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Last of the First - Part 2

D869

Entry posted by D869

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A second installment of the D604 build...

 

In the previous episode the body was just starting to go together but was still short of quite a few important external panels.

 

Next step was to fit the nose ends. Unlike the class 22, these are far from flat so they had to be bent to the correct curve. This was tricky for a couple of reasons. Firstly there is no good reference to use to find the 'correct' curve, so I had to judge this by studying photos.

 

The NBL factory photos showed that that there was a shallow curve where the gangway doors are and I thought that this became more pronounced on either side. The second thing that's tricky is forming the curve. The presence of the etched lines for the gangway doors means that the end just wants to fold along those lines so it needed some careful work with pliers to form the curve by creating small bends in the plain parts of the etch and trying to avoid creating a fold at the door edges. There was also quite a lot of straightening things out again where I'd gone too far.

 

Soldering the end on is also tricky because there is nothing that can easily be used for alignment, nor is it even entirely clear what the vertical alignment should be. I knew that the top of the nose had to curve downwards so I worked from this. In doing so I decided that the bottom edge of the nose etch was actually too low, so aligning this edge with the bottom edge of the valence was a non-starter. In the end I used the top corners and aligned these slightly below the top corners on the side etches. This gives a reasonable 'drop' between the windscreen surround and the nose.

 

I was a bit wary of the fold lines at the ends of the sides but in the end decided that I just needed to have faith, make the folds and see how things worked out. After tack soldering the ends to the sides, I got out the set square and some nice flat surfaces and spent a lot of time peering at the model to see whether the nose was truly vertical and in alignment with the central pillar of the windscreens. Naturally my first attempt wasn't quite right, so adjust and try again...

 

After the experience with the class 22 I was expecting the cab roofs to be straigtforward. The class 41 kit contains similarly shaped etches which are even labelled as cab roofs, so what could go wrong? I rolled one of these around my solder sucker and tried it in place. It dropped straight through the cab. It seems that these etches are too small in both directions which is pretty strange. I was going to need to make new ones. After a pause for thought I had an idea about how to make this easier. I dug out the used etch from the class 22 and some 10 thou sheet (brass because I had no nickel silver). I then used the hole in the class 22 etch as a template to scribe the shape of the roof. Cut it out with scissors, clean up with a file and I found that I had a pretty good fit at the first attempt. With hindsight it should have been a little longer because I had some tricky filling on the outer corners where it meets the windscreens.

 

As per the class 22, I used thick fuse wire and plenty of solder to fill the gap between the roof and the windscreen surround.

 

For the top of the nose I thought that filler was going to be the only practical answer but I needed something to apply the filler to. I cut some strips from the edge of the body side etch and curved this to the shape of the windscreen bottom. A second shorter piece was added to meet the middle of the nose end and the whole lot soldered between the sides to leave a decent gap below the windscreen surround. I also added a short piece of 20 by 40 thou nickel silver so that I could anchor the bottom edge of the windscreen surround to give it some strength.

 

The photo below shows the kit at this stage.

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I did my best to fill the nose corners using solder, but there is only so much that can be done here because there are some sizeable gaps near the top. I also had my first attempt at forming the various curves on the corners, filing off the excess etch and solder where needed, but I knew that the real work of forming the nose shape was yet to come.

 

Now it was filler time, so I attacked the nose with copious amounts of Milliput and also added some to the cab roofs because these were not in perfect aligment with the main roof. At this stage I also had second thoughts about the curvature of the nose, so I added more Milliput so that I could have a gentler curve all the way to the edge.

 

Here is the result. Looking good eh?

 

blogentry-9623-0-82260600-1346617559_thumb.jpg

 

Now I'd reached the make or break part - shaping the nose. To begin with I decided that I had to get a consistent shape with some reference points, even if it was a long way from the final shape. To do this I tidied up each face so that it was either flat (the sides) or had a simple single curve (the nose and top). I deliberately left the corners as sharp angles so that I could check for symetry and get both ends consistent. The next four photos show things at this stage. I'd also checked the photos again and decided that my initial thoughts about the nose curvature were correct, so the extra Milliput was filed off again.

 

blogentry-9623-0-13891100-1346617630_thumb.jpg

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Finally it was time to shape the corners. The top of the nose is fairly level for about half of its length and then it curves downwards to meet the front panel. The joint between the two is still quite a sharp angle though. The body corners are the really tricky ones because no two photos show them in quite the same way. In the end I decided that there was a comparatively large radius near to the bottom but that the curve was a sort of conical shape because at the top the radius reduces to almost nothing. Finally the corner between the nose top and sides was rounded off - this one was fairly simple - and the top corners blended in. After finishing both ends I was much happier with the shape of the second one, so the top of the other nose had to be re-filled and shaped again.

