FR & WHR & WHHR News

More complex than an exhaust steam injector?
https://www.a1steam.com/prince-of-wales/support-us/clubs/the-injectors-club#/

 

Taking a similar level and the price tag shows you how much these things cost. £50,000 is the lions share of a new boiler for the ALCo. I notice the Brighton Atlantic has a new Dreadnought ejector though which shows that it is possible. Assuming it works when the time comes.

 

A new Dreadnought as in found in a shed in the makers wrapping, or a newly manufactured one?
Pat

 

http://isengard.co.uk/ has webcam images of the new double-Fairlie Jim Spooner out on a test run yesterday.

 

I would imagine that the patterns to cast one would have to be very complicated to produce the internal passages, but in this modern era,might it be possible to produce a sacrificial 3D-printed wax core for the internals, to allow them to be made by lox wax casting?

 

A few cylinders were cast with polystyrene moulds but I haven't heard of any in a while and don't know if they would be suitable for such a casting.

 

Driver experience sessions. Welsh Highland Heritage Railway. 8th October.

If you are in Porthmadog for the bygones weekend…

Do you fancy having the chance to drive a 2ft gauge steam engine along our entire line. On Sunday 8th October you could do this and realise a life long dream. We are offering several slots throughout the day where you will have one to one tuition on how to drive our steam engine including the chance to drive from Porthmadog to Pen-Y-mount and return. We will be using Gelert our 1953 built Bagnall (celebrating her 70th year) to fulfil these sessions.




Sessions will run from 10.45am at 15 minute intervals, bookable in advance at bookings@whr.co.uk or turn up and wait on a first come first served basis (pre-booked time slots will take precedent over waiting participants).

Each 15 minute session cost £40 and will include driving instruction and a round trip with your hand on the regulator.

The shop at the Welsh highland heritage railway will also be open all day for all your book and model needs.

Caffi Russell's Café will also be open all Day serving Breakfast from 9am until 11am, lunch 12pm until 3pm and Pizza Night from 4pm until 7.30pm.
Drinks and Home Made Cakes served throughout the day.

(Persons must be 18 yrs old or over, must be wearing suitable clothing and footwear. Contact for further details)

 

Different technique entirely, the only common feature being that the material used is destroyed in the casting proccess.

There are three fairly novel techniques around for cheaper low volume castings:

1) Polypatterns. You make an expanded polystyrene pattern of the item you want, put it in sand as per a conventional wooden pattern, but instead of having to split the mould and extract the pattern you just pour hot metal straight in the mould. The polystyrene burns out, and metal fills the void and you get a casting. This has been used for cylinder blocks and similar. You don't tend to get a particularly good surface finish, so it's only really suitable for larger rougher items. There was a foundry which was particularly good at this which rather unfortunately went bust in 2020 - since then it's been very difficult to get castings of any quality via this method. There is a variation on this where you split the mould and break out the polystyrene before pouring, which apparently gives neater results - I've never tired it myself.

2) Printed lost waxes. Lost wax casting has been around for yonks, you make a wax version of the part you want, set it in a casing of a fire cement type mixture, put it in an oven and melt the wax out, pour hot metal in it's place and once it has cooled remove the fire cement. It's very accurate - you can cast small components to tolerances of around 0.1mm. Traditionally the waxes are made by injecting wax into an aluminum or silicone mould, the trouble with this is that these moulds are often quite expensive; to give you an idea, I had some steel clevis brackets cast for a project - they were about 2" long and 1" diameter. The castings themselves weren't very expensive, but the mould for the waxes was around £1k. The new technique here is to print the waxes directly. The results are very good, but the printable wax is extremely expensive - I think it's around £200 a litre, so for larger castings it's prohibitively expensive.

3) Sand printing. Basically a 3D printer which prints a sand mould which can be used just as if it had been made with a pattern. I've no experience of this beyond getting some quotes for a component, it seems to have a lot of potential, but it's not a cheap process.

I would have though that of these, sand printing is probably the only technique which might have an application for casting new Deadnought ejectors - polypatterns will be too crude and printed wax prohibitively expensive.

 

One of my daughters in on holiday in North Wales this week and sent me a short video of the new JAMES SPOONER:



TTFN,

Ron.

 

Before these approaches can be dismissed as too expensive, surely they have to be costed against the alternatives. If we accept that the finished items do wear out and are irreparable then further examples will be required in the fullness of time, whether for the FWHR or other users. If the cost of printed wax (probably the best method) or sand is high for the resin or the special sand, how does that compare with, say, making a wooden patterns and associated cores? Presumably producing the working drawings will be a cost common to all methods. I don't know the answers but it is surely something that ought to be investigated by someone with the right contacts. I really hate it when someone says "it would be too expensive" without really knowing the real likely comparative costs for all the options!

 

I'm sure that the world of railway preservation can and if necessary will find a way to produce more of these ejectors if necessary.

I do have some experience in this sort of field, and my gut feeling is that an approach of conventional patterns, and/or cnc machining from solid, is likely to prove more cost effective, particularly as there is likely to be a need for more than one in the future. My point was that the printed wax option, whilst very good for small runs of smaller components get expensive very quickly for larger components. By the time one has produced a printed wax large enough for casting a Dreadnought ejector, I wouldn't think you'd have much change from £1k a wax, and you won't always get a successful casting first time... Maybe it's economic, but probably not.

If you tasked me with making a batch of new Dreadnoughts, having done drawings, I probably would check the approximate costs of going for printed wax as part of my research. But in this case I wasn't actively trying to do this, merely trying to explain the various novel casting processes, and their likely suitably for an application like this for the benefit of some randomers on the Internet...!

 

Looking good in light steam this afternoon..

 

Any reason why it doesn't have a cab roof?

Tom

 

It does - removable.
James Spooner II - Festipedia

 

Thanks - looked weird, but I hadn't seen photos of Merddin Emrys as built.

Tom

 

The original had no roof at all.

 

For tall footplate crew.

Does this make it a "targa top" having removable sections?

Chris

 

Changing subject slightly, any progress with 7mm injectors?

 

A few video clips from the 'Bygones Weekend' at the weekend, featuring 'Britomart', 'Lilla', 'Blanche', 'Merddin Emrys' and 'David Lloyd George'.

Video Available Here

 

Some great sounds and sights from the Saturday and Sunday of the three-day Bygones Gala, including the Gravity trains and Lyd on the special working to Dinas