Hi all.
The back yard paving is not far from completion.
I chose indian stone and I'd like to dye the mortar between the slabs
to a more attractive colour (probably brown).
The pavior told me that there is a risk of staining.
Is this correct?

If so, how to minimize the risk? (masking tape?)

Arthur

51 wrote:
Hi all.
The back yard paving is not far from completion.
I chose indian stone and I'd like to dye the mortar between the slabs
to a more attractive colour (probably brown).
The pavior told me that there is a risk of staining.
Is this correct?

If so, how to minimize the risk? (masking tape?)

Arthur

There's a risk of staining no matter which mortar you use, with or without
dye...personally I wouldn't reccomend dye, because within 6 months it will
have gone away to leave natural mortar...it lasts slightly longer on walls
etc but on paving slabs it simply washes off, or goes green.

I've been using cement dye in lime mortar to point up around
prefinished windows (windows dark stain on meranti, lime mortar with
yellow dye to match local sandstone colour). Yes, I've succesfully used
masking tape on the frames to minimise staining. For the small amount
of paving/tiling I've done (fire hearths), I've just used care - and
yes there is a little bit of staining - but it looks right on irregular
reclaimed building materials.

....personally I wouldn't reccomend dye, because within 6 months it will

have gone away to leave natural mortar...it lasts slightly longer on walls
etc but on paving slabs it simply washes off, or goes green.

That hasn't been my experience of using Febtone Yellow in lime mortar
to repoint around windows - 1.5 winters later and it still looks just
as it should.

Admittedly none of mine is outside on horizonal surfaces.

Agree with you though, some degree of staining - with or without dye -
is pretty unavoidable.

wrote:
...personally I wouldn't reccomend dye, because within 6 months it will

have gone away to leave natural mortar...it lasts slightly longer on walls
etc but on paving slabs it simply washes off, or goes green.

That hasn't been my experience of using Febtone Yellow in lime mortar
to repoint around windows - 1.5 winters later and it still looks just
as it should.

Admittedly none of mine is outside on horizonal surfaces.

Agree with you though, some degree of staining - with or without dye -
is pretty unavoidable.


A lot depends how sloppy the mortar is. Mortar dyes are dispersions of
oxide particles so they shouldn't wash out, any more than the sand does.

Stuart Noble wrote:

A lot depends how sloppy the mortar is. Mortar dyes are dispersions of
oxide particles so they shouldn't wash out, any more than the sand does.

well, i can assure you that it does. And whats worse, it washes out
streakily. Thats with black dye. Red, which is iron oxide, might be
different


NT

Stuart Noble wrote:

A lot depends how sloppy the mortar is. Mortar dyes are dispersions of
oxide particles so they shouldn't wash out, any more than the sand does.

well, i can assure you that it does. And whats worse, it washes out
streakily. Thats with black dye. Red, which is iron oxide, might be
different


NT

Stuart Noble wrote:

A lot depends how sloppy the mortar is. Mortar dyes are dispersions of
oxide particles so they shouldn't wash out, any more than the sand does.

well, i can assure you that it does. And whats worse, it washes out
streakily. Thats with black dye. Red, which is iron oxide, might be
different


NT

wrote:
Stuart Noble wrote:

A lot depends how sloppy the mortar is. Mortar dyes are dispersions of
oxide particles so they shouldn't wash out, any more than the sand does.

well, i can assure you that it does. And whats worse, it washes out
streakily. Thats with black dye. Red, which is iron oxide, might be
different


NT


Got the hiccups today?
I think all cement dyes are oxides and there is a chemical reaction with
the cement that helps bind them. If they're added to the mortar rather
than the dry cement, I guess there's a chance that won't happen.
I'm looking at some I did round a drain cover a couple of years back.
Yellow and red. Looks bloody awful, but it hasn't washed out.

51 wrote:
Hi all.
The back yard paving is not far from completion.
I chose indian stone and I'd like to dye the mortar between the slabs
to a more attractive colour (probably brown).
The pavior told me that there is a risk of staining.
Is this correct?

If so, how to minimize the risk? (masking tape?)

Arthur

Hi Arthur,

I've just done the very same job - 'welsh slate' cast slabs from
Bowland Stone with matching dye for the mortar.

