Monday, 31 December 2018

Marbelup Models Home Page

High quality 3D-printed models of Western Australian trains in Sn3½ Scale (mostly) and HO Scale.

Due to ongoing quality issues with 3D prints from i.Materialise in Belgium, Marbelup Models is not accepting any new orders for 3D-printed models, for a while at least.  In general, small parts like bogies are printing very nicely, but some larger models are causing problems.  i.Materialise claim the problem is inherent with their Standard Resin material which was introduced about a year ago, although most early prints were very good.  Some prints are still very good, but the quality is quite variable.

New: Westrail DB Loco Project.


For information about pricing and availability of any of these models, please send email to marbelupmodels@iinet.net.au

Wednesday, 31 October 2018

Marbelup Models - Available for Immediate Purchase

The following models are available from stock for immediate purchase:

  • Sold - 4 x WW Standard Gauge Wheat Wagons (HO Scale)... $80 each.
  • Sold - 6 x WO Standard Gauge Iron Ore Wagons (HO Scale)... $40 ea., $35 ea. for 5 or more.
  • Sold - 1 x WF/WFDY Standard Gauge Flat Wagon (HO Scale)... $55 each
  • Sold - 1 x WFW Standard Gauge Flat Wagon for Iron Ore Containers (HO)... $55 each
  • Sold - 3 x Iron Ore Containers for WFW (HO Scale)... $55 per set of 3.
  • Sold - 1 x AGWY Standard Gauge Wheat Wagons (HO Scale)... $75 each.  
  • Sold - 1 x WBC Standard Gauge Brake Vans (HO Scale) ... $90 each plus 3D printed bogies... $30 per pair (bearings included, wheels not included) 
  • 1 x CXB Sheep Wagon... $95 (sheep also available).  
  • 1 x SXT Bogie Sheep Wagon... $195 each (sheep also available).
  • Sold - 1 x FD Louvre Van... $75
  • Sold - 1 x DC Van (no diagonal braces)... $85 each
  • Sold - 1 x DC Van (flat diagonal braces)... $85 each
  • 1 x VG bogie louvre van... $110.  More available to order.
  • Roofwalks only for DC Van... $30 for 5, or $15 for 2. 
  • Sold - 1 x WMD Hopper Wagon... $85 plus 3D printed bogies... $30 per pair (bearings included, wheels not included)
  • 5 x WAGR Water Columns, extended version: $15 each.
Note:  This section will be updated when items are sold or new items become available, so check in from time to time to see what is available.  Any other item from the Marbelup Models catalogue is available to order in approx. 2-4 weeks.


Friday, 9 February 2018

DB Loco Assembly Tips

Please Note - This is a "preliminary" version and subject to change during construction and testing of the development models.

Parts List (Preliminary - subject to change)


In addition to the 3D printed parts, the following parts must be obtained separately by the modeller:
  • Brass wire for handrails, etc. (0.4 mm, 0.6 mm - 3 x 300 mm lengths)
  • Air hoses - e.g. Detail Associates #6206 - 12 required.  (Vacuum brake hoses are included.)
  • Handrail Knobs (4) for uncoupling levers - e.g. Markits 1.5 mm (short) - available from Railwest Models.
  • Handrail Stanchions (optional) - A-Line D1070 or D1071.  Limited quantities available from Marbelup Models.
  • Vi-Trains Class 47 mechanism.  Limited quantities available from Marbelup Models,
    OR
  • Hollywood Foundry mechanism, with NorthYard Wheels and Mashima 1833D motor - see below for details.
  • DCC decoder and speaker (both optional)
  • Light Emitting Diodes (LEDs) for headlights 4 x 3 mm (sunny white) and optic fibre (2 mm)
  • LEDs (red and white) and optic fibre, if operating marker lights desired
  • lead or other weighting material
  • Kadee couplers #146 for scale coupler height,  #149 for HO coupler height (see below)
  • Kadee draft gear boxes #262 (supplied)
  • Fixing screws for body, couplers and fuel tank:
    2-56 x 19 mm, 4 required for central body fixing screws
    2-56 x 6 mm, 8 required, for remaining body fixing screws and couplers.
    2-56 x 12 mm, 2 required for fuel tank.
    Kadee #256 nylon screws can be used for the fuel tank, couplers and end body fixing screws.
  • Fixing screws for motor (ViTrains mechanism only) 2-56 x 25 mm (1"), 4 required - to be trimmed to required length.
  • Fixing screws for speaker M1.4 x 6 (slightly longer is OK) - 4 holes are included correct size (1.1 mm) and screws should make their own thread, tapping shouldn't be required.  Suitable screws are available from DCC Concepts - Part No. DCS-PHB156 or in assortment DCS-PHBSet.  Although described as 1.5 mm, the DCC Concepts screws are actually M1.4 thread.
  • Fixing screws for bogie sideframes - self tappers, 1 mm dia. x 3 mm long (8 required).  Suitable screws are available from DCC Concepts - Part No. DCS-PH103
  • Fixing screws for nose - self tappers, 1 mm dia. x 5 mm long (2 required).  Suitable screws are available from DCC Concepts - Part No. DCS-PH105
  • Paint and decals, as desired.

