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7/8 Scale Model of a 1/2 Scale Model Boiler?

Posted: Wed Nov 29, 2023 4:07 pm
by dudeface
It would be nice if I had some large diameter copper tubing for a boiler, but this is all I have. I think it might be enough for a small speeder/inspection car that wouldn't be required to pull a load, besides maybe a small trailer.
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The larger tube is 7/8" diameter, 1.5" long and holds about 9 ml 3/4 full. The smaller tube, which would be the steam dome, is 0.5" diameter and 1.25" long.

I do have a heck of a lot of the smaller stuff though!

Re: 7/8 Scale Model of a 1/2 Scale Model Boiler?

Posted: Sun Dec 03, 2023 6:39 am
by Old Man Aaron
You're gonna need something bigger if you want it to work. As I mentioned in your intro thread, your best bet would be a cheap used "toy" steam engine as a donor. Every critical part is already made and works. You could build something like this, but with the boiler mounted transversely.
Image

Try punching "live steam" into Farcebook marketplace, Craigslist or even check your local garage/yard sales and antiques shops. Lots of cheap steam engines about, just takes some searching. Maybe your parents could buy it for you and you could pay them back by doing chores? Building them from scratch is slow, difficult and takes a lot more than a drill press.

Re: 7/8 Scale Model of a 1/2 Scale Model Boiler?

Posted: Sun Dec 03, 2023 3:45 pm
by dudeface
Like I said, this wouldn't be a loco, it would just be a small speeder, with an extremely tiny engine, but a nice big flame to heat it, and the boiler would be mostly filled with water, hence the "large" steam dome. If you can make a working scale model of a steam engine shouldn't you be able to make a working scale model of a working scale model of one? I've seen some extremely tiny ones on YouTube, for example a traction engine that was about 3 inches long, and ran fine.

About needing more than a drill press, I really just want it to work, it doesn't have to be a precision model. Yes pistons and cylinders are best turned on a lathe, but a well drilled hole should provide a good enough seal. Guys like Thomas Techs on yt do it all the time WITHOUT a drill press, so if his engines are pieces of crap, imagine how much better they would be if he did have one.

Re: 7/8 Scale Model of a 1/2 Scale Model Boiler?

Posted: Sun Dec 03, 2023 4:04 pm
by dudeface
If it doesn't work, then I've found out for myself. Building it myself would be more interesting and would allow me to get closer to my drawing, besides, I wouldn't have the heart to take apart a functional Mamod, and would just want to repair a broken one.

Re: 7/8 Scale Model of a 1/2 Scale Model Boiler?

Posted: Sun Dec 03, 2023 4:21 pm
by philipy
dudeface wrote: Sun Dec 03, 2023 3:45 pm If you can make a working scale model of a steam engine shouldn't you be able to make a working scale model of a working scale model of one?
Not necessarily. Dimensions can be scaled but not the laws of physics and there comes a point as you reduce the dimensions that the physics no longer works.

Re: 7/8 Scale Model of a 1/2 Scale Model Boiler?

Posted: Sun Dec 03, 2023 4:33 pm
by dudeface

Re: 7/8 Scale Model of a 1/2 Scale Model Boiler?

Posted: Sun Dec 03, 2023 6:12 pm
by drewzero1
I think you should try it if you want to, just don't be too discouraged if it doesn't work out well.

Re: 7/8 Scale Model of a 1/2 Scale Model Boiler?

Posted: Sun Dec 03, 2023 6:24 pm
by -steves-
Building a simple mini boiler is one thing, getting a working piston and drive from it, with the correct "everything in the right places" is another. This I know from practice and a number of failures, but that said. without failures, we would have nothing :thumbup: Always go for it I say :thumbup: You should see the amount of scrap from the Garett project, literally, 2 very large carrier bags full of PLA scrap, and don't get me started on resin scrap and metal scrap over the years. :lol:

Re: 7/8 Scale Model of a 1/2 Scale Model Boiler?

Posted: Sun Dec 03, 2023 7:17 pm
by dudeface
drewzero1 wrote: Sun Dec 03, 2023 6:12 pm I think you should try it if you want to, just don't be too discouraged if it doesn't work out well.
I've attempted several piston engines, and the only two that worked were lego vacuum engines, so by now I expect failure but I would be extremely happy if it worked.

