Pragmatic Pre-Grouping - Mikkel's Workbench

[Collett]

Lovely wagons, that red oxide livery is much more appealing than the later grey.  One thing puzzles me though.  Where do you keep finding these Cooper Craft kits???  It has to be ages since they stopped supplying.. have you found a little time warp somewhere and keep popping back to buy more kits?   

[Simond]

I would certainly avoid using lead and pva.  It will, eventually swell and spoil your model.  I do use lead shot, usually mixed with epoxy, casting resin, uhu or blu tak. 

 

I also avoid using PVA to fix granite ballast as it gets a strange green hue to it.  I use watered down latex instead.

 

I do use PVA for guing card, wood, etc!

 

atb

Simon

[Compound2632]

28 minutes ago, Collett said:

Lovely wagons, that red oxide livery is much more appealing than the later grey.  One thing puzzles me though.  Where do you keep finding these Cooper Craft kits???  It has to be ages since they stopped supplying.. have you found a little time warp somewhere and keep popping back to buy more kits?   

 

Can I just jump in and point out that it's almost certainly not red oxide but read lead - a rather redder, warmer colour that @Mikkel has caught well? It's the classic Forth Bridge colour and adequately matched (to my simple-minded way of thinking) by Halfords rattle can red primer.

 

There's usually a trickle of 4 mm scale Coopercraft kits on Ebay - the provender wagon is especially common, as the least useful wagon, whereas the really useful and common (on the real railway) 4-plank wagons can require a bit more patience.

[Andy Hayter]

Having checked Deluxe's website they say that liquid gravity is non-toxic and as such cannot be lead.

 

They do however recommend fixing with their cyano or epoxy glue. 

[Collett]

1 hour ago, Compound2632 said:

There's usually a trickle of 4 mm scale Coopercraft kits on Ebay - the provender wagon is especially common, as the least useful wagon, whereas the really useful and common (on the real railway) 4-plank wagons can require a bit more patience.

 

Thanks for the pointer on the colour, coming to think of it "oxide" would be browner?  Anyway it's a lovely colour.

 

Ebay for Copper Craft - blimey I've just seen the prices!  Trickle or torrent too rich for my taste.

[Compound2632]

45 minutes ago, Collett said:

Ebay for Copper Craft - blimey I've just seen the prices!  Trickle or torrent too rich for my taste.

 

Patience. Despite my comment on rarity, I've had unopened 4-plank kits for £12 - £14, which really isn't so bad going for a plastic wagon kit - the re-issued Slater's wagon kits are mostly at £12 w/o wheels - another £3.

[PhilJ W]

I read somewhere that its a nickel alloy, here is a chart of the relative densities of different metals.

The ideal metal for weight would be pure gold. The cheapest solution would be offcuts of nickel silver track.

Edited September 28, 2020 by PhilJ W

[AlfaZagato]

There you go.   Weigh your wagons with gold.   Better investment at this point than much anything else.

[Mikkel]

10 hours ago, Andy Hayter said:

Isn't the advice to avoid using PVA with lead weights?

 

Fortunately, as mentioned above Liquid Gravity from Deluxe models isn't lead.  As some may remember I have been regularly monitoring a wagon that uses Liquid Gravity for weighting. This is a good opportunity for an update:

 

The wagon was built in December 2014. 

 

In January 2017 I took this photo:

 

 

 

 

In June 2019 it looked like this:

 

 

 

And now in September 2020 it looks like this:

 

 

The wagon is now approaching its six year birthday, and there is no change that I can detect. Some of the balls appear loose in the photos, but when poking at them with a scalpel they are still firmly fixed. The signs of cracking  initially worried me, but they don't seem to have gotten any worse (compare first and last photo).

 

I will continue to monitor it, because we know that these things may change over longer time spans.

 

Edited September 28, 2020 by Mikkel
Cartoon removed, seemed to be crashing the page!

[Regularity]

3 hours ago, PhilJ W said:

The ideal metal for weight would be pure gold. The cheapest solution would be offcuts of nickel silver track.

True, but lead is not far behind it.

Alternatively, osmium: specific density of 22.6.

Unfortunately, as well as being the world's densest metal, also it's rarest.

 

[Northroader]

At one time, the Model Railroader was full of articles about rolling stock weighed down with depleted uranium. Generally, I put a block of wood inside the body, under the load in an open.

[kitpw]

Recently, on stripping down a loco for repainting, I found that, twenty-five or so years ago, I more or less filled the smoke box with Plastacine - a rather fetching pink colour - it certainly increased the weight: it must have been retro-fitted before the smoke box door was put on and doesn't seem to have done anything more than dry out a bit (but not to the point where it rattles).  I will re-paint with it in place and post an update in another 25 years or so.

 

Kit PW

 

https://www.rmweb.co.uk/community/index.php?/blogs/blog/2502-swan-hill/

 

[Penrhos1920]

1 hour ago, Regularity said:

True, but lead is not far behind it.

