Contractors Loco Project

[Andrew]

I'm shortly going to have to bite the bullet and weather it, which fills me with trepidation. Weathering is a subject which I've never been any good at.
I've been reading through your posts about rusting and using iron powder. It all makes sense and I did get some powder quite a while ago when something you wrote inspired me, but I've never plucked up the courage to use it! The only thing I'm not clear about is how you actually apply the powder evenly to the wet paint? If I did it I'm sure I'd end up with big piles and bare patches, rather than an even distribution.

Funnily enough, I'd be wondering how I'd weather it if I made one...

I don't think I'd go for iron filings, which I tend to use for larger patches of quite well-established rust, and this loco looks relatively well maintained, given its surroundings... I think I'd give the whole thing a wash of dilute dark grey first (with a drop of washing up liquid, if it's acrylic), wiping it down (in an up/down motion, replicating rainfall) to leave the grey in the crevices. That'll give you more "depth". Then I'd make myself a brown mixture and attack the lower parts of the loco the same way, representing grot thrown up from the ground. And then I'd mix a browny-orange and dry-brush that into the metalwork, again going for an up-down motion so that any streaks act like real streaks of rust - you can make your mixture progressively more orange as you go, so there are a few spots that look more recently rusted.

I've never tried it, but I've heard that rubbing pencil graphite into handrails/controls etc can simulate parts that are polished shiny by handling. With all of that, any brighter bits of pipework etc, lumps of coal and coal dust, plus the crew and their clothing, you'd have a fair variety of colour to alleviate the blackness...

If you do go for iron filings, make sure you've got nice fine ones - I just paint the area I want to rust (I use car spray for whole models, acrylic craft paints for smaller parts) and sprinkle it on pretty liberally, then tip off the excess when it's dry, seems to work OK. Copper sulphate solution gives a more orange finish than vinegar, which can stay disappointingly dark - shout if you want some copper sulphate, I've got more than I need. I'd test it first if I were you, you wouldn't want to spoil such a lovely model...

Good luck,

Andrew.

[philipy]

Thanks Andrew.
I actually made a start today, and what I've done so far is very close to what you've suggested.
Obviously I had already sprayed the whole thing black, as in yesterday's pictures - Halfords Matt black which is surprisingly satiny!
First thing this morning I airbrushed a dilute dark grey acrylic all over, but not evenly. That has not only relieved the black but lightened the overall colour effect to something approaching the picture, and also picked out some detail.

As you say it does look surprisingly well maintained, but once you start looking there are quite a lot of very light coloured areas of mud. The London Clay in the Chingford area is quite yellow when first dug but then quickly oxides to a dark brown, so I'm assuming the light colour indicates fairly fresh yellow spatter. On that basis I've dry brushed an Earth colour where the light patches are. It's actually quite a light brown shade, almost yellowish, so fairly close to reality I think. I'm thinking I might run some darker colour into the corners to represent the oxidised material and then dry brush a bit more of the Earth on top.

As for the rust, I've tried a few small patches on top of the roof, there aren't any pictures so nobody can tell me it's wrong! I applied some small patches of matt varnish and dropped pinches of powder on them. Left it a couple of minutes and then dropped vinegar on a couple of the patches and left the others. I didn't know how long to leave it but nothing seemed to be happening after half an hour or so, so I put copper sulphate ( I've got plenty, thank you) on top of both the vinegared patches and the unwetted ones. They all started to go brown almost immediately, quite a nice brown rust, but then they turned much more orange as you suggest.
I would prefer the deeper brown because I'm assuming that the small rusty bits along the edges of panels will be fairly longstanding build ups. So I'll have to experiment with the vinegar again, I think. The only other thing is that where I dropped the liquid on to the little heaps of powder, it washed some of it out and formed ring tide marks, which hardly look realistic!

[philipy]

I've been asked about the motor and it's mounting. If you look at the underside picture back on page 6, you will see I've identified the gearbox but what you can actually see is the gearbox cover, the bottom item in the picture below. The motor is actually an "N20 dual shaft gear box motor" with a 42:1 ratio. It is mounted to the floor/chassis with two 3D printed brackets,one from the bottom and one from the top, which simply sandwich it to the floor. It would be pretty easy to design different brackets to do the same thing at any required angle, down to horizontal.
Hopefully this drawing will make things easier to see.

