Slightly Loco

[J. Tranter]

That looks and runs great. Thanks for posting this. I am still working on mine I can only hope it turns out as good as yours.
J. Tranter

 

[shred]

I've been doing way too much playing with the loco instead of finishing it, but having fun is what this is all about

I did get some time to clean up the gas and burner plumbing-- I built a right-angle jet holder, installed a pipe cap as a basket to hold the gas tank and shortened the valve up so it only barely sticks out the window (it can be easily rotated to out the back, front or side as needed). Now the big loop of silicone tubing out the back is gone, replaced by a small loop under the cab roof (I like having it as a thermal barrier-- the jet parts can get very hot, which does bad things to the butane valve delivery, so a snippet of tube stops any heat conduction through the pipework)

I also installed the steam dome cover-- I'll post more on it later since cutting the saddle curve took some creativity, and there's a funky bayonet-mount for the steam pipe but here's an overall picture for now (you can see how dirty it is from playing with it )

 

[shred]

I've been running this far more than building on it, but I did get around to doing a little 'bling' work-- making a saddle and a top for the smokestack as well as re-plumbing the exhaust with 1/8" copper instead of 3/32"-- back pressure was hindering performance a little. At the moment, the record is 50+ laps of the extensive test track facilities, or about 500 feet on one tank of water.

The other thing is I bead-blasted some parts and put mounting rails on the roof. That was a little tricky since it's all curved and I had no measurements, so what I did to locate them was to set the rails on the sides of the cab, dab a little superglue on the tops and stick the roof on. That won't hold up long-term, so I then took the roof off and clamped the now-superglued rail to the roof so it wouldn't fall off during soldering and soft-soldered it on.

Here's the 'before' picture. Note the flux and short bit of soft solder lying on it. The whole setup is in a vice to let gravity help with the solder flow.

Apply heat with the Creme Brulee torch to the other side (it's actually burning, though you can't see the flame in the picture)

and moments later... the rail is soldered on. It's not the prettiest joint since there's leftover superglue goo around, but as this is up under the inside of the roof, you can either leave it like that, or soak the roof in acetone to dissolve the old superglue, then clamp and solder again, but this time being neater since everything will be clean. As yet, I've taken the former path

The cool thing with soft soldering is if you're careful with the heat, you won't even discolor the parts. I did no cleanup to the roof since soldering and these pictures (and even the 'soldering' picture above is of the second rail, the other edge having already been done). Had I wanted to, I probably could have tinned the rails and just soft-soldered them on right there and skipped all the supergluing.

 

[J. Tranter]

Shred a couple of questions if you remember. What size holes did you drill for the bushings and what thread did you use for them? The plans call for an 8 and 10mm thread I believe and I'm wondering if I should go and buy metric taps or if I can use what I have.
Thank you for any help you can give.
J. Tranter

 

[shred]

Shred a couple of questions if you remember. What size holes did you drill for the bushings and what thread did you use for them? The plans call for an 8 and 10mm thread I believe and I'm wondering if I should go and buy metric taps or if I can use what I have.
Thank you for any help you can give.
J. Tranter

I used "what I had", which no doubt would horrify any Proper Model Engineers . IIRC that was a fine-thread 5/16" and maybe 3/8", but I think they're both 5/16" UNF (-24?). As long as you plan to make the mating parts yourself (safety/filler/steam/gauge/plugs/etc-- model boiler fittings are only made in a few thread styles), and have enough threads for strength it should be ok. At a guess the holes were 1/2"-- some convenient size on the step drill anyway. I used 3/4" bronze to make the bushings, but turned it down to 9/16" or so for the flange.

If you haven't soldered up the boiler flanges yet, I'd consider moving the front one to right behind the smokestack hole and making the rear one a little bit of an 'outie'; that picks up a little more water volume, which is good in a tiny boiler like this.

At the end I did buy one metric tap for the Ronson-style gas filler valve I recycled from an old pencil torch-- IIRC it was a slightly odd fine metric thread, but one Enco had. 3.5mm*0.5 or something-- I can look that up if needed. Officially the gas jet was also threaded some oddball metric size, but I loctited it in place since it's not part of a pressure vessel [edit: see SandyC's comments below re; Loctite]

 

[J. Tranter]

Thanks for the reply. Will aluminum bronze be ok for the bushings? And what gas jet did you wind up using? Thank you for all your help.
J. Tranter

 

[shred]

Thanks for the reply. Will aluminum bronze be ok for the bushings? And what gas jet did you wind up using? Thank you for all your help.
J. Tranter

Al-bronze for the bushings I don't know about. I was all set to use some brass I had, remembering my old Mamod, but after reading about de-zincification, and not wanting to risk it I went out and got a foot (well, 13".. I have no idea why bronze is sold in 13" lengths) of regular bronze for the job. Enco puts it on sale a lot. You might want to ask the boiler specialists about Al-Bronze (if any are reading this, chime in!).

