Another SILICONE ! question

[robgraham]

As the 'first' OP with the **silicon** typo (it was that no more), which clearly allowed the pendants hanging around here to shine their lights, I've another question.

Many years ago I assembled the bathroom sink into a piece of marble. There are several joints around the marble which were made with silicone, but in my ignorance in those days I made the silicone joints with minimum to zero bead, which has resulted in one going crinkly and the other joints looking grotty.

Bearing in mind that there is virtually no bead, can I just now go over these joints with fresh silicone, having done a scrupulous clean of course, and bead them properly ?

Thanks

Rob

[Tim Decker]

Why not rake out the old silicone with a Stanley knife or similar and redo. I would think this would adhere much better. I recently had to do this on my shower, which was installed about 3 years ago. It didn't take long.

[Bruce]

Silicone adheres well to almost any dry surface, except silicone.

There's no quick fix here, you will need to remove as much of the old silicone as practicable. The fresh silicone is very unlikely to adhere to anything you don't remove.

[Stuart Noble]

The most recent stuff I used doesn't stick to the spout on the cartridge. Put a screw in the base it and pulled out easily, much to my surprise.

[The Natural Philosopher]

I haven't found silicone sticks to anything at all. It seems to adhere by suction. Its usually easy to pull it off anything..

[Cash]

No comment on that one. LOL

Not if you want a lasting job.

Scrape out the old beading as deeply as possible into the joint[s] and clean the areas as thoroughly as possible to remove soap, grease and old silicone residues.

Once that is done, apply the sealant to the joint and then push it down into the joints for as deep as you can get it [1] and then either using a finger (or relevant tool) dress the surface of the sealant to the required finish.

[1] Mastic or silicone [2] sealant performs better when there is a relatively large amount in the opening, as it works by forming a skin on the 'outside' of the bead, leaving the core soft and flexible to do its job properly (in your case, that may not be possible because of the lack of width in the joint[s] - hence your problem).

The ideal *minimum* thickness of this type of sealant is usually about a quarter of an inch thick - any less than this and it completely dries out in a very short time.

That is why I try to leave around a three eighths of an inch gap (bigger if possible) around door and window frames enabling a good thickness of the goo, and ensuring a flexible and long-lasting weather seal.

[2] For the pedantic[s] amongst the group - there is a difference between the two.

Cash

[Bruce]

I think you meant "pedants".

Clearly your grasp of the English language is extremely poor. Perhaps you should consider adult education classes?

[Bruce]

Hoist by his own pendant. ;-)

[Gib Bogle]

That's "pedants", not "pendants", which means hanging things - perhaps you are making a joke? ;-)

[Rob G]

Thanks for that - the basic construction was wrong then in that I created a shelf behind the main surface and just sat the upstand on it with some goo along the joint. The tiling to marble joint is not that much bigger.

I'll do the scrape out, but I'm now wondering if there is another material that bonds better than silicone to seal what is really rather a narrow gap. Any guidance guys ?

Rob

[Cash]

Goodnight Brucie boy - methinks that you are better qualified as an Engleesh teacheher than a D-i-Yeer! Gid help your studentts!

Cash

[Bruce]

That's why I said *almost* any. ;-)

The spout is probably made of a material that is impregnated with some kind of oil that means even silicone won't stick to it.