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Another project, this one steam related, renovating old steam toy.

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  • #16
    Calibration in bar is certainly possible, since the origin is German. However, the flat ends of the boiler are made of sheet well under 1mm in thickness, and there appears to be no staying at all. At least there is no external evidence of it.

    With a diameter of about 3 inches, the total pressure on the end at 3 bar would be roughly 300 lb, with steam temp of around 230F. I doubt that the unstayed soft-soldered boiler is intended to hold that sort of pressure, and the engine operates well on only 1 psi (.07 bar, gauge). That pressure would be inappropriate for a toy boiler, which is in no way an ASME-stamped "fired pressure vessel".

    It was the 1950s, but still......
    Last edited by J Tiers; 03-12-2022, 12:25 PM.
    CNC machines only go through the motions

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    • #17
      This video shows a Wilesco pressure gauge clearly marked and red-lined at 2.5 bar...



      I'm guessing that your gauge is calibrated in bar.
      Regards, Marv

      Home Shop Freeware - Tools for People Who Build Things
      http://www.myvirtualnetwork.com/mklotz

      Location: LA, CA, USA

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      • #18
        As I said, it may indeed be in bar. It is a German product. But nobody should expect thin flat copper boiler ends without internal staying, to withstand that pressure. Nor is it required to have that pressure to run the toy.

        CNC machines only go through the motions

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        • #19
          I measured the end cap thickness. It is 0.5mm, and the ends are dead flat. I put a piece of wire in through the open drain hole where the bush will go, to feel around for any obstructions. There is positively no staybolting, no through stay, no angle stays in there of any kind.

          The main cylindrical shell seems to be about 1.5mm copper, at least in the areas where the gauge, throttle valve, whistle, and safety valves are screwed in or otherwise attached.

          I can't see that holding 40 psi without the thin flat ends bulging something fierce.

          That need not make the gauge read psi, it could still read bar, even though a sensible pressure would not give much reading on it, and it would not look very impressive. This one needs fixing, so I can't just check it.

          I agree with Mr Powell above, I'd not trust the boiler with even 10 psi, really, and that's well over enough to run the engine just fine.

          To your thought, however, there are two safety valves, a spring type, and a weight type. Both do seem heavier than they ought to be for very low pressures.
          Last edited by J Tiers; 03-13-2022, 01:09 AM.
          CNC machines only go through the motions

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          • #20
            I recommend reading this discussion http://www.rmweb.co.uk/community/ind...g-mamod-locos/

            Rick Hann

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            • #21
              Originally posted by rickhann View Post
              I recommend reading this discussion http://www.rmweb.co.uk/community/ind...g-mamod-locos/

              Rick Hann
              This boiler is COPPER, and is already soft soldered in other places from the factory (you probably saw that from the pictures, but....). I am familiar with the K N Harris boiler book (have it, have been through it several times).

              The soft solder in question to use would be the 95/5 lead-free, which is about 100F higher melting than 60/40.

              If I was really super-safe, I'd probably use sil-flo, but that needs to be red hot to flow. I would have to remove other fixtures on the boiler, which will almost certainly damage them. As it is, soft solder may already damage the join of the barrel to the end.

              I am quite familiar with the varieties available, I have done small metal sculpture, and have used just about all the types of silver braze there are. Have not ever had trouble with de-zincification due to heating (as sternly warned against in the link), but it does not matter, as the boiler is not brass.

              So I am NOT going into this with some kind of "Can I use JBWeld?" type attitude. But I appreciate your concerns.
              CNC machines only go through the motions

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              • #22
                Where did the "JB Weld" snarky comment come from? The site I referenced has some very good information on toy steam engine boiler construction by people who obviously know a few things about toy steam boiler construction. You can choose to ignore it as I can see from your previous post's that you are an expert on toy steam engine construction, I can't recall ever seeing a steam gauge that would read 3 psi !!!!! Rick Hann

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                • #23
                  Originally posted by rickhann View Post
                  Where did the "JB Weld" snarky comment come from? The site I referenced has some very good information on toy steam engine boiler construction by people who obviously know a few things about toy steam boiler construction. You can choose to ignore it as I can see from your previous post's that you are an expert on toy steam engine construction, I can't recall ever seeing a steam gauge that would read 3 psi !!!!! Rick Hann
                  I have never seen one either.....however they exist. Many steam heat systems apparently have them, for example. (Reference Gellfex's heating system problem thread, where one is mentioned, and might even be shown) No reason an obviously low pressure toy boiler might not have such a thing. And while this may indeed be in bar, I don't know for sure WHAT it reads, yet. I also don;t know where the safeties blow off yet, either.

