Plasticard coach techniques

[bertiedog]

I well know that PVC cannot be easily laser cut, it releases chlorine, but there is no restriction on Styrene with most services that offer cutting, so it must be down to a particular companies restrictions due to the equipment in use.

 

As I said, we used it for screens to support graticule's for optical targets, the plastic was plain white Stryene, same as plasticard, and cut very neatly indeed to within 100 micron. The plastic did not have to be that accurate as it expanded and contracted with temperature somewhat, but retained the glass target.

 

Stephen.

[Sidecar Racer]

 

David also published a series of articles in the model press including Railway Modeller April, May, June and July 1979 which I am now actively seeking.

 

 

Hi Mike , if you are still looking for these I have them . PM if interested .

[scotcent]

Brunel Hobbies (in Australia) advertise laser cutting of styrene down to 0.25mm. I don't know anthing else about them

http://www.brunelhobbies.com.au/LaserCutting/Materials.htm

Allan F

[MikeTrice]

Thank you to all those who have responded.

 

I have been watching with great interest the various threads currently running relating to building coaches in plasticard. There are some aspects of David's approach that I rather liked:

 

• Fitting glazing after painting without glueing.
  
• Strong sides that hold their shape
  
• Keeping the roof separate and fitting it into a rebate in the sides (and being able to strip it down again later)
  

 

What I am not so keen about is inserting the glazing from the end which means creating removable ends.

 

After lots of thinking about the problem I finally bit the bullet and had a go. The results of my experiments are presented here.

 

In gobbler's topic GE/LNER Suburban coaches, 2512silverfox posted some images of GN coaches built from layers of plasticard but with the glazing inserted into slots in the top of the side. After a lot of trying to work out the various thicknesses from his picture I eventually put knife to plastic.

 

I did not think it worth trying a full set of sides as I was really experimenting to see what worked for me and what did not. My first attempt was to model a couple of compartments from a Gresley 3rd non-vestibule as the dimensions of these are about the tightest I am liable to find.

 

I started with several prints of a drawing. In the past I have used double sided tape to stick the drawings to the styrene and then cut through the drawing and plastic. This started well. Having stuck a print onto a piece of 15thou styrene the windows were carefully cut out. I then tried to remove the print and tape. Hmmm, funny it has left a very sticky residue on the plastic side, something I have never experienced in the past. In the end I threw it away and started again.

 

This time I stuck the print to the styrene using Pritt Stick. Success.

 

I now needed to cut out 4 layers which was tedious work. After a clean up they were glued (or welded) using Mek Pak and a very long haired brush. Part of the problem was working out what sequence to glue them in and to which part, the inner of the outer. As you can see I got them out of alignment.

 

As David pointed out trying to see detail on plasticard that is predominently white is difficult and to be honest I struggled at times as you will see from this first attempt:

 

 

Unfortunately coloured plasticard is not readily available in a range of thicknesses so the red and black coloured beading has been done with a permanent marker. The Mek Pak has dissolved it slightly however that will be hidden under paint.

 

The slots for the glazing when view from the top show how tight the dimensions are in 4mm:

 

 

Glazing was added using 15th clear styrene from Evergreen.

 

OK, not bad, not very accurate, but I did learn a lot. A big lesson was that with the thickness of the sides (10thou + 15thou + 20thou + 20thou + 30thou = 95thou) the side look thick when viewed from the side. The inside faces of the apertures were all created slightly larger than the exterior to try and reduce this and in the end I even bevelled the back however to no avail:

 

 

The resulting side is quite strong (it should be for the thickness) and the tumblehome is well formed but it was not quite what I was looking for. I did give it a quick spray with Halford's acrylics to see if the visible side thickness was not so apparent, and to ensure that the paint would take on the permanent marker (which it did by the way).

 

So that is my first attempt. A lot learnt in the process especially my lack of neatness (2512silverfox's by comparison are miles ahead).

 

Second attempt in next post.

[MikeTrice]

As stated previously I was concerned about the visible thickness of the sides when viewed from an oblique angle. Clearly I would need a different approach to attempt to get the side thinner.

 

A Gresley side is approx 3.125 inches in thickness at the waist, so I reasoned if I could dispense with some of the laminations then I could improve the situation.

