About Comments

Comments are enabled on all postings. Click a posting to find the comment box. Comments are moderated and appear after my review.

Friday, 19 April 2019

0 Gauge 16T Mineral Wagon

This time I opted for a Peco chassis R0-8 since it is designed for the 16T mineral wagon. The body is 3D designed and printed by me. The framing around the doors came out a bit ragged compared to crisp injection moulded parts. Nevertheless it adds to the worn weathered finish.

I am very pleased with the Peco chassis because it has sprung buffers and compensation. Both utilising innovative and simple mechanics with compensation provided by working leaf springs no less! Very impressive. It went together quickly but thought needed to be given to assembly of a couple of parts as the instructions were unclear to me and a referenced diagram was missing from them.

There are many variants of the prototype wagon. I opted for that built to diagram 1/108 - a welded body with double brake arrangement. This avoided the need to show rivets!

It may be of interest to elaborate on the paint finishes that I applied.

Chassis

Referring to prototype photographs of weathered wagons the underlying colour appears greyish, arguably with a touch of blue. I sprayed the entire chassis (not wheels) with Humbrol matte enamel 144 followed by sponge painting dabs of Humbrol matte 62 for rust here and there.

Body

The weathered look was achieved using the salt chipping technique. Here is a video tutorial. People use rock or table salt. I found table salt worked best for larger areas in particular.

The body was first sprayed overall using Halfords grey primer followed by brush painting Humbrol matte 100 with a splash of matte 160 to give an aged rust look. When dry, masking tape cut to the size of the white diagonal lines was applied. Each body side was then painted with clean water and salt sprinkled on in key areas where rust is to show, with reference to prototype photographs. Quite a deep patch of salt was applied to the large areas of rust. The body was then set aside to dry thoroughly overnight.

I am undecided what payload to fill the wagon with so, left the inside empty and a rust colour. When  I design the model railway layout the most likely mineral payload needed for the scene will be realised.

The wagon (and salt overlay) was sprayed with Humbrol 128 mixed with a large amount of matte white to lighten ('cos that's the only grey I had). When nearly dry the salt was brushed away with a toothbrush except it was hard to remove in places so, scraping gently with a small flat blade screw driver worked well. To my dismay the process had lightened  the dark rust colour,  either due to salt erosion of the paint or, leeching of the thinned grey spray paint. Thinking it was leeching grey paint I used thinners and gently rubbed the rust patches with cotton bud to no avail. Maybe it is not so bad considering it would appear lighter from normal viewing distance. Some miniscule salt particles are embedded in the grey paint here and there giving a nice textured finish.

The masking tape was removed and new tape laid either side of the white lines to be. The white lines were added by lightly sponge painting matte white.

Finally, wagon numbering was designed, printed and placed.

Cost 

Peco chassis: £16.56 (discounted RRP incl postage)
Peco wheel set: £8.03 (discounted RRP incl postage)
Plastic body: £0.3
Extras: pennies

Total: Less than £25

RTR from the trade then probably around £45 or in kit form £35.

References

Mineral Wagon Variety: The Model Railway Journal #54
Mineral Wagons: Railway Modeller November 1980.


Next up is a brake van.


Friday, 12 April 2019

0 Gauge 15T Ballast Wagon Hut Carrier

I have trodden the sad road to rivet counting, which I swore I would never entertain because life is too short!

This is my first attempt at scratch building 0 gauge wagons. What can be said about it is yes, greater attention to detail is required than for 00 gauge; I had to remind myself of this being used to 00 gauge modelling. In so doing there are small parts revealed in the analysis that are just as fiddly to create as in 00 gauge! Nevertheless, it has been a rewarding experience since it stretched my design and modelling skills and given insight to another aspect of historical railway practise and vehicles.

The Result (ignore the track. I have not invested in 0 gauge track yet)


Historical Facts

The hut carrying wagon is a SR 15T Ballast Wagon (Diagram 1773) with the drop side doors removed. A few of these converted wagons were deployed by the SR Exmouth Junction concrete works for the conveyance of huts. Most did not carry identification, apart from the number plate fixed to the solebar.

I did not have a drawing of 1773 but I did have a drawing of the steel plated door variant. This has the same overall dimensions and similar chassis. The main differences being buffer style, brake arrangement and four door stops instead of six. This together with several photos of 1773 on the web enabled me to design the wagon. The web photos were of aged wagons showing a distinctly grey weathered finish. I adopted same.

Design (also see modelling referemces at end of posting)

The wagon was deigned as a kit of parts in 3D CAD (FreeCad Application). The image shows the parts for the chassis. Other parts not shown are axlebox, buffer, brake mechanics, door stopper and hut cradle. The parts were 3D printed on my own printer

Buffers

Since my Terrier locomotive has sprung buffers I decided that the wagon would have them to.

The buffer shank is a panel pin and the spring is made of phosphor bronze wire netting from a wine bottle. I wound the wire around the nail to make the spring!