Alternatively, osmium: specific density of 22.6.

Unfortunately, as well as being the world's densest metal, also it's rarest.

 

 

How about depleted uranium?  SG 18.7 and freely available at your local army range.

[Simond]

Lead shot is cheap and easily available  - £37 for 10 kg - probably too much for an individual (particularly in 4mm!) but an easy buy for a club.  I bought a 1 litre pack of #8 shot 20 years or so ago from our local gunsmith, and I’ve still got half of it!  
 

A small roll of lead flashing has probably been more use.  150mm wide, 1.3 thick, 7 kg, £17

 

atb

Simon

[PhilJ W]

I've started cutting up short lengths of scrap nickel silver rail (Peco code 100) to use as weight in rolling stock. Liquid Gravity uses tungsten.

[Simond]

Tungsten?  I’d be surprised at £9 a kilo scrap price.  Mind you they’re charging £40 per kg for it, and i5 is very dense, so maybe.

 

I’ve just requested the MSDS out of curiosity.  Will report back in due course.

 

atb

Simon

 

 

 

[Craigw]

7 hours ago, Compound2632 said:

 

Patience. Despite my comment on rarity, I've had unopened 4-plank kits for £12 - £14, which really isn't so bad going for a plastic wagon kit - the re-issued Slater's wagon kits are mostly at £12 w/o wheels - another £3.

 

When exhibitions start up again keep an eye out for those that Mr Coopercraft is listed as attending. He will often have sprues for sale. I have a friend in the UK who has purchased in this manner for me and I now have 18 x 4 plank wagons  that i have accumulated. I only purchase the body sprues as  i replace the underframe totally with Morgan design parts and make a new floor from Styrene.

 

Regards,

 

Craig W

[Compound2632]

18 minutes ago, Craigw said:

 

When exhibitions start up again keep an eye out for those that Mr Coopercraft is listed as attending. He will often have sprues for sale. I have a friend in the UK who has purchased in this manner for me and I now have 18 x 4 plank wagons  that i have accumulated. I only purchase the body sprues as  i replace the underframe totally with Morgan design parts and make a new floor from Styrene.

 

 

I bought a small supply of Midland 6-wheel carriage parts that way at ExpoEM over several years in the last decade but I have the impression he had become persona non grata with exhibition managers over the couple of years up to last March.

Edited September 28, 2020 by Compound2632

[Collett]

I finally have an update on brass etching of windows, and the good news for Mikkel is that it involves a Silhouette portrait cutter.  As Valerie Singleton used to say, you will also need... a Chinese Takeaway, a washing-up bowl, Ferric Chloride, Lemon Juice, hot water, garden wire and... some sticky backed plastic (vinyl).  And of course some brass sheet, I've used 5 thou Albion Alloys from Antics.

Degrease with Acetone (nail varnish remover) and sand the brass with a medium/fine grit paper circa 600 grit.  Cover the brass with the vinyl and send it through the Silhouette to cut out those parts of the vinyl where you want the sheet to be etched, carefully weed out the panes and a border around the part.  You don't need to leave tabs connecting the part to the sheet, this is single sided etching and you need to cover the back of the brass with a complete piece of vinyl, I would recommend this is transparent.  You must make sure you thoroughly burnish the vinyl mask on to the brass, I used the glossy backing from the vinyl to protect the mask, but don't rub too hard or the brass will distort

Eat the Chinese takeaway and wash out the plastic container.  Put about two inches of warm water in the washing-up bowl - ideally it wants to be between 18 and 30 degrees C - one of those electronic aquarium thermometers is useful.  Put the take-away container in the bottom and pour in about an inch of Ferric Chloride (diluted as necessary) and Citric Acid (Edinburgh Etch https://www.nontoxicprint.com/etchcopperandbrass.htm).  With a piece of thick garden wire (plastic coated) bend a shape I can only describe as a Crank Shaft, this will be a handle to tape on the back of the brass sheet with transparent parcel tape.  It should suspend the brass face down in the Ferric Chloride but not letting it touch the bottom.

 

Agitate the brass in the solution by rocking it gently, lift it out occasionally to monitor progress.

YOU MUST TAKE APPROPRIATE PRECAUTIONS USING FERRIC CHLORIDE, EYE PROTECTION IS A MUST, RUBBER GLOVES ARE STRONGLY ADVISED.  Work where a splash on your work surface is not a problem and likewise wear your gardening/decorating clothes - once Ferric Chloride gets on something it tends to stain it... forever.

Ideally the solution would be agitated with a stream of air bubbles, but occasional rocking will also do, but be careful not to slosh the solution about YOU DO NOT WANT THIS STUFF IN YOUR EYE! 

