A dry diamond blade is laser welded. These types of blades are more expensive, but they give you the extra flexibility of both wet and dry use. Make sure that you buy a dry diamond blade that has the right arbor size for your saw, or your new saw blade wont fit on your saw and will be make it useless.
Trying to operate a wet blade as a dry diamond blade will damage the blade due to overheating. When a blade overheats, you risk deforming the blade and even dislocating the segments, which can lead to injury and untoward accidents.
A diamond blade can be used to cut through different surfaces, from metal to concrete, to asphalt down to masonry. If you want to achieve a deeper cut, you may have to use a wet diamond rather than a dry one.
One can choose from a variety of diamond saw blades and accessories including general purpose blades, multi-purpose blades, concrete blades, asphalt blades, masonry blades, brick blades, block blades, demolition blades, ductile iron blades, tuck point blades, glass blades, porcelain blades, tile blades, granite blades, and concave blades.
Wet diamond blades, on the other hand, tend to last longer because the water keeps them cool when in use. The lifespan of dry blades are considerably shorter than wet saw blades. This is the rationale why most contractors choose to use wet saw blades over dry saw blades.
For wet cutting applications, water acts to flush the fragments, keeps down dust and acts as a coolant for the diamond blade. As a rule of thumb, most dry diamond blades can be run wet but on the other hand, you cannot use a wet diamond blade for dry cutting.