                  But do YOU actually STILL think this 3 inch diameter boiler with 0.5mm flat unstayed ends is intended to carry 40+ psi? Really? Without bulging out and maybe even cracking the glass water gauge? (the frame around it may keep that from happening)

                  Much of the linked thread concerned Mamod boilers, which do seem to be brass (IIRC confirmed by K Appleton in his series on the Mamod traction engine). I am no longer as sure what this is made of.

                  My friend said it was copper, and he ought to know, as it was his. Some areas on top sure look like copper. He does not want to polish the boiler, so I have not. Polishing would have shown for sure. But two things have occurred.

                  First, I need to solder on a bush for the drain, as that is an open hole. But it is corroded, and has to be cleaned up. Just a bit ago, before I knocked off shop work, I started to clean up enough to get the bush soldered, it looks like brass to me, at least the end cap. If the end were brass, the rest ought to be as well, I'd think.

                  Second, while washing out the crap inside just now, I discovered that the sight glass leaks like a sieve. So I had to take it off, no choice. That left enough holes to shine a light in and look through others.

                  I think the barrel looks like brass inside, although there is a good deal of rusty-looking scale on the bottom part of it. Where the rust might have come from is not clear. The scale makes it doubtful as to firing it, and since it looks like brass, the use of typical descaling compounds would probably de-zinc the brass more than whatever has already occurred (if any).

                  I visually verified that there is no sort of staying anywhere in the boiler. It's just cylindrical with flat ends.

                  I also saw that there are doublers for each of the places where things screw in. But the whistle doubler has come loose, and is just spinning. That's no good. Not sure what can be done about that. The others are corroded tight, and things will break if I try removal.

                  Rattling around inside is a cylindrical "thing" that is coated in scale. It's currently solid with scale, and appears about 10mm diameter and maybe 20mm long. There is no real clue as to what it is, unless maybe it was a piece of screening used as a steam separator. That sounds like a German sort of thing to put in.

                  I'm questioning whether this thing can be made reasonably safe to be steamed at all. It is not looking too good at the moment.

                  Now, the JB Weld? Yes that was intentional "snark", if you would rather call it that than straight up sarcasm. Might have been a bit strong, but I was beginning to feel as if that was the level on which I was assumed to be operating. Maybe I took it wrong.

                  Much will be made clear if and when the boiler is able to be put under some pressure to see where the safeties go, and to check dimensions under pressure and at rest.

                  The gauge is also not fixed yet, I'm trying to find a good pic of the innards to see what is missing. It appears to only be a "stirrup" that fits in the slot in lever #1. Once that is fixed, we'll see what the actual range is. The bourdon moved quite a bit with a very low pressure, under a pound, so......
                  Last edited by J Tiers; 03-14-2022, 02:13 AM. Reason: Edited to put in new information from work late this evening.
                  CNC machines only go through the motions

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                  • #24
                    I'd love to see this restored and working again as the maker intended, but the more you tell about the boiler, especially now you say its probably brass, not copper, the more nervous I get about it.
                    Whatever you do, give it a hydraulic test first, not an air test. 3psi is probably nearer the mark than 3 bar.
                    'It may not always be the best policy to do what is best technically, but those responsible for policy can never form a right judgement without knowledge of what is right technically' - 'Dutch' Kindelberger

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                    • #25
                      Agree on all points. I'm not even sure the brass is the worst thing about it. The scale and the stuck as well as broken-loose parts in it are real issues.

                      Before any sort of hydraulic test, I'd need to get the loose whistle secured, and be able to remove and plug the safety valves. Currently those things are not possible due to corrosion. We'll see what happens.

                      I'll get some penetrating oil on the threads, from inside if I can, and try to do something about the loose "doubler" on the whistle. I can't get anything in there to grab the doubler, the holes are big enough to see through, but not to get any sort of "grabber" through. Not even surgical forceps, the holes are too small.

                      Not sure what is safe to do with the thick scale. Vinegar might be safe enough if not in contact for too long. I'll probably set this aside to let the penetrating oil soak in while I think about it. The owner won't be in town again for three weeks or so.

                      As is not surprising for a "toy", it was, and has been, rather neglected as far as "maintenance". Doubtful it was "blown down" very much, and I'd bet on it having been overheated from running dry. The owner thinks it may have sat for some time part full of water.
                      Last edited by J Tiers; 03-14-2022, 10:13 AM.
                      CNC machines only go through the motions

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                      • #26
                        I have experience descaling copper tubes in pressure vessels. If calcium scale, we used dilute muriatic acid. A plastic barrel with a recirculation pump was used. Circulation was stopped as soon as copper was detected in the barrel with a chemical test kit. An alternative test method was to hang a piece of steel in the barrel and stop when the steel had a copper color on it. The tubes we cleaned were around .028 wall and acid eating through a tube was a very expensive repair. The chemical reaction generated a lot of foam that the chemist would counter by adding a defoaming agent. The acid disolves calcium and also copper. If you get it running use soft water.

