Pointing cracking when drying

[Jrevel]

Hi, have started to point my Victorian house using 1 part cement and 3 builders sand mixed with clean water. Have racked out about 10mm-15mm. Within about 30 min of pointing, the pointings starts to crack every 30cm. Any advice on what I'm doing wrong?

Thank you in advance.

 

[Johnmelad]

I would go 4 to 1 and dampen the joints.

 

[catlad]

Spray the wall with the garden hose before pointing.