Monday, 12 October 2020

October 2020 FCAG meeting

This month's virtual meeting was on the theme of soldering: Andy, Graham, Richard, Stephen, Martin, James, chairmanJim, Simon, Chris G and Chris M provided the audience and Jim, Nigel and Alisdair formed the "panel". The following write-up is in no way a primer or even an exhaustive description of each panel member's favoured methods, but simply a quick record of what they said on the day. Those seeking a reference are directed to Chapter 5 of the 2mmSA's "Track" book.

Jim kicked off with an explanation of his personal technique. He uses a silicon phone-repair mat for a work surface, ceramic-tipped tweezers to hold components or pieces of etch, and a small piece of plywood when a firmer work surface is needed. A small brass sheet acts as an anvil on which to separate etch parts.

Soldering, he explained, requires formation of an alloy between the surface of each metal piece being joined and the solder itself. The three indispensable elements are heat, clean metal, and effective flux. The flux dissolves oxides on the metal surface and coats it, preventing new oxides from forming so that the alloy is strong, and transferring heat quickly through the joint area.

Jim's soldering iron is an ERSA RDS80 temperature-controlled model with three presets at 180°C, 300°C and 400°C - he tends to use the 300° setting.

His preferred bit is a 2mm chisel shape - this, combined with the 80W iron power, allows him to use a "quick in and out" technique to work quickly and cleanly, dwelling on the joint long enough to ensure good solder flow and an effective joint.

He prefers 188°C solder paint to paste, cream, wire or sticks, and after years of using a cocktail stick to apply the paint to the work, has recently switched to using a plastic applicator which is less likely to shed fragments into the paint. His tin of paint has lasted years: if it dries out, a drop of water restores it. Tap water in Scotland is generally soft (slightly acidic),which does not affect the chemistry of the flux in the solder paint, but those in hard water areas should use deionised or distilled water (such as is supplied for car batteries) to ensure that the flux, generally phosphoric acid, is not neutralised by the carbonates in hard water.

In the image, a drop of paint has been placed on the holes for the bearing cups in a wagon chassis etch. The cups are placed face down on the mat and the etch manoeuvered over to locate them. They are then soldered with a  touch from the hot iron, which is cleaned first by plunging it into a small wad of brass wool such as this.

When laminating layers of etch together with solder paint, Jim finds it unnecessary to tin the surfaces first - instead he simply paints the inside of the sandwich, folds the etch over, holds the two layers in contact using the tweezers, then applies the iron and draws the tip slowly round the metal surface so the solder flows. In the shot below, a multi-layer window is being built up.

The fold tabs and etch frame are not removed until the laminations are all secured.

If solder paint is not used, however, then both sides of the sheets to be laminated should be tinned first.

If the edges of laminations are apparent and this is visually obtrusive, for example on solebars or wagon framing, a useful tip is to flood the edges with low-melting-point solder or whitemetal (that is, the stuff that melts at below 100°C, not the 145°C solder) , which fills the gaps, then the edge can be tidied up with an old file. (Solder clogs files and reduces their effectiveness, so only old or worn ones should be used for this).

Another use for LMP solder is to attach smaller fittings such as chimneys and domes to larger metal objects such as boilers; the joining surfaces are tinned first with ordinary, then with LMP solder, which makes it easier to attach the small items in spite of the larger thermal mass of the boiler which can otherwise make it hard to bring both surfaces simultaneously to the temperature required for a good joint with ordinary solder alone. The bit must be cleaned after use to avoid corrosion by the different solder; alternatively, a different bit can be reserved for LMP use only.

Nigel took up the discussion with some pictures of his equipment. His soldering station, an Antex 660 TC, allows variable tip temperature and 50W of heat, and plug-in irons. Nigel works at 275-300°C most of the time. He has two irons, one with a small chisel tip, one with a round tip, and just plugs in the best one for the job in hand.

Like Jim, he cleans the tips on brass wool. Two kinds of cored solder are visible in this photo - one has a tiny amount of silver which aids flow for some joints -  as well as Carr's 188 solder paint and Green Label flux.

A wooden work board has "fences" of stripwood fitted to stop small items sliding away from the iron. Clamps of the David Eveleigh skewer-and-clothes-peg variety are also very useful to position work.

