Mickoo's BR modelling

[mickoo]

Pritt Stick

Steph

Really! Is it strong enough, will try on the next piece, as suspected the double sided tape is hellish sticky but it's getting there. The pile of swarf and off cuts grows by the minute

I actually found a decent sturdy pair of scissors best for trimming off most of the exterior waste, followed by the fret saw and finally a file and sandpaper to clean up.

 

[adrian]

The other option could simply have been to mark out the shape direct on the metal, but that did seem a trite hard work and being as I'm not very good at this metal work malarky I opted to take all the help I could LOL.

Right, time to turn some perfectly good brass into scrap

As an ardent scratchbuilder I'll be watching with interest. I think my next project will be a scratch build job, the kits have been nice to get the castings but I'd prefer to build up the plate work my way.

In all honesty I would mark up the metal directly for a couple of reasons. One is that I feel it would be more accurate, not sure that's the right word! I'm sure the paper template can be accurate but it's just that in sticking it to the metal will it distort when you glue it down? and can you guarantee that it won't move when cutting out the metal? At least with marking out directly you know that the marks won't move.

Also how do go about filing to the final dimensions without shredding and losing the line on the paper template? The one thing I like about marking the metal directly is that the scribed line also helps to provide a filing indicator. It's hard to describe but when filing down to the line it is possible to watch the metal carefully and when you get to the line rather than looking at the line watch the swarf coming off the metal, you get a thin sliver peeling off as you get to the scribed line which makes a great indicator to show that you should stop filing at that point. I'll have to experiment and see if I can get a photo to show what I'm trying to describe.

My final comment would be to ditch the brass and use nickel-silver for the plate work. N-S is so much nicer to use, doesn't work harden or tarnish in the same way, it's much nicer to work and takes paint much better.

 

[mickoo]

Adrian,

In reverse order, I'm an N-S devotee and I think I said whilst doing the class 40 bogies I'd never go back to brass, however, when one has 'several' yards of brass buck shee it's as good a material as any to learn on, when I get better I'll certainly go over to buying N-S sheets and working with that, certainly any etch work I do in the future will be N-S.

Filing, well I just file until it looks right, the paper most certainly does not move with this tape, nor loose its shape...that I can ascertain. In fact I used it to stick two 10 thou templates together for the o8 bonnet, they didn't come apart without distorting the two parts, this stuff'll stick aircraft wings on and its pretty thin too so when filling the paper just tends to scuff ever so slightly at the edge.

However! I do take your point about accuracy and it is something to consider. When I did the art work for the class 40 bogie the snap scale was 0.05mm, the art work for this project is 0.25mm, how accurate do you really need to be? I don't know and going from uber accuracy to yard broom accuracy is basically a trial into seeing what can or cannot be accomplished.

Scribing is much more accurate and yes it does give you a nice line to file up to, but can one be sure the scribed line is accurate, even under a glass I have trouble discerning 0.25mm on a rule, to scribe to say 0.1mm would be very difficult, yet you can easily etch to that level, again, how accurate do you 'really' need to be?

If the part was a simple shape then yes I'd probably would have scribed it, the wrapper and boiler and probably firebox will be scribed, not necessarily for accuracy but speed, its easier to scribe them than it is to work them up in CAD, print off and stick down.

The primary reason for printing was laying out the rivets for pressing, there's a good 50+ on the cab sheets alone, scribing all of them would send one mad LOL

Regarding accuracy, there is off course the ultimate get out of jail card, take my reading glasses off, then everything looks excellent The resultant cab sheet part which is first up will be the true acid test of the above techniques, if it all goes together and solders up with minimal dressing then I'll be happy, if it doesn't then it'll go in the bin and I'll try another way

All sounds a bit amateurish and garden shed sort of thing, but sometimes I think we can perhaps go just a little too far in the search for perfection (40 bogie to 0.05mm) when in reality we'd be better off making representations that look good in an overall context. Not saying engineering perfection is wrong, just that there may be other ways to achieve inner piece LOL

 

[mickoo]

Just a little update, the double sided tape is holding up well, maybe a little too well LOL and the test piece for the rivets worked really well, almost better than bare metal, neat close and small rivets with no distortion to the metal, even close to the edges, so that's looking good for the main part.