The jet I'm using is the JetBoil backpacking stove jet. They sell a spare parts kit of the jet, a spare piezo igniter and sometimes some o-rings for ~$10 at backpacking and camping stores. I checked it out under a loupe the other day and it appears to be a .008" / .21mm orifice which is pretty close to the recommended sizes. That makes sense since it's designed to run a little gas burner not very different from the engine burner (that's pretty much how I picked it-- I was impatient over the holidays and didn't want to order in a model jet, so I went to REI and looked for the smallest butane/propane stove they had and asked about spare jets for it.)

 

[Maryak]

In the OZ model boiler code for copper, bushes in direct contact with the boiler shell are Phosphor Bronze. Aluminium Bronze is not listed in the code.

Hope this helps. ??? ???

Best Regards
Bob

 

[SandyC]

Hi Shred,

It looks like you are having a great deal of fun with that loco and what a great job you are making of it.

You mentioned that your gas jet had a weird 'metric' sort of thread..... well, the majority of the small gas jets used by manufacturers of camping gas cookers, DIY blowlamps and model steam loco's ('G' gauge etc) have a 1BA thread..... which is based on a metric form..... 5.3mm OD  x  0.899mm pitch  (0.2087" dia x 0.0354" pitch (28.25 TPI))

The gas jets I use (as do the majority of UK/EU manufacturers and at least 1 American company) were originally manufactured by 'Calorgas' who eventually sold their camping gas division to 'TAYMAR'...... who were then bought out (taken over) by 'COLEMAN'.... an American company.
It is, therefore, possible that JetBoil get their gas jets from 'Coleman', with their own 'CUSTOM' markings on them...... if so then they would most likely be 1BA thread.

These gas jets are available (mail order) from the following (amongst others): -

www.roundhouse-eng.com

www.polymodelengineering.co.uk    Then look under the 'BRUCE ENGINEERING' section.

sizes commonly available are: -

Number 3 which has a 0.15mm dia jet bore

Number 5 which has a 0.2mm dia jet bore

Number 8 which has a 0.25mm dia jet bore

Number 12 which has a 0.3mm dia jet bore

Number 16 which has a 0.35mm dia jet bore

All have 1BA thread.

The NUMBER system shown is still used in the UK/EU since this ties in with the original 'Calorgas' numbering system.
and you Know how us Brits just hate to change things.....  :big: :big: :big:

I hope this is of some help to you.  ;D ;D

As for your question "why do they sell Bronze in 13" lengths?"... I suppose it is that they may purchase in 1 metre lengths (39" + a bit for cutting), and cut it into 3 pieces for resale... just a thought.

Here in the UK you can buy it in whatever length you want up to around 4 metres..... you need DEEP POCKETS though.... :'( :'( :big: :big:

J.Tranter.....

I would not recommend ALI-Bronze for bushes.... it is difficult to Silver Solder...... it can be done, providing the Ali content is not too high, however, it does requires special flux additives (required to clear away the inevitable ALI-OXIDE) to be certain of good joints.

A much better choice would be either SAE 660 Bronze, Colphos 90 or Gunmetal (LG4).... all of which are both easy to machine and take Silver Solder very well.

Straight PB102 Phosphor Bronze is also suitable, however, it is much more sticky to turn and thread.

I use SAE 660 for all of my bushes.

Best regards.

SandyC.  ;D ;D

BTW Shred..... Might I suggest that you keep a  very very close eye on the LOCTITE joint you used for the GAS jet on your burner...... Loctite is not very good at high temperatures, and if the jet comes loose it can easily be forced out by the gas (typically 25psi pressure @ room temperature, but much higher depending on temperature... can reach 6BAR (87psi @ 40deg C))....well.....you don't want to see the results..... much better to get the right tap and screw the jet in. :'( :'(.... PLAY SAFE.

 

[shred]

Hi Shred,

It looks like you are having a great deal of fun with that loco and what a great job you are making of it.

You mentioned that your gas jet had a weird 'metric' sort of thread..... well, the majority of the small gas jets used by manufacturers of camping gas cookers, DIY blowlamps and model steam loco's ('G' gauge etc) have a 1BA thread..... which is based on a metric form..... 5.3mm OD x 0.899mm pitch (0.2087" dia x 0.0354" pitch (28.25 TPI))

Number 5 which has a 0.2mm dia jet bore

[...]

SandyC. ;D ;D

BTW Shred..... Might I suggest that you keep a very very close eye on the LOCTITE joint you used for the GAS jet on your burner...... Loctite is not very good at high temperatures, and if the jet comes loose it can easily be forced out by the gas (typically 25psi pressure @ room temperature, but much higher depending on temperature... can reach 6BAR (87psi @ 40deg C))....well.....you don't want to see the results..... much better to get the right tap and screw the jet in. :'( :'(.... PLAY SAFE.

