Track bonding
- Thread starter Neil Robinson
- Start date
TheMartin
Registered
Hi Neil, I wondered if you were still using/reccomend this method? I've bought some screws from this company and tried a few test joints and it seems to work very well.A relatively easy and inexpensive method from GSM
[h4]Posted by: fnrobinson Jun 3 2009, 08:19 PM[/h4] When I visited Fred (Dragon) on Sunday I was impressed by the amount of track he had acquired but concerned about the lack of cleanliness of the rail ends and fishplates. Track was being laid enthusiastically but I feared that when power was applied trouble would occur at many of the joints
A really good method of bonding track properly is detailed on http://www.girr.org/girr/tips/tips1/track_soldering_tips.html < Link To http://www.girr.org/girr/...ck_soldering_tips.html However I wanted to try a quick fix, minimum expenditure (on both tools and materials) and minimal preparation method.
IMHO there is little point in cleaning the rail ends without cleaning the fishplates. This means removing (sometimes awkward) and replacing (expensive) or cleaning (not easy) them. Using rail clamps at around £1.40 each isn?t an option as Fred?s layout will have several hundred joints!Drilling the rail and using small nuts and bolts wouldn?t guarantee good electrical connection between bolt and hole in the rail and would risk fouling wheel flanges if the bolts were slightly long. Tapping the holes should resolve the connection issue, but tapping that many holes would be tedious especially with the care needed with such small taps and the potential problem with over long screws would remain.
I finally managed to waken a few of my brain cells and a web search revealed a supply of small stainless steel self-tapping screws. I chose the No 2 x 6.4mm pozi head countersunk type from http://www.modelfixings.co.uk/self_tapping_screws.htm < Link To http://www.modelfixings.c...elf_tapping_screws.htm This company is mail order only but their address is less than seven miles from Fred?s home.
So I decided to try the following method. Strip out a little wire from some mains cable, in my case the earth conductor from 2.5sq mm flat twin and earth. Any similar sized wire will do and using freshly stripped wire will ensure that it is clean. First twist one end using round nosed pliers, then kink the middle, put another twist around 15 to 20mm from the first, then cut where the excess wire crosses on this second twist. A final squeeze between a pair of pliers should ensure it lies flat on the workbench and looks like that in the photo. I decided on this shape so that the ends curve in the direction that the screws will tighten and the small kink in the middle should allow for any movement such as expansion.
Now drill a 2mm dia. hole into the rail through the fishplate at 45 degrees from the vertical some 7 to 10mm from the rail end at the point where the foot meets the web on the outside edge of the track. This means that any excess length will protrude through the bottom of the rail rather than the inside. Also drilling at 45 degrees on the outside edges of the rail is relatively easy with track that is laid. Next fix one wire link into one rail with a screw and then drill the hole for the other at the same angle as before using the link as a guide to position.
The self tapping nature of the screws should ensure good electrical connection between screw and rail and the countersunk head and clean wire should give good electrical connection between the screws and therefore the rails.
On test, with 1.2A flowing through the joints of the old uncleaned prototype in the picture, my multimeter detected a 2mV drop on the plain joint on the far side but none on the treated one on the nearer rail to the camera.
This method is my idea and, AFAIK, no one has published this method but I wouldn't be surprised if it has been tried before.
If anyone tries it, or has already done so or something similar I'd appreciate any feedback.
N.B. the wire link is not needed.
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[h4]Posted by: minimans Jun 3 2009, 10:42 PM[/h4] I've been doing this for years Neil and I found long ago that the wire is redundent as the fishplate performs the same function I now just use a dab of grease when screwing in the screw to stop it galling on the brass and as an anti oxident!
TheMartin
Registered
All our code 332 is joined with trackclamps, I'm just interested in investigating an alternative for code 250
TheMartin
Registered
One of the reasons why I'am asking Neil if he still recommends it. It's been a few years since the original post and i'd be interested to hear.
If I was going to use the screws for long runs I'd look at only screwing short lengths and bonding the other joins with wire, just a way of reducing the amount of soldering I might have to do in awkward positions!
Rhinochugger
Retired Oik
Yep, the perceived wisdom is firstly, don't even think about using fishplate joints for expansion - electrical connectivity is more important.
Secondly, track expansion is not a mega issue in this scale, so even if you use pre-curved track, most people fix it to the ground / board / whatever at fairly generous intervals, and the track will move, as you say in the ballast, but generally by an imperceptible amount. Even in very coarse, oversize ballast that I have been wont to use, the track will, over time, settle into the ballast, but you can never see where expansion or contraction has taken place.
I'd love to have time to bond with my track. 
TheMartin
Registered
I tend to agree though I think each railway is different due to weather/climate/location. When we first laid our track we did so in winter and left expansion gaps. And apart from one spot that receives full sun we've not seen any other expansion - I appreciate that just means it's likely been imperceptible.
I do think however there is merit in Neil's screws into fishplate method especially for code 250 peco where railclamps are not so readily available and to fashion longer lengths to make track laying quicker... that is unless all these years later it turns out it was a disaster for him!
