[Pauli]

On the bewildering pleothora of threads used on Aster models, one fellow live steamer and professional engineer, suggested it might just be governed by what fasteners are available on the market at the time of design. That doesn't explain an odd choice of thread on a crosshead though, as its Aster inhouse production...

 

[Pauli]

Fixed! Thanks Alberto
This makes sense Pauli, thanks for sharing!

View attachment 71417

Like many posters before me, though they put it in milder wording, I think your insulation is basically a disaster. A "brisk" clear airflow of hot gases along the outside of the boiler is the point of a smithies type boiler, that lacks internal flues, that otherwise would serve this very same purpose.

It's not just that your insulation is too thick, obstructing hot air / cumbustion gases flow. The fact the insulation has anything but a flat surface, is equally bad. The rough uneven "surface" (which you earnestly don't have at all) will obviously cause turbulances and friction to gasflow, to put it mildly.

Aster provides pretty flat surfaced insulation, but personally, I did not find this an entirely satisfactory idea. However for some actually not important reasons! At the time, I just didn't like insulation material beeing exposed to sot & water - but that actually doesn't matter in practice.

Though I'm still very satisfyed with the lining idea, but mainly perhaps because the smokebox is perfectly sealed around the blast pipe, increasing draught. (That was done with another two small sheet metalpieces, that slide on top each other from diffrent angles, and that are held in place simply by springing compression.)

Anyway, therefore i lined the smokebox of my P8 (BR38) with very thin sheet brass. (Think layers "smokebox - insulation - sheet metal".) This is very simple to do, as this lining isn't visual, nor does it have to be perfectly fitting and perfectly sealing. Any halfway decent fit will do!

So just make some reasonable paper try-out pattern, and grab the scissors on the very thin metal sheet! It's an hour's simple work, but would eliminate any "friction" to air/gasflow.

I have given this a lot of thinking, because I think one could build a very simple smithies type coal fired boiler. (Layers would be "outside casing - shiny foil - insulation felt - simple casing - space for gasflow - boiler").

Small tipmight be that you can hold insulation in place during assembly with paper masking tape. I figure, if it incinerates, it won't smell & doesn't matter.

Also, apart from insulating "felt" material (glass fiber / asbestos), one can also add a layer of kitchen aluminium foil, with the shiny surface towards the inner boiler. This obviously adds basically nothing to insulation thickness, but will further improve insulation effectiveness.

 

[Pauli]

I probably didn't explain well what I did on the P8. First, I insulated the boiler (with internal smoketubes) differently than the smokebox. Unfortunately I did not take any photos I can show during assembly.

The main point / idea here, is using a thin sheet of metal to press the insulation against the outer boiler casing. This is what I did in my smokebox. I wanted to protect the felt insulation from water / vapor / sot - which however is unnecessary. (For whatever reason, if there was one, I'm not sure I used any shiny aluminium foil in the smokebox.)

But in this Aster smithies type boiler, it promotes airflow by giving a completely smooth surface against the hot air / gasflow, improving draught.

In my internal firetube case, I did what everyone else also does, which is wrap the boiler directly with insulation material - using paper tape to hold in snuggly in place. I then also wrapped one layer of (shiny side in) aluminium foil around it - also held in place with paper tape. It was then very easy to showe the insulated boiler into the outer (painted) boilercasing.

The aluminium foil does not have any direct contact with the heated surfaces - it's on the outside of the felt insulation. It just adds a reflective layer. Like a coffe thermos has shiny coating of the inner (glas) liquid container. It does work - like you can even make a makeshift thermos from any bottle, by just wrapping it with shiny aluminium foil, shiny side inwards. (Just as you can preserve heat in heated food the same way.)

The outer boiler casing has no reflective inside surface, so it will make a difference, even as the foil is in direct contact with the outer (painted) boiler casing. (Preferrably, one would add yet another layer if felt insulation in between the foil and outer casing, but there wasn't room for that.)

I haven't tried my boiler without the aluminium foil, but I am extremely satisfied with the boiler's performance. It steams up very quickly. This may however also be due to perfect seal around the blast pipe in the smokebox (and definately no air leaking in along the boiler).

In this Shools' smithies-type boiler, adding an inside thin sheet metal, "protecting" the insulation against flames and sot, would very likely take up a lot of the heat that is otherwise, when built normally, according to instructions, is transferred to the painted outer boiler casing - which the damages the paint.

