Angle grinder diamond blade - straight lines in concrete?

[CoolHands]

Will a diamond blade I can use on a regular angle grinder cut 2 straight lines in the concrete? Reluctant to hire a heavy stihl type 300mm petrol one as you have to buy a blade so whole rental will cost £65+ for not very much work! Just going to install 2m of drainage channel in a concreted driveway.

I have a normal grinder (I think 115mm is standard disc size?)



https://www.toolstation.com/general-purpose-concre...

I have a large SDS drill / breaker with chisels so I’m thinking after I cut the lines I should be able to a hammer the middle bit out.

[21TonyK]

The obvious question is how thick is the concrete and how deep is the channel?

[finlo]

It will cut it just fine but it will be painfully slow and very little depth.

[JoshSm]

How thick is the concrete? 50mm? 100mm?

It'll cut it OK but it'll be hard work as it just won't go very deep even if you can keep it straight enough. You'll just be notching it.

Also the cheaper type of the 115mm sized disks might not last long as it'd be doing a lot of work.

Really needs a bigger grinder for that job like a 230mm, if not more.

[CoolHands]

Damn. This is from round the corner (from some other work) so I imagine like this? Looks a good 5 or 6cm?

If it is 5+ cm then I would be better off hiring do you think? I’m tight but I don’t want to struggle!

[CoolHands]

21TonyK said:

The obvious question is how thick is the concrete and how deep is the channel?

One of these drainage channels I think they’re 90mm deep, haven’t purchased it yet. I was planning to go ‘through’ the concrete to the earth.

[21TonyK]

The deepest you will get is about 35mm and a small grinder will either bind up or burn out. Easier (and cheaper) to just hire the right tool or buy a cheapie...

https://www.screwfix.com/p/hyundai-hyag2000e-2000w...

[TA14]

21TonyK said:

The deepest you will get is about 35mm and a small grinder will either bind up or burn out. Easier (and cheaper) to just hire the right tool or buy a cheapie...

https://www.screwfix.com/p/hyundai-hyag2000e-2000w...

Youbeat me to it! £80 is a good price.

[JoshSm]

If you want to go all the way through and do straight lines then a bigger cutter is the best plan.

A 230mm could work (you could buy a cheap one + a disc) but might not make it all the way through, which is fine for a lot of things when used with a breaker but maybe not ideal for dropping the drain in and you need straight edges.

[Simpo Two]

SDS drill on roto-stop with a chisel bit?

[hidetheelephants]

Simpo Two said:

SDS drill on roto-stop with a chisel bit?

One of those will be helpful, but it will still be a lot easier if most of the work's been done with a grinder or stihl saw.

[CoolHands]

I think I’ll buy one like the one above, as it’s barely more expensive than hiring one
Ta

[hidetheelephants]

Take care with it, 230mm grinders don't take prisoners; gloves, goggles and ear defenders at a minimum, ideally safety shoes too.

[dmsims]

hidetheelephants said:

Take care with it, 230mm grinders don't take prisoners; gloves, goggles and ear defenders at a minimum, ideally safety shoes too.

Yep it's the only power I am (really) scared of

They have quite a bit of inertia

[BobM]

I've had one of these for over 5 years. Occasional DIY use, it's been great and is still fine. Still on the same blade too.

https://www.screwfix.com/p/titan-ttb879grd-2000w-9...

[Purosangue]

CoolHands said:

Damn. This is from round the corner (from some other work) so I imagine like this? Looks a good 5 or 6cm?

If it is 5+ cm then I would be better off hiring do you think? I’m tight but I don’t want to struggle!

if you are installing Aco drains divert the water via a gully pot either to your storm drain or a soakaway
either way divert away from the property

[CoolHands]

Thanks there is a drain just round the corner I intend to go to with a 90 degree junction. Intention is to route it like this:

[TA14]

I think that you'll need a lot more access around the gulley. I'm not sure that I'd bother with the inside cut line. Cutting concrete is slow and dusty, breaking out a little extra and re-instating what you need is easy, esp. when the original is not great.

[GasEngineer]

dmsims said:

hidetheelephants said:

Take care with it, 230mm grinders don't take prisoners; gloves, goggles and ear defenders at a minimum, ideally safety shoes too.

Yep it's the only power I am (really) scared of

They have quite a bit of inertia

+1 on taking care and wearing proper safety gear.

I lent my 9" grinder to my neighbour to cut some paving slabs. He ended up in casualty after one cut.
He didn't hold the grinder straight up and it caught, jerked out of his hand and went into his trainer clad foot.

[TA14]

dmsims said:

hidetheelephants said:

Take care with it, 230mm grinders don't take prisoners; gloves, goggles and ear defenders at a minimum, ideally safety shoes too.

Yep it's the only power I am (really) scared of

They have quite a bit of inertia

How do you feel about chain saws?

I'm relaxed about angle grinders, just keep a firm hold and don't press hard.
Gloves for the vibration, goggles to see, safety boots just incase, a half face mask to save holding your breath, and they are heavy. Also think about protection for where the dust will go (plywood)