Pointing mix?

I can't say for certain, but recently I needed to set new glass into a stone mullioned window. I made up a 3:1 mix of silver sand (labeled as block paving sand at Wickes) and lime putty. Made it a lot easier to get a good finish, has bonded well to the limestone masonry and so far has proved stable.

On one occasion I also made up a mortar using building sand rather than sharp sand (all I had to hand), and used it point in a wooden window frame with quite satisfactory results. The usual sharp sand lime mortar mix can be tricky with closely-jointed masonry, so I wouldn't be afraid of trying alternatives for difficult locations. Unlike portland cement, lime mortar can easily be knocked off if there's a need to change it.

I've just mixed up a mortar that ended up about with 3.5 lime, 2 soft sand, 6 sharp sand and 1 chalk. (It's a long story). The soft sand and chalk has made if /very/ smooth and easy to push around ... and the pointing hasn't fallen out since the weekend.

I wonder if the OPs fillet is made with a) hydraulic lime; b) pozzallano's (sp?); c) Portland cement.

It could be anything, an analysis would tell if necessary. But with old soft bricks you'd do better with a lime based mortar, its now known cement mortars sometimes cause various problems with these bricks.

NT

Dear Alistair Not sure how you can tell if it is a Portland cement mix once it has set Please explain

What you describe sounds like a version of "tuck" pointing

This is usually pure lime putty and sand (open to correction here) Chris

You could test a bit. Lime once set (chalk) would fizz and dissolve in an acid (such as vinegar or kettle descaler). Cement also dissolves in acids, but very much more slowly.