Cutting curved stones for kidney shaped patio?

[diyonly]

Hello guys,

I've decided to do indian sandstone patio myself and have been reading up how it's done. I want a kidney shape patio, which requires curved stones, but I don't know how to cut curved stones.

So can anyone please advise, how do people cut the stones and what tools would they require to cut the curves, to something similar to the picture below?

 

[Ian H]

An angle grinder. A 4" one with diamond blade may cut deep enough for Indian stone.

 

[r896neo]

A stihl saw is the proper tool, it will cut a decent radius similar to your picture but smaller tighter radius requires a smaller blade.

A 9" grinder is pretty good but no dust suppression like a stihl saw.

 

[diyonly]

Thanks very much guys. But how does one do the curve? What's the technique?

Also I've already got an angle grinder with a 4" stone disc, but when I tried to cut the indian sandstone, it hardly made a difference and also the disc wore down extremely quickly.

 

[Ian H]

Lots of straight lines to get the curve then you can chamfer the outer face for a nice finish.

A guy I work with, Scouse Col, could do it with a hammer and chisel but I wouldn't even try.

 

[diyonly]

Cheers Ian.

I'm in two minds regarding the indian sandstone because I've heard it might look nice at first, but after a while, it looks awful. From experience, what type of patio is good?

 

[r896neo]

The soft sandstones get green and slimy quite quickly. To stay looking good they need cleaned a couple of times a year. The harder ones are much better and need about half the maintenance.

Kandla grey, autumn brown, raj green are all good.

Avoid rainbow, teak and fossil mint as they are the softest.

You must use a diamond disc to cut it and it cuts relatively easily. Ti cut a curve you simply mark it out and run the grinder along it. No need for straight cuts just folliw your curved mark and go deeper with each pass, tight internal curves are you only problem.

Its often easier to lay the bulk of the flags and leave your cuts until the end then lay them in dry and mark the whole curve on all the cut flags. You can freehand it or use a stringline and post to make an accurate radius .

Of all
of them kandla grey is the one I recommend and have at my own home.

 

[diyonly]

Well that's extremely helpful information r896neo, thank you.

Since my current grinder is crap, I'm thinking of getting another one to do this job. In fact I like the makita 230mm (2000w) for £79.99 in argos, with the added bonus of accidental damage cover.

What, 4" or 9" diamond make disc can you recommend?

 

[Nozzle]

Do people actually shop at Argos any more? Give Toolstation a shot! Or their (more rubbish) competitors Screwfix, though they often have stock problems.

Nozzle

 

[London Mike 49]

Something to help you;
http://www.pavingexpert.com/cut_in01.htm
http://www.pavingexpert.com/cut_in02.htm

Mike

 

[r896neo]

You dont need a good grinder but you do need a good disc. I have used a crap £25 grinder with a disc twice that price. A 4'' grinder will be too small for lots of cuts, it just so slow and underpowered compared to a 9'', I only use it for the very tightest corners and cuts outs for rodding eyes, soil pipes or other small covers etc in the patio.

Any diamond disc will do for one patio but spectrum are relatively good budget ones, probably £30-40 for a 9'' disc. Many higher end grinders like a makita will come with a free diamond disc, mine did and it was ok.

All that said consider hiring a stihl saw if you can leave all the cuts til the end and just hire for a day. It is much safer as it has a clutch and if the blade jams it will stop whereas in a 9'' grinder your wrist is the clutch...

 

[diyonly]

Nozzle - I agree argos is not the ideal place for buying good quality tools, but the benefit is that if I pick a tool and it turns out to be crap and breaks down, so long as I've got the extra guarantee, I can return it within 3yrs and I'll be given a refund.

London Mike 49 - That's exactly the type of guide I was looking for, although a bit too many mathematics involved, lol!

r896neo - There are many spectrum discs, so which model do you recommend? ...So if I follow your advice, are you saying I do the patio for all the area, but leave all the edges out where there are curves?

 

[r896neo]

You basically lay all full flags and leave any that need cut until the end then do them all together. Its how most professionals lay and usually quicker.

That said there are sometimes cuts which have to be done as you progress if for example when laying yourself out of a corner etc or when you need a cut to maintain the pattern. I cant remember the last spectrum I used but it was a turbo type disc with continuous rim and was red. The bosch ones are ok too. Avoid Norton and silverline.

 

[r896neo]

It was a tx10r, I was given it by a rep to try and tempt me away from marcrist. It was good value and lasted well for the price but a bit slow compared to a top spec blade. More than up to a few diy patios.

 

[diyonly]

Thanks r896neo.

The spectrum tx10r 230mm (9 inch) is around £50. Seems to be only one major seller.

I'm happy to lay the uncut flags first before all the cuts and then get the cut ones done at the end. But I'll show you the shape of the design incase you think I may need to lay some cuts at the same time.

A bit off-topic, but let's say I've successfully laid the cut flags. Now if you have a look at the example photo in my first post.... How are the edging stones/flags so neatly laid at the end?