BTW: You must not dispose of Ferric Chloride down the drain, it can be reused time and time again before it is exhausted.  When that time comes it can usually be disposed at the local waste site that accepts used engine oil etc.  Call your Council for details.

 

Try to keep the water temperature (and therefore the solution) above 20 degrees C.  Don't put too much water in the bowl, you don't want the container with the Ferric to float and possibly tip over.

After about ten or fifteen minutes you should see that the Ferric is biting and the bare brass is indented and looks a deeper brown.  After 30 minutes or so you might start to see the pattern coming through on the back of the sheet - this is why I recommend using transparent vinyl and sticking tape for the back.  Keep gently agitating and watch the back, you don't want to over cook the brass or you might start to lose detail. 

When it appears fully 'cooked', remove from the solution and wash in clean water. As mentioned, you don't need tabs because the backing sheet will hold the pieces until you get to this next stage.  Pop the sheet into a bath of Acetone and give the vinyl and tape a few moments to come free, then wash in water and carefully rub with a paper towel, hey-presto, your very own etched brass windows to your own design and dimensions.

 

Cover the brass sheet with stencil vinyl and cut out the areas where you want the brass etched away.  You could also cut out the stencil with a scalpel.  Alternatively you can paint/draw the design onto the brass with a permanent marker (Sharpie) or Spirit Ink (StazOn).  In fact there are many ways of getting the design onto the brass, check out YouTube for various options. 

There's an existing RMWEB article on this subject and CWJ makes reference to an excellent document by The Hollywood Foundry of Adelaide, South Australia who, sadly, are no longer on the web.  I have  a copy of at least part of that document and I'll see if there's some legal way I can get it put into RMWEB or Scalefour Society  archives.

 

Just located (11:00 04/10/2020) a link to the Hollywood Foundry documents - also note there's a thread/heading(?) opened 'Etching in 2mm - 2mm Finescale'.  If something works at 2mm/foot it should certainly work at 4x the size in 4mm. 

 

 

  

The end result, a Silhouette cut pattern in brass.  It may be possible to make the glazing bars thinner using other techniques, they're just a little under 0.5mm, but I daren't measure them in case the vernier jaws snipped through - it's only 5 thou brass after all.

 

 

And finally, that all too revealing close-up after a quick coat of Tamiya Fine Surface Primer

 

I hope folks have found this useful, interesting even.  Remember, the chemicals involved can be harmful, but then so is a bottle of MekPak.  Use common sense, keep this stuff away from pets and children, use eye protection and a pair of rubber gloves.  Have fun.

 

Edited October 4, 2020 by Collett
Important detail

[Andy Hayter]

That is brilliant Collett, but can I comment that you are being a bit wasteful with your etching material (Ferric Chloride).  There is no need to etch the whole pane away and if you etch a thick line round the edge of the pane, the pane will drop out as a brass square and can be fished out after the process is completed.

[Collett]

51 minutes ago, Andy Hayter said:

That is brilliant Collett, but can I comment that you are being a bit wasteful with your etching material (Ferric Chloride).  There is no need to etch the whole pane away and if you etch a thick line round the edge of the pane, the pane will drop out as a brass square and can be fished out after the process is completed.

 

Thank you

 

I understand about minimising the etched area, but the small panes in this case are 2.8x3.24mm, so a 1mm thick line would be fiddly to weed out and would only reduce the etched area by 1 sq mm.  Not worth the trouble.  As regards the larger holes, on the middle picture there are a couple of small rectangles of brass (I should have put them back in the holes for clarity), those are the centres of the 12.16x7.18mm holes where a 1mm inset was drawn reducing the etched area significantly.

Using a backing sheet of vinyl holds the pieces in place, so no pieces float to the bottom of the tank and you don't have to half etch tabs to retain the pieces as you do with a double sided etch. It also stops the 5 thou brass becoming 2.5 thou brass which you really don't want.

Edited September 29, 2020 by Collett

[Mikkel]

Thank you @Collett, I have now read your post carefully twice, and have learnt a lot.  As you mentioned, it's interesting to see the Silhouette used for such purposes also.  Will you be fitting the etchings as a sandwich around the glazing?

 

On a different note, this arrived today. It has interesting details on the early one- and two-plank wagons:

 

 

 

For details and drawings, see Stephen's excellent post here:

 

 

Edited September 30, 2020 by Mikkel

[Mikkel]

Spending some time in our little 'shed' out in the wilds at the moment. It's only 25m2, so no room for a railway but I'm allowed to play on the table sometimes. This leads to all sorts of dilemmas 

 

 

 

For those who haven't seen it, some recent layout photos and stories in the blog:

 

 

[ianmaccormac]

Just a point about Ferric Chloride disposal. If mixed with plaster of paris and let set, it can go in the normal bin. That was info from teaching in secondary schools but 20 years ago so may be things have changed?

Cheers Ian

[Compound2632]

Interesting. Long wheelbase.