I too was aware of the potential for staining and so I followed the
comprehensive 'coloured mortar' case study at
http://www.pavingexpert.com/point04.htm (great site in general, if a
little *too* much information!).

The key to minimising staining is minimising water - you need enough to
hydrate the cement but too much to cause staining to the surrounding
slabs. Indeed, choosing the right day was the most difficult for me -
I've been taking an unnatural interest in the weather and the so-called
forecasts for a couple of weeks now and finally struck lucky on
Wednesday when the seemingly-endless rain finally stopped.

As the case study suggests (which aligned with the instructions on my
dye which was reassuring) the absolute minimum amount of water is
needed... the water in the sand is pretty much sufficient alone.

My dye was mixed 1 part to 20 parts cement. Whilst the dye was jet
black the abundance of cement soon made it all disappear and I was left
with a very-much-cement colour to this 'coloured cement'. However, when
the coloured cement was mixed 1 part to 4 parts building sand the
colour *really* came out and the mixture was very dark very quickly...
it must've been down to the water already in the sand. In perhaps half
a bucket of mortar I added a splash of water (literally that little)
which had some plasticiser in it however the mixture itself was
aggregating quite well and could be smoothed to a relatively smooth
finish.

As the case study mentions, if the slabs are dry then any spillover
whilst working should not stain - I can confirm they didn't too (which
was a relief). Indeed, the loose (non-compacted) mortar on the
surrounding areas soon dried out thus not staining the slabs. I could
see that the slabs were soaking moisture from the mortar and was
worried they'd be sucking in dye too however 24 hours on I can confirm
that they didn't.

All-in-all I've extremely pleased with the final result - I must say it
was the pointing that I was dreading the most given the 'stain' factor
but in reality it wasn't a problem given the steps I followed.

I've got a few photos which show some of the steps in general if
they're of any interest... indeed given the pointing took me 7 hours I
want as many people to see the final result as possible!

Mathew

"Mathew Newton" wrote in message
ups.com...

I've got a few photos which show some of the steps in general if
they're of any interest... indeed given the pointing took me 7 hours I
want as many people to see the final result as possible!


Oh go on then, I'm about to lay some black limestone for a hearth.
I was going to just mix some ash in to a standard mortar mix.
I'll try it first.
Bung it on tinypic.com or wherever.

--
Mike W

In article om,
writes:
Stuart Noble wrote:

A lot depends how sloppy the mortar is. Mortar dyes are dispersions of
oxide particles so they shouldn't wash out, any more than the sand does.

well, i can assure you that it does. And whats worse, it washes out
streakily. Thats with black dye. Red, which is iron oxide, might be
different

Well, the front of my house is lime mortar with a black die.
It's nearly 100 years old and the die hasn't washed out.
When I've needed to repoint a few bits, I have been unable to
make my mortar dark enough, even by chucking in much more black
die than you're supposed to -- it still looks grey in comparison.
I do wonder what they used 100 years ago? (Soot maybe?)

--
Andrew Gabriel

Andrew Gabriel wrote:
In article om,
writes:
Stuart Noble wrote:

A lot depends how sloppy the mortar is. Mortar dyes are dispersions of
oxide particles so they shouldn't wash out, any more than the sand does.

well, i can assure you that it does. And whats worse, it washes out
streakily. Thats with black dye. Red, which is iron oxide, might be
different

Well, the front of my house is lime mortar with a black die.
It's nearly 100 years old and the die hasn't washed out.
When I've needed to repoint a few bits, I have been unable to
make my mortar dark enough, even by chucking in much more black
die than you're supposed to -- it still looks grey in comparison.
I do wonder what they used 100 years ago? (Soot maybe?)

then it isnt dyed lime mortar, its black mortar. Dying white mortar
wont give you a match, as you've found.


NT

wrote:
Andrew Gabriel wrote:
In article om,
writes:
Stuart Noble wrote:

A lot depends how sloppy the mortar is. Mortar dyes are dispersions of
oxide particles so they shouldn't wash out, any more than the sand does.

well, i can assure you that it does. And whats worse, it washes out
streakily. Thats with black dye. Red, which is iron oxide, might be
different

Well, the front of my house is lime mortar with a black die.
It's nearly 100 years old and the die hasn't washed out.
When I've needed to repoint a few bits, I have been unable to
make my mortar dark enough, even by chucking in much more black
die than you're supposed to -- it still looks grey in comparison.
I do wonder what they used 100 years ago? (Soot maybe?)

then it isnt dyed lime mortar, its black mortar. Dying white mortar
wont give you a match, as you've found.