Screenshot 2022-02-02 06.46.25.png (10.99 KiB) Viewed 4458 times

Two things I should point out. The shaft/axle is only 30mm o/a which is a bit tight for a 28mm B-B. I had to mount my motor off-centre to allow room for the chain drive sprocket, so when I printed the wheels, one has a simple flat back and the other has an integral hollow shaft extension, which effectively lengthens the axle on that side. It really needs to be in metal for strength and a longer life, but I don't have that luxury!!

[GTB]

The motor is actually an "N20 dual shaft gear box motor" with a 42:1 ratio.

I wondered if you'd found a source for an N20 with a worm drive gearbox, but they aren't available from the local suppliers.

Motor drive shafts that are too short for model train use is sadly common. Extending that 30mm axle to fit one to my 45mm gauge rail motors would be interesting to say the least, so I think I'll stick with a mitre gear final drive.......

You've done a good job of getting that one to work, definitely worth an attaboy I think.

Graeme

[philipy]

I wondered if you'd found a source for an N20 with a worm drive gearbox, but they aren't available from the local suppliers.

I got mine from a UK supplier called "The Pi-Hut", who specialise in Raspberry Pi and similar, mainly for robotics I think, and they have it available at 6v with 42:1, 118:1 and 300:1 options.
However there are a few on UK ebay https://www.ebay.co.uk/itm/203531982725 ... Swujtg9-KF but coming from China.
This is a 12v one but I'm sure that when I was looking a month or so ago there were more options from China.

[-steves-]

I wondered if you'd found a source for an N20 with a worm drive gearbox, but they aren't available from the local suppliers.

I got mine from a UK supplier called "The Pi-Hut", who specialise in Raspberry Pi and similar, mainly for robotics I think, and they have it available at 6v with 42:1, 118:1 and 300:1 options.
However there are a few on UK ebay https://www.ebay.co.uk/itm/203531982725 ... Swujtg9-KF but coming from China.
This is a 12v one but I'm sure that when I was looking a month or so ago there were more options from China.

I do wonder if you unscrew that gearbox and try to knock out the final drive shaft and replace it with a longer one. No idea if it would work, might need some heat, but worth an idea.

[philipy]

I do wonder if you unscrew that gearbox and try to knock out the final drive shaft and replace it with a longer one. No idea if it would work, might need some heat, but worth an idea.

Something along those lines did cross my mind, but the gears themselves are so fine, that the chances of getting it run smoothly after all the heavy surgery are vanishingly small, I suspect.

[Lonsdaler]

Thanks for the extra post re. the drive Philip. I think the orientation you have fitted the motor explains why I hadn't noticed your use of that motor/gear combination.

Graeme - take a look on Aliexpress - several suppliers it seems.
https://a.aliexpress.com/_mKeSTfw

[ge_rik]

take a look on Aliexpress - several suppliers it seems.
https://a.aliexpress.com/_mKeSTfw

I bought mine from Ali Express. Take a bit longer to arrive but they are slightly cheaper and there's a wider selection.
I also bought my HO gauge wheels and couplings from Ali Express for my GVT project. I'm really pleased with the quality.

Rik

[philipy]

Well the loco is finished....sort of!
I had expected to post some pics and a video over the weekend when I hit a snag. The plan was to use the "LED Controller" r/c system from SMT 157 & 159 and I had that wired in and working. The only snag is that it doesn't have reverse, but Mike Jeffries, who wrote it up, has designed an add-on board to provide that function. It actually also has other functions that I don't need so I dropped Mike a line asking about omitting part of the circuit, to save space in my very tight location. We've exchanged half a dozen emails and got it down to a managable physical size. Trouble is that I then had to get the components. Then I discovered that the controller I had is a different version to the one Mike wrote up, but he has done a revised write up for that, so that meant more emails asking for the update! Then that required two more components that I didn't have, so I'm currently waiting for Mr Amazon to deliver what I hope is the last package.

