Idiots guide to silcone sealant

[Richard Savage]

Trying to re-silicone my shower enclosure:

[1] remove all old silicone. [2] apply thin bead of new silicone along junction to be sealed [3] run wet finger or similar shaped tool along bead of new silicone pushing excess ahead of tool.

Now what am I doing wrong? The excess builds up in front of my finger until there is too much and it then deposits either side of the bead like a little snow drift!

I assume that this means that there is too much silicone laid down in the first place but if I don't put enough down I get gaps in the smoothed bead.

All this is even worse were I'm sealing the side panels into the wall fixings because I'm trying to seal against only a 1.5mm edge where two panels meet rather than into a 90 deg corner.

TIA

Richard

[Dave Plowman (News)]

I use masking tape either side of the fillet I want to achieve. Then the 'snow drift' can be removed easily - provided you're reasonably careful with the amount you use.

[mrcheerful]

Always apply the silicone ahead of the tube, rather than drag the nozzle, this fills better so you need to apply less. Try to get the nozzle cut to the right width and shape so that no extra smoothing is necessary. But if you need to smooth try the following: put masking tape either side of the line, then after smoothing lift away the tape leaving a clean straight edge.

mrcheerful

[Richard Savage]

Thanks,

Feeding ahead rather than dragging sounds intriguing. I've never had much (any) success with masking tape but I could give it another go.

BTW did you know that Vinegar removes silcone fairly easily from hands!

I'm almost tempted to dismantle the shower enclosure and sit it on a bead of silcone. I realise that that might make it impossible to remove from the tray but . . . .

Cheers Richard

[Lobster]

I find it much easier to "pull" my finger along the bead, rather than "push" it

Yes - you need to get the balance right and judge how much silicone to apply in the first place; it may mean varying the bead thickness according to the size of the gap to be filled as you move along the interface

Are you saying that as you apply the bead, you are moving the nozzle away from you, ie over the top of the newly-injected bead? Sounds much more difficult; you can't see the size of bead you've just laid down...

Try to get the nozzle cut to

Yes, the correct nozzle size helps enormously, but I disgree about not smoothing over the bead - you should always do so as the action of smoothing helps to ensure the silicon is properly bonded to the substrate, and there are no tiny gaps which could allow water penetration.

David

[mrcheerful]

If the nozzle is the correct width and the application speed is correct then there is no problem, plus the silicone gets pressed in well as the nozzle passes over it, this also shapes the bead. This is really good when you get the hang of it and extremely satisfying!!

mrcheerful

[Dave Liquorice]

And taking into account how deep the gap is, the amount put down does need to vary along the length of any normal sealing operation. Rarely are the two edges at a uniform distance and depth.

Thats how I read it.

With a correctly sized nozzle it forms just the right sized bead for a quick smooth over later. As you are injecting the silicon into the gap watch the *little* bulge that builds in front of the nozzle, you want to try and keep this a constant size that ensures that the gap is filled but not to excess. It's also important to do each run in one constant an operation as possible pauseing produces a blip, it can be tricky if one or both of the edges aren't nice and smooth though.

| | --> Direction Nozzle --> | | | / | /\ | / \

[raden]

In message , Lobster writes

Or do it in two passes, one to fill the gaps and holes, and the second to give a nice finished profile

[Andy Hall]

There are several things here.

If the gap is fairly large, put in the sealant in layers, letting it partly cure in between each.

When you get to the last one, don't use a tool, use your finger, and importantly pull along the silicone bead, don't push.

Get a pot of water to which you have added a small squirt of washing up liquid.

Dip your finger in it and run it *lightly* along the bead in a continuous motion.

Have a rag ready and if there is any sealer on it, wipe it off and use another moistened finger.

.andy

To email, substitute .nospam with .gl

[Ian White]

Andy Hall displayed the English talent for understatement :-)

It works even better if you add a *large* squirt of washing up liquid (even up to 50/50), and thoroughly *soak* your finger in it.

I've had very good results with masking tape, laid down carefully in a double run. It avoids the need to lay down an absolutely perfect bead without repetition, hesitation or deviation - which most people find very hard to do.

Simply lay down a little more sealant than it's going to need, and then use your finger-end to squeeze the bead down to a constant size. The excess comes off onto the masking tape and your finger. If your finger is well pickled in the liquid, the sealant won't stick and can easily be flicked off .

More details of this method are in the FAQ.

[Ziggur]

All previous replies are excellent advice, but to be a real expert you must wear the sweater she gave you for your birthday and wipe your hands on it every 2 minutes.

[andy]

Nice One LOL