Cutting Paving Slabs

[nick_walch]

I need to shave about 1cm off one edge of some 45cm slabs (32mm thick). Whats the best tool. Is this too small a cut to do with the angle grinder.

Nick

[Guy King]

The message from nick [e-mail] contains these words:

Diamond disc in an angle grinder.

[Jim]

I'm no expert but I'd certainly give that a go with an angle grinder. If they are concrete slabs you'll need a diamond blade.

HTH

Jim

[Dave]

How durable are these diamond disks? How long do they last, compared to cutting the OP flag, to a stone cutting disk?

Dave

[Guy King]

The message from Dave contains these words:

I ain't worn one out yet.

[The Medway Handyman]

They reckon they last 50 times longer than abrasive disk.

I have, albeit a B&Q el cheapo. That did about 12 x 600mm slabs.

[John Rumm]

Yup, agreed (230mm grinder, not a little one)

Get a good one and there is no comparison...

I just wore out my first decent diamond disc (the one that came with the grinder). Prior to going titsup it cut at leat:

20 paving slabs (full cuts) 50 engineering bricks 20m through a concrete path 200 concrete roof tiles (9" cuts lengthways) 300 8x4" hard concrete paviours

• a good load of smaller misc jobs along the way

I then decided to trim the edge off one of the councils granite paving slabs and that just about did for it.

So I replaced it with a nice Norton one from screwfix.

[Andrew Gabriel]

Never having worn one out, what are the symptoms? Did it just stop making any progress whilst cutting, or did something more catastrophic happen? Is the edge now polished with no diamonds left?

[Dave Plowman (News)]

A wet tile cutter will manage it taken gently, but won't cut all the way through in one go. You can either turn over to do the 'other' side or split it.

[meow2222]

You just end up with a metal disc with no diamonds. The outer edge is rough due to scraping over stone/crete, so it does cut a bit but not a lot.

NT

[meow2222]

Its not just the fact they last longer, they also deliver far superior performance. If you havent used one, you need to, it saves loads of labour.

NT

[John Rumm]

Nothing exciting happens, in the case of my one it just stopped cutting, and the cutting edge was visibly no longer there - just a plain steel disc remaining.

[Dave]

Many thanks for that. If they are that good, I'd better get one and go out to play :-)

Dave

[meow2222]

So which makes are the good ones, and which not? The toolstation ones I've used certainly dont last that sort of time.

NT

[John Rumm]

Likewise, the 115mm silverline ones I had were a waste of space - they would not even touch a hardish marble tile.

The last one I bought was:

seems very good - has done probably 400 cuts in marshals paviours without much visible ware.

I have also used :

gives very smooth polished cuts in really hard stuff like porcelain tiles.

The Hitachi one that came with my grinder also seemed very good.

I have not used enough of the others to form much opinion. I watched someone using one of the multi material Makita discs - that also seemed to make very fast cuts in masonry, but don't know how it will ware long term.

[keith_765]

Take a look at the site of Applied Diamond Products

[keith_765]

There is a lot of misunderstanding about diamond cut off disc. I use them constantly in my work. The main thing to go by is, the harder the material the softer the disc compound. The softer or more abrasive the material the harder the disc compound. Most general purpose disc will only cut clay bricks and soft clay, block pavers and concrete tiles.If you are cutting Hep drain pipes, Rosemary or Hawkins roof tiles general purpose disc will only cut about 3 cut and then glaze up and wont cut. There are about four different compound types disc, select the right compound for the material you intend to cut. Pavement slabs are hydraulic pressed and are of hard density. Check the details on the information packet be for you buy. If after you have cut a few slabs and the disc starts to glaze, providing its the correct disc, just run it through a lump of sand stone, this wares the weld to expose the diamonds. General purpose disc start at about £12-25 for 9" the better ones round about £60 - 120. depending on segment size. Just on thing, worn disc can also snatch jam and snatch the angle grinder out of your grip

Keith

[The Natural Philosopher]

Da man spikka da troof. I tried an angle grinder on sandstone with normal metal cutting discs. The discs abraded faster than the stone.

Then I went to the hire shop and asked for something to do the job properly.

I got a brand new disc - about 50 quids worth on a man sized grinder plus transformer.

After three hours hire I had cut twenty or so slabs to form the quarter circle SHE wanted, and when I took the thing back the hirer measured tech blade, and announced that he would charge me the minimum on wear, as none was actually measurable.

My tile saw also managed to cut one slab that I had left over that I didn't cut that time. Slow, but ear free, more or less.

There is a reason why any manufacturer of abrasive cutting discs carries about ten type in his catalogue. The right one is vitally important. I don't know what makes a good one for a given purpose, but I know the difference between the right and the wrong is chalk and cheese.

[meow2222]

Thanks to everyone for all the explanations. Now I know I dont know which ones to choose :)

NT

[somebody]

That would be the 64 million dollar question :-)

I inherited a 9" grinder with a diamond disc already on it but it had no diamond left. Off I went to buy a new disc. In the local (independent) tool shop they had discs priced at 15, 45 and 90 quid +vat.

I asked what the difference was and the guy said "the quality of the diamond and how much of it". That seemed to make sense.

I bought the 45 quid one.

Quite separate to that, I had hired a petrol Stihl saw with a 12 inch diamond blade to cut through a 4 inch concrete slab. As a previous poster has said you are charged by the half or millimetre of wear on the blade. 7 metres of cut fine, not a problem. In the last metre I totally shagged the blade - every visible piece of diamond gone. On returning it all to the hire shop, the guy behind the counter said "it's one of those things... if you're unlucky and you hit a bit of concrete with a high [flint/granite or something] content you can easily shag the blade".

I got off lightly by buying a new blade rather than paying for the wear.

The 9" disc I bought for 45+vat has now long gone and worn out, I now buy the 15 quid blades and I cannot honestly see any difference in them. They tend to get shagged out by a bit of "bad" concrete long before I've ever had the chance to compare longevity. Maybe if you only ever cut paviours/slabs etc you will get to notice the different wear rates?

Get a 15 quid blade and abuse it, or get an expensive one and worry about it :-)

Hth Someone