Can I re drill a drain and return?

Patto005 · Feb 17, 2015

I have a 1" drain line and a 1/2" return line, can I re drill these holes in their current spot with larger diameter ones? I was thinking of going with a 2" drain and a 1" return

heathd.hd · Feb 17, 2015

Seems big... what kind of flow u looking 2 get through it?

Patto005 · Feb 17, 2015

Around 2400gph

heathd.hd · Feb 17, 2015

No idea why you could not just drill over the old holes. People do that all the time.

Patto005 · Feb 17, 2015

heathd.hd said:
No idea why you could not just drill over the old holes. People do that all the time.

I was wondering if it would easily break? My glass is 1/2" thick
How hard would it be to keep the bit from "walking" since there is no pilot hole to use

VicD81 · Feb 17, 2015

We dont use pilot holes when drilling glass. I think you need to do more research on drilling glass before attempting to do it.

redfishbluefish · Feb 17, 2015

First you need to use a guide. I typically make these out of scrap plexiglass.

Second would be how close the two holes would be. Can't remember the rule, but look it up.

And finally, would the sump be able to handle 2400 gph flow. Look at the total turnover rate. Might be too high.

racin2438 · Feb 17, 2015

In our 150g main tank , I had a 10 " overflow box made with a 2" hole to the sump and and 3/4" return about 2"apart.

I'm using a mag drive 108 at 3' head height .

Using the hole saw started on edge and slowly rotate upright would work.

But your best bet is make a template as suggested above by others.

Or do you have a option of plugging the current ones and relocate the new holes?

davescrews · Feb 18, 2015

I've done freehand it before, it's a little sketchy though! A guide like this would help with the smaller hole, you'd have to make a guide for the larger one.

s2nhle · Feb 18, 2015

Make sure you do it slow and let the weight of the drill press on it. Do not rush it and start with angle first before straight down.

Patto005 · Feb 18, 2015

Thanks for the tips guys. No I cannot plug the existing holes and relocate new ones, my overflow is relatively small. It's only 7-1/2"x4-1/2"

jdl513 · Feb 18, 2015

You may want to check out a how to video Melevsreef posted recently.

Only difference I see in your case is you would need to plug the existing holes temporarily to keep the water pooled while are drilling the larger hole over top.
Plumber's putty may be enough to plug as you just need it to pool water to keep the bit cool and flush cuttings.

Patto005 · Feb 19, 2015

jdl513 said:
You may want to check out a how to video Melevsreef posted recently.

Only difference I see in your case is you would need to plug the existing holes temporarily to keep the water pooled while are drilling the larger hole over top.
Plumber's putty may be enough to plug as you just need it to pool water to keep the bit cool and flush cuttings.

Is there anyway to accomplish this without having to drain the tank and flip it over? Can it be drilled from underneath? How would you keep the bit wet?

jdl513 · Feb 19, 2015

I am by no means the expert.
I would not attempt to drill it unless drained and flipped upside down.
That is just asking for a very very bad outcome.

If I could not get the tank positioned to drill properly I would live with the drains I had.