Drilling an extra hole
 

As I rebuild I consider a second drain hole. Beside the first. A couple inches apart.

How risky is it for some who has never done it?

Tips and tricks appreciated.

It's pretty easy but I would try to keep it 3" apart. And have another person ther to pour water for lube

?

Keep the holes 3" apart. Is there something that you were unsure of.

I rock the bit side to side so that its not cutting flat. And keep water on bit to wash away glass dust
Also use a guide to start hole or it will slide around

It's pretty scary the first time, but actually not that difficult. I usually use plumbers putty, role it in my hands and make a rope with it, and lay it on the glass 1" or so bigger all around the area I'm going to be drilling. Press is down just a bit so it seals up against the glass and fill it with water.
Take your drill (highly recommend a cordless drill) and turn the torque way down. Probably to it's lowest setting or close to it. You should easily, very easily, be able to grab the chuck with one hand and be able to stop the drill. This way if your bit binds in the hole it doesn't grab and break the glass.
I believe the spacing is 2X the hole diameter between holes and/or to the edge of the glass as well.
Hope that helps and if I'm wrong anywhere there, please feel free to correct me :)

+1 on clutch setting. Learned that the hard way

This is what scares me.....

What happened with me is the clutch was off and when the bit started to break through it tourqed up and cracked glass. So with the clutch at lightest setting and a couple inches between hole it will be ok. Like stated you should be able to hold the chuck very easily

It's honestly not that bad at all. Have you tried to practice on a junk sheet of glass yet? If not, I highly recommend doing so. Thats what I did to get started. I drilled 4 holes before even touching my main tank. All came out great in the the Practice runs, so I did my main. Aside from a few small chips on the outside when the bit came through, all went well.

The worst part IMO is getting the hole started. I learned the best way is to brace the drill with one hand on the glass and drill, hold the bit at an angle so that just one tiny part touches the glass first, then slowely start angling the bit so that it's flat and 100% of it is touching the glass. This works great.

I also had a garden hose pouring constantly on the bit/hole for lubrication and it worked great. It also washes away the glass dust.

BRS how to :

http://www.bulkreefsupply.com/video/...rnal-overflow/