The only down side is that a lot of the cab fixings are not rivets but quite large bolt heads so I'm not sure larger rivets are going to pass muster, which means scale hardware bolt heads and the ache sticking all those one, there's a fair few on the footplate front valance as well. Are they worth it, can they be ascertained at normal viewing distances, is this something that will disturb the inner peace, all questions I'll sleep on over night LOL.

Working side (inside)


Visual side (outside) ignore the apparent creases in the work, that's just where different bits have been sanded smooth.


Also just found out that only the Southern region locos had this style of cab back draught plate arrangement, so that will need revising to the more common type, though some Scottish locos had full height partitions but the upper portion was an add-on and had no rear spectacle plate.

 

[Ressaldar]

Hi Mick,

thinking aloud now, what thickness is the brass sheet? could you consider printing directly onto the brass, setting the printer as for 'hi gloss' photo paper and spraying the resulting 'print' with the type of varnish that is used with and supplied by Crafty Computer Paper for their waterslide transfers - "Nitroacrylic spray - Transparent" says it can be used on metal.

cheers

Mike

 

[Pugsley]

Really! Is it strong enough, will try on the next piece, as suspected the double sided tape is hellish sticky but it's getting there. The pile of swarf and off cuts grows by the minute

I actually found a decent sturdy pair of scissors best for trimming off most of the exterior waste, followed by the fret saw and finally a file and sandpaper to clean up.

I've used it on brass with some success, but it does seem to stick a bit better to plastic sheet. Likewise, I also use scissors for the cutting as much as possible, using a file to tidy up at the end.

 

[mickoo]

Hi Mick,

thinking aloud now, what thickness is the brass sheet? could you consider printing directly onto the brass, setting the printer as for 'hi gloss' photo paper and spraying the resulting 'print' with the type of varnish that is used with and supplied by Crafty Computer Paper for their waterslide transfers - "Nitroacrylic spray - Transparent" says it can be used on metal.

cheers

Mike

Mike, the sheet is 10 thou, a bit thick to pass through a printer, especially as most ink jets wrap the paper around a roller by several degrees, in my case about 80° LOL, but a good tangential thought none the less

 

[mickoo]

Part one rolls off the production line

In the flat


Folded up




I umm'd and ahh'd over the large rivets around the perimeter, in 1:1 they are bolt heads and quite prominent, however looking at scale hardware products raised an issue, their smallest bolt head is too large at 0.7mm across flats, I was looking more for 0.5mm across flats, and, as I don't have any or the patience of a saint I opted out. If it niggles me too much I can always files the rivets flat and drill holes to fit them.

So as a compromise I simply formed larger rivets and then squashed them a little in a vice to take the dome off, a quick rub with a large board covered in lions tongue finished them off. Not hexagonal but not pure domed rivets and at a viewing distance of a couple of feet hard to tell the difference, certainly with my eyes.

I also pondered the spectacle frames and will take one of two approaches, a thin plasticard over lay, plasticard being infinitely easier to work in such small fidelity (for me), or, a CAD photo etch. I might get brave and try a thin brass overlay but I've still not acquired enough metal work skills to tackle that sort of thing just yet....maybe next week LOL. I'm still also undecided on how to replicate the cab side windows beading which unlike the cab front is not flat but a flattened D shape.

Part two soon.

 

[Dikitriki]

but I've still not acquired enough metal work skills to tackle that sort of thing just yet.....

Utter rot - you've just manifestly demonstrated the opposite.

Great stuff, and so quick too

Richard

 

[adrian]

I might get brave and try a thin brass overlay but I've still not acquired enough metal work skills to tackle that sort of thing just yet....maybe next week LOL. I'm still also undecided on how to replicate the cab side windows beading which unlike the cab front is not flat but a flattened D shape.

Very nice - it's looking good.

As for the spectacle plate frames I would cut out a blank slightly bigger than the window and solder it on, you can then drill and cut out the centre of the blank using the existing window opening for the guide.

The side windows you can get fine D shape bar stock in brass. I can't remember where I got the last lot from but it came as a small reel like wire. I heat it to cherry red and then leave to cool to soften it. I then cut off a suitable length, one end clamped in a vice and a small pull with a set of pliers straightens it up nicely. I then solder it to edge of the side window, slowly forming it to shape and soldering a bit as I work around the window.

Happy metal bashing!