Thanks for the expert advice Sandy-- I confess to not being very happy about loctiting the jet in, though I did use #620 hi-temp Loctite and have limited the gas valve itself so even flat out it would only make a medium-size flamethrower Unfortunately (well, not that unfortunately, I have even less access to BA taps) it didn't seem to match a BA thread either-- it was somewhere between 3.5 and 4mm x 0.5mm thread, though I've forgotten the exact details. What I'll do is silver-solder the current jet into another threaded piece that has a thread I do know so I can still fish it out for cleaning, but not worry about it coming loose.

Looks like it's about #5 size by your chart. Elsewhere somebody said they believed the jet-number was the diameter in thousandths of an inch, which would put it at #8 size and that sounded a little big.

 

[shred]

Following up to my own post, it was less than an hour's work to turn up a threaded sleeve, silver solder the gas jet in, tap the burner and reassemble it all properly. Thanks for the additional kick in the pants SandyC.

And I had a thought to address this particular thread, my expectations for it and tie it to the rudeness one just in case people are wondering (btw, I've got no complaints so far)--

• 
  I expect any and all to jump in if they see safety problems.
• I invite interested parties to comment and contribute as desired, especially if they see something that might be missed by a relative novice such as myself or the others playing along ("When are you planning to martinize the whiffer bearings? ... I found it easier to do that before pinking the rasterfratz", to make up an example).
• Should you want to post about your fully functional live-steam, rivet-correct 2-10-10-2 Big Boy in N-scale, you are kindly and politely invited to shove off and start your own thread (seriously, I'd love to see it, but not here) ;D

Thanks

 

[rleete]

"When are you planning to martinize the whiffer bearings? ... I found it easier to do that before pinking the rasterfratz"

;D I found this particularly funny. Just struck the right note.

Personally, I have little interest in locomotives, my main focus being stationary engines. But, I do enjoy reading all the related projects. I have been following this thread because of the detailed build and accompanying pictures. If you were building something completely different, I'd still read it all because of the nice pictures and 'how I did it' comments. That is worth the time in itself.

 

[J. Tranter]

Seriously thank you for all your help Shred. I greatly appreciate it.
Thank you also Sandy C. and Maryak for the answer on the bronze.
J. Tranter

 

[artrans]

thats cool as hell but the nicest one I ever saw was relax just kidding sorry again the the past post that really is cool why don't we see any steam vapors what scale track is that ho g o very nice.where are the palns for that or is it your design.

 

[Brian Rupnow]

Shred, I think you have done a marvelous job, and a great job of documenting it. I enjoyed the video.---Brian

 

[SandyC]

;D ;D

it was less than an hour's work to turn up a threaded sleeve, silver solder the gas jet in, tap the burner and reassemble it all properly.

Shred,

An excellent and correctly engineered solution to a tricky problem. :bow: :bow: :bow:

I hope the kick didn't hurt too much. ;D ;D ;D..... I have seen to many accidents with leaking LPG gas.

From your latest description, it would, indeed, seem that JetBoil are producing their own gas jets.... and what a weird thread!

Keep happy.

Best Regards.

SandyC. ;D

 

[shred]

thats cool as hell but the nicest one I ever saw was relax just kidding sorry again the the past post that really is cool why don't we see any steam vapors what scale track is that ho g o very nice.where are the palns for that or is it your design.

It's O-gauge track, but it's 'narrow gauge' for the scale, if the term 'scale' still applies In theory it can run on the next size up track (Gauge 1) by moving the wheels outboard of the frame rails, but mine doesn't actually fit G1 track since the frame rails are a little too thick (I have resisted making the axles even longer to make a slammed 'hoopty' locomotive for wider-gauge track :big

The reason there's no visible steam is the steam exhaust is piped into the smoke-box chamber at the front of the boiler. The gas-burner ends there and the burner exhaust is so hot and so much more volume that it makes the steam disappear. If I pull out the exhaust pipe so it exhausts to the air, then you get some visible steam, but it comes from the exhaust pipe, not the smokestack. Since I like steam clouds, I tried putting a tube inside the smoke-box to route the exhaust steam straight to the top of the smokestack, but it's still not visible enough.

 

[J. Tranter]

Shred what size did you cut the 3/8 tube on your burner?
John Tranter

 

[shred]

Shred what size did you cut the 3/8 tube on your burner?
John Tranter

Hmm.. I don't remember. I can check later. It's not terribly critical-- there's about half an inch sticking into the flue, and the air hole is just behind the plug, so I suspect I put the center of the air hole 1" from the end. The rest of it holds the jet in place and you may want to shorten that or make it right-angle to clean up the plumbing. The flue end has the slotted tube telescoped into it, so as long as it grips that tube well and puts the first slot around 0.75" from the plug, it should be ok. The idea is that the slotted tube can be moved and rotated for tuning or replaced to try different slot configurations.

Also I ended up silver-soldering the end cap on the slotted tube-- the 'press' fit I made wasn't tight enough so it didn't like to stay put.

 

[stevehuckss396]

Now that the little loco is running, any plans for paint and polish? Maybe a few dressup trinkets?

Steve