 

So, more research. Colin park's Bullied 2HAP EMU build is really my main inspiration for having a go. He used a different approach of using thinner sides but introduced the curve into them backed up with another curved backing to hold it.

 

So I now started attempt number 2.

 

For this I decided to use 15thou for the outer side proper, use a 20thou spacer (to fix the tumblehome) with another 15thou inner side (a total of 50thou - not far off the scale width). This time I used black plasticard for the inner side.

 

This was much more successful. I used Evergreen 5 thou styrene for the droplights which were then carefully welded behind the outer side (taking greater care to align them this time). They should be recessed more, but this is a compromise I think I can accept. Once again the apertures for the inner side are slightly larger than the outer side. This time I decided to create a single window aperture across the drop light and the two side windows. The 20thou gap, minus the 5thou droplight would permit 10thou glazing (using PVC this time).

 

I also carried out some more experiments with permanent markers. Letraset produce a range of permanent markers under their Promarker range and I found their gold colour pretty good (it is golden yellow rather than metalic gold). I also tried a water based paint pen. As you might guess, the water based paint pen does not really take to the plastic surface, however wipe it with a tissue and it does taint the surface. Unlike the permanent marker Mek Pak does not seem to dissolve it, and it can be washed off afterwards before painting if desired.

 

The tumblehome was formed by rubbing a knife handle across the back having supported the side against a steel ruler and the curve introduced. Unfortunately it could have been more pronounced.

 

 

 

 

 

 

So I am far happier with this approach as it is considerably less cutting and has resulted in a thinner side. I have tried to take more care in the assembly but has still not made a good job of the upper beading which is only really noticable when enlarged like this. The side is still reasonably rigid so looks a viable approach.

[coachmann]

David did beat you to it Mike with glazing dropped into slots from the top. It was the only way with coaches that had recessed end doors like WCJS 12-wheelers and MR coaches with clipper sides.

 

Re the tumblehome, I found that if each of the layers were given a tumblehome prior to assembly this would hold it in place.

[MikeTrice]

David did beat you to it Mike with glazing dropped into slots from the top. It was the only way with coaches that had recessed end doors like WCJS 12-wheelers and MR coaches with clipper sides.

I am not claiming originality for this

[coachmann]

I am not claiming originality for this

Ha ha, I don't think DJ could do that. I had a 7mm pre-war Mills Bros bakelite LMS coach in 1957 that had glazing dropped into slots from above.

 

Your building in styrene is certainly food for thought.

[MikeTrice]

Your building in styrene is certainly food for thought

Strangely satisfying.

 

I do have an ulterior motive. I fancy building a twin from the Coronation set.

[Steph Dale]

Strangely satisfying.

 

Surprisingly quick too.

 

I see I'm not the only one who's looking towards the 'challenging' end of the spectrum for their first foray into carriage scratchbuilding!

 

Just a quick thought on the tumblehome - you could use a variation on Jenkinson's techniques, only curve the back layer as well as the front. The gap ('stringers' if you will) will help hold the form with the stresses in the inner and outer skins holding the form.

 

Or, step the backing layer so that the upper level is thinner than the waist and the outer skin(s) then follow the tumblehome to the floor.

 

I must confess I've never been hugely satisfied with cold forming laminates of plasticard as a way of getting shape. If I read your notes and pictures correctly I think you've got an external laminate of 0.010"? The long term stability of that skin, with the potential for trapping solvent behind it, would worry me a little too.

 

I'm not meaning to be negative; in fact I look forward to seeing your model take shape and hope to offer a couple of alternative thoughts. It's part of my usual thought process; there are, I think, four possible arrangements of the laminations, skins and reinforcing for my 'Continental' in my log book before I fixed on the one I'm using.

 

I like the idea of the small test sections. I've got a couple I need to have a go at for my flush-sided stock.

 

Steph

[Colin parks]

Hi Mike, Your experimental side looks promising and you have certainly got a good debate going here!

 

There is a lot of food for thought re. sides, glazing and tumblehomes.