Underframe Preparation


Remove the support structure from the 3D-printed underframe.  Take particular care around areas with delicate detail, including the vacuum hoses and ... (details to be added).

Clean out the indicated holes with a 1.8 mm drill bit and tap with 2-56 thread.  Note that the four holes closest to the motor cutout are for the ViTrains mechanism only.  If desired, the coupler mounting holes can be drilled right through as the top surface of the underframe will be hidden by the loco body.

Underframe Holes to be Tapped 2-56 (viewed from below)
If intending to fit couplers at HO height, file out 1 mm from the bottom of the coupler mounting holes, as per diagram below.  The headstock is only 0.5 mm thick in this region.  Up to 1.25 mm can be removed, if required, to accommodate fine adjustment of coupler height.

Headstock Modification for HO Coupler Height

Bogies and Drive Train


There are two mechanism options: Hollywood Foundry and ViTrains.  The DB loco underframe is specific to each mechanism, so the choice of mechanism must be made at the time of ordering.

See comparison of the mechanism options.

Please refer to the separate assembly tips for:

Couplers


The coupler height of the DB loco has been set at the correct scale height for WAGR/Westrail narrow gauge rollingstock, i.e. 12.2 mm (above rail height) rather than the HO coupler height (9.9 mm) which is commonly used for most Sn3½ models.  This has been done because the correct height "looks better" for modern locos and rollingstock.  For correct scale coupler height, use Kadee #146 couplers.  

Provision has been made in the underframe design to lower the couplers to match the HO coupler height by using Kadee #149 couplers which have an "overset" shank together with a spacer approx. 1 mm thick between the coupler box and mounting pad.  The bottom of the coupler openings in the headstocks is only 0.5 mm thick, and this thin section needs to be filed 1 mm deeper to allow for the lower coupler mounting height.

The #146 and #149 couplers are both "long shank" style which avoids the problem of the "glad hand" on opposing couplers from fouling the cowcatcher.  The suggested draft gear boxes are Kadee #262 (supplied).  Kadee suggest assembling the coupler so that the main part of the draft gear box is on the bottom and the lid is on top.  The draft gear boxes simply snap together.  

Due to the length of the DB loco and long end overhang, coupling of 4-wheel wagons next to the loco is not recommended on curves of 850 mm radius or less.  The loco itself will operate on curves of 700 mm radius, or slightly less, but the coupler overhang is probably the limiting factor.


Underframe Details

There are four large air pipes to be added to the air reservoirs on the underframe, as highlighted in yellow below.

Underframe Air Piping (viewed from below).
These can be formed from 0.8 mm brass wire, and glued into the holes provided in the air reservoirs and underframe.  

Approx. dimensions for the L-shaped pipes are as follows:
  • Front left: 5 mm + 8.5 mm
  • Front right: 13 mm + 8.5 mm
  • Rear left and right: 34 mm + 8.5 mm.
Note that the front right pipe should have a gentle upwards bend, about midway along the longer part, to match the height of the hold in the underframe.

DCC and Sound


The underframe is specially designed to accept a 23 mm square high-bass speaker (Soundtraxx 810129 or equivalent) if a sound decoder is to be installed.  The speaker faces downwards on a "sound duct" which has a "tunnel" through it for the front drive shaft.  

The underframe speaker mount include four holes, nominally 1.1 mm diameter, which are suitable for M1.4 fixing screws, 6-8 mm long.  Ideally, the holes should be tapped with a M1.4 thread, but the screws can be inserted without tapping.  (DCC Concepts sell suitable screws - part number DCS-NB14x6 or as part of an assortment DCS-Nbset.)

The recommended sound decoder is the Soundtraxx Tsunami EMD 645 Non-Turbo.  The Tsunami "AT" style decoder model 828048 is suitable and slightly cheaper than the TSU-1000 style model 827109.  More recent equivalents are also available in the Soundtraxx Econami and Tsunami 2 ranges.

