Building an MMP RMB - a box of delights

[Heather Kay]

You may recall I had been baulked by some issues around the roof. I let the model sit at the back of the workbench while I got on with other builds. I needed to formulate a strategy, and leaving things alone was the first step.

At the end of last week I decided it was time to pick up where I had left off. I reviewed the relevant section of the instructions, and set off.

The insides of the ends, the bits with the bolts which go through the floor into the chassis, are designed to be fitted to the ends of the roof itself. The bolts help align things, and then pull the roof down onto the body. Well, that's the plan.

The top of the body sides has etched tabs. These fit into slots in the roof gutter assembly. The roof has tabs which slide inside the body, keeping it all in alignment when the roof is fitted.

So, first task today was to fit the inner ends to the roof.

I tack-soldered the central and outer tags to the roof, aligned as best I could and as square as possible for one end. I then test-fitted. This led me to decide that the inner end needed a pass or two with a file down each side and to round off the bottom corners, just to allow a smoother fit.



It only needed the merest pass of the file, and the end slipped neatly down behind the outer end.



Here I am checking fit and making sure things fit snugly, complete with glittery brass nail polish from the filing. I repeated this procedure with the other end.

Both inner ends were tacked in place, in what I think is the correct position slightly rebated from the end of the roof itself. More test fitting. This might just work...



Things still didn't quite fit. Bearing in mind a full interior is yet to be fitted, I wanted to be sure the roof would slip into place without undue stressing of the body - which will probably be painted inside and out by the time of final fitting. At least, that's the plan. I opened out the bolt holes to let the bolts slide in without excessive fiddling about in and through windows that won't let me have access later.

Now things seem to be going my way. Except one gangway had come loose, and the window frame overlays had decided to part company. Now seemed a good time to remove them carefully and clean things up. With hindsight, the end and gangway details should be left until the bodywork and roof fettling is mostly done, rather than done before the ends are fitted. Anyway… time to try fitting the roof again.



Well, the ends seem to fit okay, and with a little persuasion I could get the sides to line up with the roof slots. How I would do that with the windows fitted - and the paintwork done - is a worry. The roof, during fitting the gutter details, acquired a subtle bow, but enough to give me some grief. Perhaps fitting the interior will help hold the sides in register?

Anyway, feeling the sides could be dealt with later, I checked over the ends.



Okay, that's not good. The roof is supposed to overhang the ends. I spent some time fiddling and fettling to see if the overhang could be created. Something has gone wrong somewhere earlier in the build, and I fear it involves removing the ends of the body and starting over. I'm not sure if it's the bends for the sides, or whether construction sequence needs the ends to be fitted inside the bodysides. Either way, right now, I'm looking at deconstruction rather than construction.

As I type, the model is once again sitting on its length of track at the back of the workbench. I was hoping to get on with the bodywork and start the interiors, but it looks like I need to leave things alone before I break it good and proper.

 

[Heather Kay]

I gave myself a day of not modelling yesterday, partly to catch up with some back office stuff and partly to let this build fester gestate a little longer.

After getting some new front tyres fitted to the car this morning, I settled at the workbench and set to. There are some times when all you can do is take things apart and do them over. This is one of those times. I needed to gain some measure of overhang for the roof, and I reckoned the way to do that was to refit the ends inside the sides.

First thing, remove the ends from the body. As I'd used low-melt solder to fit them, this wasn't as painful as it sounds. Some of the styrene corrosion strips at the vestibule end suffered a little, as did one detail part I had fitted with low-melt solder, but otherwise no major harm done. I cleaned up everything, and dug out some 145° solder I'd bought over the weekend.

Odd how 145° solder needed 250°C on the iron to actually melt. Still, it's lower than the other soldered details so I pressed on.

The etches aren't designed to fit inside the ends, so I had to compromise. The top has been soldered to be inside the sides, but the bottom has remained outside. The difference is the thickness of the etch, so it's only noticeable now I've told you I did it.

I tinned the inside corner edges of both body and ends. The technique was to tack solder the top corner of the end in place then, with plenty of flux on a scrubbed joint surface, run more solder into the joint along the outside as best I could to hold it and act as filler. Once I was happy with the fit, I carefully ran the iron down the inside of the joint.

I test fitted the roof assembly, reckoned it was heading in a direction I liked, and therefore fitted t'other end.



A degree of careful fettling returned the characteristic corner of these coaches. As you can see, some of the glued-on detailing has taken one for the team. I wasn't overly concerned. This is stuff that's pretty easy to replace.