 

I haven't got a copy of DJ's book yet, but it seems clear that from what everyone is saying, or in your case doing, is to build the coach sides in a more prototypical manner. As for glazing dropped in from above or inserted from one end, I don't fancy the idea as I like to have the roof and ends solidly fixed to the sides - permanently. This does mean it is harder to paint and detail the inside of the coach, but there is no danger of gaps in the bodyside/roof/end joints. What about inserting from below? Perhaps it is possible, I don't know, plastic glazing ought to be flexible enough to negotiate the curve of the tumblehome though. The cavity below the window could then be 'plugged' with a piece of plastic sheet, curved of course.

 

I only have experience of scratch-building one EMU, so I'm absolutely no expert, and the model I have made is of a steel sided design. What would D.J. have done there? It seems that for steel sides 10 thou outside+ 20 thou for glazing + 10 thou inside would give the right kind of thickness for steel-sided stock (perhaps a bit thick but there has to be some strength somewhere). I have found laminating has to be done carefully with the minimum of solvent for, if any can't vent off, it will continue to melt the plastic for weeks, causing depressions (and depression!), so the less layers and solvent the better.

 

The glazing on my models is quite crude; it consists of strips of clear cobex fixed in a recess in the side, held at the top by a strip of plasticard at cantrail level and superglue on the bottom edge. It'spretty basic but the prospect of cutting out all the window apertures twice would have daunted me to the point of giving up!

 

I agree with Coachmann that tumblehomes seem to keep their shape if both - or however many layers you have, are pre-formed to the correct profile then carefully laminated.

 

I know I have said it before elsewhere on the forum, but what about the coaches of Mike Peascod? He built really nice models, mostly LMS if I remember correctly. Perhaps somebody could say how he went about coach construction. He had some method of clipping sides onto the roof and floor I think. I saw some of his coaches at a Westminster Central Hall exhibition in the 70's and I was very impressed.

 

I suppose in the end, it's down to whatever technique works for you.

 

Colin

[Jim Martin]

Mike

 

Your method reminds me of (yet another) article from long ago. This was by a gentleman whose name escapes me, apart from a vague idea that his last name began with "F" - Fleming, perhaps? He published a piece in, I think, Model Railway Constructor about thirty years ago (sob!) describing his LNER coaches. He used a laminated side and fabricated the upper panelled layer in the same way that you have, as opposed to David Jenkinson's approach of cutting out a single panelling layer. As I recall, he sanded the tumblehome (this was feasible because, like you, he had a pretty thick body side to work with). The other things that come to mind about his methods were a very golden shade of teak, which I think was achieved by applying some sort of dye over a red oxide base coat, and the use of thread for the beading on the lower panels. The photos in the article showed a number of coaches including some quad-arts. I started, but never finished, a model of some sort of Gresley GNR articulated twin based on drawings from MRC using his methods. The sanding wasn't as hard as I'd feared, but the sides warped quite badly and I abandoned it.

 

Jim

 

Edit: I was thinking about this while cycling into work this morning. I think the article was by Barry Fleming.

[coachmann]

The coaches I built from styrene in 1962-4 lasted the course for many years. All I did with the tumblehome was stick a backing piece onto it so that it would retain its shape. I may have to resort to plastikard for some of the one-off coaches I need for the layout instead of going down the increasingly expensive etched brass road. That said, no matter how much one puts into building a plastikard coach, it has little resale value.

[MikeTrice]

David did beat you to it Mike with glazing dropped into slots from the top.

He does mention it briefly in his book, but mentions it in far more depth in Modeller's Backtrack April-May 1992, a secondhand copy of which arrived yesterday.

 

I see I'm not the only one who's looking towards the 'challenging' end of the spectrum for their first foray into carriage scratchbuilding!

I have dabbled in the past without any great success.

 

Or, step the backing layer so that the upper level is thinner than the waist and the outer skin(s) then follow the tumblehome to the floor.

 

I must confess I've never been hugely satisfied with cold forming laminates of plasticard as a way of getting shape. If I read your notes and pictures correctly I think you've got an external laminate of 0.010"? The long term stability of that skin, with the potential for trapping solvent behind it, would worry me a little too.

The true outer side is 15thou with a 10thou overlay to present the three tier panelling used by the GNR and LNER.

 

Part of my problem with the cold curved version is possibly down to my lack of patience. I probably needed to glue the two pieces together and leave then in a curved press for a week to fully cure. Life is too short. Subsequent work on the sides has not helped as without support underneath pressure from the exterior of the curve tends to flatten the structure.

