Saturday, 26 September 2020

Axleboxes

If you look closely at what I have achieved so far with the 3D printer it has been very much a case of how to join circles and squares together and how to curve and chamfer edges. I've made plenty of progress and this summer seems to have been very successful in terms of how few failed prints I have had.

Over drinks one evening, my friend Simon was showing his progress on an early GWR horsebox. It has the most intriguing axlebox and spring arrangement where the ends of the springs are connected to J hangers rather than directly onto the solebar which is the more traditional way of doing it. Of course, I decided this was the next challenge I needed.

As always, there is a lack of good photographic evidence since most photos of wagons have the underframe in shadow. There were a couple of good pictures so dimensions were taken and the following was drawn up.

The axlebox itself is still a collection of squares and circles but the spring was the challenge and was built up from 3 point arcs. A circle was put on each end of the top leaves and then it was about trimming the shape to form the circle. It was a couple of hours work but I learnt so much about how to build up more complex shapes. It came out alright but when offered up to the vehicle my interpretation of dimensions was off.


Revisiting the dimensions led to a design that had more depth to it, the axlebox was chunkier and the width was narrower. I also needed to improve the printing supports. I am surprised it printed with what I did on the first pass.




In this form they have gone onto the model. I've learnt quite a bit more about printing and it is nice to give something back to my friends who have been so generous with their time and support for my modelling.

Sunday, 20 September 2020

Welshpool Coaches & 3D Prints

 Another huge break between posts. How does that happen? The last 3 months have been largely devoted to 3D printing. After the success with the side windows on Triumph I knew I had to get back to the Welshpool & Llanfair Pickering coaches. The big outstanding task was the roof. How to do it? How to roll it and then the fittings. What were the best fittings, the torpedo vents and the oil lamps. After a couple of purchases that really weren't what I was looking for, I decided I must surely be able to design and print suitable ones.

I've been following Vladimir Mariano on YouTube and he has some excellent courses that have been advancing my skills at 3D design. I had to learn a few more commands but eventually I came up with the following design. There are no drawings for these so they are an interpretation of all the photographs I could lay my hand on.

Having the design is one thing, working through the practicalities of printing took more effort. Essentially the printer prints upside down so you have to think about supporting edges that are in free air. There are also issues around where resin can collect and build up in unexpected places. The final design looked like this - you chop off all the unnecessary bits after printing.

There are nearly always supports required with 3D prints and if you let the printer software add them then they conspire against you and make these size prints take 3 times the time they should. I have developed my own technique for adding supports within the CAD program which is working so far for me. I also replicate items to create strips of 12 items, 5mm apart which nicely fits the printer build plate

Bearing in mind the body of these lamps is only a few mm high they are a tad challenging to photograph but here is the best I could achieve with my camera


The torpedo vent was done in much the same way. There are some drawings but their accuracy is not assured and the photographs are challenging simply because most are taken from ground level and the Pickering coaches had an enormous rain strip which consistently hides useful detail. the WLLR does have some replica coaches but with anything replica there are going to differences with the original and I have no way of knowing what is accurate.

Again, only a few mm high so hard to photograph but the end results do seem to have been worth it.

I have also done the guard's stove chimney for the composite coach along with a brake cylinder to go under the coaches. Who knows, the coaches may make an appearance soon!

Thursday, 25 June 2020

Hotel Chocolat Saves The Day

I needed a break from paid work so took a week off. There wasn't a clear plan for the week except to spend time modelling and possibly going to a non-essential shop! I have a few projects on the go and really wanted to complete Triumph and make progress on the Pickering coaches.

What happened was I had some inspiration about how to do something on the 3D printer and, despite the recent problems with printing (not sticking, test file not printing, build plate shifting), I just decided to get stuck in and see where I got to.

What I ended up doing was going on journey printing windows. All the Bowaters engines had sliding windows and stable type doors. It's not clear why but there are two reasonable possibilities

  1. the land is very flat and so the wind howls through
  2. the paper business is very dusty so maybe there is a lot of paper dust flying around
Do a Google search for Triumph then you will see what I am talking about. These windows vary between 1, 4 and 6 panes and I've manage to find examples in green, black or plain wood (presumably paint worn away). The time in question for Triumph they were a green, 6 pane affair.