Re: 7/8 Scale Model of a 1/2 Scale Model Boiler?

Posted: Sun Dec 03, 2023 7:38 pm
by dudeface
Is this a terrible idea? (Probably.) It's a pressure vessel, but it does say "may burst if heated"... Does anybody know what kind of pressure these can take?
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Re: 7/8 Scale Model of a 1/2 Scale Model Boiler?

Posted: Sun Dec 03, 2023 7:43 pm
by dudeface
I just looked it up and apparently the pressures vary from 2-8 bar, I assume that means most cans can take 10 bar or more.

Re: 7/8 Scale Model of a 1/2 Scale Model Boiler?

Posted: Mon Dec 04, 2023 9:15 am
by -steves-
dudeface wrote: Sun Dec 03, 2023 7:43 pm I just looked it up and apparently the pressures vary from 2-8 bar, I assume that means most cans can take 10 bar or more.
These are super thin metal and will distort under heat, by distort, I mean it could blow up in your face, something with a thicker wall is strongly advised. :shock:

Re: 7/8 Scale Model of a 1/2 Scale Model Boiler?

Posted: Mon Dec 04, 2023 9:51 am
by philipy
-steves- wrote: Mon Dec 04, 2023 9:15 am
dudeface wrote: Sun Dec 03, 2023 7:43 pm I just looked it up and apparently the pressures vary from 2-8 bar, I assume that means most cans can take 10 bar or more.
These are super thin metal and will distort under heat, by distort, I mean it could blow up in your face, something with a thicker wall is strongly advised. :shock:
Most ( all?) aerosol cans carry the warning "Do not incinerate even when empty". I know you are not intending to incinerate it but applying a naked flame to part of it would effectively achieve the same result!

Re: 7/8 Scale Model of a 1/2 Scale Model Boiler?

Posted: Mon Dec 04, 2023 12:07 pm
by Phil.P
Fit a safety valve..
Would be my advice, and don't re-purpose an aerosol can.

If it pops, it is the hot contents, you need to worry about..

And I doubt anyone would certify it, or any association insurance cover you for public liability?

But if you want to mess about in your own shed, no one can stop you.

But please be careful!

Phil.P

Re: 7/8 Scale Model of a 1/2 Scale Model Boiler?

Posted: Mon Dec 04, 2023 3:38 pm
by dudeface
philipy wrote: Mon Dec 04, 2023 9:51 am Most ( all?) aerosol cans carry the warning "Do not incinerate even when empty". I know you are not intending to incinerate it but applying a naked flame to part of it would effectively achieve the same result!
It would be filled with water so it would be kinda hard to ignite the residue, but don't worry, I'm not going to do it.

Re: 7/8 Scale Model of a 1/2 Scale Model Boiler?

Posted: Mon Dec 04, 2023 4:40 pm
by SKGLB
117 posts (as of today), some ancient threads brought out of obscurity.
https://gardenrails.org/forum/viewtopic ... 32#p176532

Marc Horowitz, whom I greatly admire for his "locomotive of the month" page, which is unfortunately no longer being continued, doubts his opinion.

And then ideas like this, an empty can as a steam boiler. : :scratch: (

I know such members from our forum, they glow brightly like a comet for a short time on the firmament of a forum, but then burn up just as quickly and are no longer seen.

Sorry for my words, I think I realized that you are still very young.

I also started the live Steam hobby many years ago, at a time when internet forums didn't yet exist.

Since these forums have existed, I have tried to give tips based on my modest experiences, and I have also received a lot of help, for which I am very grateful.

I hope that here too, at my modest 62 (63 including this one), I have achieved this take and give.

Greetings from Austria
Gerald

Re: 7/8 Scale Model of a 1/2 Scale Model Boiler?

Posted: Mon Dec 04, 2023 7:08 pm
by dudeface
SKGLB wrote: Mon Dec 04, 2023 4:40 pm 117 posts (as of today), some ancient threads brought out of obscurity.
https://gardenrails.org/forum/viewtopic ... 32#p176532
It was bumped by Sir Clothem Cap, who started it.
SKGLB wrote: Mon Dec 04, 2023 4:40 pm
I know such members from our forum, they glow brightly like a comet for a short time on the firmament of a forum, but then burn up just as quickly and are no longer seen.
I think I'll be here for a while. :thumbup: