Any reportable experience of slotting aged coarse tarmac with an angle
grinder? Probably 50mm or so thick on hardcore.

I want to let in some sloping concrete edging blocks to retain loose
crushed granite forming our drive and parking area. Perhaps 25mm rising
to 50mm.

I have 225mm and 300mm diamond blades or plenty of stone cutting 225mm
abrasive discs. The big one has a water feed.

What do the road menders use?
--
Tim Lamb

Tim Lamb wrote:

Any reportable experience of slotting aged coarse tarmac with an angle
grinder? Probably 50mm or so thick on hardcore.

Give the grinder a rest every now and then ... I was cutting across the
width of a driveway, similar about 2" of tarmac, with my old B&Q 9"
grinder and a diamond disc ... got about 95% of the way across and it
let the smoke out.

On 12/07/2020 21:28, Tim Lamb wrote:
Any reportable experience of slotting aged coarse tarmac with an angle
grinder? Probably 50mm or so thick on hardcore.

I want to let in some sloping concrete edging blocksÂ* to retain loose
crushed granite forming our drive and parking area. Perhaps 25mm rising
to 50mm.

I have 225mm and 300mm diamond blades or plenty of stone cutting 225mm
abrasive discs. The big one has a water feed.

What do the road menders use?

Don't know for sure. I've seen the water board people cutting out a
square of tarmac before digging a hole - using a petrol driven device
with a cutting wheel. Might be a brick saw. Can't remember whether they
keep the cut wet. [If they're digging to fix a water leak, it happens
automatically anyway!]
--
Cheers,
Roger

In message , Andy Burns
writes
Tim Lamb wrote:

Any reportable experience of slotting aged coarse tarmac with an
angle grinder? Probably 50mm or so thick on hardcore.

Give the grinder a rest every now and then ... I was cutting across the
width of a driveway, similar about 2" of tarmac, with my old B&Q 9"
grinder and a diamond disc ... got about 95% of the way across and it
let the smoke out.

:-) I guess the 2 stroke is the one to use then. I rather wondered if
melted bitumen would clog the disc and interfere with cutting.

--
Tim Lamb

In message , Roger Mills
writes
On 12/07/2020 21:28, Tim Lamb wrote:
Any reportable experience of slotting aged coarse tarmac with an
angle grinder? Probably 50mm or so thick on hardcore.
I want to let in some sloping concrete edging blocks* to retain
loose crushed granite forming our drive and parking area. Perhaps
25mm rising to 50mm.
I have 225mm and 300mm diamond blades or plenty of stone cutting
225mm abrasive discs. The big one has a water feed.
What do the road menders use?

Don't know for sure. I've seen the water board people cutting out a
square of tarmac before digging a hole - using a petrol driven device
with a cutting wheel. Might be a brick saw. Can't remember whether they
keep the cut wet. [If they're digging to fix a water leak, it happens
automatically anyway!]

OK.

--
Tim Lamb

On 12/07/2020 21:34, Andy Burns wrote:
Tim Lamb wrote:

Any reportable experience of slotting aged coarse tarmac with an angle
grinder? Probably 50mm or so thick on hardcore.

Give the grinder a rest every now and then ... I was cutting across the
width of a driveway, similar about 2" of tarmac, with my old B&Q 9"
grinder and a diamond disc ... got about 95% of the way across and it
let the smoke out.

You can get a sense of the "windings" temperature by putting a
non-gloved hand over the ventilation exit slots from time to time (with
motor running, of course). More effective than feeling the outside
casing temperature. Also let the motor run on for a few seconds after
"big" cuts. You can feel the air exit temperature drop off.

On 12/07/2020 21:53, Roger Mills wrote:
On 12/07/2020 21:28, Tim Lamb wrote:
Any reportable experience of slotting aged coarse tarmac with an angle
grinder? Probably 50mm or so thick on hardcore.

I want to let in some sloping concrete edging blocksÂ* to retain loose
crushed granite forming our drive and parking area. Perhaps 25mm
rising to 50mm.

I have 225mm and 300mm diamond blades or plenty of stone cutting 225mm
abrasive discs. The big one has a water feed.

What do the road menders use?

Don't know for sure. I've seen the water board people cutting out a
square of tarmac before digging a hole - using a petrol driven device
with a cutting wheel. Might be a brick saw. Can't remember whether they
keep the cut wet. [If they're digging to fix a water leak, it happens
automatically anyway!]

Water probably not a bad idea. Tarmac is a bit more "grabby" than
concrete especially as it melts so try to keep the blade straight.

On 12/07/2020 21:28, Tim Lamb wrote:
Any reportable experience of slotting aged coarse tarmac with an angle
grinder? Probably 50mm or so thick on hardcore.

I want to let in some sloping concrete edging blocksÂ* to retain loose
crushed granite forming our drive and parking area. Perhaps 25mm rising
to 50mm.

I have 225mm and 300mm diamond blades or plenty of stone cutting 225mm
abrasive discs. The big one has a water feed.

What do the road menders use?

Well for what its worth, some of the diamond discs I have bought claim
to be suitable for tarmac.

--
Cheers,

John.

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Roger Mills presented the following explanation :
Don't know for sure. I've seen the water board people cutting out a square of
tarmac before digging a hole - using a petrol driven device with a cutting
wheel. Might be a brick saw. Can't remember whether they keep the cut wet.
[If they're digging to fix a water leak, it happens automatically anyway!]

They use water to cool the disk/cut and stop the tarmac from melting,
becoming sticky.

One might have expected a thermal cut out long before self destruct mode.
Brian

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"Andy Burns" wrote in message
...
Tim Lamb wrote:

Any reportable experience of slotting aged coarse tarmac with an angle
grinder? Probably 50mm or so thick on hardcore.

Give the grinder a rest every now and then ... I was cutting across the
width of a driveway, similar about 2" of tarmac, with my old B&Q 9"
grinder and a diamond disc ... got about 95% of the way across and it let
the smoke out.

Tim Lamb wrote:

Andy Burns wrote:

got about 95% of the way across and
it let the smoke out.

I rather wondered if
melted bitumen would clog the disc and interfere with cutting.

No, a nice clean slot.

In message , Harry Bloomfield
writes
Roger Mills presented the following explanation :
Don't know for sure. I've seen the water board people cutting out a
square of tarmac before digging a hole - using a petrol driven device
with a cutting wheel. Might be a brick saw. Can't remember whether
they keep the cut wet. [If they're digging to fix a water leak, it
happens automatically anyway!]

They use water to cool the disk/cut and stop the tarmac from melting,
becoming sticky.

OK chaps, I'll use the big one with a dribble of water.

--
Tim Lamb