Cement mortar rake for a patio, etc.

[brianr47]

The cement joints on my north-facing patio had suffered in the frosts of past winters and needed to be replaced.
Having tackled this job in the past, I didn't relish spending hours on my hands and knees with an angle grinder and diamond disc mortar rake, getting covered in dust and aching for days after.
YouTube kindly helped by showing demonstrations of 'finger' mortar rakes being used with angle grinders on brick walls and from that sprang the idea for a patio version.
As can be seen in the pictures, the angle grinder is mounted on a frame, with wheels donated from a child's roller skate. Direction is controlled by an old lawn trimmer handle.
For safety, I wired the power cable through the original trimmer switch and kept the angle grinder switch permanently on.
The rear wheels take the weight, while the front wheel controls the depth, which is adjustable.
The first attempt used an 8mm x 28mm diamond finger rake which did the job but was too slow. The Mk 2 version used a 3-sided tungsten-carbide rake of similar size which was more aggressive and so was quicker.
The concept works very well and allows me to stand up and easily guide the grinder along the gaps between the slabs, whilst not being covered in dust. I found that finger rakes produce much less dust than disc rakes as most of it stays in the joint.

[ductape]

One of the rare angle grinder modifications that doesn't look like an eventual trip to a hospital. It's a good one!
The only change I would suggest is to rotate the handle 180 degrees in order to have a better view of the rake.

[brianr47]

[QUOTE=ductape;252081]One of the rare angle grinder modifications that doesn't look like an eventual trip to a hospital. It's a good one!
The only change I would suggest is to rotate the handle 180 degrees in order to have a better view of the rake.[/QUOTE

Yes, I had wondered about guidance at the 'prototype' stage of the build, but found that in practice the centre-line of the angle-grinder gearbox is sufficiently accurate an indicator to place the rake above the joint as it is 8mm diameter and most of the joints exceed that.
It was also easier on occasion to control it by pulling, rather than pushing, the rake especially when encountering a section of hard cement.
Despite any shortcomings of such an amateur tool, the benefit to my non-aching back and knees is very welcome, but when the dry weather returns it remains to be seen how I fare with re-cementing the joints on all fours!

[DIYer]

Thanks brianr47! We've added your Cement Mortar Rake to our Miscellaneous category,
as well as to your builder page: brianr47's Homemade Tools. Your receipt:

Cement Mortar Rake by brianr47

tags: grinder, concrete