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How to put smooth coating on concrete windowsill - a grout?

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Maria

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Sep 19, 2011, 5:49:20 AM9/19/11
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I have a sculpted concrete windowsill (exterior) on my Victorian house, which had decayed and crumbled over the years. I got rid of all the paint and rubbish on it, and rebuilt the profile using cheapo Wilko exterior filler, smoothing it off with a wet trowel. It looks like a new sill now, except for a few patches where the filler is powdery (presumably because I overwet it when smoothing off).
What I would like to do is give it a final thin coat to fill in the rough parts and make it more stable - I did a quick search on the net, and saw an article that suggested using a home made 'grout' for this purpose, which can be put on thinly - to prevent the surface from crumbling due to its thinness, they mixed it with something, but being a US site using US trade names, I don't know what it is.
Any ideas what I could mix with this filler to keep it smooth and adhesive please?
Thanks

stuart noble

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Sep 19, 2011, 7:47:58 AM9/19/11
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This is the stuff I'd use

>> http://www.toolstation.com/shop/Painting+Decorating/Fillers+Putty/Pro+Fill+500g/d150/sd3169/p17703

Not easy to apply, but rock solid, even in very thin layers.
Use the plastic applicator (or scraps of wood) instead of your wet trowel.

Maria

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Sep 19, 2011, 7:52:15 AM9/19/11
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Excellent thanks - and should I use this stuff alone, or mix it with the mortar filler I've been usin?

Jim K

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Sep 19, 2011, 8:06:50 AM9/19/11
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post up the US web link for analysis.

(& no, don't mix 2 part epoxy filler with anything else....)

Jim K

stuart noble

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Sep 19, 2011, 8:17:54 AM9/19/11
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On 19/09/2011 12:52, Maria wrote:
> Excellent thanks - and should I use this stuff alone, or mix it with the mortar filler I've been usin?

Use it alone, and make sure surface is dust free and dry.
As I said, not easy to use, so only mix up golf ball size bits at a time.

Jim K

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Sep 19, 2011, 8:28:12 AM9/19/11
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"not easy to use" is probably somewhat of an understatement,
especially given the OPs apparent level of expertise.

what colour will it be when it sets? concrete colour? or will it need
painting?

Jim K

stuart noble

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Sep 19, 2011, 9:17:31 AM9/19/11
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Pale grey IIRC.
Not easy but a skill worth acquiring because it allows you to do all
kinds of otherwise impossible jobs.
Points to remember:
Once mixed you only have a minute to do whatever you're planning to do
with it.
It can be sculpted with a sharp blade (and/or removed from tools) for a
further minute or two.

Maria

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Sep 20, 2011, 4:24:23 AM9/20/11
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Ok thanks for your help.

Maria

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Sep 20, 2011, 4:23:56 AM9/20/11
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On Sep 19, 1:28 pm, Jim K <jk989...@gmail.com> wrote:
> On Sep 19, 1:17 pm, stuart noble <stuart_no...@ntlworld.com> wrote:
>
> > On 19/09/2011 12:52, Maria wrote:
>
> > > Excellent thanks - and should I use this stuff alone, or mix it with the mortar filler I've been usin?
>
> > Use it alone, and make sure surface is dust free and dry.
> > As I said, not easy to use, so only mix up golf ball size bits at a time.
>
> "not easy to use" is probably somewhat of an understatement,
> especially given the OPs apparent level of expertise.

I used to work in a car body repair shop if that helps (which is how I
know how to sculpt a new windowsill and it looks ok!)

Maria

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Sep 20, 2011, 4:25:24 AM9/20/11
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I can't find the link now, but I've found something else called Epoxy
Mortar (available here). Reckons it can be smoothed to a feather edge.
That sound any use?
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