Hi Scott,
Relies embedded below -
I recently bought one of these (mine's a 40mm I think, but I'm
boasting now!)
They're good, but need some practice.
In breeze block they can be a bit brutal - My drill is a quite a
biggie - Makita SuperMak/ 4.5kg. A smaller (less joules of hammer)
drill would be better for breeze block.
Mine is great for cutting channels in brick + masses quicker than a
cold chisel.

Like a lot of these type of tools, practice makes perfect + try a
small
section first & beware of all the mess.

John


"McGowan, Scott" wrote in message ...
1. What's the best way to mark cutting/chiselling/channelling lines on
breeze block that has lots of "lines" from an angle grinder (chalk or
something better?)? A big marker pen is fine on plaster, but not on breeze
block!
Some sort of guide line to follow does help, but is not essential.
I use my 4'x2" spirt level & mark/score a line down each side of it.

2. Is it best to "score" or "define" the channels/chases (e.g. manually with
a cold/bolster chisel) before going in with the SDS+ channelling chisel or
can I just put the chisel to the breeze block and follow the marked lines
like a maniac (I don't know because I've never used an SDS+ drill)?
No need to score etc. Trick is in the careful angling of the drill to
the wall.
When chiselling a plastered wall I normall manually chip the plaster
top coat with hand chisel first, so Iit comes away more neatly.

3. Do the channelling chisels (or any SDS+ chisel attachment) have a
tendency to "wander" if you're not very very careful?
They can wander.

4. Is it likely that I will accidentally channel through into my neighbour's
house if I'm not very very (extremely) careful when channelling the breeze
block wall?
I would think it should be a double skin of block with a gap.

5. Will a 20mm (wide) x 10mm (deep) ceiling-to-box or floor-to-box channel
weaken my breeze block wall considerably?
Not significantly, esp. as I assume you'll be plastering it
afterwards.

6. With two channels per box, there's a total of about 70 metres of
channelling to do (for the whole house)...Am I being irrational in tackling
the job with such tools?
I don't think so - breeze block is fairly soft material - if it were
engineering bricks then...

7. Will the SDS+ drill with channelling attachment be quicker (and tidier)
than an angle grinder and cold/bolster chisel?
I would say yes - far quicker than a bolster chisel & less dust than
angle grinder.

8. Approximately how long does it take to channel 1 metre of breeze block
using an SDS+ drill with the correct attachment? 2 minutes? 10 minutes? 1
hour?
With skill, I would say about 2 mins - then about 1 hour to clear up
the mess & dust (see next item)!

9. Alternatively, shall I just get my gloves and goggles on and learn from
my first channel!?
I would add -- and a dust mask (I've now got a respirator which is
even better,
esp. for use with Armegs box sinker.


PS You can get special wall chasing machines with dust extraction etc.
But I have not tried these.