Lime putty is a high calcium, non-hydraulic lime slaked from the finest Buxton quicklime, and matured for a minimum of three months. For conservation work, it is usually used in a saturated form. It is supplied to a site covered by a thin film of water in air tight plastic tubs, to minimize the risk of carbonation.
Lime putty is ideal for making fine plasterwork and limewash. It is also widely used for pointing masonry and making render, daub and other lime-based mortars.
How to make Lime Putty:
Tools: Wire whip (like used in cooking) Trowel, An electric drill with a paint mixing attachment if it is available, A bucket of water: Keep tools wet until you can clean them.
Ingredients for Lime Putty: Two buckets(10 litre each), One 50 lb (23 kg) bag of hydraulic type S lime
- Fill the buckets with 2/3 rd of water. Open a new lime sack. Separate the lime from sack into two equal parts. Don’t breathe in the powder.
- Slowly add the lime to the two buckets. Never pour water on top of this kind of powdered lime.
- Mix it well. Wipe and rinse your hands and face often if you get spots of lime on you.
- Add a little more water if you think there is a need to mix all the powder in smoothly. Scrape the sides of the bucket. Continue to mix until there is no powder visible, and the putty is a very smooth and thick paste.
- Finally, pour a little water on top of the lime putty and seal it with a lid. As long as it doesn’t freeze, the putty will only improve with time.
- Wear a long-sleeved shirt, rubber gloves and glasses for mixing. Pure lime can cause burning if it stays on skin or eyes.
- Keep some diluted vinegar and a wet cloth nearby to remove spots.