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Bit of weathering done & loads added to the flat wagons. Few more details & we should be there. I kinda figured that the loco would not last too long in works

And now for something Completely Different   Been busy with other projects! Another hobby of mine is cabinetry, and I decided to marry the two hobbies together.   I find during the wint

Now that I have a practically complete cabinet to work with, I decided to finish off the mineral wagons.   The previous buffers were too long for the model, so I got some others from Dart Ca

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Posted November 25 2018

A little teaser for the next loco on the bench

Hello Ken,

I have just come across your posts and I have another possible answer to your teaser.

Sometime in the early 1950s, I was travelling from Dublin to Bray.    Somewhere along the way I looked out the window of the carriage to see what engine was pulling us.   I saw the side tanks, cab and bunker and it seemed to be one of the 0-6-2T 670 class tank engines.    When we reached Bray,  imagine my surprise and joy when I saw a tank engine with outside cylinders.    It was 850  the  2-6-2T  tank engine.    It was the only engine with outside cylinders I ever saw in Bray.     It was built in 1928 and was said to have parts of the unbuilt Woolwich  2-6-0.   The side tanks, cab and bunker, even the hand rails, seem to be almost identical to those on the 670s.  So if you have these stored on your computer, and if you can get a Woolwich frame and motion,  a pony truck and a boiler,   you could have another model of an engine running on the  DSER.

Great Work.

DSERetc

 

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Some minor tweaks to the 3D model to Rev 4 to include changes to the lower straps on the uprights to more prototypical detail.  Also the holes for the bars were opened up to ease the installation of same.

30026484_CattleWagon-Rev4.1.thumb.jpg.f31ff6596442d985e7466f5f68e3410b.jpg

 

And the advantage of printers is the ability to gerenate a train quickly.

1242774733_CattleWagon-Rev4.2.thumb.jpg.d5ca6ceb9d90cf4c7b4eba08d7faf0b4.jpg

 

I'm planning to use brass compensated chassis for these, so there is still some work to do, but not having to do all the uprights and rivet detail on the bodies is quite a relief.  Will need to add weight to the wagons bring them up to the weight of the other wagons already made.

Very pleased with the results & quality of the print.

 

 

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23 minutes ago, popeye said:

Could the underframe not be printed too?

Thanks for the comment.

 

For OO gauge, it would be possible, however to provide enough strength the thickness of resin would make printing for 21mm difficult, but not impossible.  The overall wagon width at the axle location is c. 30 - 31mm whilst the pinpoint axle dimension is 28mm, so it would be rather close.  I am a fan of the detail in the brass underframes with cast axleboxes and springs, so made sense for me.

Most of my wagons are compensated as I am working to P4 standards, with the exception being the very short DW&WR ballast wagons which have a 6' wheel base.

I would consider an underframe print for an OO version if there was an interest.

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The wagons look great, Ken. How long does each one take to print? Not sure it would be practical to resin cast sides and ends for open structures like these, so certainly the way to go. However, just for comparison, a set of resin castings for a van take about 30-40 minutes to set, with about another half hour to assemble into a box, so am wondering if I need to consider changing to 3D printing any time soon?

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We have successfully printed wagons chassis suitable for OO & 21mm gauge, though a rigid brass or compensated chassis with metal detail castings is likely to be a better option using S4 or EMF wheel standards. A brass chassis is likely to be freer running and more dimensionally stable than a 3D printed chassis.

The main risk in printing a chassis is part breakage as many of the SLA resins are very brittle, particularly in cold weather.

We originally considered resin casting for production version of the CIE Brake Van but settled on 3D printing as we were unable to find a business with vacuum resin casting capability as small scale manufacture has moved on to 3D printing.

We overcome the brittleness problem for wagon chassis by using a resin with ABS properties and have printed the IRCH wagon chassis in one piece complete with brake gear, door springs and hopper operating gear something that would be extremely difficult to achieve using resin casting or plastic injection molding.

I use a freelance designer with experience in 3D printing, local and Chinese 3D printing bureau as it would have taken a long time to develop adequate 3D modelling skills to design and print a 3D wagon and could not justify the expense (at this stage) of buying a SLA printer capable of volume production.

The challenge from my perspective was finding a designer and a printing house prepared to push the boundaries on what could be achieved using 3D printing.

1178853043_IRCHwagonchassis.png.b4549a0003d668bb661ccc69580f24c5.png1804756089_GrainwagonChassis.png.05e60592614a35bbd83476a837f6f566.png

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16 hours ago, popeye said:

Would you consider printing the wagon bodies

Pop,

Up to now, I had not considered printing as a venture, but if people are interested in the body only, they would be immediately available for order.  I would need to think of a price - something reasonable naturally.  The cost is not in the physical printing, but in the origainal design and development.

 

7 hours ago, David Holman said:

How long does each one take to print?

David,

If one were to print a single unit at a time it takes 3 hours, but my build plate can take up to 5 wagons at a time - the time is not per unit but the build height, irrespective of the amount of material on the plate (resin SLA printing).  Thus I can print 5 bodies in three hours.

