Copenhagen Fields & TFW’s workshop

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Atlantic 3279
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Re: Copenhagen Fields & TFW’s workshop

Post by Atlantic 3279 » Sat Jan 04, 2020 6:10 pm

Robinson anticipated our needs, all those years ago.
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Tim Watson
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Re: Copenhagen Fields & TFW’s workshop

Post by Tim Watson » Sun Jan 05, 2020 2:59 pm

One couldn’t sleep easy in one’s bed knowing that a lamp iron was missing from the tender inside front sheet. So I fitted one. 

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I also reduced the size of the sandbox horizontal linkage. 
Tim

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Re: Copenhagen Fields & TFW’s workshop

Post by Tim Watson » Mon Jan 06, 2020 10:20 pm

A few details at the back and the second fire iron support. 
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Re: Copenhagen Fields & TFW’s workshop

Post by john coffin » Mon Jan 06, 2020 11:02 pm

Looking really nice Tim, can't wait to see the paint job.

Interesting new kind of self trimming part too.

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Re: Copenhagen Fields & TFW’s workshop

Post by Tim Watson » Mon Jan 20, 2020 10:39 pm

I spent a pleasant weekend at the London Model Engineering exhibition whittling some styrene on the MRC demonstration stand.  All it has to do now is cast OK. 
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Re: Copenhagen Fields & TFW’s workshop

Post by nzpaul » Tue Jan 21, 2020 4:05 am

I think I'll go and set fire to my work bench.... :shock:
That's really remarkable.

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Re: Copenhagen Fields & TFW’s workshop

Post by Tim Watson » Tue Jan 28, 2020 1:00 pm

As promised some time ago, the styrene back head pattern was sacrificed to make a metal substitute, using investment casting.
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The pattern was mounted on a casting cone with wax, sprued  into the back of the pattern in a non critical area and angled to give optimal metal flow.
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A cristobalite investment was used.
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The casting ring is lined with an aluminio-silicate tape to allow expansion of the investment on heating. 
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The vacuum mixed investment slurry is poured into the ring taking care to avoid air bubbles on the pattern.
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The cone former is removed and the ring then placed in a furnace at 600 deg C to burn out the styrene and wax pattern.  This also expands the investment to compensate for the shrinkage of the cooling alloy. 
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The metal used is a high copper (80%) brass alloy - “students alloy”.  It has a liquidus at 1015 deg C and is heated in an induction furnace. 
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The cast button can be seen and, once cool, it is then broken out of the ring. 
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The moment of truth is when the casting is divested using grit blasting. 
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The sprue was cut off and then the casting polished with glass bead blasting.  It is a amazing how the casting picks up all the faults in the original pattern!
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There will be some extra details added to the back head casting such as the firebox door and seat backs.   Apologies for the rather long post, but I thought it might be of interest to see some of the technical aspects of ‘lost wax’ casting.

Tim

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Atlantic 3279
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Re: Copenhagen Fields & TFW’s workshop

Post by Atlantic 3279 » Tue Jan 28, 2020 2:53 pm

It was very interesting.
Most subjects, models and techniques covered in this thread are now listed in various categories on page1

Dec. 2018: Almost all images that disappeared from my own thread following loss of free remote hosting are now restored.

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Re: Copenhagen Fields & TFW’s workshop

Post by Tim Watson » Wed Jan 29, 2020 1:59 am

Belle Isle Up Home gantry, probably one of the most prominent on our model.
Image photo: Pro rail 
Model under way. 
Image

Tim

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Re: Copenhagen Fields & TFW’s workshop

Post by Tim Watson » Fri Feb 07, 2020 12:06 am

I wasn’t originally going to make the signal work, but it seemed a shame not to.
https://youtu.be/2DIW4LYRZdg
The operating mechanism should prevent any interference between the arm movements. 

Tim

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Re: Copenhagen Fields & TFW’s workshop

Post by Tim Watson » Thu Feb 13, 2020 5:34 pm

The BI Up Home gantry is now pretty well complete, apart from bedding in and connecting up the mechanisms.  The secret of making the linkages work was to chemically black the cranks so that they could not be soldered up.  Another useful dodge was to make the dolls out of square brass tube: that way they didn’t act as a massive heat sink when soldering nearby.  The railing stanchions were trimmed to length in situ using a bit of brass tube as a cutting guide for the Xuron cutters.  All the rails and wires were made from phosphor bronze wire, as it has more resilience than brass or nickel silver. 
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The finials were filed up from a Peco track pin and buried down the hollow post, with a separate piece of syringe needle fettled into shape for the round bit. All of these bits were epoxied into place. 
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The final bedding in will have some fixings modelled on the retaining wall and a plastic ladder glued into place: these are more robust than etched ladders. 
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The video shows the signals working by hand on the baseboard.  It may be a little while before we connect up actuator servos.  These will be operated by the passing trains  

https://youtu.be/mPHxJPS-ZNw

Tim

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Re: Copenhagen Fields & TFW’s workshop

Post by Tim Watson » Sat Feb 15, 2020 6:37 pm

It’s now a scorching hot day at Belle Isle Down box. You can smell the hot creosote and grease on the point rodding.
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(The box was made by Matthew Wald I just bedded it in).

Tim

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manna
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Re: Copenhagen Fields & TFW’s workshop

Post by manna » Sat Feb 15, 2020 10:21 pm

G'Day Gent's

I can remember those days at Kings Cross when it was so hot on the footplate, and thinking the 'bobbie's' had it so good, door's wide open, windows all open and a breeze, I know we had window's, but we had a Thumping Great diesel engine only a few feet away pumping out so much heat.

Lovely models, though.

manna
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Re: Copenhagen Fields & TFW’s workshop

Post by Tim Watson » Tue Feb 18, 2020 10:53 pm

Goodbye old friend. 
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When we started surveying Belle Isle to make CF in 1983, the Ebonite Tower still existed: it was demolished soon after.  Ebonite was a hard vulcanised rubber. The tower was a feature in the background of many of the classic railway photos of the 1950s & 60s.  
However, not long ago, we discovered that up until 1955 (a very good year) it had been the works of Tylors, who made hydraulic and sanitary ware products.   The tower acted as a chimney and also supported  a water tank for pressure testing their products. 
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The company moved away from KX to south of the river.  Interestingly, we have ‘Tyler’s Sanitary Ware’ products advertised on some of the lower buildings (clearly mis-spelt Tyler- soon to be corrected). 
Some artwork was made up using PowerPoint, saved as a photo, re-imported to PowerPoint and stretched  vertically to make the font fit the required dimensions.  The colour is conjecture, but blue seemed appropriate for hydraulic equipment. 
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The tower itself was mocked up many years ago by Mike Randall from a lump of mahogany. He has subsequently made some laser-cut & etched sides for it which were fitted a couple of years ago. 

Loosing the Ebonite Tower is the end of an era - wonder how long it will take for the new name to catch on. 

Tim

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manna
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Re: Copenhagen Fields & TFW’s workshop

Post by manna » Wed Feb 19, 2020 5:00 am

G'day Gents

Absolute icon, I didn't know it had been demolished. :shock: :shock:

manna
EDGWARE GN, Steam in the Suburbs.

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