Realistic (Blacketty) Water

It's been a while since you last saw the actual diorama as I've been slowly adding the water for the stream. I've lost count of the number of layers I've poured (I think six but I could be wrong) but it's finally at a reasonable depth, both in terms of resin and how it looks.

Rach layer was very thin (about 5ml per layer across the entire scene) and then painted with thin washes of black and burnt umber to try and add depth. I also had the model resting on an angle for the entire duration so that the stream surface was kept horizontal. This means that now that it is dry it looks like it's flowing downhill. The main problem of course is that the surface is too smooth and looks like slow moving water rather than a fast flowing stream. Hopefully some Woodland Scenics water effects should solve that problem though.

Etched Couplings: An Experiment

Virtually all my OO9 locomotives and rolling stock are fitted with Greenwich couplings. While these are the standard coupling used by most people in OO9 they are not without their problems. Firstly the loop is quite large which leads many people to only fit the pin part on locomotives, and they require a slot at the right height in the buffer beam. While many kits are designed with an appropriate slot, not all are and it can be a pain to cut one. The solution that some people use to bend the shaft of the coupling at right angles and glue this to the front of the locomotive, but again I think this is a little unsightly.

While I'd thought about this before I'd not come up with a better alternative, but then in May Paul blogged about some couplings he'd made from a bit of left over brass etch. These were designed to look more natural and be easy to fit, and so I decided to see if I could come up with an etched version.

The plan was that you would bend them around an etched former but in the end that doesn't really seem necessary as the etched fold lines work well enough. The half etched holes can ether be punched out to form bolt heads or drilled through so that metal rod can be used to represent bolts and add extra strength by going into holes in the loco as well. I was a bit heavy handed trying to punch out a rivet and went straight through the etch but you get the general idea.

I'm not sure what the plan for these is yet, but I'd be interested to know what other people think.

Rusty Girders

Over the last few days I've done a little more work on the girders etc. that make up the bulk of the bridge. After posting about this previously I realised I'd missed out the bolts that connect the girders to the concrete block so these have now been added (a small piece of folded brass and more rod for the bolts) and then the whole thing painted.

On the real thing the plates are a lot darker than the girders which I've attempted to replicate. I'm fairly happy with how it looks although it will get a little more weathering when it's bedded into the scene to help tie the bits together.

Flutterby Chunky

If you've been following this blog for any length of time you'll have noticed that my modelling tends to focus on the man made aspects of a railway (locomotives, rolling stock, bridges, etc.) rather than the natural environment it runs through. One of my main reasons for entering the Dave Brewer challenge this year was to force me into thinking about the scenery around the bridge and so far it seems to have worked. I've experimented with lots of different approaches to painting rocks as well as figuring out how to model dark peaty water (which I promise I will come back to soon). The third major part of the scenery on the diorama is the heather and this has had me worried for a while.

I'd looked at a number of really nice commercial grass mats but none really matched the scenery around the real bridge well enough for me to be happy with, partly as I couldn't find a good representation of the heather. While I still need to decided exactly how I'm going to do the bits of grass not covered by heather (probably a mixture of scatter and static grass) I think, after a number of experiments, that I now have a good way of producing heather.

My first attempt at heather involved using some Woodland Scenics forest blend bushes covered in scatter. Having seen other people have good results using Flower Soft to represent.... flowers and given that they do a packet called heather this seemed like a good starting point. While the colour in the packet looks okay there was quite a lot of white bits that I wasn't happy with as I thought they would be too bright. Given the others colours seemed reasonable I picked out the white bits and then scattered the other bits over a bush covered in glue, and you can see this on the left hand side of the first photo. Unfortunately I think you'll all agree that this doesn't look like heather. The bits are too big (the bush is a reasonable size for the scale I'm working in) and the colours are wrong.

To try and fix at least the size issue I tried again this time with some Ultra Fine Flower Soft called Raspberry Fizz (strangely the Ultra Fine stuff no longer seems to be listed on the website). Unfortunately again there is too much white and this time the bits are so small I couldn't remove them, so I think it looks even worse (right hand side of the first photo).

At this point I was fairly stumped. I knew, from the photos I have of the bridge, roughly what colour the heather should be but I had no idea how to make it. Fortunately my wife had an idea that seems to have worked really well; she suggested I use some chenille. Now given that she has been buying chenille so she can crochet baby blankets I wasn't initially convinced by the idea but she was convinced that chopping the fibres up into little pieces should work so I gave it a go. My first attempt was horrible as the bits of yarn, while the right colour, was way too fluffy. For a second attempt I dunked a piece of yarn in scenic cement and left it to dry before cutting it up and this seems to have reduced the fluffiness to acceptable levels.

Now in close up you might not be convinced that it looks like heather, but if you stand back and look at it from a slightly more sensible distance I think it does a very good job. Yes I could do with separating the fibres a little more so it doesn't clump but in general I'm really happy with how it looks.

For anyone wanting to try and replicate the idea I used James C. Brett Flutterby Chunky yarn, mostly the Mulberry (B21) but also a little Rose Pink (B19) to give a little variation.