As mentioned above, the time is not in the printing, and as John attested above, the time is in the design of the model and running of test prints to establish a final design.  What looks good in 3D CAD, even if it is to exact scale, does not always translate to a reasonable looking model.  Some tweaks are needed to provide a reasonable looking model whilst maintaining strength.

 

6 hours ago, Mayner said:

a rigid brass or compensated chassis with metal detail castings is likely to be a better option

John,

Agreed.  It did not even occur to me to print a chassis for this model for P4.  

I am very interested in your comments regarding the ABS type of resin; so far I have used three types of resin, a translucent green as seen on other posts which provides very detailed models, but is very brittle.  The standard resin (Anycubic grey) proved to be less brittle but detail was not as good.  The problem with both those resins was the need to use IPA (Isopropyl Alcohol, not India Pale Ale) to clean up, which really is a pain to use and then clean afterwards.  The models above were printed with the Elgoo Mars water washable resin, which I have found to have good physical properties whilst holding detail - the ability to clean up with water makes the process much eaiser.

The detail on your chassis is excellent - I assume these are gauged for OO?

I may look at developing a simple OO chassis for these (and others) which will be suitable for the short wheel base of earlier Irish wagons.

 

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Given the success of the cattle wagon, I had drawings from HMRS for the DWWR Convertible wagon, which was quite easy to translate to CAD (particuarly for a model build).  With the experience and methodology used for the cattle wagon, it was possible to develop a basic model in 3D for one of these wagons.

15438558_DSERConvertibleWagon-3DRev1.thumb.jpg.5c2fc9ebf5cb0e80350b9f225ab3a6a3.jpg

 

Again run through the printer we get:

405207192_Convertible1.thumb.jpg.596b38ea6c96bb79dadf432b8482221d.jpg

1395097710_Covertible2.thumb.jpg.f878ecf7252a94903ea069cbc2c047f4.jpg

 

There is a some tidying up needed on these models.  The model is supported on the build plate by an network of thin supports (see below) - this is to ensure that each layer, particulary new layers are lifted of the base film without distorting.  These supports leave very small marks that need cleaning up before the model can progress.

74014268_CattleWagonfromPrinter.thumb.jpg.1231ec2110197e25d944dc3163986d55.jpg

 

Anyway, on to building chassis for these wagons.  Should keep me busy for a while!!

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Little bit of progress.  Wagon lightly sandblasted prior to a dusting of paint to get a feel for how the detail will work.  Coming up rather nicely.

672416883_CattleWagon-progress1.thumb.jpg.f4fc78226db377e3f79546fb52711b32.jpg

888429813_CattleWagoninrake.thumb.jpg.0c034f8f60639646d06acd5630e73823.jpg

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5 minutes ago, KMCE said:

Little bit of progress.  Wagon lightly sandblasted prior to a dusting of paint to get a feel for how the detail will work.  Coming up rather nicely.

672416883_CattleWagon-progress1.thumb.jpg.f4fc78226db377e3f79546fb52711b32.jpg

888429813_CattleWagoninrake.thumb.jpg.0c034f8f60639646d06acd5630e73823.jpg

The shortie (13-14')

 

7 hours ago, KMCE said:

Given the success of the cattle wagon, I had drawings from HMRS for the DWWR Convertible wagon, which was quite easy to translate to CAD (particuarly for a model build).  With the experience and methodology used for the cattle wagon, it was possible to develop a basic model in 3D for one of these wagons.

15438558_DSERConvertibleWagon-3DRev1.thumb.jpg.5c2fc9ebf5cb0e80350b9f225ab3a6a3.jpg

 

Again run through the printer we get:

405207192_Convertible1.thumb.jpg.596b38ea6c96bb79dadf432b8482221d.jpg

1395097710_Covertible2.thumb.jpg.f878ecf7252a94903ea069cbc2c047f4.jpg

 

There is a some tidying up needed on these models.  The model is supported on the build plate by an network of thin supports (see below) - this is to ensure that each layer, particulary new layers are lifted of the base film without distorting.  These supports leave very small marks that need cleaning up before the model can progress.

74014268_CattleWagonfromPrinter.thumb.jpg.1231ec2110197e25d944dc3163986d55.jpg

 

Anyway, on to building chassis for these wagons.  Should keep me busy for a while!!

Cleaning up removing un-cured resin and the supporting structure is very labour intensive and a significant cost in SLA printing. 

The business that I use for prototyping was very reluctant to take on volume production due to the risk of a slender part being knocked over during the "build" and loosing a nights production.

Both my suppliers use isopropyl for clean up, one uses a converted car painters mixing room with mechanical ventilation and intrinsically safe electrics for the clean up process.

Some models are printed vertically or at an angle to improve strength and improve finish by reducing the layering effect and the cleaning up to one face.

The wagon chassis were designed for 21mm gauge wheelsets, the brakevan steps were printed integral with the chassis to reinforce the w iron axlebox spring assembly, while we increased the thickness of the W irons on the IRCH wagon chassis. 

We learned a lot about the capabilities and limitations of the 3D printing process during the design of the Brake Van originally designed as a pattern for resin casting with a lot of individual parts, it went through several iterations before we arrived at the final design once it was established that resin casting was not a practical proposition, by contrast apart from missing some of the rivet detail we got it right first time with the IRCH open wagon.

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