Having got both ends refitted and tidied up, I tried the roof again.



Well, it's better. It's not perfect, but it's better. The small tags above the windows slot into the gutter. I noticed they didn't quite slot in place, so with the aid of my magnifier light I identified which side needed a pass with a file. This is what the mark indicates.



Well, it has a little overhang. At this stage I had also moved the inner ends in a gnat's under the roof, though I don't think it made much difference.

So, the plan worked, more or less. What didn't work is the roof still doesn't sit down along the sides, and the kitchen side of the coach has a definite outward bow. The interior detailing may help there by keeping the sides under more control where vestibules and kitchens meet the outsides.

Now, at some point, things have to be painted. Ideally, this is before glazing. I need to check the instructions as to whether the glazing can be slipped in after the interior is fitted. I can probably mask the interior adequately. What worries me at the present is the roof still bows upwards slightly, and needs some help to sit down onto the sides.

So, I need to revisit the guttering to see if I can persuade it to let the roof relax to nearer the flat. If I can't, fitting the roof will be a somewhat messy and permanent affair.

Watch this space!

 

[lancer1027]

Looking very nice Heather

Rob

 

[john lewsey]

It looks really nice to me I'll pop over in the next day or two

 

[OzzyO]

Heather, if your still not getting the overhang that you require, could you solder a length of square brass wire (approx 0.7mm) on the end of the roof with the bottom edge flush with the under side and then file the top edge flush with the roof..

A nice looking build,

OzzyO.

 

[djparkins]

I gave myself a day of not modelling yesterday, partly to catch up with some back office stuff and partly to let this build fester gestate a little longer.

Heather -
At the risk of making myself [even more] unpopular than I am already I will reply to your two most recent posts - and I very carefully considered not doing so for as long as around 30 seconds!

I can see around 3-4 points at which you could be making this difficult. The roof is supplied basically formed. You will need to finalise this BEFORE soldering the side guttering sections to the lower edge on each side of the roof. Now you will obviously know that both of these parts are straight on the fret. If, when you have soldered them to the roof, it is bowing outwards on one side, then this is your mistake and indicates to me that the roof was not finally formed correctly beforehand. The bottom of the roof edge [excluding any lugs] ends EXACTLY where the top of the lugs on the coach sides end. I have checked this in relation to the coach sides and ends tonight and against the CAD drawings and it is an exact match to +/- .01mm - 100th of a mm.

It is also, I suggest, a little mischievous to say that the roof is mean't to overhang the coach ends, when you must know very well that it does - by approx. .7mm at each end. You can see this for yourself by matching up the longest part of the roof with the floor of the coach body, when taken over the outer part of the ends [where the gangway doors are]. Any bowing at the top of the ends is not the fault of the kit as the ends should be the same profile at the top as at the bottom. Maybe reinforce the two folds in each end with a very thin fillet of solder and sand off? Which leads me to the next part.

It looks to me from the shot without the roof fitted, that there is a gap between the inner ends and the outer ends when the former are bolted into place. The thickness must be no more than the two thicknesses of metal - .6mm. There is a further clue here as you should not have needed to open out the holes for the bolts in the coach floor. I've just done a dry run on this and it is simply not required. You do not need to have access to the bolts from inside as they are locked into etched housings soldered into location slots atop the flaps on the inner coach ends. Grrr!

And where in your text have I read that you followed the instructions by applying Evo-stik to every other lug on the top of the inner ends and to the roof - and centring it upon the inner ends [and also lengthways] and letting this set BEFORE releasing the retaining nuts and soldering the roof to the inner ends in its EXACT location via the tabs that you did not use Evo-stik on?

And if this didn't work out [which I do not think you tried] then you are left with the only other possble explanation - you soldered the outer ends in the body at the wrong height! The ends neither fit inside or outside the body but are an angled butt-fit to the sides and as I suggested much earlier in your build, are best soldered from the outside and blended in with the sides. However it would have been a pretty obvious thing to do to tape the ends into the body first and the roof also - to ensure that everything was set up at the correct height before soldering. There is no tolerance really with these kits and one variable will throw things out of kilter.

I suggest you will be unable to avoid using a small amount of Evo-stik on the central one or two lugs on each coach side when you finally fit the roof [and this was never the intention as Evo-stik is your friend!], since one inadvertant picking up of the coach in the middle [one hand over the body gripping the solebars over each of the bogies is best!] will possibly send the sides inwards under the roof. Depending on coach type, the interior may help with this but I wouldn't rely on it. A thin film of Evo-stik on one or two lugs on each side will not show and can be easily prized apart with the aid of a scalpel for removal of the roof.