Since this partickular Aster Schools seems to have beatiful undamaged paint, I would really try adding this extra metal layer, once the felt insulation has been fastened to the inside of the boiler casing. (Perhaps using a little paper double sided tack type tape, if one prefers it over the silicone? I did, because I want to have easier disassembly. I also only used oil on gaskets, and teflon tape to seal fittings.)

In fact, in this case, using thicker sheet metal would add more material that can absorb heat. At least in the firebox, this might be a really good idea? Why not try whatever you skills and tools can manage, like something like 0,5-1mm!?!

Thinking about it again, the aluminium foil part might not be that practical / a bit akward to mount in this case?

The general idea with the shiny reflective metal surface as boiler insulation, actually comes from a Swedish SAAB Viggen fighter jet engineer, and builder of a large 5" (or was it 7 1/2" ?) gauge pacific type locomotive.*

He simply insulated the locomotive boiler the way the Viggen fighter jet engine was insulated - with layers of highly polished reflective metal sheet. And it worked brilliantly, from what I've read. (If he used insulation or just air between the sheets, I don't know.)


Swedish F1200, among the last steam locomotives built in Sweden, 1914-1916. Absolutely state of the art at the time! (Technically probably only superceeded by the very successful heavy Swedish 1936 type M3t mining operations turbine locomotives - built to save on coal.) The beatiful pacifics never really came in to much use though, because by 1933 Swedish mainline railways had already been electrified. (Sweden was very early with broad adoption of electric locomotives - it's still an export product, bought by for example Amtrack!) However, the Danish railways needed locomotives, as they did not go for electrification, so they got the whole fleet built basically in very good condition, including spare parts! They ran them untill the late 1960's. And one of them was transferred back to Sweden, where we run it every so often! A really beatiful locomotive, in stunning light blue livery. (*Sweden has no coal, but plenty of hydro electric power. I'm guessing Denmark bought coal from neighbouring Germany, so an economically viable alternative. Coal for steam engines have always been a really troublesome cost in Sweden.)

https://sv.wikipedia.org/wiki/F-lok_(%C3%A5nga)#/media/Fil:F_1200_G%C3%A4vle_13.08.08_(1).JPG

TGOJ M3t 73 tillverkades av Nohab 1936

Turbinlok. Beredskapslok Grängesberg 1953-80. Sålt 1980 till GBBJ.

www.svenska-lok.se

Sorry if I diverged, but I hope it was OK reading?😉

 

[Pauli]

I don't think, for most people, it's a quite reasonable suggestion to replace a non-defective boiler. The Aster schools class was Aster's first model, an iconic model, and it changed the gauge 1 live steam world, with the idea of a painted and "ready to assemble" kit. (I've read the first version was just single cylinder, and then there was an upgrade for the single cylinder versions, am I right?)

It is however, by today's standards, it's a pretty basic design from the 1970's. But cherish it for what it is, as you should, in a similar way you would, a 1910 tin plate live steamer!

Getting dents and burns to live steam models is normal in my view. It's just very diffrent from running electric models. With live steam, it's for real! And the fires, and what not that goes wrong when operating live steam, it just happens! I retouch my locomotives with paint ever so often. I don't mind. It tends to come with the live-steam territory, at least the way I see it.

However, there are locomotives that just have VERY poignant liveries / colours. Among them is the Aster Schools in shiny apple green. If there is any way to try and protect the paint, please do!!! But completely replacing a working boiler, is asking very much, in my view.

Trying my suggested modification, with an "intermediary" thin sheet metal casing, hopefully (?) catching most of the heat, is however not an expensive or compliated thing to try, so why not?

Beware though, especially with the invisible extremely hot alcohol firing, an accidental external fire damaging paint, doesn't take much of a misstake. (I'm lucky, my locomotives have matte green, rust-red and black colours, where touch ups really don't show.) But I really would try extra hard protecting the outer shell casing's paint, in this case.

 

[Pauli]

Sébastien, you've undersood my idea, so I'm sure you will figure out a good practical design! You can (should) try out the idea just cutting and bending a template out of paper cardboard (Pizza carton?) - you pretty much already did so for the insulation.

My gut feeling is to use brass rather than aluminium for this inner casing. It has a much higher melting point, and since it will be directly exposed to the extremely hot alcohol flames in the firebox, that is my "feeling". I used to do casting in aluminium, so to me it feels like like low temperature. I wouldn't be surprised if it would break / deform in the firebox. -But this is my guessing and gut feeling, I might be wrong! And if you use aluminium, and it should break, well you can redo/ replace it later with brass.