Note: The above links are for the SoundTraxx web site.  SoundTraxx do not sell direct but their products are available from many retailers.


Body Preparation and Details


Take care when removing the support structure from the body, especially around the cab windows to avoid damaging the vertical dividers between the windows.  

Once the body has been "cleaned up", it is also necessary to remove the two temporary braces which link the fixing posts near the centre of the body, as highlighted in yellow below, as well as another one just behind the cab.  These have been included to protect the body during production and shipping, and must be cut away to provide clearance for the motor, etc.  These can be cut with a fine-toothed razor saw or a cutting disk in a rotary tool, at low speed.  

The ten fixing holes in the body shell and nose should be tapped with a 2-56 thread.  If necessary, clean out the holes prior to tapping using a 1.8 mm drill bit.


Nose Assembly

The nose is a separate 3D-printed part.  This has been done to avoid stepping on the sloping top surface of the nose from the 3D printing process.  Once the supports have been removed from the nose, a light sanding may be required on the bottom surface to remove the slight stepping present there.

Small holes have been provided to secure the nose to the cab with small screws, e.g. 1 mm dia. x 5 mm long.  The screws should be inserted from inside the cab, into the nose.  The holes are angled so there is some hope of reaching them with a small screwdriver.

Once satisfied with the fit of the nose, it can be superglued onto the cab, preferably from the inside to avoid traces of glue on the visible surfaces.


Handrails on Body


Starter holes are provided on the body for three handrails which can be formed from brass wire (e.g. 0.3 or 0.4 mm).  The starter holes should be drilled out slightly larger, e.g 0.05 mm larger than the wire size.

One handrail is inside the topmost recessed step on the left side of the loco, next to the radiator grilles.  The spacing between the holes is 3.5 mm (centre-to-centre).

Photo by G Stallard
The other two handrails are on the roof, adjacent to the recessed steps.  The spacing between the holes is 8.5 mm.  Photos indicated that the bends in the top handrails should have a radius of approx. 1.5 mm.  Radiussed corners can be formed by bending the wire around the shank of a drill bit, or using special pliers with round jaws made for wire forming.

Photo by G Stallard
Starter holes are also provided on the sides of the long hood for the handrails for the rear steps, and on the nose for the front handrails. - see below.

Handrails on Cab Front


Two handrails either side of central window:
  • Right side: 7.5 mm between hole centres
  • Left side: 7.5 mm + 12 mm between hole centres, with 65 degree bend between straight segments to match slope on nose.

Handrails on Top of Nose

  • Left side, on top step notch: 4 mm between hole centres
  • Left side, on sloping section: 8.75 mm between hole centres
  • Right side, on sloping section: 11 mm between hole centres*
* Front hole for this handrail is missing from some nose prints, but can be easily be marked and drilled.

Handrails on Front of Nose

See diagram below for the handrail shapes.  DB1581-1584 had straight handrails.  1585 originally had unique "curly" handrails but the hole positions are the same as for the straight ones, and it was later fitted with straight ones.  1586-1593 had angled handrails.

Handrails on Underframe


The 3D-printed chassis incorporates holes approx. 0.6 mm diameter to house the vertical handrail posts, typically cut from 0.6 mm brass wire.  There are also starter holes on the rear steps, and on the headstocks, for the end handrails.

One option for the long handrails is to solder each section of handrails from 0.6 mm brass wire.  Marbelup Models has developed a PDF template for the handrails which can be downloaded and printed.  Ensure it is printed at 100% size - check the scale on the bottom of the template to ensure the scaling is correct.
Handrail Diagram - Download PDF for Accurate Dimensions

Handrail Diagram (PDF)

On the real locos, the rear handrails and the rear end of the long side handrails have 2 fixing points near the rear steps.  Holes been provided in the underframe for the additional fixing points, if desired, which would entail soldering additional short lengths of wire to the respective handrails.  The vertical spacing between the upper and lower fixing points is 8 mm.

Use of A-Line Handrail Stanchions


An alternative, which is potentially easier than soldering, is to use preformed steel handrail stanchions available from A-Line (Division of Proto-Power West, USA).  These are available from various online hobby shops and/or eBay.  (Marbelup Models has limited stocks of these stanchions available at $15 per pack of 35 stanchions.  Each loco requires 16 stanchions.)

A-Line Handrail Stanchions
Although these stanchions are intended for HO locos, the two longest sizes are sufficiently long to be trimmed to the correct length for the DB .  The A-line part numbers are D1070 (extra long) and D1071 (long).  The stanchions should be trimmed at the bottom.  After trimming, file off any rough edges from the cut end.  