 

OK then, stepping the backing layer so that the upper layer is thinner than the waist: hmmmm!

 

Attempt number three. Given up bothering to cut the windows in these experiments as I wanted to validate the possibilities for following Steph's advice and try an extra layer:

 

 

The inner 15thou piece has been shortened and a piece of 30th black laminated to the back. The 15thou outer side is then bent down and sealed at the lower edge of the new strip:

 

 

I am not known for my patience. Again I rushed this through to prove a point and did not attempt to precurve the outer 15thou skin. As a result of either the solvent having not set properly and/or the outerside wanting to return to the straight, the lower backing piece has gone out of true.

 

Attempt number 4:

 

This time I used a slightly wider strip of 30thou and bevelled the top edge, gave it longer to dry out, and precurved the outer side. Much better and surprisingly solid. This might be it (famous last words).

 

 

 

Having the additional strip has improved the tumblehome.

 

I don't fancy the idea as I like to have the roof and ends solidly fixed to the sides - permanently. This does mean it is harder to paint and detail the inside of the coach, but there is no danger of gaps in the bodyside/roof/end joints.

With Gresleys it does complicate painting somewhat. What appealed to me with David's technique is that the roof fits in a rebate between the sides hiding any joint. I have yet to prove this aspect.

 

I only have experience of scratch-building one EMU, so I'm absolutely no expert, and the model I have made is of a steel sided design. What would D.J. have done there?

From you model so far I would not have dreamed you were also a plasticard coach virgin like Steph and I, your workmanship is phenominal and has been my primary inspiration to have a go. DJ would have left off the outer panelling but not certain about a fully curved side. Now you know why I favour making up small test pieces . Pre rolling the sides might be the only option.

 

the prospect of cutting out all the window apertures twice would have daunted me to the point of giving up!

They would me as well, however it is in 15thou. DJ also cuts the inner apertures slightly bigger and you could avoid the rounded corners.

 

I know I have said it before elsewhere on the forum, but what about the coaches of Mike Peascod? He built really nice models, mostly LMS if I remember correctly.

The only time I remember seeing something of Mike's in print was an early (60s, 70s)article in I think Model Railway Constructor and suprisingly it was of a SR emu. If anyone has a reference please jump in. Mike was due to demonstrate his techniques at Scaleforum 2009 but is not listed for 2010. If I see him I will speak to him.

 

I was thinking about this while cycling into work this morning. I think the article was by Barry Fleming.

Somewhere I have a small sample made by Barry. It was interesting watching him work. He used dividers to mark the plasticard directly, cut into pieces using a small engineers square and laminated them together. You are right, he build the whole thing up from a flat base and filed the base layers to form the tumblehome before fixing the final panelling layer. Oddly at the time he used cotton thread for the lower beading and finished the exterior with Ronseal Teak stain, which is very effective on white plastic but would not work on brass. I think he also let the glazing in fomr the top but need to rack my brains of where the sample is. As an aside at the time Barry was living in Nigeria (I hope I have remembered that correctly). I recall his stories of having to stand his Mek Pak in a container of water to stop it evaporating away.

 

Anyone remember a series of articles by E.R.H.Francis starting in Model Railway News Feb 1969? I seem to recall these eventually went over to another magazine and there were a lot of them. One covered Gresley stock but I have not traced it yet. Try as I might I have not succeeded in tracking down a list of his articles, other than the Feb 69 and July 70 ones I have. He used 10thou panelling layer and 20th for the sides proper cold curving them and laminating together then leaving them for several hours to cure before proceeding.

 

Anyway, thanks for the interest folks.

[Steph Dale]

Mike,

 

I like that - it seems to work okay though your last photo shows a problem if I'm reading the red line correctly. How long did you leave the 'stock' before glueing the 'skin' on? Leaving it for a full 12 hours or so (weighted, on glass ) may help - you can always add a small strengthening strip inside the top edge to make it easier to work with.

 

I just wonder as a further slight refinement why you couldn't use 0.015" for the top half and a simple 0.020" layer on the waist/tumblehome. DJ makes his sides out of 0.020", so it should work. Hence a suitable construction order might be:

1. Build stock

2. Fix upper sides

3. Fix upper edge of lower side

4. Form and fix tumblehome

Leaving it as long as possible between build stages will help the long-term stability of the model too.

