Thursday 23rd April

Worklist:
Generator room extension
Gas holder

Laurence was doing his bit for the advancement of medical science again, so just the two bods.

The gable brickwork panel was thought to be a bit big and needed something to break it up. Enter a tin of old Grandt Line plastic windows, from which a circular frame was chosen. The hole was chain-drilled and then opened up with a milling tool (very satisfying job). The desired effect was achieved.

There have been misgivings about the extension, but it is starting to look more 'at home' now. Add some gutters and downpipes, a bit of paint and grime, and it'll probably be OK.

Geoff returned to the gas holder area. The steel frame was mounted on an odd shaped base, which we assume represented concrete. After much discussion, it was decided to remove the ring firstly in part, but then completely, leaving just the nicely modelled steel base plates. To protect the edge of the hole into which the gas holder dropped, a new steel plate ring/upstand was devised. To mount this, a sheet of 2mm plastic was cut and shaped to the general floor area and a suitable hole cut for the ring.

Lastly, laminated plastic bases were made and glued in place under each stanchion base. The effect was one of greater practicalness and finesse (It looked better). The original bolts will be cut down to just heads and refitted. 'Gravel' will be laid throughout the area and up to the new bases and upstand ring, which will receive some small, riveted plate details.

Finally, we discussed the method of coke delivery, storage and distribution, together with the corresponding ash removal process. To create a believable scenario, these all require much more thought than given before. Full wagons can be temporarily stored on the adjacent road (to the workshop) and the contents shovelled into small staithes or tubs by the main opening. Likewise, ash from the gasifier and scrubber will need to be removed. Part of the track may need to be filled, to allow carts in and out. All interesting stuff!

Thursday 16th April

Worklist:
Review proposed point actuators.
Gas holder retaining wall.
Generator building extension.

Stephen brought along his Gn15 layout that now included two point actuators using the micro-servos (as previously described).

The units are wired in tandem and still worked well with just one AA battery. The whirr of the motors seemed more prominent than before, possibly due to the use of a new battery. We'll have to look into ways to reduce it, if it becomes a problem on Worton Court.

Stephen had received all of the servos and micro switches required to replace the solenoid motors on the layout. Mass production options to be discussed in due course. He had also received a 1.5v power supply, purchased on eBay, but this has yet to be tested.

Geoff carried on working on the gas holder retaining wall. He had replicated the irregular profiled curved wall and added the coping brickwork. This was then printed onto plastic sheet using his cutter-printer set to the partial-cut setting, which produced a scribed sheet. This was cut out, laminated with plain sheet to obtain the correct depth and cut to length. The edges were radiused and the perpends (vertical mortar joints) scribed.

Stephen (with a little help from Laurence), completed the slating of the generator building extension.

A round window will be inserted in the gable, to disguise the amount of plain brickwork.

Thursday 9th April

Worklist:
Generator building feature window.
Generator rooms lighting.
Future point actuators.
Generator building extension.
Gas holder retaining wall and tank walls.

Geoff has an electric paper cutting machine (die cutter). It's planned that the design for the glazing bars of the new feature window will be cut out of coloured self-adhesive vinyl, and applied to a clear plastic sheet. Before we get to vinyl, the first task was to cut out Geoff's design in paper, to see how it looks on the building and answer a few questions - are the beads too thick? are the panes too small to see the future engine inside? There were problems with the design file conversion and not all panels came out cleanly, but we had a reasonable panel.

We wanted to perform a decent test of the interior visibility and, therefore, needed suitable
interior lighting. Fortunately(!) Stephen had prepared a test-rig, comprising three short strings of 3 clear Christmas lights. The filament lamps had a wonderful warm glow - much more authentic than a bright white led. Five lamps were placed in the generator room and four in the gasifier area.

We were very pleased with the result of both the window and the lighting. The glazing beads didn't look too thick, and they will appear even thinner, in dark green (vinyl).

