Try an electric mixer made by Belle if one is availble to rent. When I use to due concrete curbs we used this mixer and wanted almost a mortar type mix so we had a zero slump mix. You just might need a stronger mixer to get your desired mix. We mixed in a half ratio of 8-4-8 for this 3 cube mixer. Actually if your not mixing a ton of mortar it's quicker to mix by hand than draging a mixer around seting it up and cleaning it out etc etc.
St.louis Ponds and Waterfalls
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