Resistance Leak from Fast Track turnouts
Brent Johnson
I recently started wiring my first section of a large layout and am using a short detection beeper, built like the one described on the wiringforDCC website. I noticed a couple times the beeper reacting as I attached feeders located near some turnouts. I checked the track with my ohm meter and am detecting a small amount of resistance between opposite rails stemming from some of my Fast Track turnouts. I have double and triple checked my isolation cuts on the frog and printed circuit board ties and everything appears ok. When hooked up to the NCE DCC system, everything appears to work ok.
My question is, shouldn't there be zero resistance between two opposite rails? Secondly, could this pose any issues down the road? Thanks, Brent Johnson |
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Tom O'Hara
There should be infinite resistance between opposite rails unless you have some type of connection between them. ... Tom |
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Chris Elliott
Had the same issue, for me it was flux residue. Had to give them a bubble bath to get ride of the residue.
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Chris Sent from planet earth On 5 Feb 2020, at 06:28, Brent Johnson via Groups.Io <Brntjh@...> wrote:
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Paul O <pomilian@...>
Brent, Chris is probably correct about the flux. The problem is a path from the top copper of one rail to the bottom copper of the tie strip and back to the other isolated top copper. I always cut gaps on the bottom side of the ties to avoid that problem in the future from ballast or anything else after installation. Paul O
On Tuesday, February 4, 2020, 03:58:19 PM EST, Chris Elliott via Groups.Io <cpelliott100@...> wrote:
Had the same issue, for me it was flux residue. Had to give them a bubble bath to get ride of the residue. Chris Sent from planet earth On 5 Feb 2020, at 06:28, Brent Johnson via Groups.Io <Brntjh@...> wrote:
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Steve Haas
>>>> I recently started wiring my first section of a large layout and am using a short detection beeper, built like the one described on the wiringforDCC website. I noticed a couple times the beeper reacting as I attached feeders located near some turnouts. I checked the track with my ohm meter and am detecting a small amount of resistance between opposite rails stemming from some of my Fast Track turnouts. I have double and triple checked my isolation cuts on the frog and printed circuit board ties and everything appears ok. When hooked up to the NCE DCC system, everything appears to work ok. <<<<
There should be _infinite_ resistance between opposite rails, as they are (hopefully) isolated from each other. If you have less than infinite resistance, you have some leakage between the two rails. Have you ballasted this area recently using water/glues/alcohols ???? Residual moisture from this application could create a high resistance path between rails of alternate polarity.
Best regards,
Steve
Steve Haas Snoqualmie, WA |
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Brent Johnson
I have not done any ballasting. I am intrigued by the flux issue. I had one turnout that was bad enough even after cutting gaps on the back of the ties I ended up giving up. I will try “bathing” the turnouts from now on. The current turnout that prompted this issue is a curved one that I built specifically for this location and not using a Fast Tracks gig, although I used the same construction technique. I would prefer not to have to tear it out so I will try to clean it in place the best I can and see if that resolves it.
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Brent On Feb 4, 2020, at 4:22 PM, Paul O <pomilian@...> wrote:
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Richard Sutcliffe
Brent
I didn’t think Fast Tracks supplied double sided ties. Our club used double sided for a short while years ago. We had considerable leakage between the top and bottom after we ballasted. We then slotted the bottom below the top - a little better. Then we slotted just below the rails - a little better still. Then used a soldering iron to heat and peel the foil from the bottom of the ties - problem solved. Hope you haven’t got your turnouts glued down.
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Hi Gang: A friend used so much graphite on a turn out that it caused a current path. Carl. On 2/4/2020 4:51 PM, Brent Johnson via
Groups.Io wrote:
I have not done any ballasting. I am intrigued by the flux issue. I had one turnout that was bad enough even after cutting gaps on the back of the ties I ended up giving up. I will try “bathing” the turnouts from now on. The current turnout that prompted this issue is a curved one that I built specifically for this location and not using a Fast Tracks gig, although I used the same construction technique. I would prefer not to have to tear it out so I will try to clean it in place the best I can and see if that resolves it. |
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Brent Johnson
Yes, the ties they supply have copper on both sides.
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Brent On Feb 4, 2020, at 5:05 PM, Richard Sutcliffe <ras1@...> wrote:
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Jim Zarnick
Unless you have isolated the section from the power supply you will be reading the resistance of the power supply...
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Sent from Xfinity Connect Mobile App ------ Original Message ------ From: Tom O'Hara To: w4dccqa@groups.io Sent: February 4, 2020 at 2:32 PM Subject: Re: [w4dccqa] Resistance Leak from Fast Track turnouts There should be infinite resistance between opposite rails unless you have some type of connection between them. ... Tom |
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If you are using anything other than rosin flux or rosin flux core solder then residual flux can cause a weak short. Non-rosin flux is usually a weak acid flux which is conductive if there is any medium like water or something similar. Rosin based flux does not conduct. The primary advantage of the newer kind of flux is that it is easy to clean. Cleaning rosin flux requires a strong solvent.
Sometimes when you cut the copper you can leave a tiny sliver that will also cause a short. Best Regards, Ken Harstine |
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Brent Johnson
I was using the acid flux recommended by Fast Tracks.
