Planning a scratch building project

[relaxinghobby]

Any model build is a big project of many stages, any thing can go wrong at each stage increasing the risk of the project floundering and no model being built or forever waiting unfinished.

 

Preparing paper patterns to check drawing accuracy helps during the planning stage and can find problems with easy to make paper parts before committing to the slower and more

 

 

difficult stage of making metal or plastic parts. Dimensions and clearances can be check and adjustments made before final committing to the time and effort of more solid materials.

 

 

 

This is from Ian White's Rowfant Grange layout website (http//: early-lbscr.co.uk/rowfant/rowfant.htm ), he has posted a plan or drawings of the basic parts to scratch build a small 19^th century outside frame 2-4-0.

 

I printed it out on to thick paper and cut out the parts, gluing them together to see what the finished object looks like. Although it is of a London and Brighton engine of the 1860's it typical of many railways of that era. The wheels are undersized and should be outside cranked but this is just a test run. The chassis needed it's front narrowed to get around No. 2 curves.

 

 

 

 

 

Other patterns of my own, drawn out on TurboCad 10 technical drawing package program on the computer have led to these two designs for a model of a typical Isle of Wight tank and of the Irish 0-6-4 tank which actually got made into a solid plasticard working model based on a Hornby chassis.

 

 

 

 

[Atso]

Looking very good there! I've used CAD for creating paper patterns for a while now and it certainly makes life easier. I've got a few cardboard LNER bogie brick wagons to finish in N gauge which have been made in thin card printing the patterns directly onto them.

 

Interestingly I think cardboard is a perfectly good material to build bodies out of as long as it is treated in some way to make it slightly more ridged. I usually use superglue or a coat of casting resin - the traditional method was to use shellac. Slightly OT but I thought it fitted with the spirit of this topic.

[relaxinghobby]

 

I suppose the next stage would be to send one's CAD drawing to a laser cutting firm or get one of the computer driven card cutters.

The cheaper option using the computer equipment already there is just to print straight onto the plastic, using an ink jet printer not a laser printer

as the laser has a hot roller to fuse or melt the toner ink into the paper or in our case melt the plastic.

 

So using a cold ink jet I got he above, a printout of Ian White's plan onto 20 thou plasticard which passed through my Canon Pixma printer easily.

The only trouble is that the ink is still wet 48 hours later, is there a way of fixing the ink, see smudge on lower right.

[Mike G]

What sort of price does this sort of software cost? I really enjoy this sort of thing, look forward to seeing how these develop.

 

regards

 

Mike

[Horsetan]

I seem to remember a modeller who featured in early MRJs named Bob Fridd (I think). He built everything in card - whole engines, stock.....

[Campaman]

Not sure if you would be able to fix the ink afterwards, but I have had sucess with printing onto materials like that by spraying with a primer first before printing.

 

Its like Inkjet transparancies, they are coated on one side to take the ink.

[Jol Wilkinson]

What sort of price does this sort of software cost? I really enjoy this sort of thing, look forward to seeing how these develop.

 

regards

 

Mike

 

Mike,

 

you don't need a full CAD package such as AutoCad. A good 2D drawing package, such as CorelDraw or Illustrator is ideal. You can often get older versions (but completely suitable for our purposes) on that well known internet auction site.

 

I use CorelDraw 12 which I got for £30 (they are currently on issue 15 or thereabouts, but have rebranded it X5) for 4mm kit etch artwork. Until recently I used CD7 and CD9 on different PCs but a change to Windows 7 required something a bit more modern. The 2D software programmes are a bit more straightforward than the 3D versions and hence easier to learn.

[meple]

What sort of price does this sort of software cost? I really enjoy this sort of thing, look forward to seeing how these develop.

 

regards

 

Mike

 

 

DoubleCAD is free: http://www.doublecad.com/

[dajt]

What sort of price does this sort of software cost? I really enjoy this sort of thing, look forward to seeing how these develop.

 

I use a program called Inkscape. I've used it to do the artwork for home etching, and also for laser cutting components for 5" gauge stuff.

 

Regards,

David.