 

I haven't attempted any detailed photos to show the final shape because the combination of white Milliput, shiny solder and shiny nickel silver makes it very difficult to see with the Mark 1 eyeball, so I reckon that the camera will have no chance. Running my finger over it seems to be the best way to check the shape, but I don't think you can do that yet on RMWeb

 

So here's a photo of the loco with the nose shape fully formed. I've also started to add the nose detail, but more on that next time.

 

blogentry-9623-0-42417400-1346617651_thumb.jpg

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richbrummitt

I tried running my finger over it but removing the greasy mark from the screen afterwards has proved a little difficult. I really need to get it off so that the model can be painted. Sorry about that.

 

I'm not really sure why I tried because I have no idea what shape this engine is meant to be, but so far it does look pretty, and the construction solid.

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D869

I tried running my finger over it but removing the greasy mark from the screen afterwards has proved a little difficult. I really need to get it off so that the model can be painted. Sorry about that.

 

I'm not really sure why I tried because I have no idea what shape this engine is meant to be, but so far it does look pretty, and the construction solid.

 

Thanks Rich. I remember a workplace joke (long long ago) in which someone tried to convince a not too computer savvy colleague of the need for 'electric tippex'. Maybe you need something along those lines?

 

I wasn't too sure of the shape myself, even after looking at photos because they all seemed to tell me something different. Fortunately it starts to make more sense when you try to form the curves in three dimensions. I pity anyone trying to do it on CAD though... I suspect they used good old fashioned lumps of clay to figure out the shape back in the 50s.

 

I must admit that I wasn't too keen on these locos before I started but they certainly have 'presence' and are rather growing on me, at least up to the point when some bright spark tacked headcode boxes to the fronts.

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bcnPete
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Very nice work as usual Andy,

 

That side profile pic is awesome - you have captured the look of it just right with your filling and shaping.

 

With those skills you should be able to find a job as a shaper for surfboards in Hawaii...:sungum:

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D869

With those skills you should be able to find a job as a shaper for surfboards in Hawaii... :sungum:

 

Thanks Pete - one to ponder if I'm thinking of a new career move. I must admit that one had not occurred to me.

 

Another thought - a layout on a surfboard? ... maybe not.

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Donw
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Very nice result shape is very subjective. As a matter of interest I discussed the shape of a A4 with Tony Reynaulds who was making a batch. He used a number of profiles of the cross section and then cut brass panels the same as the prototype and soldered them on because the original was made in a similar fashion the result was good. I suspect that Diesels used pressed panels where the metal is stretched to a curved shape and there is no way we can replicate that (pause for someone to announce they are pressing out panels). So I think you methods are as good as you can get. I am very impressed with the achieved symetry often the hardest bit.

Don

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Jon020

I'm no expert on the technique or the loco... but you've explained your work really well and the results look very tidy... and, from what I can tell.., pretty "right".

Nice model; good project, well explained.

well done!

 

Jon

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D869

Thanks Don and Jon.

 

I suspect that Diesels used pressed panels where the metal is stretched to a curved shape.

 

Probably true, but I've read that the cabs on the class 41s were originally done using alloy castings welded together. I'm not sure how far this construction extended. I've also read that some cast body parts were replaced with sheet fabrications when they realised that it was all getting too heavy.

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bcnPete
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Another thought - a layout on a surfboard? ... maybe not.

 

Probably right...strolling onto a beach in Bermuda's ready to 'hang ten' with a surfboard layout tucked under one's arm would certainly be the talk of the town...:P

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Etched Pixels

The cabs were indeed not steel so didn't rust but flaked instead. One end of one loco if I remember rightly ended up with a steel cab when it needed replacing. The nickel silver does at least make that bit easy as well as the window frames as they can be scored not painted silver.

 

I had the same experience with the cab roof etches being the wrong size and cut mine of scrap 5thou brass.

 

Alan

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D869

The cabs were indeed not steel so didn't rust but flaked instead. One end of one loco if I remember rightly ended up with a steel cab when it needed replacing. The nickel silver does at least make that bit easy as well as the window frames as they can be scored not painted silver.

 

I had the same experience with the cab roof etches being the wrong size and cut mine of scrap 5thou brass.

 

Thanks Alan - didn't realise that you were a 'fellow traveller' in building this kit. I agree - scraping some paint off (although fiddly) is a much better option than silver paint.

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