Bulkhead help!!!

ADawson23

Plecostomus
MFK Member
Oct 7, 2021
230
250
51
36
Midwest,Missouri
Okay all, so I’m trying to get everything ready for when I’m done polishing the 375 gallon tank. An issue that I’m currently running into are the bulk heads. In the back of the tank there are 3 returns and in the center of the tank are the overflows with 2 holes drilled in each box. My plan with the overflows is a 1” siphon in each overflow and a 3/4” drain in each one. The drains will be off set for water changes, one drain at 50% and the other at 75%. This way all I’ll have to do is open a ball valve to drain the tank.

Now my issue is that a standard 1” bulkhead head needs a 1 3/4” hole but when I removed the original owners bulkheads, (a total of 7 holes all drilled at 1 5/8”) the holes that are drilled are 1 5/8” so I’m having a pretty hard time finding bulkheads to fit.
I need the 3 back holes to be 3/4” thread x slip then for the overflows I need two 3/4” slip x slip and two 1” slip x slip.

I know the best route to remedy this situation is to get a 1 3/4” hole saw and make the hole bigger. This is an acrylic tank and I’m afraid that the hole saw might walk when starting it.

If anyone has an idea, or where to get slightly smaller outside diameter bulkheads please let me know.

4E811BB4-B9F7-41F8-9078-8079E8232938.jpeg
8A921EDE-A147-4DB3-9956-CC94E7207CC9.jpeg
planned on using the 3/4 life guards for the drains
019BB1F4-1A75-4B4D-95B6-A3081BD64A95.jpeg
Here is also another issue, the holes in the overflow box’s are pretty close together
87D21D82-2D79-462F-A14A-518AD3937682.jpeg
 

fishdance

Redtail Catfish
MFK Member
Jan 30, 2007
1,788
950
150
To stop your holesaw "walking", clamp a sacrificial offcut of acrylic over the hole with an F clamp (or two). Then drill through the scrap acrylic piece which will "seat" your holesaw securely in the drilled groove before it reaches your tank acrylic.

So you continue drilling through both pieces. Don't stop or let the clamp(s) move. And as per acrylic work, don't let it overheat.
 

Backfromthedead

Potamotrygon
MFK Member
Jul 12, 2017
4,524
6,070
164
Fredericksburg va
Agree with above, but for me a piece of wood would work just as well as acrylic.

If its me, I'm cutting those middle overflow boxes out and patching the bottom holes, then reconfiguring/redrilling the back panel with larger drains and returns. I dont trust bottom drains, they take up floor space and just look at all that old filth in that overflow tower...they are crap for maintenance.

Looks like a fun project, keep us posted on your progress.
 

ADawson23

Plecostomus
MFK Member
Oct 7, 2021
230
250
51
36
Midwest,Missouri
The odd filth is from the previous owner running salt water. All my current tanks are drilled in the bottoms, so it doesn’t bother me much. This will be the first tank I’ve owned that has center overflows.
 

duanes

MFK Moderators
Staff member
Moderator
MFK Member
Jun 7, 2007
20,883
26,058
2,910
Isla Taboga Panama via Milwaukee
A template (as said above) is what I use, sized for the appropriate bulkhead. to keep the dill from walking.
I just tape it to the area I want to drill, and start a hose with cooling water over the area.
CBC7E544-8E25-48C0-95B8-E5EA11A6E59F_1_201_a.jpeg
I drilled two holes in a 5/8" glass tank yesterday, did the first hole, replaced the tape and did the other hole with fresh tape.
35085F4C-8801-4E47-9358-561ECBB74527_1_201_a.jpeg
Below bulkheads added, a few moments later.
433CFC91-7DA1-4618-A617-8144201DF187_1_201_a.jpeg
 
zoomed.com
hikariusa.com
aqaimports.com
Store