Best way to increase the diameter on an overflow for a bulkhead?

infin

Jack Dempsey
MFK Member
Sep 3, 2005
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0
36
ca
I have 2 overflows that are built in on my 200 gallon acrylic tank.

I had standard bulkheads but one cracked so i bought some heavy duty ones.

The heavy duty ones are about 1/4" wider in diameter and will not fit into the holes on the tank.

What is my best course of action to make these holes larger?

the acrylic is 1/2" thick.

tank is currently all drained out.
 

DB junkie

Gold Tier VIP
MFK Member
Jan 27, 2007
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I use a pneumatic die grinder with a carbide bit in it. The bits are for metal but eat up acrylic with ease. Have used them on acrylic up to an inch thick.

IF using a hole saw I use water with it, same with a jig saw/sawzall. All would work as well......
 

brich999

Jack Dempsey
MFK Member
Jul 3, 2010
4,312
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38
New Hampshire
The issue with using a hole saw is you wont get the middle pilot hole to bite which will make it difficult to hold in place making a good clean hole. Drilling acrylic isnt difficult at all but your case may be tricky because you really need that guide to hold it straight
 

DB junkie

Gold Tier VIP
MFK Member
Jan 27, 2007
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Iowa
I actually use a home made jig with the hole saws. Made from a small piece of plastic with rollerblade bearings and spacers. Suction cups on the bottom.

No pilot needed. ;)

Definitely makes drilling glass easier, works with acrylic too......

IMG_1811.JPG
 

brich999

Jack Dempsey
MFK Member
Jul 3, 2010
4,312
11
38
New Hampshire
I actually use a home made jig with the hole saws. Made from a small piece of plastic with rollerblade bearings and spacers. Suction cups on the bottom.

No pilot needed. ;)

Definitely makes drilling glass easier, works with acrylic too......
Well isnt that nifty. Learned my new trick for today.
 

DB junkie

Gold Tier VIP
MFK Member
Jan 27, 2007
9,036
1,863
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Iowa
Well isnt that nifty. Learned my new trick for today.
Saw them for sale on glass-holes.com, had the stuff laying around here so thought why not give it a try? The things worked flawlessly.... lol Bearings have even held up to the water used when drilling......
 

Drstrangelove

Potamotrygon
MFK Member
Oct 21, 2012
2,693
1,227
164
San Francisco
I actually use a home made jig with the hole saws. Made from a small piece of plastic with rollerblade bearings and spacers. Suction cups on the bottom.

No pilot needed. ;)

Definitely makes drilling glass easier, works with acrylic too......

People like you drive me nuts since I am so incompetent with materials and mechanics. :thumbsup:
 
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