Making Lime Putty

[rebeccac]

Hi all I'm new here and my house is in Italy rather than the UK but we do have experience in old buildings here too!

I bought a fantastic book on natural plasters and in the chapter on lime the author states that its possible to make a lime putty from adding hyrated lime to water.

I always believed that hydrated lime that you buy to mix with cement, was no good for this purpose.Last time I made up some mortar forrepointing I used a special mix by Biocalce with tiny quartz vchips.Very pricey at 18 euros a bag whereas our local builders merchant has 25kg bags of hydrated lime for 2 euros!!!yes 2 euros in Italy 10 euros in the UK!

rebecca http://www.myabruzzohome.com

 

[Roger H]

Hi. I found making this extremely straightforward. There is a detailed discussion under the "Lime Mortar: What Ratio?" thread back in October.

In brief: Get your bag of Hydrated Lime (usually not Hydraulic Lime). Half fill a few plastic 25L buckets, or similar (ideally with lids) with the lime, then add water and mix with a spade until you get a sloppy mix. Then cover with tight lid or top up with water to form an airtight seal. Leave for a couple of weeks or as long as you can (gets better the more it sits). Then mix the gloop (which will have settled and will resemble mozzarella) with your chosen sand at a ratio of 1:3. Usually add no more water. There is plenty in the 'cheese'. Point.

Takes a while to mix up the mortar by hand I find. Chopping and smacking with back of spade eventually works.

 

[CHRIS]

Roger is right about how to make putty. I used a plastic dustbin from B and$ with a lid and put the whole 25k bag in and covered with water, I then gave it a stir with a piece of copper pipe and left it for 2 months, if you have a few on the go you can stagger the time so you always have "matured" stuff over 2 months old.

I bet the quartz chips were used as a pozzolon

http://www.geocities.com/CapeCanaveral/Launchpad/2095/pozzolan.htm

to add strength

I bet you would have no trouble finding this in Italy!

 

[rebeccac]

Hi

thanks for that.It's great that someone else thinks that the putty resembles mozzarella!

In Italy its called 'crema di calce' sometimes too!I like it

btw how do you get an image in your post????[/img]

 

[MdB]

btw how do you get an image in your post????

http://periodpropertyshop.co.uk/phpBB2/viewtopic.php?t=7515&start=0
I think we need to make this thread a sticky.

 

[biffvernon]

I've just spent the day lime plastering a lath ceiling. I used a barrow full of sand dug up from my garden and a bucket full of lime, that's the hydarted lime bought in a bag from the nearest builders' merchant. I mixed the two together in the barrow with a spade and then added enough water to make the mix just sloppy enough to spread and stick to the ceiling. Plus a goodly pinch of goat hair.

My shoulder aches

 

[Penners]

My shoulder aches

And I imagine your goat's chilly.

 

[rebeccac]

That's interesting.we plastered our concrete block garden wall with hydrated lime and sand.Its looking fine.We need to do the final coat but this wet summer means anytime we can do it it rains!

I read that mixing ordinary hydrated lime with sand to make a mortar is a bad idea.You should always use NHL.I think there must be someone here who can explain!

 

[Nemesis]

No, if by NHL you mean hydraulic lime that should only be used in specific circumstances.

What most home applications require is non-hydraulic.

That's usually bought as lime putty, but you can make putty from bagged hydrated lime.

There is some controversy about whether or not it is as good as the stuff bought in tubs, But many think it OK and much cheaper.

Just make sure it is fresh, and stored in the dry, or it can carbonate in the bag and is then not much use.

 

[GK]

Hi all, still here then

After using only posh stuff lime putty I relented and tried Biff's quick and dirty mix. Just chucked a bag of lime hydrate in the mixer with 3 times as much sharp sand. Not dug out of the garden but from quarry down road.

Mixed for 20 minutes, put in dustbin, used 3 days later on this old wall which is falling down from the bottom up. Can barely, if at all, tell the difference between this and the 2-years plus matured mortar made from putty. Winter will tell, I've even mortared up verge on a roof with it.

 

[Nemesis]

Wondered where you'd got to...

 

[Penners]

He's been busy pointing up an old wall and mortaring the roof verge...

...and probably a hundred other things.

 

[biffvernon]

It's encouraging to see you think you've got time to attend to the garden now. Well done

 

[GK]

Haven't really got time to attend to the wall but the alternative was to see it fall over before the year's out

 

[gsport george]

Does anyone know why my lime mortar always goes really white? I assume this is because the sand is fairly light coloured and there is a lot of lime on the surface? Or am I doing something drastically wrong?

George

 

[MdB]

Does anyone know why my lime mortar always goes really white? I assume this is because the sand is fairly light coloured and there is a lot of lime on the surface? Or am I doing something drastically wrong?

Wet lime is fairly transparent and goes white when it dries. Lime wash shows this fact off very well. The same thing happens with lime mortar though you can show off the colour of the sand in the mix if you brush the surface as it dries. It gives a better looking finish in my book too if you brush it. Without brushing, the wet lime on the surface dries to white covering the underlaying sand.

 

[Mark]

probably also that your lime (either home made or bought in putty) will be a lot purer than the stuff made when the house was built.

Some people use red sand (dont know what its really called but the builders merchnats stock it) to get a cream coloured mortar,

I've experimented with ash and clay to get slightly differetn colors.

 

[BMcD]

Mark wrote:

I've experimented with ash and clay to get slightly differetn colors.

Will the addition of ash and clay (if burnt) not act as a pozzolan and make your lime Hydraulic?

 

[Mark]

not sure.

I think its not just impurity but also what the impurity is. Im not too sure of how the pozzelan impacts on the chemical set.

In any case I think a fairly high level of impurity would be needed. I did 1 lime:1 ash: 3 sand (by shovelful) and it seemed to behave much the same as without but gave a grey rather than white colour

 

[biffvernon]

Your sand is too clean! Add some earth to the mix.