I did a crude measure of the gap on the engine where the window should go and came up with the following:


The dimensions are roughly 11mm by 9mm. The dimension of the edge probably works for a house window but those on Triumph are much slimmer. I adjusted the dimensions and came up with this variant that was worth painting just to see how it fared:


Getting better, though really I have gone too thin. The core dimension is 0.5mm and, after curing, there is enough strength for the item but I felt it needed refining and so I came up with this:


That looks right. It may not be dimensionally accurate but it looks the part and has the strength to withstand some handling. Time to add the glazing. I have been meaning to try Kristal Klear for a while so I broke it out, read the instructions and achieved this:


It really does dry clear and provide a glazed look. Put the unglazed and the glazed next to each other you see a brewing issue:


The glazing has made the window panes smaller and the frame larger. It's unclear if it is a trick of the light or a leeching of the paint but suddenly it doesn't look so fine. If you put it on the locomotive then it starts to grate for not being as fine as some of the other parts:


If that was the best I could achieve then I would live with it but I wanted to do better.

I had an idea from how doll's house windows are done, typically full sized front but recessed at the back with an insert that holds in the glazing. Doll's house windows are often 10cm in length, not 10mm so would it work?

First I had to find a suitable glazing. That non-essential shopping led us to Hotel Chocolate from which purchases had to be made and said purchases were wrapped in clear cellophane which, according to the micrometer, was 0.05mm thick. 

Back to the CAD package (Fusion 360, free for personal use). If I made the outside depth and edge 0.7mm and put a 0.4mm recess into the frame and produced an insert that was 0.3mm thick then it should just go together with a tad ofspace. Here's what it looks like on the screen.


Those parts are thin but, painted up, glazed with Hotel Chocolat Cellophane, held in with Kristal Klear you get this:


The printing layers are showing at this magnification but the bars have retained their thickness and aren't distorted.

Here is the end result stuck onto the engine with a piece of blu-tak:



It's definitely a case of using the right material for the job. With much encouragement I have been working in brass and made the fire irons on the cab roof out of 5 thou brass and some nickel silver wire (every engine at Bowaters had fire irons on the cab roof).  The oil cans on the buffer beam were another 3D print (again, all engines at Bowaters had them, sometimes just 2, sometimes as many as 5). It took me probably 7 goes to get those right but they really have handles on them and now I have got it right I can print some more.






Sunday, 7 June 2020

A green, a green, my kingdom for a green

Finding the right green has been quite a saga through lockdown, requiring several deliveries, none of which were right. Of course, right is a matter of perception but I knew the look I wanted to achieve. Early in the process, Simon de Souza had suggested Humbrol grass green but I had ignored him, as you do. When he suggested it again and did a paint swatch it was, of course the green that most closely matched what I was looking for. A burst of British summer meant I could do the spraying. I elected to paint the black with a brush rather than mask it up as the black blends round the end of the tanks anyway. It would be faster this way.

Another suggestion from Simon was to not use pure black but to use a dark grey. I decided to listen this time. Not having a dark grey I took the quarter full pot of black and added a couple of dollops of white and one dollop of reddish brown - precision mixing.

Then came the lining. Suffice to say I almost threw the engine at the wall. Matt Kean produces beautifully lined models and he would have done this one for me but I wanted to learn. I have several locos tucked away and they all need similar lining so it seemed a skill I should learn.


This is all I have managed so far, one side, both water tank fronts and one cylinder. Some of the lining has had 4 or 5 attempts. It just would not lay flat. I've experimented with red and blue Micro Sol and still not got the technique right but I will get there!

It looks a little toy like without the roof (did I say I bent the one I made...) and would be much better with the correct chassis but that will have to wait until I learn how to make my own chassis. So many skills to learn...

Monday, 11 May 2020

How riveting

With several projects on the go it is inevitable that they go slowly. Lockdown hasn't changed the time available during the week for modelling but at least there are good solid modeling times at the weekend.

Here is the work of a labour of love, adding rivets. I lost track of the number of hours spent doing this and there is still the other 3/4 of the engine to do.


It's a job that can be very rewarding when they go on well but when they don't... It is also so fiddly that I lost track of which spacing of rivets to use. The difference is so small that I went "space blind" at one point and definitely used the wrong ones. Also, having started the other side tank I now realise I have missed 3 rivets off this side. I think I may have just labelled myself!

Ultimately I am still pleased with the first attempt at using these decals. I am hopeful it will add depth to the model when finished. I'm guessing another week until all the rivets are on and by then the next attempt at finding the correct green will have been delivered by the postman bearing gifts.

Tuesday, 28 April 2020

Triumphant Progress

In my last post I showed work on Triumph, an 0-6-2 Bagnall tank that used to be part of the Bowaters mill complex in Kent.

The body had gone together okay but, being a whitemetal kit, it was not crisp at all and the side tanks just didn't want to be parallel with each other but we got there.

