steam engine need help!

This forum is dedicated to the Live Steam Hobbyist Community.

Moderators: Harold_V, WJH, cbrew

User avatar
Fred_V
Posts: 4196
Joined: Sun Jan 12, 2003 3:26 pm

Re: steam engine need help!

Post by Fred_V » Tue Dec 26, 2017 8:24 am

As to your boiler, I don't think it would need to be as large as you are thinking. I built 2 locos that had 3" by 4" cylinders and the boiler was a piece of 10" pipe and a grate of 100 square inches. This would produce more steam than the engine needed. You are talking about less cyl area so the same boiler would be more than enough. I would consider a vertical boiler for your application and use a 10" pipe.

Most state boiler codes exempt hobby boilers that have less than a certain amount of heating surface and water volume so check your state code. This would make life much simpler for you. Also look at firing with coal. Wood burns so fast and puts out much less BTU's.
Fred V
Pensacola, Fl.

rkcarguy
Posts: 819
Joined: Tue Aug 22, 2017 10:33 am

Re: steam engine need help!

Post by rkcarguy » Tue Dec 26, 2017 2:41 pm

I am not against using steel for cylinders, but it must be cared for. Cast iron or steel will both rust if the bores are not oiled after a run.
If you are using steel and fabricating cylinders, it's got to be made a certain way. I would complete all the welding, then heat cycle the fabrications in the oven several times to your estimated operating temperature. *Then* do your final boring of the cylinders, facing of the ends, and bolt everything together.
I think one could even use stainless pipe, although expensive in seamless, along with a brass piston it would be pretty bulletproof as far as corrosion. I think that with the low rpm and clearances common in steam, that any heat deformation beyond this is going to minor and not of consequence.

User avatar
Bill Shields
Posts: 5093
Joined: Fri Dec 21, 2007 4:57 am
Location: Somewhere in the World
Contact:

Re: steam engine need help!

Post by Bill Shields » Tue Dec 26, 2017 3:04 pm

Stainless for a cylinder is not the best way to go. Corrosion may be less, but I would be more concerned about operation and wear of stainless on anything.

Harold_V
Posts: 17083
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: steam engine need help!

Post by Harold_V » Tue Dec 26, 2017 4:15 pm

What Bill said. Stainless, especially the 300 series, makes a miserable bearing, a feature that walls must have. Stainless is well known for its ability to gall.

Might have acceptable results using 416, heat treated, however, assuming one has deep pockets.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

rkcarguy
Posts: 819
Joined: Tue Aug 22, 2017 10:33 am

Re: steam engine need help!

Post by rkcarguy » Tue Dec 26, 2017 4:25 pm

^ Agreed, however this would depend completely upon what ring material was used.
Honda, for example, uses a fairly soft ring material and in most engines the liners are steel, cast in aluminum. I've taken apart engines with 150K-225K miles on them to find the factory cross-hatching still there, and the rings in various states of wear from decent to nearly gone.
If the piston and rings are made properly with the design of these steam cylinders(the piston has no skirt), the piston should never touch the cylinder walls.
I'll have to take a teaser pic of the stainless pipe scrap bin at work for you guys:)

rkcarguy
Posts: 819
Joined: Tue Aug 22, 2017 10:33 am

Re: steam engine need help!

Post by rkcarguy » Tue Dec 26, 2017 4:43 pm

stainless.jpg

User avatar
Bill Shields
Posts: 5093
Joined: Fri Dec 21, 2007 4:57 am
Location: Somewhere in the World
Contact:

Re: steam engine need help!

Post by Bill Shields » Tue Dec 26, 2017 6:00 pm

ring material matters not...anything sliding on stainless steel is a bad combination.

rkcarguy
Posts: 819
Joined: Tue Aug 22, 2017 10:33 am

Re: steam engine need help!

Post by rkcarguy » Tue Dec 26, 2017 7:17 pm

A lot of air cylinders are built with stainless bodies and PTFE (Teflon) rings, and they last for decades.
I'd agree that anything metal sliding on stainless would be bad.

User avatar
Bill Shields
Posts: 5093
Joined: Fri Dec 21, 2007 4:57 am
Location: Somewhere in the World
Contact:

Re: steam engine need help!

Post by Bill Shields » Tue Dec 26, 2017 8:47 pm

totally agree, however air cylinders are an entirely different situation from a steam application.

Harold_V
Posts: 17083
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: steam engine need help!

Post by Harold_V » Wed Dec 27, 2017 1:56 am

Bill reflects my thoughts nicely.
I like stainless---like it a lot, but it is best used for the appropriate application.
Something to ponder.
17-4 PH rivals 4140 in many ways----with the added benefit of corrosion resistance. Were I tempted, I'd likely try it for steam, along with 416.

Nice box of stainless tubing. Tell your boss I have plenty of room in my shop to store it if he'd like to donate to the cause! :lol:
H
Wise people talk because they have something to say. Fools talk because they have to say something.

joe36
Posts: 5
Joined: Thu Dec 21, 2017 12:37 am
Location: 46947

Re: steam engine need help!

Post by joe36 » Wed Dec 27, 2017 11:58 am

Again, a whole lot to consider. This is why I would ask of those who have the knowledge and experience. In the hope to minimize the chances of mistakes. While having a reasonable background in industry, when it comes to steam. I was, born yesterday. With some study and the advice given I hope I am beginning to grasp some of the concepts as of materials needed.

It sounds like cast iron will be the logical choice. If I go with a casting. Should I be looking at ductile or gray iron? I had considered Teflon rings but ring design / material along with the piston. Will be a major component that will be one of the later parts fabricated. I will be visiting this subject in great detail in the spring. Thoughts now are for a cast turned bronze piston but once again this will be determined later with advice from those more knowledge on the subject than myself.

Joe

rkcarguy
Posts: 819
Joined: Tue Aug 22, 2017 10:33 am

Re: steam engine need help!

Post by rkcarguy » Wed Dec 27, 2017 12:10 pm

Harold, research shows that many manufacturers "formula's" of PTFE have a temperature rating to 400*+. I've made several pieces of equipment for production environments that used air cylinders to clamp something several times a minute, and these fixtures are still working well after 10 years and who knows how many parts. Also, I found a manufacturer that makes "X-seals" which have a 435* rating in reciprocal use, applicable for steam, and in a whole bunch of various sizes. They look like they'd work really well.

Sadly, 99% of us have little use for the pipe remnants and about twice a year it just gets dumped in the recycle dumpster which we only get $20-$40 a ton for. We also get stuff back from the jobsites that just goes in there as well, it kills me to see, but it's not worth it to have somebody sell it all in a surplus situation. Chain, bolts, nuts, washers, anchors, threaded studs and rod, cable, pipe fittings, metal rems, buckets, welding cloth, you name it. I dumpster dive on occasion lol. I'm sure I could get you some with a small donation to the office donut fund if you are up this way. :)

Post Reply