Now finally a warning from the future! If you do NOT get the roof forming correct now, you really will be whinging when you come to fit the interior, as the bulkheads follow the EXACT upper profile as the coach ends - and the roof will just not sit down at all if it is incorrectly formed in the middle. So if you just do not want to bother with all of that I suggest you trim the tops of the interior bulkheads before fitting them, although it is cheating!

Nw retreating into my nuclear fallout floating duck house!

Regards,

DJP
　

 

[Heather Kay]

David, thank you for that. You've confirmed in my mind I've made a fundamental error at an earlier point.

I don't know where you get the idea your input might make you unpopular!

Now to work out how to correct my c0ck-up!

 

[Heather Kay]

Well, it's been a while, hasn't it? After consulting with Richard, we've agreed a way forward with this build. It's been lurking at the back of the bench for ages now, intimidating me each time I looked in its direction.

It was fairly obvious I'd made some construction errors which were not making my life easy. This kit is designed with close tolerances, and the slightest smidge out somewhere in the build can throw things out badly later on - usually when it's a bit too late to correct the original error. Take note, if you have one of these models waiting to be built.

How to overcome my problems was the focus of some exercise of ze leedle grey cells while I wrestled with a series of late-Victorian and early-Edwardian coaches for a while. A chat with someone at Telford, who encountered some similar problems with their build, also opened some possibilities of how to overcome my problem - how to fit the roof properly when the designer's method wasn't working.

Mr Parkins, please look away now. You might not like what I have in mind!

To recap, the kit roof is designed to be attached to the inner ends of the body, which in turn have bolts which drop through the body floor and through the underframe. My problem was I had induced a slight upward - not outward - bow in the roof when fitting the cantrail and guttering. This bow didn't let the roof sit neatly down on the body's tags, at which point things stalled.

The plan is to begin fitting the interior, and to fit the inner ends permanently at the same time. The roof will not be attached to the ends. Instead, brass strip will be fitted across the roof at strategic points as stretchers, with matching strips across the top of the body. An original idea was to cut holes in the roof, with captive nuts in the body stretchers, so bolts could be fitted holding the roof in register and pulling it down to the body. The bolt holes would subsequently be filled, and the roof finished and painted.

Thinking this through further, the idea has arisen of using rare earth magnets to hold the roof. This has the double advantage of not causing damage to the roof with holes and allowing the roof to be removed if Richard subsequently wants passengers installed (or my shonky soldering and gluing comes adrift inside the coach!).

I haven't reached the stage of fitting the stretchers, mainly because the interior needs to be fitted out. Having trial fitted the interior etch, and managed to get it to slide in without too much aggro, it's obvious some of it will need to be constructed and painted inside the coach body. I am currently weighing up how much of the fiddly stuff can be done outside the body before I have to commit to dropping the interior in place for keeps.



The interior fits! I've had to trim about half a millimetre from each side, and adjust the length of one of the inner ends slightly. In an ideal world, these adjustments wouldn't have been required, but I really don't think they'll be visible once I've finished.



Before I leave to begin some further work on the shell, here's another of those little details. Well, the real thing has them, so why not?

 

[Heather Kay]

As is always the case when choosing to bypass the Written Word, I had a spot of headscratching this morning.

My ponderings were over how to fit the door drop light frames. If following the instructions, the neat etches would be glazed and fitted inside the body after painting it, with the interior dropped in later. As I intend to drop the interior in before painting, this causes a problem with glazed doors. It turns out I may well be able to insinuate the drop lights into the gap between inner and outer assemblies after all the painting is finished, at least, that's the hope.

I am prepared for that to come back and bite me hard.

Anyway, having got the interior shell to pretty much fit in the body without too much heartache, I started to fit it out.



First up, the lavatories, seen here posed with the vestibule partition. Each of the main interior parts is shaped to suit the curvature of the coach side, which I found a useful aid in forming the curve for the inner shell. It's quite satisfying for a part to click neatly into the half-etched line it's meant to sit in. Kudos to Mr P!

I fitted the other end partition in place, tack soldered, nothing more.