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My initial test of cleaning one of my off layout problem turnouts appears to be a success with resistance eliminated. I’m waiting for the cleaning solution to dry on my installed problem turnout to see if I have the same success. Thanks for everyone’s input and suggestions. Brent On Feb 5, 2020, at 12:51 PM, Ken Harstine <kharstin@...> wrote:
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Vincent Ficca
hi All: This what I do building turnouts using Fast Track system. I am building a large layout and have been building turnouts using Fast Track system for years for others in the area. For what it's worth. I use silver solder rosin core for solder all track work (same solder used for electronic wiring) to the PC ties. After completing all the soldering of PC ties to track, I make the center line cuts on face side and on the bottom side, to make sure no electrical current will flow through one side of rail to the other side. I test the finished turnouts using DC power to make sure I have no electrical issues, before putting on layout.. I an others using the turnout I built, have not had any problems to this date. Vince Ficca On Wed, Feb 5, 2020 at 2:19 PM Brent Johnson via Groups.Io <Brntjh=aol.com@groups.io> wrote:
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Chris Elliott
Had the same issue, for me it was flux residue. Had to give them a bubble bath to get ride of the residue.
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Chris Sent from planet earth On 5 Feb 2020, at 06:32, Tom O'Hara <tomohara5@...> wrote:
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Brent Johnson
Yes, cleaning with toothbrush in soapy water fixed issues. I previously just did what their online video recommended which was clean with a wire brush. Apparently that is not always enough.
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Brent On Feb 5, 2020, at 6:07 PM, Chris Elliott via Groups.Io <cpelliott100@...> wrote:
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Allan AE2V
Instead of using rosin core solder that you have to scrub with a toothbrush, consider trying liquid flux and solid solder (no rosin core). You can wipe away any extra flux with a damp sponge or wet paper towel. Learn more about liquid core flux on my website at: http://www.wiringfordcc.com/solder.htm#a10 Liquid flux comes in a liquid or gel. The gel is a misnomer as it is more like watery syrup. The liquid is like water. I use both depending on the job. The gel is easily applied by dipping a toothpick into the bottle. You will get one drop on the toothpick. I use this approach when soldering feeder wires to rail. I use a Q-tip to apply liquid flux like when I solder feeders to bus wires. I think you could use either one for building FastTrack turnouts based on your preference. Allan Gartner Wiring For DCC |
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Brian Lewis <brian@...>
For eleven years I owned a company that manufactured solders and
fluxes. Another company I owned, manufactured components in 4mm
and 7mm, enabling modellers to construct their own track. Included
in this was double sided copperclad, of which we must have sold
countless thousands of metres. As well as being a manufacturer, I
am also an enthusiast. I first exhibited a layout in 1967 and
currently have an exhibition layout in P4 and a static one in 0n30
- both are DCC powered. I have written articles on best soldering
practice for various hobby magazines. So I guess I have a fair
amount of experience pertinent to this subject. But in all that time, I have never heard of resistance leakage when using copperclad. So really I cannot understand what is happening! But one comment made displays a certain lack of knowledge regarding fluxes. This is talk of washing off rosin fluxes. All that I know of are totally, 'no clean' and require no after treatment. (If you do want to remove residues, use Iso Propyl Alcohol). I use rosin fluxes for all electrical wiring, but for soldering trackwork, you really need a more active flux. Traditional active fluxes are becoming hard to obtain, but I would look for one that is based upon Phosphoric Acid, (the acid that gives a 'bite' to some fizzy drinks). If you cannot find one, food grade phosphoric acid should be easy to obtain. It will be concentrated, so dilute one volume with eight volumes of water. An alternative is a flux based upon Hydrobromic Acid - one trade name is Radsol 540. But whatever you do choose, avoid fluxes containing Zinc Chloride and/or Hydrochloric Acid and also any flux that is in the form of a paste. These are almost impossible to clean and/or neutralize properly and will give trouble, years after the joint was made. So what caused this leakage problem? I do not know, but suspect
is was a combination of a unsuitable flux, coupled with inadequate
cleaning. As in so many operations, in soldering, cleanliness is
next to Godliness...... Regards and thanks
Brian Lewis |
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BTW rosin core does not need to be removed with regards to shorts as it is a good insulator. You do need to scrub it from the tops of the rails and this be done with fine sandpaper or some other similar abrasive.
In my years with hand built prototypes at various manufactures we often did not clean the boards as it we did not care about how it looked and it still functioned fine. Ken Harstine |
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Vincent Ficca
Hi Brain: Since you have a lot of experience with solder, I use Kester solder with 2,0% silver. It contains rosin, and I have not had any issues with it. I use if for all my soldering. Fast Track, and wiring. I solder all my rail drop to the bus wires, no suit-cases used. I have not had any issues so far. What your opinion? Vince. On Fri, Feb 7, 2020 at 1:46 PM Brian Lewis <brian@...> wrote:
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Brian Lewis <brian@...>
Hi Vince. I assume you refer to a tin/lead/silver solder, what
in Europe is called 62S - SN62 PB36 Ag2. It is the best all
round solder for electronics and one I turn to first when
soldering. Its flow characteristics make it ideal for most jobs. Most tin/lead solders will work OK, but avoid
lead free solders if you can. On 07/02/2020 23:14, Vincent Ficca
wrote:
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Regards and thanks
Brian Lewis |
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