Townsend Hook Update

Apologies that this is a bit later than planned [see end of previous article for the reason].

In the last episode I detailed how the new prototype castings were coming from two sources. One a complete CAD to brass package via Shapeways and the other printed waxes via Precision Wax and then on to C Harding Castings to be turned into brass bits.


Both have, in my opinion, produced acceptable results with some of the bits coming out better in different methods.

This first image is the Shapeways collection which are a bit harder to photograph as they insist on coating the castings with a gloss coat as they seem to think everyone is doing shiny stuff.

If I were building a model these could be used directly on it but this method is too expensive for supplying production – ie these cost more then the we’re charging for the kit.


This next group is the wax from one source, cast at another method. Some of these need some work before they can be used as patterns as they need the casting runners cleaning and altering.  I have two set of these so I will be using one set to complete a model and finish the instructions.

I do have a dilemma though. I think I have decided what I am going to do but I will run it by you here just so that you know some of what is involved.

Here we have the Salter Safety valve castings from the two methods. One of the risks with the wax route is that the waxes this process produces are very brittle (the ones i can print aren’t but we won’t go back to that just now) and both the examples were broken up and cast or broken as they came out of the ceramic mould and whilst they could be assembled to make a model they are pretty useless as a pattern. The complete one piece casting is the Shapeways example that has been lightly abraded in my grit blaster to take the shine off. This is how they should have all looked and how the waxes looked when I mailed them. I think the Shapeways part gets to to be the pattern for this bit!   I would make the observation here that the photos are cruel enlargements and that the actual parts are pushing the minimum thickness limits of the process.

Now What

Probably by the time you read this the example of each part selected to be a pattern will have been cleaned, prepped and tested on a model to check the sizes and is probably on its way to the casting company. What they do now is: –

  • Make silicon moulds around the patterns sent (I think they use a third party for this)
  • Cast wax copies of the parts from these moulds making as many as we order
  • Add runners to these and assemble them in tree shape
  • Pour a fine ceramic moulding liquid around the tree and cure it
  • Heat it to remove all the wax
  • Pour in brass and wait for it to cool
  • Break up the moulds and clean the parts
  • Ship the parts

How long this takes I am not sure but I will be having a conversation about that tomorrow. I suspect it will be two to three weeks. Meanwhile my plan is to use the second set of castings I have to complete the instructions and to have the kits packed and ready to go just needing the castings dropping in and the lid putting on.

An added bonus. You may have seen previously that I did cast parts for and NGG16 valve gear. I never got as far as using them on a project but Nick Dunhill did to make a superb model with my parts.

I never really intended them to be a sales item but having been asked several times it looks like they may become one. It won’t be a cheap set and it will probably be done to order given that the supply of NGG16 kits has now dried up with the demise of Backwoods Miniatures.

However, whilst getting a set for a customer a little upgrade happened. In the original version the expansion link was simplified to provide a pivot hole in the middle but this meant that the valve gear could be set in forwards or backwards but couldn’t move between the two.

Well, with a bit of CAD work the expansion link has been redesigned to feature the prototypical pivots allowing working valve gear.

There is still some fitting work to do of the fiddly and frustrating variety to fit nickel silver wires as the pivots but then if you are fitting working valve gear on an NGG16 you are probably certifiable already.


More progress reports will follow when there is something to report



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A Little Train Driving

A Townsend Hook update will follow shortly.

Back from two weeks in Wales in which I drove Linda, Blanche & David Lloyd George adding 543 miles to my driving total miles, did some cycling and sight seeing and, well, buggered my right ankle.

It was always going to be an “interesting” time as Merddin Emrys decided it needed a summer holiday and retired to the engine shed by the sea. With only one double Fairlie of the two we usually have (or 3 we really need) there was some interesting double heading in prospect.

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Due to an unexpected evening off (should have been driving the evening train tonight) I can do a Townsend Hook castings progress update in between the excitement of defrosting the freezer and reading Felix the Huddersfield Station Cats latest best selling book.

In the last update I explained the two sources and the two processes being used to get the castings for this project back on track and the slightly different routes being followed.

Method One was to get the items printed as waxes. These arrived today via Royal Mail and internal FR mail. I had arranged for them to be sent to Julie, the works administrator (& Garratt fireman) rather than to me.  This was a shrewd move. In the past I’ve had mail addressed to me handed to me whilst I am on an engine. Yesterday was the hottest for a long time and I was driving a double Fairlie, not the best place for heat sensitive parts!!

I took the parts out of a mass of cotton wool to mark them for where they need runners attaching and took this photo at that time. All is looking good and they will go off in the post tomorrow to the casters in the Jewellery Quarter in Birmingham.

