Having issues drilling tank

[Schlafrig]

In preparation for drilling my new 75 gallon I thought I would to a test run on an old 10 gallon I had laying around. Both times it was going good right until towards the end where it cracked both times. Im drilling pretty slow and not using much pressure. My only thought is maybe I dont have enough water, I was stopping every few seconds to add water since I didnt have somebody to help. Is there anything that I should do differently? Or could it be an issue with the glass being thin on the 10 gallon?

Thanks

 

[KrisReef]

Thin glass is more difficult than thicker as it deforms (and breaks) when the tool binds up.

Put a garden hose on the work and let it run while you drill .

Let the tool do the work, hold the motor as steady as possible. Pushing through at the end can easily break the glass, the tool grinds, not cuts through the glass. Hold the drill parallel to the glass and let it grind through evenly until the last bit gives way.

 

[troublemaker]

I’ve drilled enough tanks to just be dangerous with my advice, but 10 gallons are incredibly hard to drill because of the glass being so thin, so don’t consider it a failure. I normally use vegetable oil and a small piece of board with a hole slightly larger than the bit and another small piece on the back side. I clamp the boards with wood clamps, you don’t need a lot of pressure, just enough to keep the boards in place. I fill the hole with oil, go slow and constantly dip the bit in a bowl of oil, let the weight of the drill be the pressure. You want the cut material to keep overflowing out of the board. The hardest part is the end, that’s normally where it goes bad. I have never had issues on glass at least 1/4”, but have broken thinner glass.

 

[Schlafrig]

Thin glass is more difficult than thicker as it deforms (and breaks) when the tool binds up.

Put a garden hose on the work and let it run while you drill .

Let the tool do the work, hold the motor as steady as possible. Pushing through at the end can easily break the glass, the tool grinds, not cuts through the glass. Hold the drill parallel to the glass and let it grind through evenly until the last bit gives way.

Should I be applying any pressure or just let the weight of the drill apply pressure?

 

[landlubber]

Should I be applying any pressure or just let the weight of the drill apply pressure?

"Let the tool do the work" means avoid applying pressure.

 

[Mr. Mojo Rising]

My tips are don't put any pressure at all, let the drill do the work, just hold it straight, it took me about 20 minutes per hole. Add lots of water. Tape under the glass, so when you drill the weight of the glass doesn't pull it down and chip, use tape to keep the glass in place until you push through it

 

[exnisstech]

I've only drilled a couple but I used wood as a guide like @troublemaker described above. As mentioned let the weight of the drill do the work, don't push on it.
Your probably not using a corded drill but I'll mention it anyway, a battery drill should be used if your cooling the drill with running water.

 

[Jamie814]

Good advice above—if you’re using a drill with a clutch, set it very low so that if it binds, the clutch slips instead of grabbing the glass. A garden hose works best, as it will flush away the fine drilling powder so it doesn’t build up on the bit, keeping it cleaner and cooler than a pool of water around the drill hole. Thicker glass is actually easier to drill, as there’s less chance of cracking.
At a minimum on the back side if not clamping a board you will want a towel or cardboard underneath the drill hole so that the glass slug does not fall, hit and crack the glass on the other side of the tank.

 

[Schlafrig]

Third attempt went much better. I set the cutch on the drill as low as it could go, and had a hose going on it the entire time. The back blew out a bit. The panel still formed a tiny hairline crack but Im going to blame that on the thin glass. I did have one last question how many uses should I expect out of each bit? Should I replace it before using it on my new tank? I still need to buy another bit, is there any difference between the ones off BRS or Amazon?

 

[UncommonSense]

how many uses should I expect out of each bit? Should I replace it before using it on my new tank?

This really depends, but I typically get at least an inch of glass thickness out of a diamond hole saw! (A 10g rimmed tank is typically 1/8” glass)

Recently, I’ve found ways to refine my technique and improve bit life, getting 1.5” of glass thickness out of a bit with plenty more left in it!

— A photo or two of the bit itself would definitely help to determine if the diamonds are all broken off the bonding layer!

I still need to buy another bit, is there any difference between the ones off BRS or Amazon?

This also depends… I haven’t bought a diamond hole saw from BRS in a good while… I recall them being just ok…

This said, I semi-recently got a 12-pack of diamond hole saws from 1/4”-2” diameter for $15 off amazon which look/perform identical to the BRS examples…

The primary things you’ll be looking for are:

— continuous diamond hole saw rim, no rim grooves/notches, and no centering point is the ideal choice….

— hole saws marketed for use on glass are ideal; the diamond grit is usually finer than is often seen for use on stone!

— minimum hole saw bit “wobble” (aka “runout”)… that is, how much the bit deviates from spinning in a perfect circle… some of this runout will be from the drill’s chuck, but a bad hole saw bit can wobble quite violently, leading to ugly holes at best!


Regarding your drill’s clutch, I find that 5-7ft/lbs (as denoted by the numbers on the drill’s collar) seems to be the sweet spot between spending half your time slipping the clutch/vibrating the glass, and actually having the pane shatter if the bit binds!

Regarding the binding of the bit: I find that completing the cut, piercing through the inner face of the glass pane is the usual culprit for bit binding… I tend to stop and check my drilled depth when I’m getting close to piercing through, correcting for any accidental angling as much as I can, then going very slow as I pierce, holding the drill as steady as reasonably possible…