Advice: Cutting stone countertops

[Bernmc]

I need to extend the hole in our kitchen counter top to install a new hob. No idea what the top is made of - some sort of manufactured stone. House was built in the 70's. It's 20mm thick. The counter top - not the house.

Any advice on cutting this stuff? I was thinking an angle grinder with some sort of diamond or masonry cutting disk, 3M respirator and the Festool vac...? It'll be 2 x 200mm long cuts, and 500mm joining cut.

counter top.jpg counter top close.jpg

[Wrongwayfirst]

Given all the hoo haa about silica dust it would be worth getting a quote from a pro.
I am certain it can be done as you have suggested but my wife would be in my ear the whole time

cheers

[BobL]

If you are going to do it

I'd be looking at a P3 mask.

A WW vac is not even going to come close to preventing the whole kitchen from becoming contaminated.
Consider hiring some serious forced ventilation to create a cross flow that constantly sucks the air across the work site and at out the newest opening.

[Fuzzie]

I think only wet cutting is approved (legal?). Something like the Detroit cutter might be the go. Check out the customer review....

[woodPixel]

That looks mighty close to a polished cement top with quartz chips in it.

I had a look at our modern kitchen where the (vandals) installed a sink. They've clearly used an angle grinder.

Maybe one the old hob is removed, the top can be taken outside and done there?

[riverbuilder]

Angle grinder, new diamond blade. Vacuum. Put masking tape on, mark on that. Respirator and other stuff. Easy.be careful in the corner that the radiused corner of the new cooktop covers, if you cut the top out square sometimes they don’t quite cover.

[Bernmc]

Thanks all. Counter top is bonded to another, so moving it outside would be a very last resort.

I'm (mildly) concerned with safety over legality - you need a permit to wipe your 4rse in this over-regulated nanny-country. I'll be able to screen the area off with plastic, and vent out of the window next to the top. Wet cutter may be an option - I'll need to check that the machine wouldn't be too big to fit in and cut where I need.

Any advice on good angle grinder blades? I used one of these to cut into the rock faces in the garden - worked well for that, but it's pretty soft rock.

[Beardy]

The turbo blade you have will do the job. Most diamond blades will cut it just some are more efficient than others. Just use a continuous rim turbo blade over a segmented one.
Follow Riverbuilders advice above. That is how it is done in the real world

[Fuzzie]

Follow Riverbuilders advice above. That is how it is done in the real world

Maybe how it use to be done in the real world. When our new kitchen was installed last year the stone installers wouldn't adjust anything in situ.

New Ban Introduced on Cutting of Engineered Stone

[aldav]

The OP is doing a one off job, we're not talking about a long term exposure. If he takes appropriate measures - ventilation, mask and vacuum - there will be no long term concerns for him or his family. Beardy's recommendation of a continuous rim blade is the way to go, those segmented rim blades create much more dust.

[Beardy]

Just fir a bit of perspective
Years back when doing some training I was talking with a fellow supervisor who specialised in air monitoring and safe removal of substances.
He is instructed to monitor the air and if it goes above X that work is to cease and area evacuated until it is back down to stipulated safe working levels.
He said that when you take the monitor out into the street the meter went off the dial .

[BobL]

Just fir a bit of perspective
Years back when doing some training I was talking with a fellow supervisor who specialised in air monitoring and safe removal of substances.
He is instructed to monitor the air and if it goes above X that work is to cease and area evacuated until it is back down to stipulated safe working levels.
He said that when you take the monitor out into the street the meter went off the dial .

You don't even need to take it out to the street. Just take it into a kitchen where someone is doing a simple fry up or using an oven.

Apart from my shed the highest I've seen my particle detector PM2.5 go was;
Outside, during last years bushfires (I am 2km from Perth CBD) ~700 µg/m^3
Inside the house in the kitchen while SWMBO was cooking a pork roast ~1200 µg/m^3 - it was probably higher that this but that's as high as the meter goes

Apart from when there are bushfires and nearby burning off, the highest I have seen outside air go is ~40 µg/m^3 and I think that was probably due to residual smoke from very distant (100's kms) burning off.

[Beardy]

That’s why I don’t go in the Kitchen Bob, it is just too dangerous. I feel the same about the laundry too although I have no data to support that theory

The shed is my safe house

[BobL]

That’s why I don’t go in the Kitchen Bob, it is just too dangerous. I feel the same about the laundry too although I have no data to support that theory

The shed is my safe house

SWMBO's craft/fabrics room is also pretty dusty.

[Handyjack]

I have done a similar job for someone changing a cook top.
Used a 9" angle grinder and diamond blade. Yes seal off as much of the surround as possible including doors and draws as dust is likely to be everywhere. Put down tape and mark the cut line on that.
Actual job probably did not take long compared to the preparation and the pack up afterwards.