Etches and parts are cleaned with wet-and-dry paper, emery cloth, Garryflex blocks of various grits, and (sparingly and carefully, on account of the sharp stray fibres which can irritate skin, lungs and eyes) a fibreglass pencil.

Workholding involves not only a conventional small vice with smooth jaws, but this highly desirable Eclipse toolmakers vice ... I think it's a model 180.

Cleaning up is made much easier by use of an inexpensive ultrasonic jewellery cleaner from eBay. Nigel simply uses a water bath for 10 to 20 seconds.

He still prefers steel tweezers ... flux spattering on these will rapidly corrode them so they must be carefully cleaned after use, or given a quick dip in the ultrasonic cleaner.
For some jobs it's hard to beat a resistance soldering unit (RSU) - this is a London Road Models unit - it comes with a probe lead, an earth lead, and a footswitch for operation.
Work is done on a metal sheet, or metal foil, connected to the earth lead.
The probe itself is a short length of carbon welding rod, brought to a fine point using a pencil sharpener, and clamped by a small collet to the probe lead. The tip is a consumable which is sharpened as often as required, and replaced when necessary.

A recent Scalefour Society video tutorial by David Brandreth gives an excellent introduction to RSU use.

Another handy technique in certain situations is silver soldering - especially where a strong joint is wanted which will not be loosened by further work with soft solder around 300°C. The work has to be bound firmly in place using fine wire or clamps, the joint prepared with small slices of silver solder and covered with paste or powder flux suitable for the two metals being joined, then heated to between 600°C and 800°C depending on the grade of solder, using a small gas torch. 

Neither Jim nor Nigel were keen on of solder balls, preferring simply to cut small slices of wire solder, but other FCAG members were enthusiastic ball users, especially for trackbuilding to create consistently-sized chairs.

Other tips shared included being sure to plunge the iron tip into the brass wool before and after every joint, so ensuring a clean bit, better joints and extending tip life. Tips, usually made of copper, are normally iron-plated to prevent corrosion by the flux; the plating must not be damaged and the temptation to file the bit to special shapes is best resisted, or done using a spare bit. Some members spoke highly of solder cream, "hot tape" to position components accurately, and Loctite TTC-LF or similar tip tinner/cleaner for situations where despite best efforts a bit has become dirty. Cleaning up joints is helped by a variety of tools, including old files, scalpels, triangular scrapers, sharpened jeweller's screwdrivers, and so on  - here are Alistair's:

After some further discussion in the group, we moved on to ponder, yet again, our proposed group skill-honing cameo shed layout. Much discussion focused on the desirability, or otherwise, of a turntable. A plan will be finalised before the next meeting hopefully, then work will be allocated to those willing to try their hand at various tasks.

The next meeting will be a call on 14 November with a theme of "your most-useful, and least-useful, tool". This should lead to an interesting series of sheepish admissions of impulse purchases at exhibitions and flea markets!

Sunday, 13 September 2020

September 2020 FCAG meeting

We had a bumper attendance of 12 at this month's virtual meeting: Martin, Nigel, Alastair, Alisdair, Tony, Simon, Stephen, Graham, Jim, Richard, Andy and James. 

This month's theme was the project you'd love to build but (probably) never will. It prompted some interesting discussion. Andy took us through his past project of Leslie and future plans for Aberdour. Jim gave us a look at Airdrie's railways in maps, pictures and scale drawings: at one point he made serious plans to model the Caledonian terminus there but eventually concluded he'd be better doing something simpler ... so built Connerburn and now Kirkallanmuir instead.

Richard talked about the monumental coal staithes at Albert Edward Dock on the Tyne, and backed it up with some excellent photographs. Tony showed us his part-completed Hest Bank project, which he stores in sections until the day when he has a 13-metre-long shed, or converted farm steading maybe, available to house it. There were beguiling photos of 12-coach trains dwarfed by the baseboards in the sections completed so far. (Remember, this is the man with nine Black Five tenders!)  His comment was "Even if I spend my time not getting there, at least I'm content on the way", which perhaps summed up everyone's feelings about their pet projects. We spent quite a while discussing ways of lightening baseboards, and the timeless dilemma of whether to scrap and rebuild once lessons have been learned, or to soldier on and persevere with what's been achieved so far.

