Making Lime Putty

[gsport george]

I have experimented with different mixtures sands and a bit of earth. The mortar always gets lighter over time and I can't seem to get a match.

The brushing sounds like the answer, is there any way to remedy it now it is dry?

If I brush in future, when do I do it?

 

[NT]

Burnt clay is pozzolanic but raw clay isnt.

You can still brush your lime with a metal bristle brush.


NT

 

[biffvernon]

If the sand is quite coarse and you brush the pointing while still soft you expose the big grains and the whole lot ends up looking much less white. With finer sand this effect is not so dramatic.

 

[Ian Bond]

If I brush in future, when do I do it?

When the mortar's firmed up enough so that it doesn't spread all over the surface of the wall when you brush it, but before it's too hard!

I test the mortar by pressing it with my thumb - it should be possible to mark it with the edge of my nail, but not press my thumb into it.

Then I try brushing the joint to bring the aggregate to the surface. If the mortar's still too soft I leave it a bit longer. Trial and (hopefully not too much) error.

I made the same mistake when I first pointed a repair to the stone wall of my house, and used a trowel to create a smooth finish to the mortar. It went white. The only way I found to remedy this was to scrape back the joint, and point it correctly - the brushing made a big difference, but was still a little too light in colour. Biff's suggestion of mixing in some earth sounds good.

 

[Ian Bond]

Just found this pointing with lime guide on my computer, may be of use

(Opens in Acrobat Reader)



http://www.hullcc.gov.uk/pls/portal...NSERVATION/LISTED BUILDINGS/LIME_POINTING.PDF

 

[Nemesis]

Leave for a day, scrape back with the blunt end of a pointing trowel to expose the aggregate.

If it's still too white now, try staining it with a teabag, which others have suggested in the past.

But lime mortar is white!

 

[Penners]

try staining it with a teabag

PG Tips or Earl Grey?

Milk and sugar?

 

[Nemesis]

Not Earl Grey, far too delicate.

No milk or sugar.

The powder stuff used to stain cement is worth trying too - make up a solution in water and test.

Lime does darken in time, but it is white and I think we are not used to this nowadays.

 

[Penners]

When I was in furniture manufacturing, we tried staining wood with tea. Very effective at first, but the colour faded considerably after a year or two. I wonder whether this would also happen with the mortar

 

[Nemesis]

I would think so - but the tip came from one R Tavendale ages ago so thought I'd better mention!

A coat of watery cowmuck might help too.

Or simply leave it alone - as I said, it's meant to be white.

 

[Gervase]

Cow crap tends to turn it olive green. Slate dust can tone down the whiteness a bit, as can Biff's method of bunging in some soil. The whiteness doesn't last, though - once the surface lime has weathered and more of the aggregate gets exposed (hence the desirability of brushing) it soon loses its starkness.

 

[Nemesis]

I tried watery cow crap on a bit and it wasn't terribly olive green. Must eat different things here!

It does, as you say, weather and tone down a little, but I think people are so used to seeing cement that they think it's wrong to have light mortar.

I like raking back I have to say as opposed to brushing, it's the M Suhr method too, but each to their own.

 

[charlie-ia]

live yoghurt (any flavour) can be used to help garden stoneware look a bit more dated. encourages a little bit of algae/ moss to start with, perhaps lichen eventualy. doesnt make it go too green and slimy.

black cherry might be a bit lumpy. try plain.

 

[Penners]

So there you have it. Yoghurt, a cuppa tea and some cow crap.

Delia Smith, stand aside.

 

[Nemesis]

Actually, I find yog simply makes for mould!

 

[Penners]

Actually, I find yog simply makes for mould!

Actually it's the other way around.

It's the mould (or something similar) that makes the yoghurt.

 

[rebeccac]

Having spent ages brushing black lichen off limestones I would be reluctant to apply anything that encourages its growth!

I bought powdered earth pigment, mixed with water then mixed into the mortar.I suspect the mortar will go off lighter than it looked when I put it on.

 

[Mark]

I bought powdered earth pigment, mixed with water then mixed into the mortar.I suspect the mortar will go off lighter than it looked when I put it on.

you suspect correct

 

[rebeccac]

I find the amout of water effects the colour.

I've been adding earth pigments mixed first with water then added to a dry sand/lime mix. 8 teaspoons of yellow ochre to 3 spades lime mix plus 1 of sand(i'm using a brand called biocalce which has sand mixed in but I can get away with adding another spade.)

After 3 months the mortar stayed a lovely buff /stone colour .i brushed it with a wire brush after 4/5 hours.

This all took place in Abruzzo.Italy with higher temps than in the UK.