How is the bulkhead size determined?

[Vark913]

I see 3/4", 1", 1 1/2", 2" for sale on line. How is that measured, is it the inside diameter of the bulkhead? I'm having my tank moved Saturday and want to buy new gaskets, which measure out to be 1 5/8" on the inside ring of the gasket (this is what fits over the threaded bulkhead). So does it sound like I have a 1 1/2" bulkhead? Thanks.

 

[Paulie 069]

I see 3/4", 1", 1 1/2", 2" for sale on line. How is that measured, is it the inside diameter of the bulkhead? I'm having my tank moved Saturday and want to buy new gaskets, which measure out to be 1 5/8" on the inside ring of the gasket (this is what fits over the threaded bulkhead). So does it sound like I have a 1 1/2" bulkhead? Thanks.

Pics

 

[Goodair]

Its likely a 1 1/4

 

[Goodair]

Whatever pipe size you connected to the bulkheads is the bulkhead size. The hole will be slighty bigger to compensate for the pipe wall thickness.

 

[Vark913]

Thank you Goodair. I measured the return screwed into the bulkhead in the tank and it measured 1 1/4". Now I just need to find someone who has that size, seems 1 1/4" is not common, but 3/4" 1" and 1 1/2 are. Likely won't be able to get new seals before Saturday so I'll have to hope I don't have any issues using the current seal which hasn't been touched since the tank was set up and has never leaked. No way I can get the tank out of the custom stand I built without removing the bulkheads. Thanks again.

 

[Goodair]

Are you looking to replace the whole bulkhead or just the rubber gaskets?

 

[Vark913]

Just the gaskets. To be safe.

 

[Mark_C]

Just FYI, if you go to one of the 2 big home improvement stores they sell gasket materials in sheet form so you can cut your own.

 

[redfishbluefish]

Here’s one of the issues with plumbing parts….is it schedule 40 or schedule 80. The difference is the pressure these fittings/pipes can take, and I’ve never understood the need for schedule 80 on fish tanks….yet people use this stuff. Anyway, schedule 40, which is still overkill for our tanks, has the following drill sizes for respective bulkhead sizes:

Size: 1/2″ = Hole Size: 1 1/8″ or 1 1/4″
Size: 3/4″ = Hole Size: 1 1/2″
Size: 1″ = Hole Size: 1 3/4″
Size: 1 1/2″ = Hole Size: 2 3/8″
Size: 2″ = Hole Size: 2 7/8″

* may differ from one manufacturer to another

And for those that might be interested, here are the Schedule 80 hole sizes:

Bulkhead Size	Maximum Hole Size	Minimum Hole Size
1" Sch 80. Bulkhead	65mm/2.55"	48mm/1.88"
1 1/4" Sch 80. Bulkhead	83mm/3.28"	59mm/2.31"
1 1/2" Sch 80. Bulkhead	90mm/3.54"	64mm/2.56"
2” Sch 80. Bulkhead	103mm/4.05"	81mm/3.18"

 

[Goodair]

Sch 80 looks better than 40, there isnt really any other benefit from it.