 

I also have to thank you for your latest test sample - it's got me a long way in deciding how to do my Maunsell stock; even if I have still got to solve the problem of using very thin skin material for '35 stock.

 

Cheers,

 

Steph

[MikeTrice]

I like that - it seems to work okay though your last photo shows a problem if I'm reading the red line correctly. How long did you leave the 'stock' before glueing the 'skin' on?

 

I just wonder as a further slight refinement why you couldn't use 0.015" for the top half and a simple 0.020" layer on the waist/tumblehome. DJ makes his sides out of 0.020", so it should work. Hence a suitable construction order might be:

1. Build stock

2. Fix upper sides

3. Fix upper edge of lower side

4. Form and fix tumblehome

Leaving it as long as possible between build stages will help the long-term stability of the model too.

 

I had problems adding the photos, for some reason they are shown as attachments and seem to be in reverse order, so the best option is to click the link against the text. The red line is to emphasise the distortion that occurred using attempt 3 as described in the text.

 

In all cases very little time was spent glueing on the additional pieces (I am too impatient), and you are quite correct that giving it a lot longer might make a difference.

 

You suggestion of using 15thou above and 20thou below only gives me 5thou for the top panelling which I typically do using bought styrene strip which to my knowledge is not available in 5thou.

 

Anyway I thought I would attempt a sample based on Colin's 2Hap to see how it would work out in 4mm and so people could judge the use of 15thou for the side (bear in mind etched coaches are typically 12thou). I am now leaving it to dry out fully to see what impact the cold curve has for staying power.

 

 

First the individual pieces have been cut, 15thou for the outer face with all windows cut out (oh boy, Colin you deserve a medal for what you did, much neater than mine), a 20thou spacer and 15thou inner side. For the inner side I have not bothered with the curved corners and combined the two door windows.

 

 

The components are curved against a permanent marker and the elements are starting to be fixed together. Yes, I have over curved it!

 

 

I added a strengthening rib along the back as the prototype has enough room for this unlike the Gresley. Glazing with 15thou PVC has been added, but is not really visible.

 

 

A view of the glazing slots. As with the gresley the room for spacers is limited which is why I chose this particular section to experiment with.

 

 

The view from behind.

[coachmann]

I cannot help thinking that you are taking a B road when there is an motorway Mike.....

 

Why not simply cut out the sides then form a tumblehome with the back of the SwannMorton handle. Form another tumblehome on the edge of a sheet of 30thou styrene, cut a peice off and bond it with Mekpak to the tumblehome on the coach side. (Leave space above strenthener to allow for glazing material and space below to allow for thickness of floor).

 

For glazing, I recommend Bayer Vivac Copolyester, available from Alton Model Centre. I used to use this and it reflects light like glass because of its thickness. Glue this with evostick to your coach after its painted. Evostik remains flexible and will allow for the styrene to contract and expand over the years.

[Colin parks]

Very interesting Mike, you have been busy!

 

Your version of the 2 HAP side is most interesting and certainly the glazing looks very neat. I have decided that 20 thou sheet is too thick for the sides, having now glazed my unit. I had opted for 20 thou + 20 thou laminated behind with a recess for the glazing to give a near-scale thickness to the sides, but this meant there was only a slot at the top and glue at the bottom to keep it in place.

 

Your windows look far more like the real thing than mine do too. The only thing I still wonder about is having a non-permanent joint at cantrail level. On the other hand, there must be a way of fixing the roof to the sides without any gaps as the neatness of the window panes makes it worth it.

 

Colin

[MikeTrice]

Your version of the 2 HAP side is most interesting and certainly the glazing looks very neat.

I am not certain it would fully solve your problem with the grab handles. You believe that a problem with your glazing laying flat is the tails of the grab handles projecting through the side and the superglue used to hold them in place. The grab rail is quite close to the window line. Using my double skin approach what might work is taking the grab rail tail through both skins and then glueing on the inside, hopefully leaving the slot clear of superglue. A safer option might be small blobs of epoxy instead. Having done this the glazing will need a notch cut in it to slip either side of the remainin tail. Hope I explained that ok.

