Disc for cutting sandstone paving?

[goldeagle]

I'm in the process of laying a DIY patio with 25mm smooth sandstone slabs.

I did consider hiring a specialist Stihl type masonry saw for the cuts, but at £30 for a weekend and knowing I would probably end up needing it for the next 6 weeks at the speed I work, I decide to purchase a 125mm angle grinder instead, as it's just for a single patio.

I am really struggling with cutting the slabs though, or specifically the diamond blades I'm using are generally only last 3 or 4 cuts (sometimes that's on a single slab) before giving up and having to replace with a new one.

So I suppose my question is - can anyone recommend any good blades or have any tips for using a 125mm angle grinder for cutting sandstone?

I general have it on speed 2 (i.e. fairly slow speed) and have tried both cutting through the entire 25mm slab at once or doing it in two passes to avoid too much load on the blade.

By the 3rd or 4th pass the blade is really struggling to get through and appears to be showing signs of over-heating - but I think this is just because it is not sharp enough to get through.

Tried all types and brands of diamond blade:

Bosch Professional
S&R diamond cutting disc
RDXMax cutting disc
Bosch Standard
Graff diamond blade

None have performed any better than others ( at least not noticeably), all fine on the first and second cut but then quickly fail.

I have a lot of cutting to do and at this rate I will be spending £300 on blades so would appreciate any advice!

 

[goldeagle]

Here is a pic of a knackered blade can see over-heating marks



The angle grinder is 125mm Makita 18V LXT. Using it with a dust extractor hood.

 

[lostinthelight]

Cut from each side and usually no need to go right through, much less strain on blade and machine that way.Id speed-it up to clear the dust and let the weight of the tool do the work
edit: you have a vacuum on it then ?

 

[goldeagle]

Thanks, that's not a bad idea actually going half through on one side and half on the other. I have noticed a lot of wear on the centre (non-cutting) part of the blade due to the depth I'm going through. Definitely worth trying anyway.

I will also try a higher speed and see if that helps (I thought I read somewhere slower speed was recommended but will give anything a try!)

 

[lostinthelight]

Have you got the blade the right way around ?

 

[goldeagle]

as far as I know, yes...the label is facing out and on the blades that have a direction arrow it's in the same direction shown on the grinder

 

[lostinthelight]

as far as I know, yes...the label is facing out and on the blades that have a direction arrow it's in the same direction shown on the grinder

Just checking,ive seen peeps turn the cutter over to fit and loose their sense of direction

 

[goldeagle]

maybe a stupid question, but what direction should the blade be turning when cutting into the paving (if that makes sense) - should it be rotating downwards as you cut forwards, or rotating upwards? Or does it not matter?

 

[cdbe]

Strange! Have you tried a "turbo" blade. Or a different grinder?. Half the problem is that tools are big boys toys and despite there being nothing "turbocharged" about angle grinder blades the manufacturers insist on these silly names instead of agreeing a common standard for performance/materials. Personally I've never used a battery grinder but given that my mains 115mm grinder is 900w and my 9" grinder is 2400w I think that could also be your problem.

 

[goldeagle]

yeah one of the Bosch discs I've used was classed as a turbo disc. I am starting to think it may be blade direction in relation to the slab, I was fixed with the blade direction due to the bust shroud only fitting on one way. Will try it in the morning

 

[23vc]

Diamond disc (including the cheaper eurbaur type ones) on a 5” grinder is fine. Couple of deep passes then snap it off

 

[23vc]

maybe a stupid question, but what direction should the blade be turning when cutting into the paving (if that makes sense) - should it be rotating downwards as you cut forwards, or rotating upwards? Or does it not matter?

blade fitted to the grinder according to the arrow on the grinder, then cut towards you

 

[Charlie George]

A cordless grinder is not the right tool,with hindsight you may have been better to lay all full flags and saved the cuts for the last weekend,and hired a petrol saw then.

 

[goldeagle]

blade fitted to the grinder according to the arrow on the grinder, then cut towards you

Diagram below is what I am currently doing...blade rotating upwards, pushing the tool away from me is that right?

 

[lostinthelight]

They're only 25mm slabs, if one has enough batteries or time to recharge I cannt see a problem with a battery jobbie.
In decades of using a disc cutter ive never had one turn blue like that