As an afterthought, the dark trim applied to the window reveal was completely removed as it didn't fit properly. The effect was surprising - the window frame looked completely different. The fragile brick reveals will need careful repair, but it will be worth it.

We then reviewed the point actuators made by Stephen and described on the previous post. It was agreed that the H&M solenoids would be replaced by the new design. Stephen will source the required servo motors and micro switches.

Stephen then moved on to the generator building extension, completing the brickwork. Laurence and Stephen then switched to preparing and fitting plasticard roof slates.

Geoff continued with the gas holder retaining wall, carving the plaster to match the stepped brickwork. The radial brick cappings have been drawn out and will be transferred onto plain plasticard using the cutting machine set to scribe rather than cut right through.

Laurence had to leave early, but snapped the other two members quietly working away....

Thursday 2nd April 2015

Worklist:

The lurgy struck the group leader this week, so class was cancelled. However, part of the session would have been to review a prototype point motor made by Stephen (and cadge some 8BA nuts to finish it off).

Stephen had been investigating the use of miniature servos for point motors on his Gn15 line and Geoff had supplied two documents produced by MERG (Model Electronic Railway Group). One used the servos electronic positioning, and the other used just the motor and gearbox. Whilst both were tested, the latter was thought to be a potential replacement unit for the solenoid point motors on Worton Court.

The supplied drilling template was redrawn to suit the servos and micro switches obtained from eBay and Bitsbox respectively. A unit was made up on a base of 3mm aluminium, left over from a sample cladding panel, but lacked a few 8BA nuts. As Geoff's component shop wasn't available, a visit to Laurence's garage was required and the project was completed. However, it failed to work and worries about the redrawing work loomed - could the micro switches be cancelling each other? Back home, Stephen checked everything and noted that two wires were incorrectly positioned and the matter was resolved. The unit now worked!

Even running on 3v rather than the usual r/c 5v, they are not silent, but it will be interesting to see what it works like in-situ. Maybe next week?

Thin piano wire will be attached to the end of the servo horn and go up into the point tie bar. Stephen uses Peco points, so the frogs are not an issue, but the live frogs on WC will require an additional micro switch to change the polarity. It should be possible to piggy-back one onto one of the units above.

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PS After re-reading the MERG article, 1.5v is suggested as a supply for a single motor. Testing confirmed this produced a nice, slow movement, even driving two motors. Cheap 1.5v supplies are available via eBay, which obviates the use of batteries.

Thursday 26th March

Worklist:
Progress generator room extension.
Progress tank platform, steps and gas holder area retaining wall.
Make a start on the grass.

Having forgotten to cut out the door openings from the front of the extension before gluing it together, Stephen had a decision to make.... Rather than risk destroying the MDF shell, he cut out the door openings from another piece and stuck that on the front of the shell. Plasticard brickwork sections were then glued to the front and individual bricks glued over the doorways, for the lintel.

Still some trimming and cleaning up of the lintel bricks is required, but the doors fit nicely.

Geoff fitted his flight of stairs in place and finished off the base and dwarf walls of the tank platform. There was long debate as to how the curved retaining wall was to be treated. What was known, was that working on it was going to be awkward, because of the gas holder frame and base. Checking underneath, two screws were found and the whole structure removed - well done again John!

A new layer of bricks was glued over the existing, after first deciding the profile of the 'stepped coping'. The area behind the thin, sheet wall was filled with plaster to form a base for the coping. Geoff wants to make this in brick, which will, no doubt, be another epic construction job.

Laurence and Geoff decided to try out Geoff's new particle accelerator charging machine - a 'fly swat come tea strainer' he purchased online. 

The test area was covered in PVA, a nail inserted and the ground clip attached. The medium length fibres were diligently sprinkled into the glue, each being 'roughly' aligned by the charge they received from the strainer.

We'll have to wait for the glue to dry to see the final effect, but these pale fibres will probably be used as dry stems amongst lusher ground-covering flock rather than on their own. More practice required!