Wednesday, 8 September 2010


So here we are with the final installment of this stage by stage account of how I build carriages out of styrene.

With the detailing work completed on the four sides and ends the last task before they can be glued into a box is to fix some locating blocks for the chassis / underframe on the back of the bodysides. These will make sure the body sits at the correct height.

And then - cue drum roll - Ta Da!

Add on the bases for the chassis and the roof and finally we have something that actually looks like a carriage.

Now, you've probably noticed that so far the roof is flat and might be thinking that that's a little odd.

You might also be wondering why I don't just bend a sheet of brass and make a roof out of that?

Good questions. Here's the answer.

Styrene - or plasticard if you prefer - is the Devil's own material and has a mind of it's own and it won't stay in shape unless you force it to, by altering it's molecules through heating and cooling them or alternatively by keeping it stressed. Here I'm using the second option.

So I make the roofs with a twin layer flat base. The lower layer is cut to fit inside the bodyshell - this will keep the sides under stress and stop them bending inwards (or outwards too once the roof is glued on). It will also help to make the whole carriage body more rigid.

The second layer of the laminate is cut wider to sit on top of the bodyshell.

Flip it over and you can see I've added a thin strip a few mm's in from the edge.

Any guesses what that's there for??

Those strips will help locate and hold the glazing in place when the model is finally assembled after painting. Keeping the glazing held tight against the inside will also prevent the bodyshell from warping inwards over time.

Now attention turns to the top side again and I glue on 3 trusses along the length of the roof. These will support the roof skin and keep its shape and stop it sinking in the middle.

Then a final piece of styrene sheet can be bent over the top to complete the roof skin.

It's one of the most tricky jobs of the whole project. The styrene will bend easily enough but overcoming the fierce natural spring in the material and getting it to stay bent is much harder.

What I do is glue one edge down and wait for it to set firm (perhaps as long as half an hour) and then test out attempting to bend it over the formers. Inevitably this will expose some weak points along the joint where it opens up. So I re-glue those areas and repeat the process until the styrene can be bent across to the other side without any lifting.

Then, being very generous with the solvent, I put the roof upside down on the workbench and roll it over and press down very hard on the second edge. Easing the pressure off will once again expose any sections that haven't bonded properly and I go back, apply more glue, more pressure until, finally, the styrene submits.

I've made that sound a bit of an epic battle - man against styrene - but the good news is that once you have got the roof skin to bond it will stay bonded. Although I am putting the styrene under great stress I have carriages that I made 20 years ago in this way and the roof skins have never lifted once.

You've also probably noticed there's a triangular cut out in the roof. That's where the domed end of the roof - a feature of the FR's Observation Carriages - is going to go. More on this later.

Let's turn our attention back to the underframe.

Here you can see I've added a strip around the edge which represents the main steel underframe of the carriage which pokes out beneath the wooden body, and also the truss rods have been bent up from a length of brass rod and glued into place.

And on the other side...

Those upright rectangles of styrene are going to hold the glazing in place at the bottom. Normally this job would be done by the interior, the seats and tables etc but the client has specified a carriage without an interior so these lengths of strip have been added instead.

Now it's back to the roof and time to form the domed end using that fabulous modelling material, Milliput.

It's wonderful stuff. Firm enough to be pressed into shape. It can be smoothed down with water. Won't shrink or crack and it sets like rock (after 24hrs). The best modelling filler I've ever used.

So now I'm just waiting for that to set so I can rub it down with with some wet and dry paper and then the roof can be glued in place and that'll be it. Job done!

1 comment:

  1. A great series of posts, Rob, thanks for taking the time to do it, i'm sure i'll be referring back to it when I get round to building my stock.