Q: 16” Demo Saw Blade Life

[Citroënbender]

I’ve got an interesting prospective job, to demolish two sides of a rectangular inground concrete pool. Well, it’s 50% inground, the rest above. The remaining two sides to be stripped of coping and clad with sleepers as 800mm tall retaining walls once the “tub” is filled to natural ground level.

There’s no access to bring in a useful sized digger, and not really any way for it to manoeuvre. So I’m looking at sawing into 35-ish kg squares that can be barrowed out. As the prospective client is not in a hurry and not expecting a whiz-bang transformation over 48H, this approach seems a good fit.

Rough calcs give me about 200m of sawing, I’m guessing the concrete will be around 100-120mm thick. Has anyone here done a lot of wet sawing in reinforced concrete - looking for thoughts on how many 16” pro grade diamond blades it might use for this meterage? Gut feeling is two, but I’m prepared to stand corrected.

[roKWiz]

Originally Posted by Citroënbender

I’ve got an interesting prospective job, to demolish two sides of a rectangular inground concrete pool. Well, it’s 50% inground, the rest above. The remaining two sides to be stripped of coping and clad with sleepers as 800mm tall retaining walls once the “tub” is filled to natural ground level.

There’s no access to bring in a useful sized digger, and not really any way for it to manoeuvre. So I’m looking at sawing into 35-ish kg squares that can be barrowed out. As the prospective client is not in a hurry and not expecting a whiz-bang transformation over 48H, this approach seems a good fit.

Rough calcs give me about 200m of sawing, I’m guessing the concrete will be around 100-120mm thick. Has anyone here done a lot of wet sawing in reinforced concrete - looking for thoughts on how many 16” pro grade diamond blades it might use for this meterage? Gut feeling is two, but I’m prepared to stand corrected.

Using a petrol powered demo ?

[Citroënbender]

Yes, I’ll actually buy a used one - don’t own ATM.

[roKWiz]

Originally Posted by Citroënbender

Yes, I’ll actually buy a used one - don’t own ATM.

Good, I've noticed new ones have come down quite a lot in price recently.
You might go through a few (3-4) blades on hardened concrete depended on how much water you keep up to the blade and reo bar in the walls.
Good sledgehammer and large prybar wouldn't go astray either.

Hiring one is reasonable but you will be charged for the blade damage anyway so be better off owning one yourself.
What are you paying for the blades $250 each ??

[Citroënbender]

Yes, seen plenty of slab cutting in the past, just haven’t done more than 4-5m at a time myself. Cut into blocks, use the bar to widen a gap in the middle and pry up. Only change is I’m no longer game to work solo with handling the blocks. Almost 10 weeks of being incapacitated then only light duties has re-shaped my attitude there.

Blade example:
https://sydneytools.com.au/product/e...zenesis-blades

Because I’ll probably be cutting 3-3,5 tonnes each workday, between hire cost and blade wear it points you to ownership instead. Plenty of interesting stuff in 16”, eg: https://www.gumtree.com.au/s-ad/hinc...saw/1308316380 versus: https://www.kennards.com.au/for-hire...m-16-in-petrol

[Citroënbender]

I suppose one of the salient points of my original post is that someone with knowledge of pool concrete or structure might chime in and say the results favour one direction or another because of (say) aggregate type, or steel fabric, or placing technique.

[roKWiz]

Originally Posted by Citroënbender

Yes, seen plenty of slab cutting in the past, just haven’t done more than 4-5m at a time myself. Cut into blocks, use the bar to widen a gap in the middle and pry up. Only change is I’m no longer game to work solo with handling the blocks. Almost 10 weeks of being incapacitated then only light duties has re-shaped my attitude there.

Blade example:
https://sydneytools.com.au/product/e...zenesis-blades

Because I’ll probably be cutting 3-3,5 tonnes each workday, between hire cost and blade wear it points you to ownership instead. Plenty of interesting stuff in 16”, eg: https://www.gumtree.com.au/s-ad/hinc...saw/1308316380 versus: https://www.kennards.com.au/for-hire...m-16-in-petrol

I've used them for cutting large long granite blocks, turning them into fireplace hearths, helped by gad pins (plugs n feathers) but of course they do not have steel inside.
Did use them occasionally onsite, cut the doorways through on the Contemporary Arts Musuem at Circular Quay. Lower plinth walls are 4ft (1200mm) thick of poilshed Balmoral granite and firebricks. Top section easy to do by hand being Bondi stone.
Concrete at least it will bite easier than a poilshed surface.
Have you got a hand trolley you can slip the squares onto for moving them off ?
Most are rated at 250kg.
Lots of water on the blades will cool the diamond cutting tip down so they should keep reasonably sharp but I would say 200m into blocks will take 3-4.

[Citroënbender]

They say nothing handles like a rented car; nothing cuts like a hired demo saw.

In cutting 30 blocks I probably used half a blade with plenty of water flow, the pool is rendered over pump concrete that’s been a really hot mix - got lime burns from the slurry where it caked thickly on my arms and legs. Also some N12 bar or similar in here around the top perimeter. Machine running time was about 2:45 over a three-and-a-hair hour period onsite. So, good productivity but yes, heavy wear costs over the whole of job.

Credit to Kennards for “tidying” the invoice down to four hours and also not charging extra on the blade wear. Lot of equipment in the shop today, as if business is down a bit for them.

[FTE217]

I knew this question was in roK territory.
Your in good hands CB as you well know.
This job will pick up your fitness barrowing out to a "bin" ? or tip drops ?

[Citroënbender]

Kimbriki, by the tonne/uteload - where else?

How’s this for chafing with added lime burn?

Got to say, it makes wall sawing in single skin brick look like a kids’ game.

[aussiblue]

How’s this for chafing with added lime burn?

Careful flashing the leg might get Cav's lustful attention even if they're not up to Tina Turner's.

[Citroënbender]

I need to add an update, the structure was grossly inconsistent in thickness to a maximum of 700mm reinforced concrete on two sides, and a bare minimum of 200mm. Farmed out the heavy cutting to a sawing company who underestimated it despite an inspection before starting. They had a ring saw with about 320mm cut depth, this was enough when cutting from both sides to crack the remaining small fillet of concrete.

Of course this changed the waste disposal methodology - as I was paying by the metre for contractor cutting, I had it sawn into the biggest chunks we could push over as a team of three with two crowbars. The caper following was endless days on a Kango breaking it into chunks and gravel.

[roKWiz]

Originally Posted by Citroënbender

I need to add an update, the structure was grossly inconsistent in thickness to a maximum of 700mm reinforced concrete on two sides, and a bare minimum of 200mm. Farmed out the heavy cutting to a sawing company who underestimated it despite an inspection before starting. They had a ring saw with about 320mm cut depth, this was enough when cutting from both sides to crack the remaining small fillet of concrete.

Of course this changed the waste disposal methodology - as I was paying by the metre for contractor cutting, I had it sawn into the biggest chunks we could push over as a team of three with two crowbars. The caper following was endless days on a Kango breaking it into chunks and gravel.

All well that ends well.

You'll be able to apply for that job at Gosford Quarries now. Head Gangsaw man