 

[JimG]

So as a compromise I simply formed larger rivets and then squashed them a little in a vice to take the dome off, a quick rub with a large board covered in lions tongue finished them off. Not hexagonal but not pure domed rivets and at a viewing distance of a couple of feet hard to tell the difference, certainly with my eyes.

I wonder if using something like bits of 0.45mm brass wire soldered in holes and filed flat to protrude, maybe about 0.3mm, might give a fair representation. They would have a sharp edge which might represent bolt heads better.

I remember machining a minute hex headed bolt on the CNC mill a year or two ago and I have to confess that I had to use an eyeglass to see that it was hex headed.

Jim.

 

[mickoo]

Gents, thanks.

Adrian, will look out for the D wire, Eileens do D stock but it's too large, not a reel but drawn like their wire I presume?

Jim, that would be an option, again lots of holes and as noted probably not noticeable without close inspection.

Richard, you give me too much credit, you haven't seen part two yet LOL

Part two didn't go so swimmingly LOL, I think it'll all fit in the end. However the rear draft plate got filed just a little 'too' close to the printed line, so it'll be in the bin once it has served as a rough template to allow the front to be fettled and soldered on.

I opted not to cut the side windows until the roof cant rail radius had been formed, any openings near tight bends like that tend to bow the material if the edge of the opening runs parallel to the radius.

Not sure on the next step, may add the middle roof section and then drop the front in, or, add the front and then add the roof section, I'm also not 100% convinced I have enough side sheet camber above the waist knuckle line, I'm not quite getting enough of a forward slant on the leading edge of the upper cab side sheet. A new front maybe in order as I cannot file the edges in as the rivets will then not follow the join line correctly.

 

[lancer1027]

Hi Mick,

Thats amazing work. Can we see some progress on the class 40

Rob

 

[Eastsidepilot]

Mick,
Excellent scratch building mate, even if you had the dead scale bolts for the cab sheets I reckon by the time it was painted in 7mm scale you would not notice the flats .

Col.

 

[adrian]

Gents, thanks.

Adrian, will look out for the D wire, Eileens do D stock but it's too large, not a reel but drawn like their wire I presume?

What size are you after? I think I got mine from Metalsmiths (often cheaper than Eileens) which was 0.7mmx0.35mm D wire.
http://www.metalsmith.co.uk/metals-materials.htm

But as Eileens do this size as well then I'm presuming it's too large for you.

 

[adrian]

I suppose if you were really keen you could get one of these
http://www.metalsmith.co.uk/wire-flattening-tool.htm

Turn a groove in one wheel and then roll your own D section.

 

[mickoo]

What size are you after? I think I got mine from Metalsmiths (often cheaper than Eileens) which was 0.7mmx0.35mm D wire.
http://www.metalsmith.co.uk/metals-materials.htm

But as Eileens do this size as well then I'm presuming it's too large for you.

Adrian, I was after 0.6-7mm actually, clearly both stock 0.7mm so no idea why I never saw that, I thought the smallest was 1.0mm

Applying it now might be tricky but applying in the flat would of meant opening the side windows out to the right size and then attempting to bend the cant rail radius which I know would of gone sour, even more so if the material is not perfectly flat in the forming tool.

I'd seen tips and tricks to adding spectacle rims, specifically your method, just not so sure I can accomplish it yet LOL

 

[mickoo]

Mick,
Excellent scratch building mate, even if you had the dead scale bolts for the cab sheets I reckon by the time it was painted in 7mm scale you would not notice the flats .

Col.

Colin, that's what I'm hoping LOL, the class 40 bogie falls into the 0.05mm accuracy I'm trying not to go there with this project, well not too far I hope It can be too easy to fall into the uber detail and end up accomplishing very little. I want something that'll look nice in a shed scene or something, not the loco you put right at the front of your photo shoots, maybe second row or something.

 

[mickoo]

Hi Mick,

Thats amazing work. Can we see some progress on the class 40

Rob

So far it's only the bogie etches, I've currently got two, one already made up and in the detailing stage, the other is still a raw etch, I'll either carry on scratch building the whole loco, or, use these bogie frames to super detail my JLTRT kit that lurks under the bench.

There are some photos earlier in this thread from post #283 onward.

 

[Eastsidepilot]

Mick,
I could profile mill some window beading if it's just flat rims

Col.