Drilling an extra hole

[The Guy]

Originally Posted by paddyob

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.

BRS how to :

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

[e46er]

Put a towel or cardboard or something in the tank so when the piece falls out it doesn't crack the other side of the tank

[rhody605]

Hey pat I have a bunch of old glass that you can practice on. Just let me know if you need it.

[reef-keeper]

The best guide I found was to drill through a wood like. 1x4 long enough to hold on to while I started the hole in the glass. Then tossed it aside once I was 1/4 way though the glass. Then you'd finish. Sand the rough edges then DONE. Mission accomplished.

[reefwars]

pat , drill on fastest setting . , drill from both sides so not to shell the glass when it breaks through.

put tape over the other side to stop the puck from falling if you have to drill down.

round out your hole by moving the drill around in circles as your drilling, that ways the bit doesnt wedge in the glass hole and the hole ends up just slightly bigger than your bit.

not much water is really needed if the glass is thin , its more for not wearing your diamond bit down , on glass 12mm and over water must be used as the glass gets hot and could split.

when first staring start on an angle like fishy fishy mentioned , then slowly lift your drill up straight , this way the bit doesnt throw you while you start and leave a mark in your panel or chip it.

gl

[2pts]

The way I have done it is to predrill a piece of plywood with a wood bit the same size or slightly larger, clamp that piece of plywood to the front with the hole lined up where you want to drill your new hole. It will give your glass hole saw a guide so your not having it spin off and cracking the glass.

Clamp an undrilled piece of plywood to the back of the glass and dont forget the water running on the hole as your drilling.

That said, after reading this thread, I would probably switch the plywood around part way through, and drill from both sides.

Also you need to find out if that pane of glass is tempered, if it is, all this is a no go.

[paddyob]

Originally Posted by 2pts

The way I have done it is to predrill a piece of plywood with a wood bit the same size or slightly larger, clamp that piece of plywood to the front with the hole lined up where you want to drill your new hole. It will give your glass hole saw a guide so your not having it spin off and cracking the glass.

Clamp an undrilled piece of plywood to the back of the glass and dont forget the water running on the hole as your drilling.

That said, after reading this thread, I would probably switch the plywood around part way through, and drill from both sides.

Also you need to find out if that pane of glass is tempered, if it is, all this is a no go.

If the tank was previously drilled... Is it safe to assume not tempered? Already three holes when I bought it used.

Back drilled.

[FishyFishy!]

Originally Posted by paddyob

If the tank was previously drilled... Is it safe to assume not tempered? Already three holes when I bought it used.

Back drilled.

Yeah you're good to go then.

[spit.fire]

Originally Posted by reefwars

not necessarily , they drill the holes before tempering the glass .

are the edges polished pat?

I've never seen a factory drilled tank that was drilled on the back let alone tempered on the back

But that being said there are always exceptions

I'd say 80% chance it wouldn't be tempered

That being said your statement is correct in lots of cases, like by rr 72 bowfront

Factory drilled bottom with tempered bottom which I find to be real common on bowfronts