Also brass is stiffer, and will probably spring better against the outer casing, for the round part of the boiler.

It's much easier to work with very thin sheet metal, like 0,2mm brass, than with thicker material.

There seems to be quite a lot of space available in the firebox. So perhaps you could even have two layers of thin insulation and shiny aluminium foil in the firebox. (A little insulation just to avoid metal to metal contact transfer of heat.) For this extra layer, one could perhaps just use glass-fiber cloth like material, like used for interior wall decorating in homes? (It has very little air in it, so gives much less insulation than the fluffy stuff you already have.)

You are not doing any irreversible change to the locomotive, so just experimet and try it out! (And please continue to post photos!)

 

[Pauli]

While I'm still waiting for my order to go on with the loco I played a bit to check the claimed 3 meters min radius of the Schools. Since I live in an appartement if I ever dream of a closed loop my Schools would have to turn along a 1.8 meter radius curve. It seems impossible but I tried
I started making a rail bender since my previous trials trying to nail the rails on a planck were a complete failure. Not the prettiest piece of hardware but it works!
I had some inline rollers old ball bearing lying around, found some wood and a piece of what I think is zinc plated steel to make this:
View attachment 71440

I then made some sleepers from wood and plastic card. I set the gauge to 47 mm wich is 1.5 mm too much I know I will try to reduce gauge widening later if I can
View attachment 71441

I will now try to bend the rails a bit more because I think they are currently bent for 2 meters. The Schools will not handle much tigher curves because the front left wheel of the bogie only touches a half of the rail!
From this test I think I can reduce gauge to 46 mm without any issue (by moving the loco by hand: not sure I will be brave enough to test this under steam)
View attachment 71442

I wish I do not annoy you with my beginners tests that have probably been made many times At least I have fun!
I may also try superelevation...
Cheers!

Gauge widening in curves is normal practice, as you seem to know. And for gauge 1 it's normally 0,5mm.

But if you can make it work for the schools class with even a little more, why not?! I think most would agree live steam engines are very sensitive to gradients and tight curves. In fact, almost all live steam layouts are perfectly level for this reason!

It's not uncommon for people to modify Aster locomotives to negotiate tighter curves, turning down inside centers of wheels and such (never change the wheel back to back distance! That will make running through switches impossible! Your strategy is novel to me, but quite clever I think!

Bending rails, you will have to bend the ends of each rail a bit extra manually, with pliars. It always feels to me I do it a bit much, but actually I get it right!

Only thing is (but I really can't think why?), you might possibly run into problems with possible future waggons and coaches, with extra gauge widening?

About testing your track running under steam, I would definately recomend you do this outdoors! Alcohol engines are very prone to igniting stuff -and of coursethis is even more true, if it would tip over on it's side, spilling burning alcohol. If you can borrow some flat area for test running, that can't catch fire easily, that would be the best idea. A parking spot / garage is good, except if the engine would tip over, you wouldeasily get some damage to the loco.

If you put wider pieces of wood / board under the track, you can probably get it pretty level on many (well kept) grass lawns.

I can't stress enough: With alcohol engines, always keep a bucket or two with water along the track, with a kitchen towel size piece of cloth drenched in it!!! Should you get a problem with uncontrolled fire, our engines can take a soak without damage, so one can just cover the loco with the wet towel. That can save track and loco paint!

 

[Pauli]

Sébastien, I think you should consider building a mobile layot. They are often built in the style shown in the photos on this page in a German live steaming forum. https://www.schienendampf.com/forum/index.php?thread/3376-module-oder-normen/

The owner says he can set it up in 1,5 hours, and with the help of his wife, take it down in an hour.

I think that layout is somewhat to high above ground.

We have two layouts like this in Stockholm livesteamers. One with 2,4m max radius, and one with 4m radius. One member has one that is only 30 cm above ground (I don't understand why), yet another built one like 50 cm above ground.

I think somewhat lower than normal table height is optimal, because you can use normal chairs to sit on when steaming up and such.

Personally, I also think having "safety" surfaces as wide as practically manageable on either side of the track, becaus in case trains fall over (which does happen!), they won't be as likely to crash into the ground and get damaged.

One of our layot has a low "fence" on the edges, that also prevent trains leaving the track all the way to the ground.

Sections can be held together with adjustable clasps used for furniture, and larger ones very often for waggon and trailer sides.

Having one bridge section to reach the inside of the track is a very good idea. (Especially when running in public, because then you can have a natural "members only" area inside the layout.)

