone resin) tray
itself.

Do the faces of the matt tiles need sealing with something-or-other at
the edges, where the silicone is to be applied? Could they be porous
and are exuding some form of grease/soap?

I expect this is probably the case... I did suggest that he try some
Lithofin stainstop on them first, but I doubt that will happen.

Perhaps I ought to mask of the section where the bead will go and spray
it with something before next applying the silicone.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:
Lobster wrote:
John Rumm wrote:

The failure mechanism seems related to the tiles; which are a large
300mm square 15mm thick travertine marble ones with a matt finish.
The seal always seems to part from the vertical surface against the
tiles while remaining stuck like **** to a blanket on the (stone
resin) tray itself.

Do the faces of the matt tiles need sealing with something-or-other
at the edges, where the silicone is to be applied? Could they be
porous and are exuding some form of grease/soap?

I expect this is probably the case... I did suggest that he try some
Lithofin stainstop on them first, but I doubt that will happen.

Perhaps I ought to mask of the section where the bead will go and
spray it with something before next applying the silicone.



/================================================== ===============\
Internode Ltd - http://www.internode.co.uk |
-----------------------------------------------------------------|
John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Stand in the tray as if having a shower and see if the gap under the tiles
increases by a large amount. We had similar probs with our bath due to
springy old floorboards underneath.

Pete

On Jun 10, 1:17*pm, John Rumm wrote:

Perhaps I ought to mask of the section where the bead will go and spray
it with something before next applying the silicone.

How about painting a little superglue on to see how well it sticks to
the tiles?

cheers,
Pete.

Pete C wrote:
On Jun 10, 1:17 pm, John Rumm wrote:

Perhaps I ought to mask of the section where the bead will go and spray
it with something before next applying the silicone.

How about painting a little superglue on to see how well it sticks to
the tiles?

AFAICR that doesn't fare well with water, does it?
David

Pete Cross wrote:

Stand in the tray as if having a shower and see if the gap under the tiles
increases by a large amount. We had similar probs with our bath due to
springy old floorboards underneath.

No, its rock solid...

(good suggestion though! ;-)

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Jun 10, 2:55*pm, Lobster wrote:
Pete C wrote:
On Jun 10, 1:17 pm, John Rumm wrote:

Perhaps I ought to mask of the section where the bead will go and spray
it with something before next applying the silicone.

How about painting a little superglue on to see how well it sticks to
the tiles?

AFAICR that doesn't fare well with water, does it?

AFAICT it's waterproof:

http://64.233.183.104/search?q=cache...wikipedia.org/
wiki/Cyanoacrylate+cyanoacrylate+waterproof

cheers,
Pete.

On 2008-06-10 12:32:56 +0100, John Rumm said:


Got an interesting problem with a mate's shower tray where the silicone
seal keeps failing.

All proper methods of prep and application have been used (Mechanical
removal, clean down with IPA, apply with Fugenboy etc) but the seal
fails within a few months. Looking at replacing it for the third time
now...

The failure mechanism seems related to the tiles; which are a large
300mm square 15mm thick travertine marble ones with a matt finish. The
seal always seems to part from the vertical surface against the tiles
while remaining stuck like **** to a blanket on the (stone resin) tray
itself.

We have tried several brands of silicone - the posh dow corning one
lasting less well than the basic screwfix sanitary.

Yes it will behave like this.


The tiles should have been treated with two coats of Lithofin MN
Stainstop before silicone goes near it.


I tried the experiment recently both ways with some limestone. No
sealer and the silicone doesn't adhere properly. Use Stainstop and it
does.