Alisdair gave a a civil engineer's perspective of the Findhorn viaduct on the Highland Railway's cutoff line from Aviemore to Inverness, backed up by a series of archive photographs, and discussed the possiblities of a roundy-roundy based on the viaduct and a simple passing-loop station on the lines of Moy or Tomatin. Graham gave a quick glimpse of three locations with potential: Clydebank Dock West Junction near Glasgow; Stannergate near Dundee: and St Ives in Cornwall.

Alastair showed us his current research into lightweight baseboards: foamboard skin separated by 3D-printed spacers along the trackbed, each with prongs to engage the foamboard and held by double-sided tape.Here's one of the blocks:

All very innovative. The difficulties of cutting foamboard neatly was raised by the audience. Alastair recommended the Logan Foamwerks series of tools, which do indeed look interesting.

We then turned to the familiar subject of our next group project ... some time was spent going over old ground but eventually we made some further progress. The tandem point, rejected in the most recent iteration of the track plan for being too hard to model due to a very short central crossing (the formation was two right-hand diverging, 1 in 5 turnouts), was resurrected in simpler form; we realised a raised coaling bench is unprototypically large for a  two- or three-road shed, which in turn meant we can simplify that part of the layout; and we discussed how we might push the project ahead even if a tighter lockdown lies ahead through the winter, as now seems inevitable, by dint of less-experienced members having a bash at making individual items (turnouts, buildings, etc) for the layout, and the more experienced members acting as mentors and applying strict quality control so that reliability is not compromised, a lesson learned from Sauchenford.

So, a briefer update than usual, but the meeting itself lasted for over three hours and was full of interest. The virtual format allows us to involve members who live too far from the central belt to attend physical meetings, and we hope we'll retain this even when (if!) we return to physical meetings in the future. Our next meeting will be virtual again, on October 10th, and will hopefully be a tutorial session. As a reminder, any 2mmSA member living in Scotland (or simply with an interest in what we're doing) is very welcome to attend - simply contact Alisdair Campbell to receive the regular invitation mails - his e-mail address and telephone number are in the newsletter in the "Area Group Contacts" section.

Sunday, 9 August 2020

July and August 2020 FCAG meetings

Two months for the price of one in this update!

Our July video meeting had the theme of wagons: Alisdair Campbell gave us a rundown on his collection, from BR prototypes to his Highland Railway fleet, from plastic kits, commercial etches, and his own etch designs, and some pure scratchbuilds. Some discussion of couplings ensued. I was not able to take any screenshots, but if Alisdair sends me his pictures I will add them here.

I had to leave the meeting at that point, but I am told there was some further discussion regarding the proposed group layout. Forfar shed is emerging as a theme. The prototype shed is still standing, in use as the headquarters of a firm of steel-framed agricultural building suppliers.

The shed building is a typical Caley design of the late 1890s but, at four roads by seven bays plus a separate fitters' shop, it is bigger than we want for our layout, which is intended as a display unit for use at exhibitions (remember them?) to convince the punters of the merits of 2FS over "N". As such, it needs to be legless (to sit on top of the exhibition table usually supplied for the 2mmSA Further North Road Show), lightweight, compact enough to go in the back of a car while still allowing four weedy FCAG members in the front (we think 3 feet long, 18 inches deep, 8 inches high when packed).
However, Arbroath shed, completed the year before Forfar, is very similar and had three roads by six bays. Thanks to the generosity of a friend we have its dimensions from an official drawing, so we can hopefully produce something visually convincing. In any case, it is only an inspiration for our scene, and we only aim to model one end of it. The whole thing is meant as a learning exercise, a short-life project to be disposed without ceremony once it has outlived its usefulness. The plan will be something like this Templot rendition:
The August meeting was again a Zoom affair, and consisted of a show-and-tell session. First up was a new recruit, Richard, who told us about his buildings based on Fenwick Pit in north-east England. They are made the old-fashioned way by drawing the shape onto brick-pattern-embossed styrene sheet and building up layers. The window glazing bars and much of the more delicate detail are from Evergreen microstrip. A full write-up is on RMWeb, but we were able to see the results all brought together, in front of a prototype picture on his computer screen:
Some discussion ensued on the best source of 2mm scale hopper wagon kits, with Fence Houses Model Foundry the most likely contender.