The next stage was to add some detailing. There were a few obvious items that needed adding:

  • There are rods that run along eh top of the water tank on each side so these were made up from a scrap of brass with a nickel silver rod.
  • The safety valve casting had a gap between it and the cab front so that was slimmed down and a piece of brass glued over to represent the lever.
  • There is a rod that runs from the cab to the sandboxes. This was soldered up from a piece of square nickel silver. It should lie flat on the side of the sand domes but I decided to drill out the sand domes and push the rod into them otherwise there would be no strength in the part and be at high risk of being knocked off.
  • There are pipes that run from each sand dome on each side which have a very visible joint in them.
  • A whistle was made up from more brass and nickel silver.
  • It also got a detailed cab from bits of plastic, nickel silver and even some wood.
  • A replacement roof was also formed as the whitemetal one was just too thick.

The photo below shows the finished result though it is cruel from being blown up larger than in real life.


Adding this level of detailing was a new experience for me and practically everything had several attempts before I was happy enough. Generally I chose materials that were too big and needed replacing with something thinner or finer.

It was then cleaned and primed with some etch primer but it has not gone on well. The primer was an existing can that I had used before with mixed results. This time it came out worse, patchy and thick in places. It afforded me the chance to see some of the blemishes that needed fixing but ultimately it's going to be stripped and another can used.

Once the primer is replaced, the next stage of detailing can begin. The real engine has a significant number of rivets on the tanks and once you see them you realise the model is too flat. I've never tried them before but I've been given a sheet of Archers rivets so I built a mock side tank from plasticard, The rivets are very fragile and it was suggested I put them on after priming to limit them disappearing in paint. There was then a question of whether to put them on before the black and/or green. In the end I stuck with straight after primer, then sprayed the green, then brush coated the black as below


After that it was time to consider the lining. Again, something I had not done before but I wanted to try it. I picked up some Fox Transfers in the smallest thickness they had. As warned, they were tricky to keep straight and it probably is better to go for thicker ones and thin them with an overlaid black transfer. Nevertheless I was pleased with the finish. I discovered to my cost that I had no micro sol/set in stock and it shows with the various transfer edges still being visible and not being able to bend a transfer round the larger curve. The smaller curves were bought. I counted that there are 30 small curves on this engine alone so that sheet was worth purchasing.


The result is pleasing and with practice I ought to be able to avoid some of the mis-joins that you can see close up.


Saturday, 4 April 2020

Not Going Out

The world has changed and not immediately for the better. Here in the UK we are two weeks into lockdown and are trusting that the measures in place will keep the number of deaths from Covid-19 under 20,000 which is what is described as a "good" figure. The immediate impact for me is working from home and I am one of the fortunate ones who can do that and carry on getting paid. Not everyone is so fortunate. There is more time and some of that time has been spent on reorganising the "office" so I can work from home all day. The computer has gone from the den where I used to occasionally work from home and, as a result, I now have a larger workbench for my modelling. I have had a serious reorganisation of the room and this is the result.


This means I can have more projects on the go at once. Usually I try to stick to just one project at a time but with multiple projects I get the chance to move to another one when I hit a roadblock on one and need to do some thinking. Also, I have the space so why not use it. Equally all exhibitions have been cancelled so now I have no deadlines and can afford to be a little less focused.

The first project is the model of Triumph mentioned in the last blog. The body is largely complete and I have been contemplating the detailing. Today I drilled out of the windows so I can put in open ones. I should have done that before building it! More on those in another blog.


It's clear that in the future there is going to be a layout based on Bowaters so I expect a Facebook page to appear soon. Bowaters itself is not easily modelable but I will find something from it to create a layout from. I look forward to building something more industrial. In the meantime the locos can run on Melin Dolrhyd provided they can get round the curves!

The second project is the 3mm 4F kit that I bought a while ago. I used to model in 3mm but could not make a working chassis. I am going to have another go and am determined to be successful this time. I invested in a Poppy's jig and have got as far as loosely assembling the parts in the jig.



I have a couple of options for motor and gearbox. I do have an N20 motor and gearbox combination produced by a member of the 3mm Society and I have a High Level Slimliner+ on order. When that arrives I will make a decision on which to use.

The third and final project is Southwold in 3.14mm to the foot. David Eveleigh designed this stock to run on 2mmFS track and it came out to this weird scale of 3.14mm to the foot which is close enough to 3mm and so there will be a layout in 3mm that contains standard gauge and narrow gauge and it will be Southwold based - you can't hide the shape of those wagons.


David's etches contains 16 four wheeled wagon chassis, 4 six wheeled wagon chassis, 2 coaches and 3 engines plus some odds and sods - a whole layout's worth at one go! As you can, see the etch above for one of the wagons is exquisite. It is also tiny!

That's it. Everything on the workbench currently and, yes, I am procrastinating over the Welshpool & Llanfair coaches!

Axleboxes

If you look closely at what I have achieved so far with the 3D printer it has been very much a case of how to join circles and squares toget...