The number and lengths of stanchions required are as follows:

  • 21 mm long, 8 required - left side
  • 18.5 mm long, 7 required - right side
  • 16.75 mm long, 1 required - right side, rearmost stanchion.
Note that the length should be measured from the top of the "loop".  When installed, the bottom of each stanchion should be flush with the bottom of the running boards.

The holes in the 3D-printed chassis should be carefully drilled out to accommodate the stanchions (suggested drill size: 0.75 mm  - test on some scrap plastic first).  

After preforming the long handrails as per the PDF template, test fit each handrail without stanchions.  Once satisfied with the fit, remove each handrail and thread on the 8 stanchions.  It is suggested to orient all stanchions the same way, e.g. with the open side of the top loop inwards.  For the right side handrail, ensure the single, short stanchion is at the rear.

Carefully insert each stanchion vertically into the drilled holes.    It is probably best to insert the stanchions part way initially, then go along and press them down to the full depth, and also insert the ends of the handrails into the holes in the underframe.  Make sure the bottom of each stanchion is level with the underside of the running boards.

Once all the stanchions are in place and the long handrails threaded through, check that all the stanchions are vertical and make any necessary adjustments.  Then, the stanchions can be glued into the holes in the running boards and the handrails glued into the holes in the underframe.  It is optional whether to glue the handrails where they pass through the loops in the stanchions.

Separately form the U-shaped handrails on the side, and the end handrails from 0.6 mm wire, as per the template.  Install and glue the U-shaped handrails into the underframe.

Temporarily fit the loco body to the underframe in order to test fit the end handrails, the top ends of which locate into holes in the loco body.  Only glue the bottom end of the end handrails, to allow for future removal of the body.  It is suggested that the top end of the handrails should protrude approx. 1 mm into the body, to allow them to be sprung out slightly when the body is removed.


Horns



Four horns are included as part of the 3D-printed underframe.  Carefully remove them from the underframe, leaving the spigots attached to the horns intact as much as possible.  Only two are required, with two spares.

(Alternate horns can be source from detail parts suppliers e.g. in brass, if greater robustness is desired.)

Starter holes are provided for the horns on the front wall of the cab (right side) and on the left side of the long hood, just behind the vestibule door.  Consult photos appropriate to the era being modelled to determine correct horn placement.

Drill out the starter holes to suit the diameter of the spigot on the back end of the horns.  Carefully trim the unwanted spigot (projecting sideways or lengthways) from the horns.

Headlights


The holes provided in the body shell for headlights are nominally 1.8 mm diameter, but typically slightly undersize due to the 3D printing process.  The headlights should be 2 mm in diameter, so drill the holes out to 2 mm taking care not damage the thin surround around the hole.

(The holes are deliberately undersize because the thin surround would not print otherwise, as the minimum detail thickness is 0.5 mm. and the outside diameter of the surround is 2.8 mm.)

One method of lighting the headlights is to use a short length of optic fibre together with a 3 mm LED (Light Emitting Diode).

The DB locos had "sealed beam" headlights for which "sunny white" LEDs are a suitable approximation.  (Many older locos had larger diameter headlights with replaceable bulbs which tended to have a more yellow appearance, similar to "golden yellow" LEDs.)

Note: Incandescent (filament) lamps are not recommended due to their high operating temperature which may damage the 3D print material.

To attach the LED to the optic fibre, 3 mm black heatshink tubing is recommended.  With the use of a hot air gun, the heatshrink tubing will shrink to form a snug fit over the optic fibre.  However, the hot air may well be hot enough to melt the plastic optic fibre, so the trick is to shrink the tubing over the shank of a 2 mm drill bit, them slide the drill bit out and slide in the optic fibre.

Typical steps are:

  1. Cut heatshrink tubing to length, e.g. 8-10 mm.
  2. Hold 3 mm LED in a small vice by its legs, with the clear lens uppermost.
  3. Push the cut length of heatshrink tubing over the clear lens of the LED.
  4. Hold the shank of a 2 mm drill bit inside the heatshrink tubing while applying heat from a hot air gun.
  5. When it has cooled, withdraw the drill bit and insert the desired length of optic fibre.  For the rear of the loco, you will probably have to feed the non-flared end of the optic fibre through the curved hole provided (from the outside) and attached the LED with attached heatshrink tubing on the inside.
CAUTION: Do not used the hot air gun or other heat source to shrink the heatshrink tubing in close proximity to the loco body or other 3D printed parts as they may distort due to the heat.

