Is it straight forward to chase out into 7N concrete blockwork using a multitool ?

What blade should I use, and will I be able to cut out the chase with a blade too, or have to chisel it out ?

Need to do about 2m down a wall.

No.  Use an angle grinder.

For 2 m I'd use a hammer and bolster.

Multi tool with a TC blade and a hoover = next to zero dust. 
 

Grinder = lots.

 

Multitool will fly through it. A regular bimetal blade for slicing downwards to do the chase after cutting the side channels is deliciously simple and controllable.

 

One hand on tool (ahem) and other on the Henry. 

1 hour ago, Nickfromwales said:

Multi tool with a TC blade and a hoover = next to zero dust. 
 

Grinder = lots.

 

Multitool will fly through it. A regular bimetal blade for slicing downwards to do the chase after cutting the side channels is deliciously simple and controllable.

 

One hand on tool (ahem) and other on the Henry. 

 

Surely not!  Grinder and SDS with chisel blade (or a wall chaser).  What multi tool and blade works on 7N blockwork for a 2m chase?

3 minutes ago, Mr Punter said:

 

Surely not!  Grinder and SDS with chisel blade (or a wall chaser).  What multi tool and blade works on 7N blockwork for a 2m chase?

Oops. Read as thermalite. Been working with these for the last 3 weeks so now brain-numbed.

 

I’ll go kneel on some pencils. 

 

(Would have gone through them……eventually) lol. 

Well I just experimented on a spare block. Multitool with a semi-circular grit blade (that came with it) will slowly cut into the block. Once you have 2 cut lines a stone chisel will remove the middle section. Likely to take a bit of time and perhaps unknown number of blades but possible and next to no airborne dust.

1 hour ago, Spinny said:

Well I just experimented on a spare block. Multitool with a semi-circular grit blade (that came with it) will slowly cut into the block. Once you have 2 cut lines a stone chisel will remove the middle section. Likely to take a bit of time and perhaps unknown number of blades but possible and next to no airborne dust.

Defo the least dusty option. 
 

But tbh if you just chisel with a 2kg SDS drill with a narrow chisel bit, there’s just debris but not much dust. 

Draw your line then go at it with the SDS chisel each side. Easy really and it's neat enough, done it plenty of times in block.