My workbench - Experiments in Resin Casting

[Blink Bonny]

Ay up!

What a great and simple idea. I'll have a go at that!

[Tim79]

Morgan,

That's a very nifty idea there sir! I shall have to copy that for my 4F under works.... Best I remove the 0.7mm brake rods from the chassis first and then take a broach to the holes.

Cheers!
Tim

[45609]

Hi Tim,

I may not be necessary to remove the 0.7mm rods that you have already installed. You could cut six short lengths of brass tube and slide these over the wire to make a stepped spigot. The pieces can all be filed to the same length by dropping them into a vertical hole drilled only slightly bigger (+0.1mm) than the tube outer diameter into a piece of flat material of the appropriate thickness. They can then be carefully filed down until flush. Depending on what you find to drill the vertical hole into will depend on how vigorous you can be with the file as the tube approaches the correct length. A thin piece of wood, for instance 2 or 3 ply "Brook Smith" type sleepers glued together, would suffice and it should last the distance as you are only doing 6. This is only the same as shortening the tubes with a filing guide in situ after soldering to the frames. The brake assembly could then be soldered up in a similar way except the top holes in the hanger clip over the spigots in the frame rather than sliding the rod through. If it is not clear PM me and I'll do you a quick sketch.

Cheers....Morgan

[52D]

Morgan did you have a look at the reported discrepancy re the K1 cab thats mentioned on another thread?

[Horsetan]

Morgan did you have a look at the reported discrepancy re the K1 cab thats mentioned on another thread?

Compare with the Dave Bradwell K1.

[45609]

Morgan did you have a look at the reported discrepancy re the K1 cab thats mentioned on another thread?

Compare with the Dave Bradwell K1.

Hmmm....how did I say that without moving my lips? There does appear to be quite a difference in the position of the windows.

[Horsetan]

Morgan did you have a look at the reported discrepancy re the K1 cab thats mentioned on another thread?

Compare with the Dave Bradwell K1.

Hmmm....how did I say that without moving my lips?.....

I must be good at this ventriloquism thing.....

[Daddyman]

Two photos attached re the cab.
I seem to remember working out that the DMR window cut-outs were actually the right size. However, they'd included a half etch within the window area for over-thick window frames, with the result that the windows look too small and the surrounds too thick. In addition it has no surrounds on the front spectacles. My (abandoned) solution is shown in the first shot: I filed out the full aperture and spent hours soldering fuse wire round the outside, but was never happy with my wobbly lines - this is gthe fifth attempt, at which point I opted for the solution seen in the second photo: combining two Bachmann cabs. This is still very rough - the purpose of the undercoat was to hightlight faults in the surface (which you will no doubt see!) that still need to be attended to. The beeding at the rear of the cab sheets has to go on next, and the cabside step.
I'm using the DMR foorplate from under the cab, the steps, the front end, and the chassis - and that's it. All the rest is modified Bachmann.
I hope this doesn't rain on the OP's parade. I've seen the DMR kit make up into a lovely model, and your workmanship on the tender is superb. With those skills and if you wanted you could probably manage the window surrounds that eluded me! And you'll probably get there a lot faster than me!!

[45609]

I hope this doesn't rain on the OP's parade.

Not at all. This thread is a retrospective. The loco has already been built and delivered but I'll note your findings for the future. What you have done by modifying the DMR cab looks OK from the photo but I guess it is all about what you are happy with. Rather than fuse wire I think I may have tried using some straight drawn nickel silver wire. IIRC I think Eileen's Emporium do it down to 0.3mm diameter. It might even be possible to reduce it a little more by using a jeweller's draw plate.

I agree that the DMR K1 makes up into a very nice model and I'll post some more pictures of the build in due course. For now it might be worth mentioning a few things about the valve gear. What I encountered could partly be of my own making, influenced by my normal endeavours in P4. This model was built to 00 gauge and I found that it was necessary to add spacing washers in various places to get the rods oscillating parallel to the loco frames rather than at an unrealistic angle. The difficulty was that, having done this, I found a couple of locations where adjacent parts were fouling. The simplest way of explain this is to refer to the page from the instructions attached below. It is marked up with the modifications and adjustments I made to get a smooth and reliable mechanism. However, a couple of further explanatory notes are useful. I found the supplied expansion link fouled the underside of the running plate but, as indicated, flooding the upper joint with solder and filing down fixed that. The best solder to use is something with high surface tension or in other words one that has good gap filling properties. Carrs 224 is ideal. The only parts that I discarded were the etched slide bars, replacing then with two lengths of square section nickel silver bar. The final modification, which is purely optional, is to replace the cylinder piston rods with round N/S bar. This was done by snipping off the cast rod flush with front of each crosshead and after carefully drilling a new hole in the crosshead the new one was soldered in.

The next two pictures show the valve gear from above and the side.

In the next posting I'll show a few pictures of the finished but unpainted loco body. There will also be a few comments on things encountered during it's construction.

Cheers....Morgan

[Daddyman]

This will all be very useful when I get back to the valve gear!

[Horsetan]

.....I seem to remember working out that the DMR window cut-outs were actually the right size.....

Contrast with Dave Bradwell K1:

[45609]

Contrast with Dave Bradwell K1

A repeat of an earlier comment albeit with a picture attached is helpful but as I no longer have the DMR model to measure and, it seems, Daddyman has filed out the windows on his DMR cab sides I think all that can be established is that they are different.

Moving on to other parts of the body I found a couple of construction issues that are worthy of comment.

The fold up side wings of the smokebox saddle were a bit too tall and in danger of affecting the boiler pitch. In other words it would have sloped upwards from back to front without modifying the saddle. I decided to cut the side wings off and after the boiler and remains of the saddle frame were soldered in place securely to the running plate I inserted some homemade infill strips.

The footsteps had the same problem as the tender footsteps. Inadequate location for foolproof and square soldering. See post #1 of this thread for details.

Etched boiler bands are, as in most kits, way over scale thickness. I never usually bother with them these days. Instead I prefer to use transfers to represent them after painting. Either clear decal film cut into strips if the loco is unlined or the lining transfer alone. It is more than thick enough.

Finally the front frame grab handle holes were over etched for the recommended 0.45mm wire handle. There was no easy solution to this other than patience and quick work with the soldering iron using 145 solder and plenty of flux. I will pre-tin the parts first and then 145 is used with my temperature controlled soldering iron set fairly cool. Circa 250degC is in the right parish but this needs to be flexible depending on the thermal mass of the parts being soldered. This will give a little bit of working time as the solder begins to change phase (solid to liquid). Once things begin to move and the solder flows the iron is quickly removed and since the temperature is (theoretically) just above the eutectic temperature the solder solidifies quickly and the handrail (again theoretically) is where you want it. In practice it may take a few attempts to get the handrail in the right place and orientation but a good tip is to leave plenty of length on the wire sticking through the inside of the frames to give you something to hold on to and a degree of sensitivity in positioning. The downside of this process is that after snipping off the unwnated wire the cleaning up and scraping excess solder off is a bit of a pain.

Here are a few general shots of the loco before I started with the painting.

[60800]

Apologies if it's slipped my gaze in a previous post, but is she going to be Br black, or LNER apple green?

[45609]

Apologies if it's slipped my gaze in a previous post, but is she going to be Br black, or LNER apple green?

Already done in lined BR black. There's a photo lurking about on a thread here or a few on RMW. In a day or two I'll post some more here.

Morgan

[Daddyman]

[quote="mlgilbert30" There's a photo lurking about on a thread here [/quote]
What a beaute!