The second method was to send the CAD files to a company that will both print the waxes and cast the items in brass.  As well as dual sourcing the slightly different production methods may mean that some castings may be better by one method and other by the other.

There isn’t a lot to show yet for this method beyond an online graphic that shows that most of it is in production and a few items have made it to packing.

I get home from messing about with steam engines on the 5th August and I expect that both these processes will deliver at about that time. I’ll do the next update around then once they have arrived.


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Castings Update

After a lot of frustrating reworking, testing and then more reworking all the revised CADS are complete and have been submitted to the two sources for the next stage.

  • Set one: Printed Waxes, should catch up with me in Wales next week so I can review them and mark on them my preferred location for the castings sprues. (if you don’t tell them they stick them anywhere and obliterate the detail).  I’ll then send them to the caster who will cast from them to make patterns for mould making.
  • Set Two: My alternative source will be printing and casting parts that will be fettled and then used to cast replica parts. These should be waiting for me when I get back from Wales on the 5th August

Now with that out of the way can I put my feet up? Not a chance. Just a day left to get the VAT quarter returns done, a heap of orders to send out and to projects to finish and get shipped.



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Grrrrr!!!!! – A Townsend Hook kit update

How to explain how p!ssed of I am without resorting to a page of expletives may well be beyond my writing capabilities.

Try this. Imagine you are walking barefoot through the house and you stub your toe on the end of a door right between your big toe and its neighbour. It hurts like hell but as you’re hopping up and down on your good leg you land on a Lego brick. Unable to stand, over you go and, on the way, down you bang your elbow (whoever named it your funny bone deserves a flogging). When you can eventually get up, you bang your head on a shelf. Think of all the bad language that would create, (if you’re not unconscious) and you’ll be getting close.

If you can take a moment to consider the good swear that would engender, I’ll try to explain where I am at with Townsend Hook without the bad language. We left the story full of hope that we had a solution to the castings from home printed patterns. That hope has, for now, been dashed.

The responses from UK casters has varied from not replying, to answering all the questions you didn’t ask in an email whilst not answering the ones you did, lecturing about the subject but quickly revealing they’ve got the topic wrong. I suspect their stubbornness may result in their Kodak moment in the future.  Truth is the majority of them are past the first flush of youth and don’t see a need to change in their lifetime.

The hope was the Polish caster recommended by the printer manufacturer. His response to my enquiry was “I print, cast and show You result.”   This seemed positive and his website showed results from prints that were encouraging.  There followed an exchange of e-mails discussing details with annoying gaps between communications. After awhile I started to realise we were going round in circles with the same questions being asked that had previously been answered but that there was nothing to show for it.  One of the discussion points was over whether to do them in bronze instead of brass as the harder material would fill the small cavities in the moulds and be easier to handle. This question was asked on the 20th June and was replied in the affirmative and with the request to get on and cast a full set as a demo.

This would be the first time I assumed he was getting on with them (and to be honest I was distracted issues with the new website).  When I received another e-mail on the 8th July asking the same questions I discovered that this was me being optimistic.

I replied to this one again saying to use bronze, asking him to confirm that he was getting on with printing them and asking for a date when I could expect them.

I heard nothing back but had to give him a day or so to reply but late last week concluded that we were on a hiding to nothing and that a Plan C was necessary. Continue reading

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The Waiting Game

I am conscious that after last weeks almost daily updates its all gone very quiet this week but things are happening behind the scenes – I hope.

Silence will probably be misinterpreted so here is a bit of a recap followed by an update.

When we left the story on Thursday the first brass castings had turned up and were horrible. Investigation revealed that most likely the caster didn’t follow the different burn out procedure required by these printed resins. At that point we had to concentrate on getting ready for the 7mm NGA Convention. The show was a massive success with some cracking layouts, more then usual due using the AGM room and no lull in the afternoon caused by the AGM. I can’t help but think that we should sack the AGM off to the back room of a pub somewhere and just have a cracking narrow gauge model show each year.

Anyway, on our return to York investigations started on finding a caster who would work with these resin waxes. With the help of the printers support three were identified for initial enquiries. There were two in the UK and one in Poland. The responses so far have been: –

  1. No response
  2. Grumble, Grumble, waxes, don’t burn out properly, no we don’t do the burn out differently. Net very helpful.
  3. Yes we use a Form 2 Printer. Use it all the time with great result. Best thing is you send me the STL file and I’ll show you what I can do

I let you guess which response goes with which company but I am looking forward to a parcel from Poland.

For the trial they are using their printer whereas for production I would be sending waxes I have printed but the whole process takes several days with print time, mould setting time, burnout time and so on but I am hoping for some results next week sometime.



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Snatching Defeat from the Jaws of Victory

Well, yes, it would be fair to say I am pretty fed up at the moment.  The first of the brass castings arrived and they’re rubbish. Not what I want to put in a kit I produce.

