Bulkhead help!!

adawson23 · Jan 28, 2022

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.

Planned on using the 3/4” life guard for the drains

Another issue is that the holes in the overflow boxes are pretty close together

Naso180! · Jan 28, 2022

Just a thought, if u cut a piece of wood the size of the existing hole, u can insert it. Then redrill it. This will act as if it's a solid piece ur cutting into preventing the hole saw from walking.

piranhaman00 · Jan 28, 2022

Look at schedule 80 bulkheads, the hole they require is slightly larger and should work

adawson23 · Jan 28, 2022

Unfortunately I need the outside diameter smaller then the current hole. Current hole is 1 5/8” schedule 80 has a larger outside diameter

Kazumi · Jan 28, 2022

Have you actually tried to get an 1" bulkhead to fit in your hole, or are you just measuring? BRS 1" bulkhead is 1.65" your hole is 1.625". I would think that they would be close to fitting. You could use a caliper to measure exactly what your hole diameter is. If it won't fit you could use a barrel sander to enlarge the hole since its acrylic