And The Bolts Attach To...

So for today's post I'm back working on my entry for the Dave Brewer challenge. The last time I posted about this I admitted that I'd made a mistake in interpreting the few photos I had by using I shaped beams when in fact they are C shaped in section. As well as showing me the correct girder shape, the photos Bobby kindly took for me also finally explained how the bridge was all held together.

In the previous photos I'd been using I could see that there were quite a few bolts in the side of the girders, but I couldn't see what, if anything, they were attached to. With the new photos though the answer is clear.

As I said with these photos the construction is nice and clear. Originally there were three U shaped plates bolted between the girders; one has broken off entirely and one is fairly close to coming loose. The missing plate explains why there appeared to be just thin air between the girders in the previous photos I was using. As well as the photos Bobby measured the plates as being 75cm long, 60cm wide, and 12cm deep making them easy(ish) to replicate.

Each plate is made from three pieces; a piece of 0.12mm brass sheet for the bit between the girders and a thin strip of 0.3mm styrene for the two side parts. I did think about making the entire plate out of brass but making it in three pieces was easier as I've drilled holes for all 36 bolts which I've made from 0.33mm nickel silver rod. What you don't see in the photos are the numerous jigs I also made to help cut the small strips of styrene, drill the holes, and hold things in position while it was all stuck together. There's almost as much modelling in the jigs as the bridge. Given my intention is to model the railway out of use I've also left off one of the panel sheets (but fitted the bolts) so that it will match the track I've already built. Hopefully the weather will be better tomorrow and I can wave some primer over it in the garden.

Tolerances

The way I produce the models that I 3D print allows me to work down to an accuracy of 0.001mm. Of course it's highly unlikely any printing process will be so accurate but so far when I've printed models in multiple pieces they have always fitted together perfectly. I was surprised therefore when I tried to put some of the second Clayton prototype together to find that I didn't have a perfect fit. The problem was that once I'd fitted the bearings to the FUD print the stainless steel keeper plate wouldn't fit without distorting the body. You can see this in the left hand photo.

What confused me was that the stainless steel part measured out at exactly 9.10mm on my digital callipers which matched the 3D model perfectly. As I mentioned before the stainless steel is seriously tough and it took ages, even with a diamond file, to reduce the width sufficiently to allow things to fit better (the right hand photo). Altering the 3D model to narrow the steel part slightly for future models is easy but I wanted to work out not only how much to narrow it by, but why I needed to.

When I develop a new model I produce virtual copies of all the other parts (wheels, bearings, motor, etc.) that I'll use to help me visualise how everything will fit together and to ensure adequate clearances etc. On this occasion though it appears I managed to wrongly measure the flange on the wheel bearings. My model of the bearings has the flange at 0.1mm, turns out having remeasured them that they are actually 0.2mm which means that the keeper plate is 0.2mm two wide. I know 0.2mm doesn't sound like much but I suppose that just goes to show how accurate the 3D printing process is.

7g of Stainless Steel

After the mostly successful completion of the 1st prototype of the Clayton locomotive I made some changes to the design to solve the problems I encountered as well as to make the loco easier to assemble. The parts for this 2nd prototype turned up today. As you can see I've doubled the number of components from two to four and not everything is printed in FUD.

One of the main design changes was to allow the axles to be completely assembled before fitting to the model which led me to the idea of a keeper plate, which also has the advantage of stopping the axles from shifting sideways which is what was causing the jumpy motion on the last prototype. Now I could have had the keeper plate printed in FUD but instead I've had it printed in stainless steel as this nicely adds weight to the loco; 7g of extra weight to be precise. The only problem is that the steel is exceptionally tough and the holes for the screws that will hold it in place ended up printing slightly under size. Opening them out has caused me to break a drill bit, draw blood, and I now have a blister but.... everything now seems to fit together!

I also made the control box as a separate piece so that not only is it easier to paint the model but it can hide the nut that holds the upper and lower parts of the model together. Unfortunately the footplate is still a little bowed and while I did make the fit tighter at the front it's still not perfect so unless I can flatten the part out a little (soak in hot water then hold flat while it dries) I might need to think about a better fixing at the front as well (harder as the pulley for the drive belt is in the way).

I've had to start packing most of my modelling stuff away as we are having family to stay at the weekend so I'm not sure when I'll get to try and put this together but hopefully I'll be able to find some time to at least assemble the axles and make sure the keeper plate works properly.

C Not I

So having been quite happy in yesterday's post about how accurate my model of the bridge up on Duchal Moor had turned out, today I'll move onto a detail I got wrong.

Virtually ever photo I'd been able to find of the bridge was either taken from the tracks or at eye level standing next to the stream. Neither of these views allowed you to see any details under the sleepers between the two support beams. Having now been kindly provided with a large number of detailed photos by Bobby I can see exactly how the bridge is constructed and I've made one crucial mistake. I'd assumed that the girders were I section beams but they are actually C shaped in section. While you probably wouldn't notice the difference on the model, the different shape would stop me adding some of the other details I now know about. Fortunately removing the girders from the rail only involved some careful use of a modelling knife to break the glue.