Neil Robinson
Registered
In my opinion track clamps are excellent, especially with pointwork that may need lifting for maintenance as they permit this with little disruption of adjacent track. Two downsides are they are quite expensive and the rail in the clamp needs to be cleaned. Self tapping screws are cheaper and can be effective without cleaning or other disturbance to the track. Using self tappers won't preclude the use of clamps at a later date if deemed necessary.
trammayo
Interested in vintage commercial vehicle, trams, t
I use Neil's method when I have conductivity problems. The only problem I experience is I sometimes round out the pozi head as the Stainless Steel is softer than normal steel.
As for expansion, I just use insulatiors - my main track is fully floating (well apart from the moss and the weeds) - although that on the trestles or the extension is screwed down without any apparent problems.
As for expansion, I just use insulatiors - my main track is fully floating (well apart from the moss and the weeds) - although that on the trestles or the extension is screwed down without any apparent problems.
My complete line is fitted with Track Clamps. Some of it in Full Sun situations and Ballasted which has been glued in place. No problems with Rail Buckling or even movement. I think this is a problem that we have associated with smaller 00 or whatever layouts with Rail at Code 150 and below that will expand along the length and indeed buckle. However in our scale I believe that expansion occures in the Height and Width of the Rail, much as happens with full size rail that is clamped and welded into very long sections indeed with rare events of buckling.
JonD
G-force1
Prevarication Rules!
The % of expansion in anything is the same in all directions and not at all dependant on size, or section. BR uses special 'low expansion' rate steels for long sections, and scarf jointing to lose the movement. The only help that size gives is the added inherent strength.
Another thing to consider is rail creep. I have a long straight section which periodically I have to ease the lengths back to their starting point. as the sun starts at one end and during the day works its way along, allowing the start to cool again before reaching the far end. Expansion pushes the rail forward through the sleeper chairs, and contraction pulls it along after it. My sleepers are probably too well fixed.
Another thing to consider is rail creep. I have a long straight section which periodically I have to ease the lengths back to their starting point. as the sun starts at one end and during the day works its way along, allowing the start to cool again before reaching the far end. Expansion pushes the rail forward through the sleeper chairs, and contraction pulls it along after it. My sleepers are probably too well fixed.
Hm not sure why but I do not get any rail creep and I have a section like yours that the sun moves along during the day. It is Peco Code 250 all clamped, pinned and ballasted down down with postcrete so no movement possible.
JonD
G-force1
Prevarication Rules!
Perhaps your section isn't long enough, or your direction of travel counteracts it (another very minor cause of creep). I don't have a great problem but it definitely happens over a summer. I find the fishplates are closer to the chairs on one side. Rail clamping would probably hold it, but as I don't run track power I have no need.
Rhinochugger
Retired Oik
Ah, I'm no expert on Code 250 - Peco or otherwise.
I have a circuit of the garden that is approx 300ft, and is a mixture of Aristo pre-formed, and second hand LGB flexi. I bought the LGB flexi with a bundle of Hillman rail clamps. In the first garden, with about 180 ft of just Aristo, I only used the Arsito screwed fishplates without issue. In the new garden I have used the Hillman rail clamps to join LGB to LGB, and have drilled the LGB for Aristo fishplates where it joins Aristo track as the bottom flange is a slightly different profile.
We're heading for the first summer of the new garden and longer track, but the fixing prinicples are as before, and I'm not anticipating a problem
Thanks for all your replies to this so far. I'll be greatly enlarging my set-up later this year (hopefully) and had been thinking about expansion, my present layout is so small it isn't fixed at all apart from the fishplates, so expansion isn't an issue as the track just moves.
So if this works for you, then continue on this way with your extension..
I would clean rail-ends, use a little 'conductive grease' / Copa-slip in the joints.
You might find a problem with joints opening / closing if you have a long run, but if you have an average circuit, I think the curves tend to hold tings in check?
YMMV, of course.
TheMartin
Registered
Thought I'd update on how we're using this method. We're screwing every 3 lengths of PECO flex together and then leaving a regular unscrewed fishplate. We then have (depending on ease of access to solder) either bonded the 4 length or have jumper wires feeding. to connect the wire to the screw we're using ring crimps which are crimped and then soldered. the PECO accounts for around two thirds of our track the rest of PIKO which we use clamps on and jumper wires.
I have to say I consider myself to be capable with a soldering iron and have never had a problem soldering bonding wires into code 250 or code 332 (I only use a 100w iron... though it does have a thick neck and tip) however using the screws is very quick and with a new drill bit even getting through the nickle silver PECO is fairly easy. Drilling at an angle as suggested by Neil seems the way to go too!
I have to say I consider myself to be capable with a soldering iron and have never had a problem soldering bonding wires into code 250 or code 332 (I only use a 100w iron... though it does have a thick neck and tip) however using the screws is very quick and with a new drill bit even getting through the nickle silver PECO is fairly easy. Drilling at an angle as suggested by Neil seems the way to go too!