Pipefitters - difference between Sch 40 & Black Steel pipe?

[MissileBear]

This is hopefully a quick question - I'm looking for some pipe for woodworking pipe clamps. The instructions say to use 3/4" black steel pipe, which I can find at the big box stores for a premium.

My local metal supplier has 3/4" sch 40 steel pipe, which is cheaper per foot and doesn't have the black coating that I'd need to remove.

I see that the black pipe is often listed as Sch 40, but can't find anything that says they are the same composition wise.

Is black steel pipe essentially just sch 40 pipe with the black coating?

Thanks in advance

 

[Northislander]

Black steel pipe comes in various schedules(wall thickness) sch. 40 is the lightest you want to use for threading as you need to thread one end for the clamp.

 

[Rock knocker]

My local metal supplier has 3/4" sch 40 steel pipe, which is cheaper per foot and doesn't have the black coating that I'd need to remove.

Black pipe is the finish, plain steel with a plastic coating. The coating has no purpose other than slight protection during shipping. Black steel pipe is basically uncoated. I don't known what coating you're speaking of.


Schedule 40 is the wall thickness. Pipe clamps can work equally well on sch 10 as they will sch 80. Since sch 80 has a thicker wall, it will be stiffer and that may help clamping in some situations

 

[GarageGuy89]

Scheduling has to do with pipe thickness, while holding the same outer diameter. Sch40 & Sch 80 pipe of the 3/4" will be the same on the outside diameter, but have different inner diameters.

Black pipe is essentially mild steel with the black 'paint' being a corrosion inhibitor.

Just take your clamps with you and make sure they fit.

 

[GrayFlattop]

Schedule 40 (or 80) refers to the wall thickness according to ASTM A53.
"Schedule 40" pipe may be black iron, it may be bare iron, galvanized or even PVC. Schedule 40 pipe may be made of Aluminum or Stainless steel.

For your purposes, just about any mild steel 3/4" pipe will work just fine.

 

[Rock knocker]

"Schedule 40" pipe may be black iron, it may be bare iron, galvanized or even PVC. Schedule 40 pipe may be made of Aluminum or Stainless steel.

Don't forget inconel, brass, copper, fiberglass or FRP

 

[Radix2]

This is hopefully a quick question - I'm looking for some pipe for woodworking pipe clamps. The instructions say to use 3/4" black steel pipe, which I can find at the big box stores for a premium.

My local metal supplier has 3/4" sch 40 steel pipe, which is cheaper per foot and doesn't have the black coating that I'd need to remove.

I see that the black pipe is often listed as Sch 40, but can't find anything that says they are the same composition wise.

Is black steel pipe essentially just sch 40 pipe with the black coating?

Thanks in advance

why do you have to remove the paint?

Im surprised that a steel supplier is cheaper than the big box stores. thebig box store carry 3/4 steel pipe in black or galvanized, either will work fine and have the correct threads.

make sure that your item from the steel supplier is the same OD, since it is not 3/4...and you need to have it threaded to 3/4NPT

 

[MissileBear]

Thanks for the replies all -

I know what schedule 40 is and the difference between schedules, I was more concerned with the composition of the pipe itself, i.e. what metal/alloy, how it was formed, etc. I was not sure if black pipe was suggested because it was a specific alloy and worked well for this purpose...not sure why it was so expensive. I'm also not sure if black pipe meant for natural gas is seamless or welded, or if it even matters.

My concern was that the pipe itself wasn't meant for the purpose of pipe clamps, so I didn't want something that wouldn't serve well.

why do you have to remove the paint?

That black coating stains the wood and tends to scrape off due to the cams on the clamps. It's easier just to remove it and wax the pipe to keep it from rusting.

 

[2level]

Is 3/4" galvanized schedule 40 pipe expensive in your area?

 

[MissileBear]

Is 3/4" galvanized schedule 40 pipe expensive in your area?

More so than the other options. Home Depot charges about $24 for a 10' section....didn't even ask the metals supplier.

 

[woodscaper]

Galvanized tends to slip at times when you crank it down I have found.

 

[2level]

I wouldn't be surprised if you find it costs half as much in full (20 foot plus) sticks.

Never slips when I use galvanized pipe clamps.

 

[MissileBear]

I wouldn't be surprised if you find it costs half as much in full (20 foot plus) sticks.

That's my plan....I want to buy it long and cut it down to 6 foot sections. I have the threaders at home. HD wants $19 for a 6' of black steel, and it's not much more, but still too expensive, for a 10'.

 

[dr_clyde]

Black pipe is just the name for the coating they put on the pipe so you don't have to paint it.

If you are intending to weld the pipe, just ordering plain steel pipe will get you pipe that is not covered in that black nasty coating, something worth noting.

Pipe schedule is the wall thickness. Note the OD does not change in pipe with different schedules.

So your standard black pipe IS schedule 40 pipe. But if you call a steel supply and as for steel sch. 40 pipe, you probably won't get black pipe unless you specify it.

BTW, don't buy plumbing stuff from the big box store unless you have to. A plumbing supply will be cheaper, and have better quality parts.

 

[3xpendable]

My clamps slip on galvanized pipe too.


Sent from my iPhone using The Garage Journal mobile app

 

[2level]

You guys waxing your pipe: take a file and notch that thing!!

 

[strength_and_power]

At most steel suppliers, pipe is typically sold in 21’ lengths. King Metals sells round tubing with the same dimensions as Sch40 but doesn’t list it as Sch40. As far as black or galvanized, it doesn’t matter, you are already using it outside it’s intended use. I can’t imagine there being an insane amount of pressure put on the pipe.


Sent from my iPhone using Tapatalk

 

[Ole Slewfoot]

That's my plan....I want to buy it long and cut it down to 6 foot sections. I have the threaders at home. HD wants $19 for a 6' of black steel, and it's not much more, but still too expensive, for a 10'.

Oddly, they will cut the 10' in half, and thread both new ends free if you can stand the wait.

 

[MissileBear]

Oddly, they will cut the 10' in half, and thread both new ends free if you can stand the wait.

Yes, but I need 6' sections :/

I'm going to grab it at the metal supply shop. Thanks for the replies all.

 

[Milton Shaw]

Six foot sections you will get a lot of bowing of the pipe when you clamp it down. I used schedule 80 for all my clamps over 18" and you can tell a difference the minute you start to clamp the wood. Your glue up will be a lot flatter if you use schedule 80 and the cost is not much when you consider they will last the rest of your life.. See if some GJ member close to you can help you out by cutting and threading it. If you were closer I would be glad to help.. The schedule 80 will be as stiff as the more expensive "I" beam style clamps.

 

[MissileBear]

Thanks for that info Milton.