On My Virtual Workbench...

S-Club-7

Western Thunderer
Rather than clutter up the West Mersea thread I thought I'd have a go at writing my own. I seem to have spent more of the last couple of years in front of a keyboard rather than a real workbench creating virtual 3d models for subsequent 3d-printing. The models that have worked may be found in the Off The Rails Shop but perhaps this thread will detail some of the processes you may need to go through to get from screen to solid object.

To start with here's my latest creation; a set of chairs for a 1 in 6 common crossing in Scale7. Firstly, as drawn (first seen on the West Mersea thread a few weeks ago but repeated here just to keep the narrative flowing) -- getting to this stage has taken me about 8 months of work and, no, it wouldn't be quicker to scratchbuild them in plasticard. How do I know? Take a look at Lumpy Sidings.
1in6 Crossing 03.jpeg
From left to right we have: the 6X chair; the knuckle block, washer-blocks and bolt-heads; the 6A chair with the A blocks; bolt-head and washer-block to hold the end of the splice rail to the point rail; wing blocks and washer-blocks; more washer-blocks to join the point and splice rails (some companies also had a rivet or two as well); the 6B chair; and finally the 6C chair. Previous request for a cast 6A chair noted and will be included in the second draft.
Ten days later this is the first one printed in acrylic "hot off the press":
1in6_first_one.jpg
Pause for two weeks whilst new computer is purchased with modelling budget, installed and configured. Then discover existing 32-bit CAD software won't run on new 64-bit computer without an upgrade. Retreat to garage for a week to do some REAL modelling... DSCN3086.JPG
A mixture of C&L, Exactoscale and Off The rails chairs make up this LNER 1 in 6 common crossing. I did manage to construct this without cutting any of the chairs so it may not be necessary to do a variant with loose chairs after all (large sigh of relief from S7 modellers around East Anglia). Some of the spacing blocks were a fraction oversize and will need reducing, but nothing that a couple of swipes with a file didn't resolve.
The incomplete diorama will be at Sudbury on Sunday, but not painted or ballasted, I need to earn some brownie points with SWMBO after spending a week in the garage...
 

28ten

Guv'nor
Very nice :thumbs: do you find the chairs sufficiently robust? Im actually just having one of my test chairs cast in resin to see how they go in 1/32, there may be a problem with undercuts around the key, but printing certainly seems the way to go for small batches of special chairs
 

S-Club-7

Western Thunderer
do you find the chairs sufficiently robust?

Whilst the acrylic used by Shapeways for their FD and FUD materials is quite brittle but I've only ever broken 2 chair jaws. One was on the first draft of the check-rail chairs (the keys were too big causing the chair to snap when the rail was inserted) and the other was the 6C chair which was stressed too far whilst trying to build the crossing. Once it's all put together then the chairs "all hold hands" so that the total strength seems to be greater than the sum of the individuals.

That, and some careful design to avoid sharp corners which are the bane of brittle materials. Cast iron chairs in particular are full of fillet radii for this very reason and a real pain to draw properly even if you do have all the dimensions!
 

28ten

Guv'nor
Having initially dismissed the idea i may well try separate keys. as you say its not about the strength of individual chairs rather the whole assembly.
 

7mmMick

Western Thunderer
Lovely work Dave, any chance of a quick run down of colours used on the rails and chairs and which stain you used on the sleepers ?

ATB Mick
 

S-Club-7

Western Thunderer
Questions have been asked; hopefully the following answers at least one of them. All paints, except one, are Phoenix Precision enamels (other colours are available).
  1. I started with the rails. This is a mix of P977 Rusty Rails and P991 Track Dirt roughly 2 to 1. If brushing then dip the brush into the open pots, dip the brush further into the rust than the dirt. If spraying (as I did) the neat paint is drawn up into some disposable syringes from whence small amounts can be measured into the airbrush cup ensuring that each mix is slightly different. White spirit is added from another syringe to taste.
  2. Chairs next. Also a mix of Rust and Dirt but this time the proportions are 1 to 2 as cast iron seems to colour differently to steel. See the notes above about rough mixing to obtain slightly different shades of the same colour. Try not to get too much on the rails but do ensure the sleepers are covered as well.
  3. Then the sleepers. P979 Weathered Sleepers diluted so that the brown colour shows through. Applied by brush.
  4. Followed by the keys. P961 Sleeper Grime with a dash of P991 Track Dirt applied by a fine brush.
  5. By now the chairs will be a multitude of different shades so they'll need touching up by brush with mix 2. Whilst you're at it do the fishplates and any other cast iron parts.
  6. Dry brush the sleepers with P990 Weathered Wood and the lighter P979 Weathered Sleepers. Some distressing with a small wire brush at various stages can also add a bit of variety.
  7. Dry brush the steel bits (e.g. bolt heads and nuts) with some of mix 1 just to highlight them.
  8. Some P978 Oil Leakings around the fishplates to represent the grease; not sure if it's quite the right colour without the addition of some dark grey (must remember next time).
  9. Ballast is then laid dry and tamped into position. Sorry, don't know the brand as the packet is unlabelled after at least 20 years under my workbench. Ash cess is by C&L. Another syringe to dispense the PVA and water mix (not forgetting a quick squeeze of the green Fairy). When dry, soak again with another helping of the glue mix.
  10. Add the greenery (Noch tufts; individual badger(?) hairs for the long grass; real Cornish moss and lichen for the scrub).
  11. At this point the track looked too dark so it was given a misting of diluted acrylic Lifecolor UA706 Dust Type 2 which sprayed too coarsely. Maybe a bit more air pressure next time.
  12. Finally, dribble some diluted P978 Oil Leakings along the centre of the track.
A week to build and a week to decorate -- but it's only 6 inches square. So the S7 Society's 33sq ft challenge should only take me a little over 5 years to complete...
 

Rob R

Western Thunderer
[quote/]
A week to build and a week to decorate -- but it's only 6 inches square. So the S7 Society's 33sq ft challenge should only take me a little over 5 years to complete...[/quote]

No where near as long as Lumpy Sidings so far then.............
 

Dog Star

Western Thunderer
No where near as long as Lumpy Sidings so far then.............

Hey - first post and not as a "New Member" topic... you will have the Flying Squad round in the morning. As soon as anyone reads your profile page we shall have another colour war, mind you, there are a couple of GER advocates here so you are not alone.

regards, Graham
 

Rob R

Western Thunderer
Hey - first post and not as a "New Member" topic... you will have the Flying Squad round in the morning. As soon as anyone reads your profile page we shall have another colour war, mind you, there are a couple of GER advocates here so you are not alone.

regards, Graham

Don't panic. It's just a bit of harmless(?) sibling banter.

I'll do a proper "hello" tomorrow when everyone is out of the house and I can concentrate on the important things in life.

TTFN
PS. The proper GER colour is GREEN

Rob
 
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