Drilling holes in glass

Now that I have started having some fusing successes, I wanted to try drilling holes in the fused glass. I have my little dremel out and set up in a mini-drill press. Also, I probably have just about every diamond drill bit known to man...and still the fused glass breaks. I have had some success with art glass by damming (using polymer clay), filling with water and going very slowly, raising the drill bit out of the hole, letting it fill with water, and then tapping again. Not so much luck with fused glass. This leads to the following questions:

Better to use cutting oil rather than water? Recommended style of bit? Higher or lower rpms used on the dremel? Go slower (uncertain I can do that without taking it into the next day...sheesh...)? A different set up altogether?

Thanks as always! Lori

Reply to
FlameNwind
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Your rpm might be too fast. Try to get them about 3500. Water and the clay dam is fine. I use a flex shaft. go in at an angle and when the bit gets a bite slowly bring the bit up and then slowly rock it in a circular motion. I've drilled fused glass that has four layers and have not had any break. I use a 1/32" bit.

Scratch

FlameNw> Now that I have started having some fusing successes, I wanted to try

Reply to
royaltd97

What size holes? How thick?

Reply to
nJb

The current hole size attempted was 1/16" and the piece was single thickness approx. 1/4".

However, I hope to eventually drill holes into at least triple thickness (although I have read that it tends to go to 1/4" thickness during a fuse whether single layer or triple layer...is this correct?) and to use some diamond hole bits up to 1/2" in diameter. Unless, of course, that isn't possible...or let's say improbable, since I figure you can pretty much do anything with enough gumption, patience and American ingenuity.

I would be interested in knowing if the size of the hole and the density of the piece somehow alters the method used.

Also, some of the diamond bits are conical, some are round, some are columns. And then I also have the arrowhead style sans diamonds that are suppose to be useful with glass that I have usually found wanting (although they work pretty well on tile.) Any recommendations on whether a particular shape/style bit is any better than another?

Thanks!

Reply to
FlameNwind

Try Glastar or Inland Core bits. They are designed to work in a drill. Use a drill press. Put the glass on a peice of styrofoam in a container and cover the glass with water so that the water is about 1/8" over the glass. Get the speed of the press at about 3500 rpms give or take. Bring the press down slowly into the glass and then lift out, down and lift out, down and lift out.

As for fused thickness...sometimes single layer will get a little thicker on the side as it pulls in but that's about it. Oh, you can get Industrial Inland Core bits up to 2" in diameter and the quality is pretty good.

Scratch

FlameNw> > What size holes? How thick?

Reply to
royaltd97

to try

and set up

diamond drill

had some

with water

letting it

fused glass.

next

L.:

Here are some lapidary drilling tips which may have applicable points for your discussion.

I use a wide, thick O ring on rock with grease as an attaching sealant to make a water dam for drilling. Excess pressure on diamond drills is deleterious to your drill and the substrate. Drilling with a gentle pumping action cools the bit and clears the hole of grit which can cause unwanted localized friction which means heat which means medium fracture. Microabrasive blasting is an alternative to drilling as well.

If backside spalling is a problem in the diamond core drilling of larger holes there are also some other techniques that may be availing and transferable to glass work.

Regards,

Edward Hennessey

Reply to
Edward Hennessey

I use a column shaped bit. Also with the thick pieces you need to make sure they are well annealed or they will stress crack. Probably shouldn't drill too close to the edge.

I bought a diamond core bit once but it was the kind with no diamonds on the bottom. I think you have to use a loose grit with it. Anyone want to buy it? 8-}

Fusing multiple layers of glass - they will spread out unless you contain them with dams. Good Luck,

Reply to
C Ryman

The best price, fastest shipping and longest lasting core drills I have ever bought have come from these guys. I can't say enough good things about them, as far as my own experience, your experiences may vary? But they sure do have the stuff.

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no, I am connected with them in no way other than I am a customer.

Reply to
Javahut

Hi, Connie! Funny that out of my 40 plus diamond bits, the column shape is the ONLY one that I haven't used! lol Going to give it a try post haste.

I am such a beginner...I have had really limited success in even getting the glass to fuse! I mean, everything I have read has threatened cataclysmic results should I ever OVER-HEAT the glass! Therefore, at this point, I have only had a few actual fusings of two and three layers where you can't tell that it is multiple layers. I am, however, learning the value of a good soak. With that said, how many layers are you referring to, what is it that you use to dam the glass and how are you using it (surrounding the glass on the shelf with the dam or in a mold?)

Thanks! Lori

Reply to
FlameNwind

Hi,

There is a saying that the glass wants to be 6 mm thick. That is 1/4 ". If you put thinner glass in the kiln, the ends round up and contract. If you use more yhan 6 mm (=2 layers) the glass wants to spread and thin out.

I have an unorthodox notion that it is not so much about thickness but the surface tension tries to pull the edges into 3 mm radius, which makes a 6 mm edge. In fact the 6 mm glass tends to curve down from a distance of abou 1/2" and then end with a bit under 6 mm radius.

OVERFIRING has multiple meanings. In the kiln we usually stay below 900 C while glass bkowers take it to 1100-1250 C. The hotter temperature may cause some flux to evaporate, shifting COE and causing stress when different glasses are fused together. It also means that the glass flows more, softening the color borders, and if not dammed, flows out if thick.

Firing in a lower temperature and long soak has many positive effects. The glass does not copy so eagerly all irregularities of your shekf primer or fiber paper. When slumping it is easier to see when to stop.

-lauri

Reply to
Lauri Levanto

For 1/8 hole I use the cylinder shaped bit from this set.

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Freehand in a Dremel. Start hole then rotate top of Dremel in a 4" circular motion.

For larger holes I use core drills. There are many on these 5 pages.

Type "diamond" in the word search.

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I use a drill press for this with a pulsing motion.

Same method, more care/time as the size/thickness/price increases.

A core drill is the best bet in most cases. I also have a set of core drills with a water feed swivel for a drill press. Not cost effective unless you're doing a lot of drilling.

Hard Rock Tool also sells a great suction cup with a hole in the center. It holds water around the bit when you're not using a water feed device.

Jack

Reply to
nJb

They have a pretty good drilling tutorial on the site.

Jack

Reply to
nJb

Hi Lori, As Lauri posted I think it is about 1/4 inches. How many layers that is depends on how thick your glass sheets are. For dams I use dams made by Bullseye (I think). They seem to be pieces of kiln shelf (mullite) cut into rectangular shapes. Coat them with kiln shelf primer. Some of this will stick to the sides of your piece. Or you can wrap them with fiber paper (not Thin Fire). I reinforce them with kiln posts. I also use a square shaped piece of stainless steel coated with Boron Nitrate to make a squarish tile.

Connie

Reply to
C Ryman

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