For the dual headlights, it is simplest to wire the two LED in series as this reduces the wiring and avoids the need for two separate resistors.  A resistor of around 2K2 (2,200 ohms) is a suggested starting point for LEDs powered from DCC decoders.

Marker lights can also be drilled out and illuminated if desired.



Marbelup Models DB Loco Kit Project

Photo of completed model, built by Chris Andrews
The Marbelup Models project to produce a 3D-printed "kit" of the Westrail DB diesel locomotive in Sn3½* scale is complete! The 3D design is done and parts for several locos have been received and delivered to customers, with only a few ordered models still to be delivered.

Photo of Test Model

Basically, the "kit" consists of 3D-printed parts for loco body, underframe, fuel tank and bogie sideframes,   The general construction is similar to the Marbelup Models D and DA locos.

The model represents the DB in "as delivered" form.  As is common, some changes were made over the working life of the locos.  The most significant change is to the steps.  The steps at the ends were built out so as to be vertical, rather than inset on the original loco (to clear platforms).  Also the side steps behind the cab, which were originally attached to the front bogie, were replaced with longer steps hanging down from the underframe.

The "kit" cost is about $410 per loco.  This is a bit more than initially estimated, partly due to the fact that the DB is a large loco.  Also, i.Materialise have removed the discount for ordering multiple parts, which adds a bit to the cost of the smaller parts (bogies, fuel tank, etc.). (Actual cost subject to variation due to exchange rate variations against the Euro and/or prices increases in 3D printing.  Current pricing is based on AU$1.00 = 0.666 Euro.)

Due to ongoing quality issues with 3D prints from i.Materialise in Belgium, Marbelup Models is not accepting any new orders for 3D-printed models, for a while at least.  In general, small parts like bogies are printing very nicely, but some larger models are causing problems.  i.Materialise claim the problem is inherent with their Standard Resin material which was introduced about a year ago, although most early prints were very good.  Some prints are still very good, but the quality is quite variable.

Note that the majority of the 3D-printed parts will be printed in "Standard Resin" by i.Materialise.  Standard resin is a relatively new material and is translucent with a yellow tint.  The "Prime Gray" material, used for most previous Marbelup Models items, is still available but is about 30% more expensive than previously.  Initial indications are that the print quality of Standard Resin is equal to or better than Prime Gray, and the material specification indicate that it is stronger and less brittle.

To complete the loco, the purchaser must also source a mechanism as well as some detail parts, screws, couplers, DCC decoder (if required), paint, decals, etc.  Assembly instructions are available online.

There are two options for the mechanism.  One is the "inline" drive bogies available from Hollywood Foundry, as have been used for the D and DA locos.  One or both bogies can be powered, depending on the modeller's preference.  Note that Hollywood Foundry are not accepting new orders as of early 2018 for an indeterminate time.

The second option is to use the motor and drive bogies from a ViTrains UK Class 47 loco.  The Vitrains motor is fitted with flywheels and the assembled mechanism is smooth and quiet.  The drive is to the outer 4 wheels of each bogie, the centre, free-rolling axles being lightly sprung.

See Summary of Mechanism Options for more information.

Marbelup Models has purchased several ViTrains locos from the UK.  These are available for purchase as a "donor" mechanism at a cost of $140 each.  This compares favourably with the Hollywood Foundry mechanisms which cost around $200 for single bogie drive and $250 for double bogie drive (including cost of NorthYard wheels.)

The 3D-printed underframe is available in two versions, to suit either the ViTrains or Hollywood Foundry mechanism.  The different mechanisms are not interchangeable.  The 3D-printed bogie sideframes are also specific to each mechanism.

The coupler height of the DB loco has been set at the correct scale height for WAGR/Westrail narrow gauge rollingstock, i.e. 12.2 mm (above rail height) rather than the HO coupler height (9.9 mm) which is commonly used for most Sn3½ models.  This has been done because the correct height "looks better" for modern locos and rollingstock.  Provision has been made in the underframe design to lower the couplers to match the HO coupler height by using Kadee #149 couplers which have an "overset" shank together with a spacer approx. 1 mm thick between the coupler box and mounting pad.

Some modellers have paid a $100 deposit as per the initial invite for "expressions of interest" published in May 2016.  Those who have paid a deposit will take priority as the kits become available.  Deposits refundable only if Marbelup Models unable to deliver, for any reason, 2 years from commencement, that is by end of June 2018..

Please note that complete ready to run locos will not be available from Marbelup Models, although it is possible that "third parties" may offer an assembly and/or painting service at additional cost.

