Confused about Schedule 40 pipe sizes...

[lyrical]

So excuse the elementary piping question I've never had to build hard plumbing before it's always been provided for. This time I am going to attempt it.

Where my confusion is... I am going to use slip x slip fittings and the primer/glue to connect everything with pipe, unions, etc.

So... if my pipe is 1.5" would I buy a 1.5" bulkhead for it to fit inside? Same with the union... if I had a 1.5" pipe would I buy a 1.5" union, or a 1.75" union for it to fit inside?

Or if it's 1.5" pipe do you buy everything 1.5" across the board? Including couplers to fit?

Thansks :)

 

[sonnus]

If you use 1-1/2" pipe you will use all 1-1/2" fittings.

All pipe has different outside diameter compared to the nominal size. You need to forget about the actual outside diameter and just go by the nominal size when buying fittings.

 

[lyrical]

Thanks sonnus :) You confused me with the nominal size and the chart.. but basically what you are saying is 1.5" across the board? So to connect a 1.5" pipe to a union I would want a 1.5" union? And to connect a 45 or 90 degree angle I would use a 1.5" coupler to fit inside the 1.5" pipe and 1.5" union? Sorry for the 1.5" redundancy question I just don't want to order the wrong size online.

 

[sonnus]

Yup, get all 1.5".

 

[lyrical]

Awesome ty :)

 

[DaveMorris]

You mentioned a bulkhead in your original post. You need to double check the size for it. Some of them with threads are a little off. It should follow the same thing for size, but be sure to check it.

 

[AZDesertRat]

Sch 40 pipe sizes go by the inside diameter where the flow is not the outside diameter which varies due to the wall thickness of the pipe. Fittings and valves are made to fit the outside diameter and take into account the wall thickness.

 

[lyrical]

You mentioned a bulkhead in your original post. You need to double check the size for it. Some of them with threads are a little off. It should follow the same thing for size, but be sure to check it.

Thank you. I'm not sure how I can check it before taking it off to change it. It's what came with the tank and was already installed. I'll see what I can find out though, :)

 

[lyrical]

Sch 40 pipe sizes go by the inside diameter where the flow is not the outside diameter which varies due to the wall thickness of the pipe. Fittings and valves are made to fit the outside diameter and take into account the wall thickness.

Thanks! That makes sense... almost... but I am still confused. I understand a 1.5" PVC pipe is 1.5" on the inside.. but for example if I needed a coupler it would still have to be a 1.5" one correct? I'm good with the rest I think lol.

 

[AZDesertRat]

The first answer to you post above shows the outside diameter of various sizes of sch 40 PVC. Measure the inside diameter of the bulkhead and match it up with the chart.

 

[Fin]

Also, when you buy your primer, buy the clear primer. Don't use the purple stuff if you don't want your plumbing job to look messy with purple stains all over it. The dye in the purple primer is not necessary for aquarium use.

 

[lyrical]

Is there a brand you suggest that you can find locally at the Home Depot or Lowes? I've only seen the purple primer.

 

[Fin]

Is there a brand you suggest that you can find locally at the Home Depot or Lowes? I've only seen the purple primer.

No, just whatever they have at Lowe's or Home Depot. They both carry it. I believe it is mostly acetone.

 

[lyrical]

Thanks!

 

[Mike in CT]

You can also get clear primer, looks a lot cleaner if your not into seeing the purple primer everywhere.

 

[lyrical]

Thanks again :)