 

The only thing I still wonder about is having a non-permanent joint at cantrail level. On the other hand, there must be a way of fixing the roof to the sides without any gaps as the neatness of the window panes makes it worth it.

David rebates the roof into the body of the coach. What this means is the rain strip is part of the coach side and the roof minus the rainstrip slips between the sides. The joint is therefore visible from above rather than the side. So far I have not shown this on the samples I have created to date. It will suit the Gresley vehicles very well:

 

 

Would the following be practical with a 15thou roof for Emus?

 

[Krusty]

The only time I remember seeing something of Mike's in print was an early (60s, 70s)article in I think Model Railway Constructor and suprisingly it was of a SR emu. If anyone has a reference please jump in.

'Construction of 4mm scale coaches from plastic sheet', Mike Peascod, Model Railways, July 1973. There's a colour photograph of a rather nice LNWR brake composite on the cover.

Anyone remember a series of articles by E.R.H.Francis starting in Model Railway News Feb 1969? I seem to recall these eventually went over to another magazine and there were a lot of them. One covered Gresley stock but I have not traced it yet. Try as I might I have not succeeded in tracking down a list of his articles, other than the Feb 69 and July 70 ones I have.

'L.N.E.R. coaching stock – a Gresley brake composite for Pendon', ERH Francis, Model Railway News, September 1970; the issue with Les Darbyshire's drawing of Morous, which is, of course, why all persons of taste and discernment have this issue.

[Colin parks]

I am not certain it would fully solve your problem with the grab handles. You believe that a problem with your glazing laying flat is the tails of the grab handles projecting through the side and the superglue used to hold them in place. The grab rail is quite close to the window line. Using my double skin approach what might work is taking the grab rail tail through both skins and then glueing on the inside, hopefully leaving the slot clear of superglue. A safer option might be small blobs of epoxy instead. Having done this the glazing will need a notch cut in it to slip either side of the remainin tail. Hope I explained that ok.

 

 

David rebates the roof into the body of the coach. What this means is the rain strip is part of the coach side and the roof minus the rainstrip slips between the sides. The joint is therefore visible from above rather than the side. So far I have not shown this on the samples I have created to date. It will suit the Gresley vehicles very well:

 

 

Would the following be practical with a 15thou roof for Emus?

 

Hi Mike, I have just read this post, having already sent you that PM!

 

The roof joint diagrams do look like neat solutions - as long as nothing moves. I suppose that the joint is to be a 'force-fit' so everything stays in place.The rainstrip on the 2 HAP EMU is, I am told, three quarters of an inch wide. i.e. 0.5mm. My roofs were made from 40 thou. sheet, which has proved very robust and stable. Roofs made from 15 thou. sheet sounds a bit thin without some strengthening ribs underneath. That could cause distortion, which styrene sheet has the tendency to do if fixing to one side only.

 

Colin

[coachmann]

Like whitemetal and etched brass, Plastikard is not useful for all ocassions. For roofs, its useless. No doubt Mike T. is using one of the MJT aluminium extrusions. He can't go wrong.

[MikeTrice]

Like whitemetal and etched brass, Plastikard is not useful for all ocassions. For roofs, its useless. No doubt Mike T. is using one of the MJT aluminium extrusions. He can't go wrong.

Suprisingly enough I am going to try plasticard first, as I think it will give a better method of producing dome end roofs.

 

I will probably use 30 or 40thou that has been "grooved" and bend it around some roof ribs, then set the lot with solvent. If that fails then I will resort to old faithful, the aluminum roof.

[MikeTrice]

My roofs were made from 40 thou. sheet, which has proved very robust and stable. Roofs made from 15 thou. sheet sounds a bit thin without some strengthening ribs underneath.

Make your 40thou roof slightly narrower and add 15thou wrapper?

 

BTW, the precurved Southern side sample has now had a few days to cure properly and is still holding its curve with no sign of flattening. It is suprisingly rigid.

[coachmann]

If making a domed roof? I recommend you save yourself a lot of heartache by buying a Hornby Gresley coach as a donor for roof, ends, chassis and bogies, and if you're lucky the interior! Your plastikard sides will glue to this roof and ends no problem.