Cutting hole for overflow in acrylic

[Biodork]

Hi everyone,

Getting ready to retrofit my 30 gallon tank for an overflow and sump. I need to cut three holes in the back, one large hole for the overflow box and two smaller holes for the return. The overflow box will have a 1.5" bulkhead, which required a 2.75" hole. To place the box (and water level) where I'd like, the edge of the hole will be approximately 3" away from the top of acrylic sheet that is the back side of the tank. Is this too close to the edge? I read in an article that a hole should be cut at least 1.5x the diameter away from any edge? But this would make my water level lower than I desire. The back of the tank is ⅜" thick. Any suggestions? Also, how critical is it to use a drill with a clutch?

Thanks!

 

[Gorgok]

It sounds like what you have been reading is for glass. The distance thing doesn't really apply to acrylic, drill where you wish. Also a clutched drill is not necessary or possibly even good for acrylic. If stops because of heat expansion and you cant turn it and back out you might have much more of an issue...

Keeping the cut from melting is really all you need to do. Clearing the cuttings goes a long way for that, as grinding them back into the acrylic really builds up heat quick. Wood hole saws aren't really good at clearing cuttings, but you can make it work good enough.

 

[CuzzA]

1.5" drain on a 30 gallon is awfully large. 1" would be more than sufficient if you're running a durso. Even 3/4" would be fine.

 

[salty joe]

Mineral spirits work well as a cutting fluid for acrylic. Just needs cleaned up afterwards because long term-days,weeks-can soften the acrylic. I use it every time.