Back with another boiler question. steel pipe for steam line on a LE 0-4-0

[ChooChooChris]

I am trying to figure out on the 0-4-0 what pipe to use the only thing it says is 3/8 inch NPT and 1/4 inch npt for the hollow stays/ throttle. Hole OD is 9/16 and 23/32. No other specs are given regarding wall thickness or material type I see https://www.mcmaster.com/1120T31/ and https://www.mcmaster.com/7972K313/ as two possible options one is sch 40 other is 80 one is not seamless other is. I tend to like to overbuild but am unsure if there is any real benefit of spending $160 more for 0.035 thicker metal.

[cbrew]

if you are planning in using a smoke box throttle, double check what size the throttle rod will be used, if sch 80 will allow, then i would go with sch 80,, assuming the 3/8 npt will be the dry pipe for the throttle, sch 80, no question.
holy smokes batman, look for a location plumbing store for your pipe. mcmaster as lost its mind with the sch80

[Steggy]

At typical hobby boiler pressures, schedule 40 is more than adequate. Seamless is better only in that not having the internal weld flash makes it harder for bits of debris to find a place to get stuck.

That said, if you can get your hands on some DOM (drawn over mandrel), pipe-size mechanical tubing, you'll have a better product than conventional black pipe.

[ChooChooChris]

At typical hobby boiler pressures, schedule 40 is more than adequate. Seamless is better only in that not having the internal weld flash makes it harder for bits of debris to find a place to get stuck.

That said, if you can get your hands on some DOM (drawn over mandrel), pipe-size mechanical tubing, you'll have a better product than conventional black pipe.

I know both are well over rated for the pressure. My main thought was longer term use before corrosion impacts it.
(assuming the seam was not an issues)

[ChooChooChris]

if you are planning in using a smoke box throttle, double check what size the throttle rod will be used, if sch 80 will allow, then i would go with sch 80,, assuming the 3/8 npt will be the dry pipe for the throttle, sch 80, no question.
holy smokes batman, look for a location plumbing store for your pipe. mcmaster as lost its mind with the sch80

I will, I just use mcmasters because it is fast to get info and general pricing

[318J]

I agree with cbrew, if sch. 80 has the ID suitable for what you need, the extra wall thickness over sch. 40 will give you that much more longevity.