At this point the toilet end partition is not fitted, because I need to get paint in and around the toilet walls. I also want to paint the partition, which would be easier on the bench. Likewise, the doors. These are a tripartite sandwich, with detailed outer faces enclosing another part holding the glazing material. Obviously, I can't really fit the glazing until the main bits are painted. Rather than paint bits and pieces, I thought now would be a good time to build up other internal parts so they too can be painted.



This diagram of RMB, the last to be put into production, had a catering storage cupboard taking the place of one set of seats. The cupboard is made of three etched parts which slot neatly together. I opted to tack solder them, at the same time adding some scrap etch support to hold the sliding door in its hole. It's a very neat fit, and I think it ought to be just slightly proud of the cupboard wall, but you'll never see the error when I've finished.

I also assembled the bar shelving. I enjoyed it immensely, and congratulations to David for some neat etch design. The shelves literally click into their slots, and are fixed by nothing more than some cyanoacrylate glue at strategic points.



Finally for today's session, I assembled the bar counter. As with the cupboard door, I added some supporting etch behind the access door. I still have to fit the runner guides.

Tomorrow, I shall consider the seating area for the bar. Some of it may have to be fitted once the inner shell is in the body itself, but it would useful to be able to paint some parts before that. I also need to begin building up the seating, which will be a repetitive sequence. I may set up a sort of production line so I do each step 11 times rather than assemble 11 seating bays individually. We'll see.

 

[Heather Kay]

Out of interest, does anyone know how big the floor tiles were in the bar area?

 

[Bob Reid]

12" square by 1/4" thick if I'm not mistaken Heather.....

 

[Heather Kay]

Thanks Bob!

I ask because someone has offered to send me a photo of the buffet floor of an RMB. It would be helpful to know the size so I can scale the image properly.

 

[Heather Kay]

The past three days have been a little disjointed, due to personal and domestic things. Today has seen some better progress with the internal fittings.



The build is aimed at the early 1980s, and most of the Mk1 coaching stock had been through a series of refurbishments. For the RMBs, things had been toned down a bit from the loud laminate sheet colours of the original builds, aside from the orangey-red storage cupboard at least. To serve as the grey patterned laminate of the main saloon walls, and the bar area seating, a quick squirt of standard automotive grey primer was deemed adequate. In the above image you can see I've painted the floor areas dark grey, which seems to have been the normal Lino colour, and picked out the window frames, doors and partitions in a suitable wood colour.

I remain to be convinced that the bar counter was white, but without further information to the contrary it will have to stay that way. Something is nagging at me the colour ought to be a pale creamy yellow, but there you are.



I've been working through the seating. Each etched seat is preformed, so no complicated sweary folding required. I've attached each handed seat pair to a back sheet, and I'm beginning to think about the end parts that face the gangway. The photo shows one section mocked up to make sure the seats fit neatly against the sides. The plan will be to install the seats once the interior has been fitted to the body shell and after the major painting has been completed.

I think this build will have to be sidelined for a spell, as I need to make some more progress on the WD and the two broad gauge coaches. I had hoped to get as far as priming the seating sets, but there's a fair bit of work before that can be done.

 

[Heather Kay]

I just thought I'd try the bar tiled floor. What does the team think as far as colour is concerned? I have used a dark grey rather than black, so it doesn't get too murky in place.

 

[Len Cattley]

Looking good Heather, wish other coaches were as good as this.

Len

 

[Railwaymaniac]

Len:
"Looking good" just doesn't come anywhere near being good enough as a comment here - "Stunning" comes closer ...

Heather:
Could you spare even a few words as to how you achieved the 'tiled' look to the floor, please?

TIA

Ian

 

[Heather Kay]

Could you spare even a few words as to how you achieved the 'tiled' look to the floor, please?

It's as simple as drawing 7mm squares on the computer, stepping and repeating to give the pattern, then printing out on the cheapest and thinnest paper I could find. I have a colour laser printer, which happily gives a slight sheen to the print, which looks nicely like a lino tile.

 

[Railwaymaniac]

Thanks Heather

And there was me, imagining that you had been slaving away with a bow pen, a ruler and a one-hair brush in there ...

Ian

 

[Heather Kay]

Still fettling away with the interior fittings. Today was mostly spent painting aluminium, something to represent the stainless steel for the kitchen area, the glazing for the internal doors and partitions, and the heater etches under each seat.













The etched vanity mirrors do indeed have BR in the centre, and it needed a good lens to ensure it was the right way up! Even the heater control knobs have etched words on them.

 

[JimG]

It's really going to be a shame to put the roof on this coach.

Jim.