NT


How do you make black mortar then?

Stuart Noble wrote:

How do you make black mortar then?

as lime mortar but some or all of the sand is replaced with ash. It was
forbidden on many building projects as it was more prone to failure
than lime mortar. In many cases it was used anyway on the non visible
areas, as coal ash was something one had to pay to get rid of.

If repointing patches of black mortar, the logical thing would be to
use more black mortar.


NT

The message . com
from contains these words:

as lime mortar but some or all of the sand is replaced with ash. It was
forbidden on many building projects as it was more prone to failure
than lime mortar. In many cases it was used anyway on the non visible
areas, as coal ash was something one had to pay to get rid of.

Having hit some with a drill a few years ago it amazes me the house that
was made with it was still standing. It was like flaky pastry.

--
Skipweasel
Pay no attention to that man behind the curtain.

visionset wrote:

"Mathew Newton" wrote in message
ups.com...

I've got a few photos which show some of the steps in general if
they're of any interest... indeed given the pointing took me 7 hours I
want as many people to see the final result as possible!


Oh go on then, I'm about to lay some black limestone for a hearth.
I was going to just mix some ash in to a standard mortar mix.
I'll try it first.
Bung it on tinypic.com or wherever.

Sorry for the delay - been waiting for it to stop raining so I can take
some 'real' pictures - these slabs change colour significantly when wet
(get much darker), and indeed the mortar joints also do except they
seem to take longer to dry out. Anyway, gave up waiting for it to dry
out however the following should give some idea what it's like:

http://www.newtonnet.co.uk/house/patio/

The smaller slabs seem to take the longest to dry out and so whilst
they, and a number of the other ones, may look like they've been
stained (particularly at the edges) they're actually not.

Have still got a bit more to do, including rebuilding the steps (to
cover the full width of the french doors) along with some gravel infill
between the patio and decking (this provides drainage to a nearby
drain) but as far as I'm concerned the hardest bits are done!

Mathew

Mathew Newton wrote:
visionset wrote:

"Mathew Newton" wrote in message
ups.com...

I've got a few photos which show some of the steps in general if
they're of any interest... indeed given the pointing took me 7
hours I want as many people to see the final result as possible!


Oh go on then, I'm about to lay some black limestone for a hearth.
I was going to just mix some ash in to a standard mortar mix.
I'll try it first.
Bung it on tinypic.com or wherever.

Sorry for the delay - been waiting for it to stop raining so I can
take some 'real' pictures - these slabs change colour significantly
when wet (get much darker), and indeed the mortar joints also do
except they seem to take longer to dry out. Anyway, gave up waiting
for it to dry out however the following should give some idea what
it's like:

http://www.newtonnet.co.uk/house/patio/

The smaller slabs seem to take the longest to dry out and so whilst
they, and a number of the other ones, may look like they've been
stained (particularly at the edges) they're actually not.

Have still got a bit more to do, including rebuilding the steps (to
cover the full width of the french doors) along with some gravel
infill between the patio and decking (this provides drainage to a
nearby drain) but as far as I'm concerned the hardest bits are done!

Mathew

Ummm.. you've put visqueen under the slabs?

Phil L wrote:

Ummm.. you've put visqueen under the slabs?

'Visqueen'? Are you referring to the blue tarpaulin? Nah.. that's just
keeping the rain off!

Unfortunately I don't have (m)any pictures of the 'main build' as I was
too busy with the back breaking side of the job!

Mathew

Mathew Newton wrote:
Phil L wrote:

Ummm.. you've put visqueen under the slabs?

'Visqueen'? Are you referring to the blue tarpaulin? Nah.. that's just
keeping the rain off!

Unfortunately I don't have (m)any pictures of the 'main build' as I
was too busy with the back breaking side of the job!

Mathew

You've done a good job of it...I always find it hard avoiding making a
pattern when using random shapes like this, I end up repeating the same
pattern without realising it.