Measurement wise though I was again fairly close. I'd been using I beams that were 2.4mm tall which would equate to 7 1/4 inches and Bobby measured them at 20cm tall or just over 7 3/4 inches so close enough. Now while I could buy C section beam of the same height I'm instead going to cut off bits of the I to turn it into a C as that will give me a more accurate width as the real beams are 3.5cm thick so should be less than 0.5mm at this scale whereas the plastic C beam would be 1mm wide.

Accuracy

I'm constantly amazed at the kindness and generosity of people I've got to know through this, and my other, blogs. Over the last year I've been given a set of track gauges by Paul and Iain has sent me some offcuts of Palight to experiment with as well as sharing numerous research photographs to help with my Welsh slate quarry wagon models. To that list I can now add Bobby who has kindly cycled out to the bridge on Duchal Moor to take some research photographs and to run a tape measure over numerous bits of the bridge. I'd already been using one of Bobby's photographs of the bridge to help with the model but this new set shows so many details that I'm going to be able to really enrich the model.

I'll keep most of the photos back for now and show them as I replicate the details, but here is how the bridge looked yesterday lunchtime.

So given I now have some measurements how accurate is my model? Well lets start with the sleepers as they were the first thing I modelled. My best guess from the photos was that they were approximately 2' 9" wide, but I modelled them as 3' due to the slightly heavier, and hence wider, rail I was using. Rather than trying to hand cut thin strips of wood I used OO gauge sleepers from C&L Finescale cut down to 12mm. This meant my sleepers were modelling 3' wide, by 10" across, by 2.4" deep. Bobby measured them yesterday at 90 cm by 25 cm by 6 cm, which when converted to feet and inches gives 2 feet 11 7⁄16 inches by 9 27⁄32 inches by 2 23⁄64 inches. So my original guesstimate of 2' 9" wide was a little out but the actual width I modelled, 3 feet, was pretty much spot on as are the other dimensions.

The two other main measurements are the span of the bridge and the height of the concrete block supporting one end as these basically set the dimensions of the diorama. I've ended up with the bridge spanning a scale 14' 3" whereas Bobby measured it as about 5m or just over 16 feet, so mine is a little bit short but not by much. The concrete support measured out at 1.6m tall by 1.33m wide and 75cm deep or roughly 5' by 4' 4" by 2' 5". The block I cast was based on measurements of 5' tall by 3' wide by 1' deep. I got the depth badly wrong due to not being able to see exactly where the block stopped and the stone embankment started. The height is spot on though even if the width is over a foot too narrow.

Given I was originally working from just a few photos I don't think I did too badly and the measurements are close enough that the difference won't alter the look of the model which means I don't need to go back and change anything fundamental.... phew!

Reinventing the Wheel

A recurring problem when modelling in OO9 is wheels. There are actually two problems. Firstly there are only a few different sizes of wheels available which limits the locomotives and wagons you can accurately model. Even if you are lucky enough to find wheels of the right size the second problem is likely to bite in that they will be of the wrong design. Fortunately many of the available wheels are actually metal tyres around plastic centres, and so as an experiment I've had a go at producing an alternative design by 3D printing replacement centres. I actually started this a while back but managed to misplace the printed parts.

To make life as complicated as possible I've tried to produce some wheels that could take crank pins for modelling inside frame locomotives. Specifically I've produced centres for a Deutz diesel locomotives.

My best guess (from that photo and some other drawings) was that the Parkside Dundas 5.1mm wagon wheels where the closest size wise but having seven curly spokes would usually rule them out. Fortunately, like many other wheels, the plastic centres push out. Some careful measuring with a set of digital callipers allowed me to determine the main dimensions of the centre which I could then use to design a Deutz style replacement. Probably more by luck than design the centres are a perfect fit inside the tyres and are a tight push fit to the original axle -- I've painted the centres red as the FUD prints are difficult to photograph.

Unfortunately I designed the centres to take a 16BA screw as the crank pin only to find I'm actually out of stock so I haven't been able to test that aspect. The plan though would be to fit a screw into the centre and then cut the head off, slide the coupling rod on, and then use a 16BA nut to hold everything in place. Alternatively you could slide the coupling rod onto a screw and screw it into the wheel so the screw head holds it in place. You'd then cut the screw flush with the back of the wheel and file the screw head flat. Either should work, but I'll have to wait until I get some 16BA screws before I know for certain.

One other interesting thing I've discovered is that the Parkside Dundas wheels, and hence my replacement centres, use the same diameter axle as the O14 axles available from KBscale. This is great as it means that you could replace the axle and model outside frames with flycranks. Usually you can't replace the axles as each manufacturer uses a slightly different size so this is very useful. Of course if I'm designing my own plastic centres then I could design them to fit any diameter axle.

For a simple experiment it shows promise although until I take the next step and build at least a rolling chassis I won't know for certain how well it will work.