Mixing and storing Lime Putty mortar

[jackg]

I have two walls to point on both sides and then to render the one westerly external wall with Lime render
The walls are stone and Lime mortar, the westerly facing and gets the worst of the weather, rain and wind, it is also the one with the largest holes in the mortar.
I have a 25kg tub of Putty and a bag each of Holm sand and stone dust which gives a nice ratio of 2:1. I can mix it in an old bath but not sure how to store it until use. Air tight plastic tubs is one way, air has to be excluded to prevent carbonisation. Is there a way of storing the mortar in the bath to exclude air by adding small amounts of water now and again or are there other storage methods?

 

[vinn]

Your post is confusing: BCO only concern themselves with enforcing the Regs.
A typical lime pointing mix is 3:1 sand & (NH) lime in a 25mm chase.
Has lime putty been used before?

 

[jackg]

Post edited.
Putty has not been used before.
My info suggests that 2:1 is better than 3:1.
http://www.buildingconservation.com/articles/mythmix/mythmix.htm

 

[vinn]

Then why use putty now? You appear to be complicating a very simple process - for instance, lime putty can be dangerous in unskilled hands, & can present various difficulties when rendering.
I have always used a 3:1 or 4:1 mix as above for pointing and render.
Lime putty for the exceptions.