Phil L wrote:

Mathew Newton wrote:
Phil L wrote:

Ummm.. you've put visqueen under the slabs?

'Visqueen'? Are you referring to the blue tarpaulin? Nah.. that's just
keeping the rain off!

Unfortunately I don't have (m)any pictures of the 'main build' as I
was too busy with the back breaking side of the job!

Mathew

You've done a good job of it...I always find it hard avoiding making a
pattern when using random shapes like this, I end up repeating the same
pattern without realising it.

I know what you mean!

I followed the 'rules' from the pavingexpert.com site, namely never
have four corners meeting and try to minimise long runs of unbroken
lines. I ended up printing/cutting out the shapes in paper and laying
them out on a plan - this worked well (apart from when the cat took an
interest) and then it was just a case of copying it out.

Even then, once I'd thought it was good to go, the guy at the builder's
merchant immediately spotted a four-corner-meet - clearly I'd got to
the stage where I couldn't see the woods for the trees! Of course,
getting rid of that 'error' without causing another one was tricky but
we managed it in the end!

Mathew

In article , Stuart Noble wrote:
A lot depends how sloppy the mortar is. Mortar dyes are dispersions of
oxide particles so they shouldn't wash out, any more than the sand does.

That would make them "pigments", not "dyes" in most uses. For
practical purposes, that equates to "inorganic and insoluble" not "organic
and soluble".
Brown pigment required, reasonably stable on a million-year
sun-&-rain basis of testing? I'd look at variations on burnt umber,
limonite and the like. Do plenty of batch testing, and specify in great
detail to the supplier that you want a hydrous iron oxide and nothing
else. Ask them for the chemical analysis - should be around about 60~70%
(by weight) iron.
Only thing I'd be a little cautions about is that I'm not sure of
how umber would react to the high alkalinity of a lime mix. Like I said,
batch test.

--
Aidan
Aberdeen, Scotland
Written at Sun, 03 Dec 2006 13:43 GMT, but posted later.

In article , Andrew Gabriel
wrote:
Well, the front of my house is lime mortar with a black die.
It's nearly 100 years old and the die hasn't washed out.
When I've needed to repoint a few bits, I have been unable to
make my mortar dark enough, even by chucking in much more black
die than you're supposed to -- it still looks grey in comparison.
I do wonder what they used 100 years ago? (Soot maybe?)

"Lamp black" is a posh name for soot, made as a pigment. 100
years ago it was a major product for making inks, paints, etc. These
days people have long since realised that (1) it's a hand-made product,
therefore expensive compared to vat-made dyestuffs; and (2) it contains
non-carbon compounds like polycyclic aromatic hydrocarbon, which are
potentially carcinogenic. So, whatever is in your modern mortar dye
probably isn't "lamp black", which is pretty much the definitive "black
man looking for a black cat in a coal cellar at midnight" version of
"black". You might be able to still get lamp black if you specify it.
Also, your 100-year-old mortar will have lost appreciable
slightly-soluble salts over the century, which will still be around in
your new stuff. Look at the stalactites growing down out of an old
brick-and-mortar bridge - that "stal" material came out of the mortar,
and is more or less white, and it's still present in your new "black"
mortar.

--
Aidan
Aberdeen, Scotland
Written at Sun, 03 Dec 2006 14:05 GMT, but posted later.

Aidan Karley wrote:

[...] So, whatever is in your modern mortar dye probably isn't "lamp
black", which is pretty much the definitive "black man looking for a
black cat in a coal cellar at midnight" version of "black". You might
be able to still get lamp black if you specify it.

The modern equivalent "carbon black" is still extensively used as a
filler and pigment in plastics and rubbers.

http://en.wikipedia.org/wiki/Carbon_black

--
Andy

Andy Wade wrote:
Aidan Karley wrote:

[...] So, whatever is in your modern mortar dye probably isn't "lamp
black", which is pretty much the definitive "black man looking for a
black cat in a coal cellar at midnight" version of "black". You might
be able to still get lamp black if you specify it.

The modern equivalent "carbon black" is still extensively used as a
filler and pigment in plastics and rubbers.

http://en.wikipedia.org/wiki/Carbon_black


All manner of pigments are available from art suppliers if you want to
get nerdy about it, but oxides are the most intense, and are widely
available from BMs.