* The DB loco kits proposed in HO and HOn3½ scale will not be produced at this stage, due to lack of paid deposits from HO modellers.  The idea of producing kits in HO scale may be revived at some time in the future but only if there is strong interest.


Saturday, 13 January 2018

Latest News

Due to ongoing quality issues with 3D prints from i.Materialise in Belgium, Marbelup Models is not accepting any new orders for 3D-printed models, for a while at least.  In general, small parts like bogies are printing very nicely, but some larger models are causing problems.  i.Materialise claim the problem is inherent with their Standard Resin material which was introduced about a year ago, although most early prints were very good.  Some prints are still very good, but the quality is quite variable.

3-May-2016 - Westrail DB Loco Project added.
28-Mar-2016 - Links updated to the WA Wagon Pages which have been relocated recently.  Please let me know if you find any links which do not work.
12-Feb-2016 - Most prices for 3D-printed items have gone up by approx. 10-15% due to a change in shipping charges from i.Materialise.
01-Jan-2016 - Added Clerestory Roof Z Vans
21-Nov-2015 - WBC Brake Vans added to Models Available for Immediate Purchase.
17-Nov-2015 - Added BHP Iron Ore Cars (4 types)
15-Nov-2015 - Added WW (AGWY/AGSY) Wheat Wagon.
14-Oct-2015 - Added instructions for WBC Guards Van.
1-Oct-2015 - Added WW Grain Hopper to What's in The Works page.
15-Sep-2015 - Added WAGR WBC Guards Van in HO scale.  New page added "What's in The Works?".
4-Sep-2015 - Added Instructions for WAGR WSH/XM ballast hoppers in Sn3½ and HO scale.
29-Jul-2015 - Added WAGR WSH/XM ballast hoppers in Sn3½ and HO scale.  Updated the WAGR WF/WFW/WFDY page to include photos of the painted models and add Assembly Tips.  Customer photo gallery updated with another photo of Simon Chandler's Tasmanian wagons.
9-Jul-2015 - Added WAGR WF/WFW/WFDY flat wagon in HO scale and iron ore containers.  Customer photo gallery updated with Simon Chandler's Tasmanian wagons.
24-Apr-2015 - Added WAGR WOB iron ore wagon in HO scale.
2-Feb-2015 - Set of parts for DA1576 Loco added to Models Available for Immediate Purchase.
29-Jan-2015 - Added Water Columns and more DC's to Models Available for Immediate Purchase.
16-Jan-2015 - Three Marbelup Models models - D and R loco, and NH Hopper Wagon - are featured in the February edition of Australian Model Railway Magazine.
16-Jan-2015 - Another CXB sheep wagon added to Models Available for Immediate Purchase.
22-Dec-2014 - CXB sheep wagon added to Models Available for Immediate Purchase.
20-Dec-2014 - Test Model of DA diesel assembled.  Photos added to D/DA Page and Sn3.5 Blog.

Back to Marbelup Models Home Page

Marbelup Models - How to Order

Due to ongoing quality issues with 3D prints from i.Materialise in Belgium, Marbelup Models is not accepting any new orders for 3D-printed models, for a while at least.  In general, small parts like bogies are printing very nicely, but some larger models are causing problems.  i.Materialise claim the problem is inherent with their Standard Resin material which was introduced about a year ago, although most early prints were very good.  Some prints are still very good, but the quality is quite variable.

In general, 3D printed models are available to order, as Marbelup Models does not hold stock of most models.  The models are printed "on-demand" for each order.  Just send an email with your requirements to marbelupmodels@iinet.net.au, and I can confirm pricing, postage, etc.

Delivery time is 2-4 weeks from i.Materialise in Belgium.  Orders for more than two of some complicated items will take longer as experience has indicated that i.Materialise take more care in production and packaging for small shipments, so larger orders may be split over several shipments.

A deposit is appreciated with your order.  For WAGR/Westrail models in Sn3½ or HO scale, a deposit of 25% is requested.  For all other models, a deposit of 50% is requested.  

If required, postage from Perth, Western Australia, to your location is an additional cost.  The typical cost for packing and postage for 1-3 models within Australia is $10 (up to 500 grams).  For larger orders, Marbelup Models can provide an estimate of postage on request.

Payment can be made by direct bank transfer, PayPal or Qantas Cash.  If sending funds by PayPal, please be aware that PayPal includes a fee which is typically AU$0.30 plus 2.6% if the funds are drawn from your credit card.  If paying from your credit card, please add this fee to your payment (or ask us to send a PayPal invoice) to ensure that the correct amount is transferred.  PayPal payments should be sent to marbelupmodels@iinet.net.au  Contact us for further details for bank or Qantas Cash transfers.