The photo shows the assembly. The buffer head is glued to the pin head. The buffer is glued to the wagon headstock. The shank passes through both and the travel limiter glued to the shank in a position that gives the outward travel required . The spring is placed over the shank and the container passed over this and glued to the rear of the headstock. The shank passes through the end of the container.

These photos show the operation. (top - closed, bottom - open)


Compensation 

Having gone to that effort I decided to include chassis compensation as well. This employs a cradle with a central rocker that gives 1 mm clearance between cradle and wagon floor. There is also 1mm gap between leaf springs and solebar. The rocker also serves to keep the wheels square to chassis. The central hole was only used for position alignment with the floor. (These macro photos reveal the roughness of the 3D print, Not noticeable at normal viewing distance.)

 Below: Normal alignment and compensating for obstruction.

The tie bar is flattened 0.5mm wire loosely held in the axle box frame to allow independent compensation of fore and aft wheels.

Rivets and Coupling

And so to rivet counting, or how to make them. I tried several "fluids' and found the acrylic matte medium gave the best result (yet another use for this versatile substance). Poke a cocktail stick into the medium to pick some up. Offer the stick vertically to the model and twist about half a turn,  lift off to leave a nice round deposit.

Each link of the 3-link coupling was made by wrapping 1mm wire several times around a rectangular bar and then cutting along the set with a razor saw. The coupling hook is a spare from a proprietary chassis kit (presented in next posting). 

I am not sure if I will get on with this authentic wagon coupling method and will need to devise a shunting pole for easy of manipulating the couplings. If that becomes too difficult/tedious I may install the Alex Jackson coupling method across all the rolling stock.

By the way, angle brackets less than 0.5mm thick, like those on the wooden end panel, were made up from thin card and after applying to the model, coated in cyanoacrylate glue to stiffen the pliable card.

Hut Cradle

There is speculation from an obscure photograph that cement bags were used to protect the corners of the concrete huts from the cradle compression. I choose 'Blue Circle' bags and applied the logo that was in use before 1967.
Cost

I suppose I should talk about the cost to make the wagon since 0 gauge proprietary products are notoriously expensive.


Plastic: £0.62
Peco wheel set: £8.03 (discounted RRP)
Extras: pennies

Total: Less than £9.

If such an 0 gauge wagon was available RTR from the trade then probably around £50 or in kit form £35.

What I have not accounted for is the hours and hours gone into the design and build of my model and the overhead costs. Perhaps that can be negated by the pleasure derived from the hobby.

Mistakes

The width of the wagon is about 1.5mm too wide because I used the dimension from the outside of the (unfitted) side doors instead of the inside.

The brake lever is partially on instead of fully off for a moving vehicle.

References

Concrete PW Huts: The Model Railway Journal #62
Non Hoppered Steel Ballast Wagons: Model Railway Constructor, December 1984
Compensation for 0 Gauge Wagons: Railway Modeller: June 1984
Paul Bartlett's Photographs.

Postscript

When I get around to a making a model railway layout I have a vision of some prepared ground with a couple of workers peering into the distance awaiting  arrival of the huts. And when they do arrive they will still be peering into the distance awaiting arrival of a travelling crane to lift and position the huts, which may never arrive!

Next up is a Mineral Wagon.

Friday, 5 April 2019

0 Gauge BR(S) Lineside Huts

The first wagon I want to make is a 15T ballast wagon with the drop sides removed as this was used by BR to transport its concrete permanent way and tool huts from their concrete works at Exmouth Junction to all parts of the Souther Region network.

Whilst waiting for some parts to arrive for the wagon I set about designing and building the huts. These were designed in CAD and 3D printed on my own printer. Each hut consists of three parts, these being the main body shell, roof and door.

The PW hut was fitted with window blinds and the chimney placed inside during transportation. Being ex works the finish is pristine. My best guess at the concrete colour is a greyish white, judging from the monochrome photos I have seen.

The 3D print reveals the vertical layers of plastic resulting from the process. These were smoothed to some degree with sand paper for large areas and smaller areas given a coating of acrylic matte medium, which has a gel like consistency. Any imperfections left in the plastic has enhanced the concrete look. The hut is spray painted with Halfords Primer and artist acrylic top coat sponged on, which gives better control than a brush to allow a little of the grey primer to show through (did not want the setup/cleanup time and mess of an air brush). The acrylic top coat was mixed 50:50 with the matte medium to reduce gloss. (Matte medium is proving very versatile and can even be used as a paper glue.)

The plastic model wagon will need some weighty ballast for stability. Rather than weight the wagon I have glued into each hut floor a 1 mm steel sheet. The two huts together weigh 140gms, which I hope will be adequate ballast for the wagon.

The photo shows a 00 gauge hut alongside for scale comparison.
Related Posts Plugin for WordPress, Blogger...