I had been warned that they hadn’t come out great with the caster complaining that the waxes didn’t burn out cleanly and that the surface was very pitted. He also said he didn’t like this resin/wax and wouldn’t do any more.

I was gutted. Felt like giving up for awhile. So disappointed that I wouldn’t have any complete kits to sell this weekend at the 7mm NGA Convention.

Well, after a bit of naval gazing during which even the cats stayed out of my way I got to thinking. Formlabs couldn’t make claims like…….

…….If it didn’t actually work

Time for a bit of digging.

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Not Sure I can stand the Tension

I’m not sure I can stand the tension of this run up to Saturdays release of our new model. The story so far……….

For this model we are doing brass castings by printing the waxes instead of  (1)printing a master, (2)making a silicon mould round it, (3)casting multiple waxes, (4)making a ceramic mould round the waxes, (5)burning the wax out & (6) pouring molten brass in.

By supplying the waxes were only doing 4, 5 & 6

A test with 3rd party printed waxes I had worked fine.

So with the deadline fast approaching the printer printed through the night producing gooey masters on the build platform. From here they’re popped off into a tub of Iso-propyl Alcohol to wash of any uncured resin.

Cleaned up they look like this. They then have to be trimmed off the printed supports, packed in sets and then shipped off to the caster.

The plan was get them to him on Monday, casting and shipping on Tuesday, I get them Wednesday.  We were at a show on Saturday but the waxes went with us and Annie posted them Special Delivery in Doncaster.  They arrived with the caster early Monday as planned. Now things have gone a bit crook……..

  • I missed a call on my mobile only finding the message in the evening. It went something like “that’s different wax, it doesn’t burn out so well. Ring me.

So now I am imagining all sorts of issues and seeing the project snatch defeat from the jaws of victory. The statement doesn’t ring true because the blurb for the resin says “A 20% wax-filled photopolymer for reliable casting with zero ash content and clean burnout”  Frustrated I can’t call until this morning but missed doing it first thing – something to do with being up changing the print job at 2am, so when I do call…..

  • Sorry , we can’t take your call. Please leave a message

So, currently none the wiser, fearing the worst and needing a nap. I’m hoping the unavailability is because he’s busy casting my parts!




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Progress With the Fiddly Bits

I said I would do updates on progress with the Townsend Hook kit as it gets closer and closer to the 7mm NGA Convention.

Here is the latest news:

Test prints of all the parts that will be brass castings have been completed in standard resin.  These are shown to the left and I have sprayed them yellow so that they look a bit brassy.  They are still on the printers support frames in this first picture.

Next part of the plan was to use these to dress up a body with these parts.

There is a nest of piping that connects all the cab valves together which will be easier to install when they are done in brass. The resin, particularly on that Christmas tree of a cab valve, is quite fragile.

Townsend Hook has Salter balance safety valves now whilst William Finlay has pop valves. There will be castings for both varieties in the kit.

In another example of me not knowing when to quit the loco has clear glass for its single gauge glass!

The firebox print has holes in it and there will be a bit of clear plastic in the kit to represent the glass. (Its actually a small bit of fibre optic)

Now I have hideously enlarged the image I can see I should have added handles for the top and bottom cocks on the gauge glass!

Now, while I pack the car for Doncaster Show, the printer is on with producing the waxes for the castings


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Playing Trains & New Models

It had  been the plan that my next jottings would have been about my trip to Wales driving trains at the last bank holiday but, as is often the case, having skived off for a few days I came back to a load of catching up that precluded sitting at the PC and writing for pleasure. I’ll include a bit about that trip at the end [so you’ll either have to read the rest – or scroll to the bottom].

The thing that is filling all my time at the moment and causing more than a little anxiety is the plan to launch our new Townsend Hook Body kit at the 7mm NGA Convention in less than two weeks. When we made that public, it looked like we had loads of time but with the date approaching its looking incredibly tight.

Until Friday it looked like the critical item were going to be the brass castings. I had a bit of a panic when I phoned the caster to discuss timescales and the first thing he said was, “I’m on holiday next week”.  Anyway, a cunning plan was hatched that actually gives me next week to get the waxes done.  Taking advantage of the 3D printer we’re doing things a bit differently.  Traditionally, you made a master, they made a mould from it, in that mould they poured wax and made many wax replicas of your master and added runners, made a ceramic mould around the waxes, burnt the wax out and poured molten metal in.  The new way is to print the multiple waxes using a castable wax resin in the 3D printer.  That sidestepped that critical item, at least for now.

Having done the design for the parts in CAD the first thing to do was to print them in ordinary resin (cheaper) to make sure they print and fit the model when done. Attempt 1 showed some opportunities to improve the designs and attempt two printed them successfully.

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