Naive lime question

[Me!]

Sorry to bring this thread back again, but the title seems very appropriate to my question!
I've just bought a bad of hydrated lime that I would like to use to make a lime filler to fix cracks in existing ceilings, and also limewash to paint them all afterwards. I'm sure I've read on this forum before about mixing hydrate and water, and that it does matter which you add to which, and the quantity of water to use, but I can't find the posts again now that I need them. (The forum search facility is driving me mad as it ignores the word lime, because it is too common!) So, can somebody please remind me whether I should be adding powder to water or the other way around, and how much water to use please? I had thought of making a tub of putty, which I could then use to mix with sand to make filler or water down to make limewash, does this seem reasonable?
Thank you.

 

[biffvernon]

I've just bought a bad of hydrated lime

Nothing bad about hydrated lime.


I don't think it really matters which way round you mix it. If you add too much water the lime putty will settle out after a while with clear water above, which can be poured off when you come to use it.

(With quicklime it DOES matter which way round you go. Get it wrong and hot stuff spits in your eye. Add a little quick lime to lots of cold water.)

 

[Ian Bond]

I just half filled a 20L tub with water, and added the hydrated lime powder in gradually whilst stirring with a stick. With care managed to get a reasonably smooth putty mix this way. Although it is a recipe for creating dust - not really a problem in my wreck of a house, as a bit more dust makes no odds.

If it's getting too thick you can always add more water - too thin you can wait for it to settle and pour some off.

I seem to remember a long while back someone suggesting a dust-free and easy method, which involved cutting the bag and placing it in a dustbin containing water. Let the lime hydrate soak then remove the bag, mix and leave for a day or two. This may be more appealing than my dusty/messy approach, and it sounds good to me.

Did you suggest that method Biff?

 

[MdB]

As Biff said, I don't think it matters which way you do it apart from safety issues. Hydrated lime is not something you want to breath in. It makes a nasty alkali when combined with water which is not something you want to happen inside your lungs. (*)

I turn hydrate into putty outside on a still day whilst wearing a mask and gloves. I use an old ice cream tub to move the hydrate out of the bag rather than pouring as this keeps the dust levels down. My process is as follows:

1) Fill container about a third full with water.
2) Use tub to transfer hydrate from bag to container. As there is water in the container, dust levels are reduced. Fill container close to the top, adding water as you go so as to keep a layer of water on the surface.
3) If you want to be super safe then wait 24 hours for the water to soak into any air pockets.
4) Stir gently as there are likely to be air pockets that need to escape.
5) Make sure there is a layer of water on the top then leave for as long as possible.

When you come to use it, pour off the liquid on the top (you may want to keep this liquid for making lime wash etc). I've found that you really want to get rid of all the liquid and use a sponge to do this. If you don't get rid of all the liquid, I find that the lime mortar is too runny.

Others make their lime mortar simply by mixing lime hydrate, sand and water together and don't hit any problems. I might try this the next time I need to mix some up.

(*) After a day of using lime, I find the skin of my hands has been attacked, no matter how careful I am trying to keep it off my hands (I wear gloves) and how often I wash them in fresh water. The same process will happen in your lungs.

 

[Penners]

After a day of using lime, I find the skin of my hands has been attacked, no matter how careful I am trying to keep it off my hands (I wear gloves) and how often I wash them in fresh water. The same process will happen in your lungs.

Yikes!! That's quite scary.

 

[MdB]

Yikes!! That's quite scary.

I've been told that lime putty is as strong an alkali as brick acid is an acid. I've no proof of this though, maybe an expert can comment.

There are people here who use lime many many times more frequently than me and they are still alive so maybe I'm worrying too much. I still don't want to breath in the hydrate though.

 

[Gervase]

It can be a beggar on the hands - particularly when very wet, so always wear gloves when limewashing or making and handling putty. It removes the skin, and the sores are tender for a while afterwards, so do take care.
And, of course, mind those eyes. ALWAYS, ALWAYS have an eyebath and clean water within easy reach. Lime in the eyes was a very common cause of blindess in Victorian times, and can still be today. It also hurts like hell.
Oh, did I mention the eyebath? Just pennies from your local chemist - or use a small egg-cup - and it could save you a lot of pain and even your sight.

 

[Nemesis]

I have, naturally, a small collection of antique glass ones!

 

[Gervase]

Eyes? :wink:

 

[Nemesis]

No, they aren't that bad yet - eye baths!

Many years ago I had a friend with a glass eye, who used to delight in going into caffs and absentmindedly scratching it with a fork...

 

[Penners]

That must have had much same effect on bystanders as the time that the late, lamented Peter Cook ate Russian salad out of a sick bag on an aircraft.

:x

 

[Me!]

Thanks for all the info, and I can add that I have now made several successful batches of lime filler simply by mixing dry hydrate with sand and then adding water. However, even with the silver sand I've been using, the mix is still a bit coarse for filling some cracks, so can anyone suggest something finer to use please? Basically, I'd like to end up with a lime version of polyfiller if that is possible?

Thank you.

 

[Carol]

My local supplier, Potmolen of Warminster recommended Whiting, (chalk not fish) mixed with lime putty (1: 4) for our cracked ceiling which I used instead of silver sand for the tiniest cracks. It seemed a troublesome mix, often cracking up and falling out and I used various different combinations of mix.

I actually found a thick casein distemper did a better job in the long term. (Thank you Nigel Watts!)

 

[Mark]

(*) After a day of using lime, I find the skin of my hands has been attacked, no matter how careful I am trying to keep it off my hands (I wear gloves) and how often I wash them in fresh water. The same process will happen in your lungs.

Just noticed this.

I cant help with the lungs, but I use vinegar to wash my hands when I'm doing limework. Splash it on until the soapy feel goes, then wash with water.

My problem now is that I can't decide between making a crack about burgundy vinegar, fish shops or aftershave
:roll:

 

[Penners]

My problem now is that I can't decide between making a crack about burgundy vinegar, fish shops or aftershave

Go on - have a bash at all three. We'll give you points out of ten for each one.