Enlarging bulkhead hole

[NanoReefer]

Anyone think there would be a problem using a dremel and a diamond bit to carve an existing bulkhead (1" bulkhead) to a larger diameter? I plan on using lots of water and the tank will be drained and dry. Would a diamond hole saw be better to enlarge the hole?

 

[G.T]

You dont mention how much bigger? It will proberly end up egg shaped using a dremel. Why not just drill a larger hole around the existing hole?

 

[NanoReefer]

I want to go up to at least a 2" bulkhead. Why would it be egg shaped? I wouldn't be cutting a ring out of it (like a hole saw) I would be grinding it to size. From your post I gather that it is possible to drill around an existing hole, is this correct?

 

[One Eye]

I've drilled all my tanks with a dremel, just trace the bulkhead with a permanent marker. Personaly I would't try a hole saw without anything for the guide bit to grab into.

 

[steevareno]

i was also thinking of doing this on my tank. How big is the risk if the tank is full? Obviously, i'll lower the water level and try it from the back. Let me know how it goes!

 

[reefphreak]

I've done it in the past with a diamond hole saw... All you need to do is make a template out of luan just big enough for the diamond bit to sit in and spin and then secure the template in place over the existing hole and spin away....

 

[NanoReefer]

One Eye: what was bit you used for that? What speed was your dremel set to?

steevareno: I may be a while as I am re-curing my rock (using the "cooking" method Here), but am unsure if I am going BB or SSB. I want to open the bulkhead up for more flow when I finally drain the tank and re-build it. I am not even going to try it on a fully stocked tank. My luck doesn't permit that kind of action.

 

[steevareno]

Too risky, that's why i didn't try it.

 

[NateHanson]

The diamond hole saws don't have guide bits Darren (at least the ones I've used. So it wouldn't matter if you were cutting around an existing hole. Just don't push hard, and either use a drill press or a plywood guide like the phreak described.

Nate

 

[One Eye]

I've never found a full diamond bit for the dremel. I end up using etching bits. The one I like the best has diamond up about 1" of the shaft. I run the dremel about 1/2 to 3/4 speed. The hardest part was always getting the hole started, after that it's simple. Just don't push to hard, you can feel it, let the tool do the work.
BTW, I've never used the hole saw on glass. I had the dremel and the hole saw bits had to be ordered....lack of patience.

 

[NeO]

Are you going to enlarge the hole on the bottom of the tank, or it is on the back?

If it is on the bottom, make sure the bottom is not tempered!!

 

[merk1_99]

What kind of drill press would you use? Maybe I am thinking of something else. But how do you get a 18''w glass aquarium set up to fit a drill press?

 

[One Eye]

you'd use a portable, clamp on press.

 

[NanoReefer]

Are you going to enlarge the hole on the bottom of the tank, or it is on the back?

If it is on the bottom, make sure the bottom is not tempered!!

Back of the tank! and I witnessed this hole being drilled. OTH it's sound advice for everyone to be sure thier tank was not drilled then tempered after by the manufacturer.

Does anyone think the plunge router attachment for the dremel could be useful. Combine it with a diamond tip it should provide more control right?