[richard carr]

CAD software is as cheap or expensive as you want it to be.

 

You should be able to get 2 D cad for free on the internet with a little bit of a search.

 

Personally I use turbocad it costs from £30 for the 2d only version to £895 for the professional version, there is a mid point 2/3d version available for £70, which is what I use.

The biggest problem with cad is the steep learning curve in getting enough skill to use it efficiently, I have never come across a CAD package that I would describe as intuitive. Turbocad has a large number of detailed step by step tutorials available for it for a reasonable cost (£30) this certainly speeded up my learning and was well worth the money.

 

 

Richard

[Campaman]

Another Vector drawing program similar to Inkscape but probably a bit easier to use is Open Office Draw that comes as part of the Open Office suite, free as well.

[Jol Wilkinson]

CAD software is as cheap or expensive as you want it to be.

 

The biggest problem with cad is the steep learning curve in getting enough skill to use it efficiently, I have never come across a CAD package that I would describe as intuitive.

 

Richard

 

Richard,

 

I would agree entirely. However, 2D vector drawing software (CorelDraw,Illustrator,etc.) is much more straightforward.

 

I have introduced 2D software to students on etch artwork courses who have found it virtually impossible to get started with 3D CAD, and they have been able to come to terms with CorelDraw very quickly. It is much more akin to drawing with pen and paper.

 

I had TurboCad years ago and eventually gave up on it. As for "free" downloaded 3D CAD, it's a false economy as most people don't seem to be able to learn how to use it.

 

Proper CAD, such as AutoCAD, is a brilliant tool for professionals, but like most sophisticated artwork it needs proper training to use it. At least with CorelDraw I found it possible, fairly quickly, to get the hang of the basics. There are probably many professional features I don't use, but then I haven't needed them.

 

Jol

[relaxinghobby]

These two photos' shows my attempt at making a serious go at a home made cardboard kit.

 

 

Printed onto 0.6 mm cardboard from Rymans Stationers. I scanned in a wagon drawing from a magazine and used

Open Office Draw ( £ free ) to resize it, and copy it and print it out onto the card using an ink jet printer.

 

attachment=71675:Salt Union Bromsgrove small wagon cardboard kit.pdf]

 

This is from the October 1964 Model Railway News, an article by Peter Mathews.

[relaxinghobby]

OK a confession, after a couple of years since I last used Turbo-CAD-10, I had forgotten how to use it.

So I just used Open Office Draw to resize the image to 4mm scale and reproduce it as many times as possible on an A4 size piece

of cardboard.

 

I then cut out the bits and stuck them together. this wagon with very little relief detail is a good example to use as a first attempt, especially as it is basically

a rectangular cuboid and has few curved surfaces.

 

 

I managed to use quite a lot of the materail, the ink runs when touched with wet PVA craft glue from Wilkinsons, so I have protected the surface with Humbrol

matt varnish, the second sheet on the right is a second printout onto thick cartridge paper, I intend to embross the rivet detail onto it with a sharpened pointed nail

and cut out the thus dimpled strapping and stick it onto the basic wagon body.

 

 

Cardboard ^ .......................................................................................................Cartridge paper^

 

Please wait for diagram which should make my methods clearer.

[relaxinghobby]

 

With this diagram I hope to show my method of construction using only flat materials that will fit through the ink-jet

printer.

[relaxinghobby]

I've finally found some of the CAD files I produced in trying to design a model of what I really wanted.

 

That is the Isle of Wight 2-4-0 tank engines supplied by the loco manufacturers Beyer Peacock.

These covered the period from 1860 unto the late grouping era of the 1930's.

 

 

This shows how tricky computer application programs can be, somehow I lost most of the plan view.

 

 

No matter what I did I could not get the wheels onto the end of the axials.

Turbo CAD 10, the program I was using then has been surpassed with more modern and easier to use CAD programs ?

[halfwit]

Hi RH,

Looking at your salt wagon in post #15, if you use MJT etched w-irons (part 2299) these have some solebar details and drawhook plates included on the etch, which could save some time cutting out small fiddly paper details. I've used some on my semi-scratchbuilt van.