Next to go was Jim, who showed us his progress with the remarkable model he has made of the awnings for the Grampian group's Dunallander station. Again the full story is on RMWeb but it was good to hear the detailed tale directly. 
Jim has also been working on further buildings for his own Kirkallanmuir layout. He showed us one or two pictures with an explanation of how he'd created the roof textures. This is a rear view of a small stable, taken part-way through construction and before weathering. Not the most elegant photo but it was what I happened to grab during the description. I hope Jim will post full details on his RMWeb layout thread in due course.
 Andy talked us through his progress with a Fence Houses Jinty chassis, seen here during its live demonstration in motion.
Simon's subject was layout legs. Walking the rain-swept streets of the south side of Glasgow, he was struck by the number of home-assembly bed frames which turn up waiting for collection by the authorities, presumably as kids grow up and need a bigger bed or leave home. Many of these beds were of the type with wooden slats to support a mattress. It occurred to Simon that these slats were likely to be well seasoned after being indoors in a warm place for several years, unlike the wood typically available fresh from a builder's merchant or DIY warehouse. A few such slats therefore accompanied him home and were allowed to recover from the rain in his garage for a month or two.

Although the slats were preshaped to a gentle curve, he realised they could be used in pairs sliding past each other to create adjustable legs by using a wood router to cut accurate slots, and pairs of M8 bolts top and bottom to lock them at the desired height. The curved shape means there is plenty tension to ensure the legs don't slip once the bolts are tightened.
Once in place under the layout, a triangular plywood flap is opened out for lateral stability. The flap is hinged so the legs can pack down flat.
The design uses T-nuts attached to the woodwork as far as possible so that there are no wing nuts to lose. Everything is held together with M8 bolts.
Tony was next. Everyone's jaws dropped when he revealed how he'd spent a wet staycation in a caravan in glorious Scotland ... batch-building 2mmSA Black 5 kit tenders.

Not one tender. Or two or three or four or five ....

NINE tender bodies! All subtly different. Apparently the worst part is the fire-iron tunnel. Next he will tackle the functional powered chassis which runs behind the cosmetic frames.

As if this was not enough, he has also been working on Farish Jinty and 4F conversion chassis. No photos of these though.

Alisdair has been working to complete the model sewage works he promised for Tony's Hest Bank layout.
The Silhouette cutter has been used to good effect to create the roof slates on the store. The capping strips are from Plasticard.
The primary settlement tanks are of conic section. Alisdair cut them using the Silhouette from a mathematically-calculated projection which, to his slight surprise and greater satisfaction, came out right first time.
The concrete-paved roadway are achieved by painting concrete colour onto black card, then scoring through the surface to create the impression of large panels.
Railings are from copper bell wire made up using an aluminium jig. His ladder-soldering technique was covered in a previous blog entry.
We were also shown stock which has benefitted from the recently-introduced nine-spoke, 7mm wheels in the 2mmSA range. The difference is most noticeable when the vehicles in motion.
The rest of the session was spent on a quick discussion of the planned group layout. Nigel had circulated a sketch of a possible design for the basic support structure - a plywood-faced foamboard, or hollow-cell board "suitcase" with welded 1/16" aluminium framing. It turned out not everyone had received the mail in time however, and Nigel himself was busy out cycling in the sunshine (second sunny day in Scotland this year!), so we deferred full consideration for another time. The folding-hoop supports for lighting, a fascia, and a cloth sky sheet are a nice touch. The idea is that it will fit transversely into the boot of a small car and offer full protection to the model. The base will be solid with wiring feeds to the track brought out to the rear for linking. Point control may well be mechanical for simplicity, since everything is on a single board, but if necessary Arduino-driven servos may be used. Design of the turntable mechanism, whether mechanical or power-driven, is still under consideration.
It remains to be seen whether a physical meeting will be attempted in September, but the balance of opinion was that it is still too early. Time will tell.


Saturday, 13 June 2020

June 2020 FCAG meeting

Our virtual meeting this month saw Nigel, Alisdair, Jim, Chris G, Tony, Mick S, Graham, Simon and Stephen zoom in for a session with the theme "Buildings".

First up was Chris, who took us through the technique he has developed for Bosaleck, written up in more detail on RMWeb, and indeed reported on from our March meeting. But you can never have too many photos so here's a sequence of what he showed us:

Starting with a "kit of parts" on 1mm card. The laser can cut holes with separation down to 0.3mm.