Anyway, I've used the last few days to sort out the loco crew and I'm feeling quite pleased with them. The driver is sitting on the water tank with his hand on the regulator, but the regulator is part of the body and the tank is part of the chassis and whichever part I fix him to means that I can't separate the two. Normally I'd put a screw up his leg from underneath, but that won't work with this because I can't get to the bottom at that point. Then I remembered reading about people using magnets to hold figures and thought that might be the answer. I managed to find some 3mm diam by 1.5mm thick Neodym magnets and got some to try. I filed the drivers heels off and Gorilla-glued a magnet to each heel, then a small piece of tinplate can lid was glued to the floor and hey presto! If I do this in future I'll print a hole for the mgnet, because the resin is too brittle to drill.

This shows him sitting in mid air to show the strength of these little magnets, and a view of the magnets from underneath, and finally, just so he doesn't feel left out, his mate leaning against the can! I'll magnet him in due course, once I can put the body back on the chassis to get the alignment right.

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[ge_rik]

They look pretty darn good!

Rik

[Andrew]

They look pretty darn good!

They do indeed!

Out of interest, and at the risk of revealing my ignorance of all things 3D printing related, were they "found" files that you modified to suit your needs? They look like they'll be perfectly suited to their quirky little loco...

[philipy]

Out of interest, and at the risk of revealing my ignorance of all things 3D printing related, were they "found" files that you modified to suit your needs? They look like they'll be perfectly suited to their quirky little loco...

No, basically I created a basic figure, with clothes etc, in Makehuman,

Screenshot 2022-02-09 11.08.07.png (149.32 KiB) Viewed 4424 times

exported that to Blender to pose it to roughly what I wanted.

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Saved that and exported it to get it into Sketchup and put it in position inside the complete drawn loco.

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Had a look at what needed to be done to the arms and legs to adjust them i.e move at the shoulder or elbow and hips or knees, angle of head, etc. Went back to Blender and made some adjustments,

Blender adjusted.jpg (9.93 KiB) Viewed 4424 times

re-exported to Sketchup and offered in again. Had to do this several times until I got it right, then exported from Blender into Chitubox ( the slicer) and loaded it into the printer, pushed go and waited just under 4 hours!

It sounds worse than it is and I couldn't have done it without Metalmunchers coaching a while ago, because Blender is a 'mare and a half, but Ok once you get the hang of this simple operation. I used the same process previously to position the figures for my Wickham Trolley project.

[Andrew]

Impressive stuff, thanks for the explanation.

I'm a little worried about the chap in the second picture, his seat looks VERY uncomfortable...

[philipy]

Well... here she is:

This shot is as close as I can get to the original 'big' picture:

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The RH side, based on the very grainy picture from the the pair:

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Graeme earlier commented about how I would get all the 'electrickery' in. So this is what is under the bonnet/coal bunker:

DSC_0009 small.jpg (131.52 KiB) Viewed 4348 times

From the left: On/Off switch; the 'LED Controller' Rx board flat on the floor; on edge above it is the reversing board; to the right of that is the charging socket; and behind that in the green sleeve is the voltage regulator supplying 5v to the reversing board. The flying lead with a small socket on the end is the connection to the sound system which is housed in the boiler. At the back, over the motor, are three of the 5 batteries, the other two being in the water tank at the back of the contraption!

Once I can get outside and find some track from under the vegetation, I'll get a short video of it in action and post a link.

[Peter Butler]

Just amazing Philip, congratulations on managing to achieve the (almost) impossible. I do hope you can get some practical use out of it now.

[Andrew]

I do hope you can get some practical use out of it now.

Is THAT why we do this??? No one told me!

The loco's fantastic Philip, I love the way you've finished it, the little details really bring it to life. The crew look great, and the rust on the roof is perfect. Congratulations!

[Lonsdaler]

That looks the business, Philip. You've done an amazing job capturing the essence of that quirky little loco.

[ge_rik]

A little gem!
Video next?

Rik

[philipy]

Video next?

Thats the plan, once the weather improves enough to get the maintenance gang out to clear the line. New contractors were required, the previous lot having been sacked for neglecting their works!
To quote from the local press, "It is believed that this Excellent New Locomotive Engine will be highly beneficial in the efficient execution of the contract."