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                        • #27
                          Originally posted by J Tiers View Post

                          My friend said it was copper, and he ought to know, as it was his. Some areas on top sure look like copper. He does not want to polish the boiler, so I have not. Polishing would have shown for sure. But two things have occurred.
                          I'm sure you have thought of it, but can you polish a bit if the boiler on the bottom inside the firebox to see if its copper or brass?

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                          • #28
                            AS enthuiastic youngsters we did all sorts of things which we should not have, and we got away with all of them with little more than a few minor burns and scaldings. Fortunately a kindly soul gave us a pressure gauge which read only to 20 lbs so our adventures involved low pressures and relatively low temperatures.
                            Woolworths Plastic draught excluder for doors made good steam lines under 3 lbs, at 4 lbs it got very soft and at 5 lbs it simply burst !
                            Our efforts at soldering, and resoldering older boilers usually leaked to some extent. There was no JB weld in those days but we had access to a supply of stuff like bondo, sold under the name Isopon.
                            So a leaky end plate could be cleaned up and plastered with this stuff. It would hold at up to about 10 lbs at which time it simply cracked off. It could only be used away from the fire.
                            And as for heat, well we thought nothing of trying to get more steam with more fire, We had a 1 pint Sievert petrol blowlamp in good order. It would work at any angle so often it was used instead of the burners supplied with the toy engines. Usually it had to be run at a low flame otherwise it would go out as the flames were choked by the surrounding tinware fireboxes.
                            We made a square boiler 1 inch cube and tested it hydraulically. It was made of steel shim material, 15 thous thick, folded where possible but butted soft soldered and not flanged for the rest of the joints. It took 100 lbs hydraulic pressure cold water before it split open, at which time it was practically round. We were not crazy enough to try steaming that !!!( Though we did boil water in it with an open outlet.
                            A lifetime later, looking back, I see how lucky we were not to have a major mishap.. One thing I believe is is that the boiler( and fittings) which has been properly designed built and tested but has a few odd small leaks is far less of a safety hazard than a badly designed untested job which is apparently sound with not a sizzle in sight.
                            Regards David Powell.

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                            • #29
                              I expect a good deal of bad operating practice went on with this little steam plant. My friend has admitted to some already, and as I look into the boiler more, I keep finding more problems.

                              I can SEE that the blow-down valve was not used particularly. With the sight glass removed and cleaned (for whatever that is worth) and a better light, I can now see that there is around a good quarter inch thickness of rusty-looking scale on the bottom of the boiler at the deepest part. Still no good idea of where the rust came from. The sight glass does have two M2.5 steel screws holding it to the shell, but they are not that rusted.

                              I think there is a seam at the bottom (covered in soot), and it looks as if it has opened, which you would expect due to the insulation provided by the scale. If that is true, the only thing now sealing the boiler is the thick layer of scale, and the boiler is now basically junk.

                              I can see very little as far as ways to save it for anything but a nice looking display. Since the boiler is riveted to the firebox tin, it is just about impossible to remove it for repairs in a practical way, and I would question if it could be repaired without taking all the soldered joints apart. That seems neither a good idea nor particularly likely to work well. It would potentially allow fixing every bad feature of the boiler, but yowza, it's way out of proportion to the result.

                              The engine does work rather well, though.
                              CNC machines only go through the motions

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                              • #30
                                OK..... I went and had a good look and cleanup of the boiler to determine if the "before dinner" assessment was right or wrong.. First, I gave the inside a diluted vinegar soak, with a small bottle brush passed in through the hole where the bush goes, to scrub with. Rinsing out provided a fine flood of rusty water. I still do not know where all the rust-like material came from.

                                Then I gave the firebox side of the boiler a good scrub with detergent, followed by a rinse-off and drying with the shop hair dryer (you should always have one if you have water laid-on in the shop).

                                1) There was a good deal of scale, but it seems to have been mostly a sort of "bubble", where the scale was not actually solid, but rather was hollow. So the "solid surface" dissolved, broke up and revealed the bottom of the boiler. The seam on the inside looks solid, and it certainly did not leak

                                2) Washing shows the outside of the seam to indeed have a separation, but it appears to be normal, a feature of the seam type. I don't know if it will show up on the photo, but you can see that with a coating of soot, this could look like a sprung seam, especially without seeing the inside:



                                So, it looks like we are back to the "normal problems" of stuck parts, loose and un-removable parts, etc. The shell seems to be brass all around, although the uncontrolled heating in the past has made parts of it turn more copper.
                                CNC machines only go through the motions

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