Earlier, this week we received a great question from Suzy. She’s using diamond drill bits for glass and tile to drill porcelain plates.
She's drilling plates to make glass garden flowers."I tried to use a drill bit to make a hole in a porcelain plate. It literally took over 10 minutes to cut through. Is this normal? Am I doing something wrong?
That is a long time. Longer than normal. Usually it will only take 30-60 seconds to drill a hole in a porcelain dinner plate.
However, there are a few circumstances that may take longer.
First. As diamond bits wear out they gradually lose the sharp edges and corners on the diamonds. It's not an "all at once" process. If the bit drilled faster when you used it previously then it's probably beginning to wear out. At this point you have to weigh the cost of your time vs. the cost of using a new drill bit. If you drill slow enough and generate no friction heat at all then diamond bits will (in theory) last forever. However, no one wants to spend three days drilling each hole.
Second. Some kinds of porcelain are harder than others and drilling takes longer. For example, Solid color porcelain also known as mono color porcelain can be very hard. It's usually not glazed so it's baked at a higher temperature making it harder, more wear resistant and tougher to drill. Solid color porcelain is usually used for floor tiles but can be used to make other things such as dinnerware.
Third. The plate she mentioned may not be porcelain. It may be stoneware or ironware. It’s very easy to confuse them all. Stoneware is extremely hard and is difficult to drill. Stoneware is made using a different composition of clay than is used making porcelain and it is fired in the kiln differently too. The result is a plate that is substantially harder than steel so that it won't be scratched by steel knives and forks. Ironware is a type of stoneware that is a little lighter and less dense. It’s sort of a “middle of the road” dinnerware between porcelain and stoneware. Stoneware is usually one color but is sometimes painted or glazed.
On a side note: A few weeks ago I was drilling a stoneware plate so hard that the diamond bit was throwing off sparks. That's not supposed to happen! It was also a reminder to use more water when I’m drilling.
The last possibility was that her diamond drill bit was defective. To eliminate that possibility we replaced her drill bit under the “No hassles, no hard feelings, guarantee.”
If you have a question or comment, I would love to hear from you. Drop me a note at Guy Reddick
Remember, you can download a free copy of “How to Drill Glass, Tile and Stone”, "Click here for your FREE copy."