[relaxinghobby]

Some more progress with the Salt Union Wagon.

I made some strapping using a thickish foil from the top of a fancy Lager bottle. It takes impressions from a pointed object well, paper does not seem

to work so well.

 

 

Yes, MJT rocking W iron etches come with wagon detail bits, they are easier than trying to cut up little bits of paper.

Cast buffers from? And the axle box W irons are also from ? Dart Castings?

 

 

Where's the handle gone from the corner? I'm sure I stuck in some wire there.

Most of the A4 size sheet of cardboard is used up, leaving only a pile of scraps.

When the roof dries I can trim it to length

 

 

Next to get the wheels on and brake gear from kit left overs.

[relaxinghobby]

 

Turbo-CAD used to workout shape to cut out plastikard. The design was printed out onto paper and then glued to

the plastic sheet with 3M Surface mount spray glue.

 

This glue does not wet the paper so causes no shrinking or distortion of the paper.

 

These are parts to cut from a 20 thou plastickard sheet to make an Isle of Wight 2-4-0 tank.

[relaxinghobby]

 

Salt Union van painted in main body colour, the drawing said 'dark red oxide', I've

used Revel Matt red/brown No. 84.

[ian@stenochs]

Hi,

 

I use a similar method but print straight onto plastikard which is then cut out and assembled. Makes panelled coaches relatively easy but I have built quite a few wagons too. See article in MRJ issue 98/1997 P267.

 

Happy modelling,

 

Ian.

[Julia]

I use a rather esoteric system for creating templates for building things. I use postscript.

 

Postscript is an ancient (in computing terms) language that is used by some printers to describe the layout of a page. It is actually a full programming language, and whilst 99.999% of postscript is written by printer drivers, it can be written by hand.

 

What this leads upto, is you can use postscript to draw very accurate diagrams, simply by specifying the coordinates for basic things like lines and arcs.

 

I was recently using it for creating a template for making a level crossing for a 700mm rad curve. To draw out the lines I needed (one at 700mm, one at 700-3.5mm one at 700-4.5, etc...), you just specify that you want the arc drawn:

 

 

%%arcs for the 700mm rad level crossing

2240 350 1984.25197 170.0 180.0 arc stroke

2240 350 1994.17323 170.0 180.0 arc stroke

2240 350 1997.00787 170.0 180.0 arc stroke

2240 350 1974.3307 170.0 180.0 arc stroke

2240 350 1971.49606 170.0 180.0 arc stroke showpage

 

Because of the inherent accuracy of the printer (600dpi typically), you can draw very precise, very accurate drawings for modelling from.

 

So, yes this is very esoteric, but thought I would add this as an alternative method for the geeks amongst us.

 

J

[Donw]

Postscript. Now that takes me back to pre-windows days. It was a very precise means of printing. I never wrote it by hand though! Is it easy to do as I cannot follow how the co-ordinates relate to want you were trying to do.

Don

[relaxinghobby]

Hi Ian

 

I think I would prefer to print onto plastikard, it is a far more stable medium than cardboard,but so far I've found that the ink-jet ink never dries and smudges when ever

the plastic it is handled.

 

How do you get the ink to fix it's self to the plastic and not smudge? do you varnish the plastic first?

 

RH

[Julia]

Postscript. Now that takes me back to pre-windows days. It was a very precise means of printing. I never wrote it by hand though! Is it easy to do as I cannot follow how the co-ordinates relate to want you were trying to do.

Don

 

I believe it is (many would say I am nuts).

 

The important thing is to remember it is all based around the postscript point, which is one 72nd of an inch.

 

 

2240 350 1997.00787 170.0 180.0 arc stroke

 

What this means is:

 

2240, 350 (x,y) postscript points from the origin (bottom left corner of page) draw an arc of radius 1997.00787 (700mm), from 170° to 180°.

 

Thus we get a 700mm rad arc of 10° length. There are other primitives for straight lines, etc..., But it all comes down to a basic coordinate system, you just might have to go off the page abit with the centre of a circle to get it actually on the page...

 

J