Many diamond blades have diamond grit suspended inside a metal matrix called the bond. The bond has two functions. First, it holds the diamond grit, which does the cutting, to the blade. Second, it wears away as you cut, shedding worn diamond grit and exposing fresh, sharp diamonds buried deeper in the bond. This constant shedding of worn diamond grit keeps your blade cutting more or less at the same speed.
The hardness of your blade’s bond affects both the rate at which your blade sheds worn diamond and your blade’s durability. In fact, it’s one of your most important considerations when choosing a diamond blade.
Soft-bonded blades cut hard, dense materials better than blades with hard bonds. That’s because their soft bonds wear away faster and expose fresh, sharp diamond grit faster, resulting in better cutting performance and speed.
However, soft-bonded blades are a poor choice for cutting soft materials, like green concrete, asphalt and sandstone. Soft materials tend to be more abrasive and wear out blades faster than hard materials. Blades with soft bonds are less resistant to this abrasive action than hard-bonded blades and burn up quickly in soft, abrasive materials.
Soft-bonded blades are also vulnerable to “undercutting” – or having their cutting segments wear away faster below the cutting edge – when cutting abrasive materials. Undercutting can cause segment loss during cutting, which can injure or even kill saw operators.
Hard-bonded blades cut soft, porous materials better than soft-bonded blades, because their hard bonds can withstand the abrasive action of soft materials better. These blades are also more durable and longer-lasting than soft-bonded blades.
They’re not the best choice for cutting hard materials, though. That’s because hard materials can wear down the diamond grit in hard-bonded blades faster than the bond. When this happens, blades can become “glazed” – that is, they cut slower even though they have life left in them. (See this blog article for everything you ever wanted to know about diamond blade glazing)
Q. So which blade bond should I use?
A. As we said, you generally want to use soft-bonded blades to cut hard, dense materials and hard-bonded blades to cut soft, porous materials. Matching up blade bonds to materials can be tricky, though. You may need your saw blade dealer to help you choose the right blade for you.
If you cut a lot of different materials and need a multi-purpose blade, you can either use a blade with a medium-soft bond, which is good for most industry-standard materials, or buy several different blades and change them out on your saw whenever you need to cut something different.
However, if you don’t want to worry about blade bonds, then you can use vacuum-brazed blades, like the Ductile Iron Safety Blade, the Ductile Iron Ring Saw Safety Blade and the Fire Rescue Safety Blade. These blades have diamond grit vacuum-brazed onto their surfaces, instead of buried inside a metal bond. A vacuum-brazed blade can cut almost everything you might encounter, so you won’t have to match blade bonds to what you’re cutting, waste money buying different blades for different materials or waste time swapping out blades on your saw.
For more information, visit Desert Diamond Industries’ frequently asked questions page.
Desert Diamond Industries. “How To Choose a Diamond Blade.” Desert Diamond Industries Product Catalog Contract 20. N.p.: n.p., n.d. 27-28. Scribd. 12 July 2012. Web. 12 Dec. 2012.
“Frequently Asked Questions.” Desert Diamond Industries. Desert Diamond Industries, n.d. Web. 12 Dec. 2012.