angle grinder technique

[Stephen]

Hello,

I was trying to cut some paving slabs at the weekend. I was using a diamond blade and it was heavy going. I thought at first that the slabs were just very tough.

I looked at the blade and there was plenty of diamond left but the diamond patches had a hint of brown. I read here that if the blade overheats it will turn a brown colour and that the glue can soften and the diamonds sink beneath the surface.

Could this be what happened? It was a cheap silverline disc from toolstation. I had an equally cheap disc from aldi that I put on instead and it cut like a knife through butter, so it was the blade, not a tough slab.

Isn't there a trick to rejuvenate worn blades? Do I have to cut a couple of bricks? Or should I just bin it?

How is the best way to prevent overheating? I would think that if you keep lifting the blade out to allow it to cool, this will make cutting a straight line quite difficult to achieve? Surely it is best to leave the blade in the slab. Is the trick to keep the blade in the slab but let it move at its own pace rather than force it?

Thanks, Stephen.

[The Natural Philosopher]

keep it all covered in water.

[stuart noble]

Sounds like the blade might be for wet cutting only (i.e. a tile saw)

[MuddyMike]

When cutting anything with an angle grinder don't force it. I use a Aldi cheap disc and bought a second one as spare when I had to cut 20+ slabs recently. Didn't need it, the original is still cutting with no trouble.

Mike

[Dave Liquorice]

As with all power tools let it do the work, don't force it. Same applies to lots of hand tools as well.

[John Rumm]

Some TS blades are designed for use with wet tile cutters (often come in packs of three). These may well oveheat without cooling.

Sometimes cutting something abrasive like sandstone of a softish brick can help.

If using a 9" machine, then you don't need any more force than the weight of the machine.

[Stephen]

Thanks for all the replies. So it sounds as if I was doing everything right this time but I guess I must have forced it on a previous occasion. It was an electric, 9", grinder, sorry for not making that clearer. The blade was not a wet cut, tile cutting blade. It was something like this:

it was Silverline. I thought I bought it from TS but they don't seem to sell them any more. I may have bought it from Amazon instead; I didn't realise they sold such things until recently and at a good price too.

[The Medway Handyman]

My experience as well. I'm becoming less & less confident with the Silverline brand. The Aldi discs are very good.

[NT]

If you search you'll find tables of diamond blades showing that different discs suit different tasks. Poeple often use one blade for all, but according to the tables some diamond discs are simply not suitable for some cutting tasks.

NT

[Andy Dingley]

Those Aldi blades (esp the 9") don't give the best cut quality on the world, but the blades do seem to last really well.

[Andy Dingley]

Last chap I heard say that then had a nasty accident with it.

"Let the weight of the machine do the work" is not the same thing as "Don't hold it properly, in case it catches and kicks". With a 9" machine, any sort of catch is a problem.

[John Rumm]

Indeed - did not intend to create the impression you can just rest it there with one hand stopping it running away! ;-)

Full concentration is required at all times with big grinders.