I would really make sure also narrow gauge LGB / Roudhouse etc locomotives can run on the track. It's a shame I can't invite guests running such engines, because I have all Märklin track, which has to high "railspikes" for most narrow gauge prototype engines.

This is a design flaw by Märklin, because PECO has even lower rail profile, but running narrow gauge models with deeper flanges is no problem on them. (Märklin code 215, PECO code 200.)

Some people use finer code (in the USA often code 250) in high visibility sections, like a station yard, and coarser larger code track elsewhere. (Because really LGB / Piko etc track / railprofile (code 332) is WAY, WAY too high, considering real narrow gauge track.

However, once you get your locomotive and waggons running, you won't be disturbed by the ridiculously coarse LGB style track, even if you (like me) run 1:32 models. And LGB compatible track can be easier to find second hand. Especially tight radius starter set track is cheap - but if yo cut ties apart under the outer rail, you can easily bend / straighten it out to a larger radius. (And cut away some railbits.) If the second hand track is very dirty etc, just run it in the kitchen dishwasher!

 

[Pauli]

Sébastien,
Seems to run very well! But you ran it rather slow, can you run it faster? Otherwise maybee the boiler isn't producing enough steam?

A tip is to use a mirror* under the locomotive, to see if all burners are lit, and what colour the flames are. Draught can be somewhat diffrent when the burner is installed in the locomotive, than just testing the burner unmounted. Flames should show no yellow part ideally. (* The kind dentists use, also car mechanics. But I knew a person who just used a small square mirror on the track.)

If you can't store a typical portable layout, maybee you could just build ca 1m sections with track fastened to 5mm board of some kind, somewhat broader than the sleepers? Because then the track will not sink down in the grass, and it will be easier to get a level track. Also make a bag of wooden sticks to stick under such "trackboards", to adjust it to level. I did similar in my parent's garden, when I was young, so I speak from experience. Laying track directly in the grass lawn does not work. (Unless perhaps on a golf-green style lawn.)

You will have to crawl around on the ground, but I have the impression you aren't that old? (I once placed track directly on the concrete floor in the industrial warehouse I had. Practical, because no one worked during the weekend, so we could run two days without dismantling the track.

That time our oldest member aged 80 something (!) crawled around on the concrete, running his latest scratchbuild. He put away his walking cane during running. After that though, I managed to arrange raised track layouts with lots of tables and stuff I had in the warehouse.

I use non-permanent thread lock on motion gear screws. I don't see why you could't use it on a gland nut also? Let it run once or twice first, so you know in what position the seal is optimal.

 

[Pauli]

I use Tamyia blue threadlock that is not very strong, in a very thin layer and this allows easy removal of screws. I also put some on the crosshead threads and on the return crank screws to get them right because I do not want these to come loose while running.

That's what I use too! I had a special very tiny screw come loose, that held part of motion gear together. It was like 2x4mm in size, and was lost in the prototypical grey gravel trackbed on a ground level track I visited. With absolutely insane luck, I against all odds actually managed to find the special tiny bolt/screw! I could not believe my luck, as I have lost many much, much larger screws in my life, that fell to the ground, and were never to be found again. Had I not found this special screw, I would have had to order it as a proprietary spare part from Regner.

This is when I decided to start using non-permanent threadlock on such parts that are prone to possibly loosening. But yes, I only use it where I think there is special justification for it. With your experience from RC helicopters, you surely will have a good idea where use is justified! Like it's not justifyed for cylinder cover screws etc, in fact it's about a very small number of screws. (I imagine vibrations are a much, much greater issue with helicopters ;-) )

I wonder if you perhaps need a little more packing in the piston gland? Having to tighten untill movement is prevented, makes me wonder? Or, also, when doing these kind of self-made packings, it is a little bit of luck, if you get it just right. Sometimes just doing it all over with new material, will inexplicably, "magically", for no aparent good reason at all, suddenly work perfectly! Same goes for all leaky pipe unions and fittings - it's a bit a question of luck and "magic touch"! That's just part of the live steam experience... (At least you can see leaks, as compared to intermittent electrical connection failiures... those can drive anyone into madening despair!)

One of my locomotives uses twirled teflon tapepa as piston seals ("rings"), packed into a groove on the piston. This has caused me constant grievances through the years. Eventually they wear down and break. And then getting it just right is a trial and error process, and even if you get it right, there is no telling how long it will work. I may have to redo one piston three times, while the other just goes on working! I'm very tired of this, as it's pretty much work, so I plan to fit entirely new pistons from Regner.