All prices, apart from those for models available for immediate purchase, are subject to exchange rate variations between the $Australian and Euro. 

Tuesday, 12 December 2017

WMC/WMD Construction Tips

Removing Support Structures

Carefully remove the support structure from the wagon.  It is suggested to use a sharp knife to cut the supports away from visible areas.  Take particular care around the brake hoses and end steps.

Once the majority of the support structure has been removed, carefully go over the wagon and cut away the small supports which typically extend from one part to another, for example, around the brake cylinders and other detail items.  An Exacto type hobby knife with a sharp pointed blade (Exacto #11 or similar) is quite useful for getting into the nooks and crannies.  For some parts around the brake cylinders where even a fine knife blade won't reach, a piece of wire (e.g. 0.8 mm spring steel wire) can be used to push against the support attachments and break them off.

Go over the model and smooth off any remnants of the fine supports, expecially in the visible areas.  A sanding stick or small file can be useful for this.

Bogie and Coupler Mounting Holes


The mounting holes for the couplers and bogies have been printed at 1.8 mm diameter to suit 2-56 screws.  Clear out the holes with a 1.8 mm drill in a pin vice, but it is preferable to NOT drill through the floor to avoid the screws being visible on the finished model.

Due to the difficulty of tapping the blind holes, the 3D print includes vertical grooves in the sides of the holes to help the screws cut their own threads, so tapping the holes is not required nor recommended.

Bogies


The bogie mounting points are designed to be 10 mm above rail level.  Depending on the bogies used and the height of their bolsters, it may be necessary to add washers or similar so that the coupler mounting surface is 11.5 mm above rail level.

Marbelup Models WMC/WMD Bogie
Marbelup Models has 3D-printed bogies of the correct design for the WMC/WMD available for sale.  Similar bogies, although of slightly different shape, are available from Black Diamond Models in Queensland.  The Black Diamond bogies are cast in white metal and are supplied fully assembled with wheels.

Assembly of 3D-Printed Bogies



The Marbelup Models WMC/WMD bogies are printed in two identical halves.  A set contains four pieces to make one pair of bogies.  As with other 3D printed parts, the first step is to removed the supports structure and clean up the small supports in the holes in the bogie sideframes, around the springs, etc.  Take care around the brake shoes to avoid breaking them.

The bolster section of each bogie half contains two holes intended for M1.4 screws (which are supplied with the bogies).  The larger hole nearest the narrow end of the bolster is a "clearance" hole and should be cleaned out with a 1.4 mm drill.  The smaller hole, nearest the bogie sideframe, should cleaned out with a 1.1 mm drill and tapped with an M1.4 tap.  (Drills and taps are available from North Yard in New Zealand.  The M1.4 tap is part No. 3014.  Refer to Page 5 of the North Yard Catalogue.)

An alternative to M1.4 screws is to use 1.5 mm x 6 mm self tapping screws, which are available from DCC Concepts - Part No. DCS-PH156.  If using self tapping screws, the smaller holes should be drilled out to 1.1 or 1.2 mm.  If the screws seem tight with 1.1 mm holes, try 1.2 mm, especially with bogies printed in Standard Resin (clear yellow rather than grey), which is somewhat less flexible.  The clearance holes should be drilled to 1.5 mm.

The bogie sideframes contain holes for fitting brass pinpoint bearings (available from Railwest Models).  These holes should be cleaned out with a 2 mm drill bit, after which the bearings should press fit into place.  The bogie is designed for 12 mm wheels with 26 mm axles.

When assembling the two halves, it may be necessary to trim the narrow end of the bolster by approx. 0.25 mm to get good alignment of the fixing holes and centre pivot hole.  (Later production will be made slightly shorter.)  After assembly, clean out the centre pivot hole with a 2.2 mm drill bit to suit 2-56 mounting screws.  (2.2 mm provides adequate clearance without excessive slop.)

Couplers


The WMC/WMD is designed for Kadee "whisker" couplers.  Either the #158 (scale size) or #148 (normal size) couplers can be used, with #262 draft gear boxes.  The WMC/WMD is also available with correct scale coupler height for WAGR/Westrail narrow gauge, in which case #252 draft gear boxes are used.

The draft gear boxes supplied with the couplers do not fit as they have a different mounting hole position.  The #262 draft gear boxes are narrower and have been used because they allow details such as the brake hoses to be positioned the scale distance from the wagon centre line.  Also, the #262 draft gear boxes are easier to use as the lid snaps into position.