Spray with ultramarine/umber mix below and white acrylic above, and dust with Attwood Aggregates Scenic Dust:

Doors added, masked and sprayed green
 Glue in the glazing:
 The window sashes sit in the reveals:

 Magnetic clamps from Smart Models: a great time-saver:

 The laseer cuter makes it feasible to design buildings with full rafter and truss detail which locate accurately into slots in the walls, without spending months or going mad with boredom cutting it out with a craft knife:

Roof tiles printed on brown 80gsm Kraft selfadhesive paper

 Two coats of Bog Oak acrylic paint:
(Very) dry-brushed with a minimal amount of white. The slight raised texture of the brown Kraft paper helps here.
Gutters also cut by laser in 0.5mm grey board: the tangs attach to the underside of the roof board. No attempt made to round off the gutter, but after painiting the correct colour, a black marker pen is drawn along the top to give an impression of depth:

Sills are similarly cut from 0.5mm material
 Bridges are made from laser-cut card with computer-printed downloadable brick paper:

Next on stage was Jim, who summarised his building technique used on Kirkallanmuir. CAD elevations are designed then a cutting file is sent off for laser cutting from 1mm MDF.
 The cutting is precise enough that the delivered parts fit perfectly in a "dry run":

Smart Models downloadable building papers are purchased then manipulated to change the colour balance in Microsoft Office Picture Manager. Signwriting details are edited in as required:

Windows from Jim's own etches: they are painted before glazing material is slipped into the slots between the layers:
 Gutters and downpipes are added from styrene and wire. A dental burr is used to scrawk a half-round groove into the guttering.
Alisdair showed us his recent experiments in producing roof tiles with the help of a Silhouette cutter. He used 80gsm white self adhesive labels. Plain water colour (on the right) was not very effective. Much better was enamel (on the left, one patch thick, one thin) with thin watercolour on top.
Alisdair's building material of choice is styrene sheet. A recent model of a Highland Railway store was made from Evergreen siding.
His technique for guttering is to use an all-round horizontal frame of styrene, with the gutter simply scribed into the surface. The frame is then cut down to the edge of the gutter and the inner part is cut out before being fixed to the top of the walls.
Alisdair took us through his multi-layer technique to build up windows. The various views in the sketch should help: the numbers identify the same part in each view.

An example of the finished result:
An earlier technique he used to represent window sashes was simply to glue microstrip behind the window apertures:

Mick's building technique starts with hand-cut card parts and brickpaper covering (Builderplus or Howard Scenics), as instanced by these shots of a pigsty for his Callaton layout. The paper is left with overlaps: when joining two pieces at a corner, one is trimmed off first, the part is joined, the overlap form the second one brought round the corner and carefully trimmed, with the white edge removed using a touch of watercolour. A razor blade and a scalpel are indispensable.

A corrugated-iron roof is added from wine-bottle metal foil imprinted with corrugations using two coffee-jar lids:

The sleeper fence is made by cutting individual sleepers from card and gluing them to horizontals of 1/32" or 1/64" plywood.

Finally the bottom of the fence is trimmed flush using a razor blade and a hammer while holding the camera in your teeth. What could possibly go wrong?
Once the blood is cleaned off the fence, it can be planted in the ground and looks very effective. The standpipe added near the corner has flooded the ground - the water is represented using the Gordon Gravett technique of microscope slide cover glass.

That ended the "Buildings" theme, but it was interesting to see how four modellers use very different techniques to achieve such high quality results.

Simon showed us the baseboard legs he has made for Glenfinnan, using IKEA bed slats as raw material. These are nicely seasoned and can quite often be acquired for nothing from discarded furniture. A base plank of 3"x1" is rebated to take the IKEA bed slats. Two slats are used for each leg, with a slot routed in one to take a sliding peg and tightening bolt on the other, so height adjustment is possible. A triangular flap, hinged so it can fold flat for storage, provides stability

We spent some time discussing (yet again!) the possibilities for a new group layout once lockdown has eased. A shed scene may offer possibilities. Our homework is to come up with some concrete ideas.

The next meeting, still likely to be virtual since Scotland will still be in phase 2 of the lockdown relaxation, will be on 11 July.