Brimsdown-The last grand project.

Tell us about your layout, where you put it, how you built it, how you operate it.
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Will L
Posts: 1698
Joined: Sun Jul 20, 2008 3:54 pm

Re: Brimsdown-The last grand project.

Postby Will L » Thu Mar 26, 2020 3:01 pm

Back in the day when peole were a great deal less fussy about fitting realistic tie bars to points I too had switch blades solder to a PCB stretcher/tie bar. The solder joint was indeed inclined to fail. The solution was to reinforce the joint with a little L shaped piece of thin metal strip. I used 5 thou phosphor bronze strip which I also used to make pickups at the time. Sides of the L no more than 1mm vertically and 2mm horizontally and the strip no wider than the PCB tie bar. You can barely tell they are there in among the solder and they can be relied on. I can't say I never had one fail, but I don't remember it happening. It was certainly not a regular thing which the plain solder joint failing was.

PhilipT
Posts: 26
Joined: Thu Mar 05, 2015 4:18 pm

Re: Brimsdown-The last grand project.

Postby PhilipT » Thu Mar 26, 2020 3:16 pm

A simple but highly effective alternative was described by Mike Norris in SNews a few years ago using vertically mounted pcb with 0.45mm brass wire soldered to the switch blades. It is not difficult to make, is reliable and unobtrusive. Where he used 1mm thick pcb, I use 0.6mm material which is more than adequately strong. I have also used 0.4mm stuff but gapping it while retaining strength is a bit fraught, hence the 0.6mm which I believe is obtainable from Hobby Holidays.

Tony Wilkins
Posts: 344
Joined: Tue Mar 20, 2012 3:57 pm

Re: Brimsdown-The last grand project.

Postby Tony Wilkins » Fri Mar 27, 2020 12:52 pm

PhilipT wrote:A simple but highly effective alternative was described by Mike Norris in SNews a few years ago using vertically mounted pcb with 0.45mm brass wire soldered to the switch blades. It is not difficult to make, is reliable and unobtrusive. Where he used 1mm thick pcb, I use 0.6mm material which is more than adequately strong. I have also used 0.4mm stuff but gapping it while retaining strength is a bit fraught, hence the 0.6mm which I believe is obtainable from Hobby Holidays.


Hi Philip.
I seriously considered using those or something like it for my layout. However as I didn't really want the tie bar on edge, for several reasons, I elected to go for the 'simple' solution for the hidden sidings. Plan B is that if their reliability proves unsatisfactory, I will replace them with a modified design as they fail. The desire to get enough track down to be able to run something being the overriding factor. For the scenic turnouts I will be using a combination of Mike Norris's design and the old MRSG / Studiolith wire in tube type utilising Exactoscale Tortoise mounting plates modified to fit the Cobalt motors. I have already successfully fitted something similar, but with Tortoise point motors to the EMAG (ex NAG) group layout. I will post details in the not too distant future.
EDIT: the pcb I am using is approximately 0.75mm thick x 2.0mm.
Regards
Tony.

Tony Wilkins
Posts: 344
Joined: Tue Mar 20, 2012 3:57 pm

Re: Brimsdown-The last grand project.

Postby Tony Wilkins » Mon Mar 30, 2020 10:03 pm

What follows is pretty mundane stuff, but may be of interest to some.

Dropper wires.
The method I use dates back to my involvement with the North London Group's layout Heckmondwike and has been successfully used on Bodmin and my layout Green Street. The golden rule is a minimum of two dropper wires per length of rail or rail section (crossing or switch). This is to build in some redundancy and increase reliability. If one joint fails, and they do, things will continue to work. Only when both fail do things stop and then there will be two joints to mend, but less often.
I use 22 swg tinned copper wire for preference. A batch of wires are cut to length (never enough) and the end 2.5 - 3mm bent at right angles to the rest.
Holes are drilled through the base board next to the outside of the rail, being careful not to mark the head of the rail. A small piece of scrap plastic drilled through and placed against the chuck can serve this purpose. My drill features a hexagon quick release system (sometimes known as Snappy) and I have some drills with quite a smooth face to the holding piece. I previously used a 1mm drill for this job, but as the smallest drill in the set was 1.5mm, I have used that instead and has the advantage of being longer.
After inserting the dropper wires into the holes, the end of the wire is pulled up and the last 5mm or so of the vertical part is gently bent inward toward the rail so that when pushed back down into position, the horizontal end of the wire lines up with the underside of the rail, ready for soldering.
Here is one that I made but removed before soldering showing the final shape.
DSCF0916.jpg

The dropper wire is then held in place from underneath, whilst Orange label flux is applied to the joint followed by a small amount of solder carried on the bit to the job. I know this is not the text book way of doing things, but this controls the amount of solder used better and it works. It takes me less time to do than to write about. I can understand why people choose to solder the droppers to the side of the rail, its easier, but does not look as neat.
Where this gets to be fun is with the tracks near the center of 2 foot or wider baseboards as there are invariably baseboard members in the way and one starts to run out of reach. Occasionally I have shifted where I put the droppers for easier access underneath.

Tag strips are then fitted in place usually under the rail ends of adjacent track panels. The end track panels have two sets of droppers fixed at the inner end, as seen to the right of the tag strips. This reduces the amount of cable needed to wire things up. The inner track panels have one set at each end.
DSCF0922.jpg

The dropper wires are then fiddled through the tags, but not soldered at this stage. Any poorly soldered joints usually make their presence known at this stage.
DSCF0924.jpg


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