Note that the height from rail level to the coupler mounting surface should be 11.5 mm, the standard for Kadee couplers.  The 2-56 6.35 mm (1/4") long screws commonly used for couplers are slightly too long for the blind holes.  Options are to shorten the screws by 0.5 to 1 mm, or to add a flat washer between the head of the screw and the coupler.  Railwest Models sells suitable washers with a 2.2 mm hole diameter.  If using scale coupler height, the height to the coupler mounting surface should be 13.8 mm. 

Stiffening Rods


The WMC/WMD model includes provision for two metal rods to be inserted within the underframe structure to provide stiffness and guard against possible future warping of the plastic material over time.  Each of the transverse frame members includes two holes approx. 2.2 mm diameter, as part of the 3D print.

Location of stiffening rods
On the end sill, the hole for the stiffening rod is covered over by a 0.5 mm layer of plastic, opposite the handbrake assembly, as pictured below.  This can easily be drilled through for installation of the rod.  There is a corresponding hole on the diagonally opposite corner of the wagon.

Drill location for stiffening rod
The rods should be a maximum of 2 mm diameter and 140 mm long.  They can be of any strong metal, e.g. steel or brass.  One source of steel rod is threaded push-rods sold for radio controlled models by manufacturers such as Du-Bro, and available from many hobby shops.  These have a threaded section at one end, but the remainder of the rod is plain, about 1.85 mm diameter. Once the rod has been glued into position, the hole in the end sill can be filled with modelling putty and lightly sanded to restore the flat surface prior to painting.

Handrails


Small starter holes have been provided to locate the various handrails.

The WMC has just two handrails on opposite corners.  These can be formed from 0.6 mm brass wire.  Viewed from above, the handrail is an L-shape, with the horizontal portions about 6.25 mm long.  The height from the floor to the top of the handrail should be about 9.5 mm.  The vertical post nearest the coupler can be cut about 2 mm over-length to provide a secure (glued) fixing into the floor.  The vertical post near the side of the wagon should only be over-length by just 0.5 mm so the end of the wire is not visible from the side.

In addition, the WMD has 3 handrails on each end of the hungry boards.  Thinner brass wire, e.g. 0.4 mm should be used for these.  The hole centres for each handrail are 4.75 mm.  The WMD also has wire handrails/steps across the tops of the "chutes" at each end of the hopper.  The 3D print includes small notches for locating these, and the length of the wire should be 9.5 mm (8 required).

Note that the position of handrails and other details varies between different members of the WMD class.  The model depicts the most common arrangement, based on photos of various prototype wagons.

Door Lock Shafts


As part of the locking mechanism for the bottom discharge doors, there are two shafts which have to added using brass wire, either 0.5 or 0.6 mm.  The length of each piece of wire is 40 mm, although it is probably easier to feed a longer length of wire through the holes provided, then trim it to length with fine wire cutters after it has been glued into place.

Location of Door Lock Shafts

Brake Levers and Chains


The handbrake ratchet assembly on the end of the wagon includes a vertical groove to house a 10 mm length of 0.4 mm brass wire, to represent the handbrake lever.  Superglue is recommended for attachment of the wire.

A distinctive detail of the WMC/WMD are the chains running across the floor which connect the handbrake mechanisms with the brake linkage underneath the vacuum cylinders.  North Yard (NZ) make a suitable fine chain which is available from Railwest Models.

Threading the fine chain through the three guides at each end is a bit tricky.  It helps to use a piece of fine but soft wire as a "needle".  The 0.25 mm diameter inner conductor from "wire-wrap" wire used for electronics is suitable.  (If you ask nicely, you might be given a piece with your WMC/WMD!)  Once threaded through the guides, one end should be glued into the small notch provided for the purpose in the horizontal "angle iron" underneath the vacuum cylinder.  Once that end is fixed, the other end should be threaded through the support bracket for the handbrake which has a tapered keyhole-shaped hole.  When gently tensioned, the free end of the chain can be glued into the tapered hole to secure it, and the excess chain trimmed from underneath with fine wire cutters.

Weighting


With the Black Diamond (metal) bogies, the completed wagon weighs around 72 grams.  The "desirable" weight for a wagon of that length (140 mm) is around 95 grams to ensure optimum operation including operation of Kadee couplers.  (See the Sn3½ blog for more information.)

If requred, additional weight can be added by gluing lead shot or small pieces of sheet lead between the various frame members of the underframe, e.g. either side of the hopper doors, where it would not be seen in normal operation.

Painting


Either enamel or acrylic hobby paints can be used to paint the finished model.  The model pictured has been painted with Revell Hobby Enamel.