"Jim GM4DHJ ..." writes:

On 30/08/2019 18:28, Bert Coules wrote:
"harry" wrote:

The secret is in an even bed of cement and plenty of plasticiser in
the mix.
You can get a special tool that lays an even cement bed. eg

https://www.youtube.com/watch?v=9tBJyn_-Bns

I like the look of that and if I were planning to do much more, I'd
get one. But I rather suspect that the core secret is in getting the
right mix of mortar in the first place, something I always find*
difficult for some reason.

and the right amount of washing up liquid ....

This seems the right point to say that you can easily add too
much washing up liquid.

A 'professional' builder did this when building a barbecue for a
friend. The result was a mortar so crumbly it could be brushed
out of the joints. The builder admitted the cause and rebuilt the
barbecue.

For more than a brick or two, I'd go for the purpose-designed
products where there is some indication of how much to add.

--
David