Lime

For some reason, none of your posts are loading on my reading list. I wonder if mine is showing up on yours?

Yesterday I finish the little job in town. I would have finished it earlier, but something is quietly draining the battery on my car. I should have taken notice of the 'low voltage' warning on the dashboard earlier, and I should have taken notice of the 'alarm system service needed' one earlier still, but I have never trusted this car to tell me the truth ever since I bought it for twice its worth from a shabby and dishonest Australian a couple of years ago.

This little job involved the application of proper lime mortar. I don't mean the inferior French hydraulic lime that is reluctantly used by English masons because they cannot be bothered with the faff involved in using putty lime. 

Real slaked lime is a magical material which has been used in building since Roman times and before. You quarry white chalk, heat in a kiln for hours until it becomes quick lime, then you put it into a container (or pit if you need a lot of it) and drench it with water. When the water has stopped boiling (yes, it really does boil) you are left with young putty lime. Depending on the sort of application, you can use it immediately or let it mature for a period of years if the highest quality is required. The lime I used on this latest job was too good for it, having matured for about 40 years. When I bought it, it had been matured for 15 years already, and that was about 25 years ago. It is creamier than cream.

Mature lime is best for small, intricate repairs which need to stay strong and resilient to exposure, and young lime is good for rough and ready mortars which can afford to take their time in improving themselves.

There is a technique called 'lime poulticing' which does a variety of things to the stone which the poultice is applied. I cannot be bothered to explain just what it does, but some time ago (like everything else these days) I lime-poulticed that frieze of classical figures on the Guildhall in Bath above.

You have bags of quick lime bits which up until the point of use, you must keep dry. Fires can be started by a bit of water getting into a bag of quick lime. I almost burnt down the tower of Banwell church once from a sack of lime which let in the rain.

You have a steel dustbin which you fill about one third with water. You carefully pour in about half a sack of quick lime, then slam the lid on it. In a matter of seconds it begins to boil so furiously that the lid rattles up and down, threatening to blow off completely.

When it stops boiling and before it cools down, you dig it out by the trowel-full  and slap it with some force against the stone to a thickness of 2 inches, making sure to get it into the crevices. You then cover it with sackcloth and plastic and leave it alone to do its thing for about a week.

When I was doing the frieze above, I was on my own and the light was failing, so I was rushing to finish the job. I slapped on one load and a large gobbet of boiling hot, caustic lime went straight into my eye. I ran for the hose and turned it on my eye at full force for minutes until the pain subsided.

The eye was red and swollen for a few days, but I didn't lose sight in it.

Moral: Always wear goggles.