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Connecting wires for a decoder installation

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Connecting wires for a decoder installation
Posted by John-NYBW on Sunday, May 24, 2020 12:01 PM

I am installing a decoder with a 9 pin JST harness. I need to connect the red wire to the right side leads from both the front and rear trucks and the black wire to the left side leads. I can pigtail the three wires together but that doesn't give a strong connection and leaves bare wires exposed which risks frying a decoder. Is there a small connector that will both give a solid connection as well as insulating it or is there some other method I should be using. 

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Posted by richg1998 on Sunday, May 24, 2020 12:13 PM

I used #30 insulated wire. Stripped a short section to solder at the pickup and carefully routed up to a small piece of PC board for a solder point. Depends on the installation. Allow wire to flex some.

Rich

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Posted by RR_Mel on Sunday, May 24, 2020 12:40 PM

 

I use heat shrink when I pig tail connections.


Mel



 
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Posted by gmpullman on Sunday, May 24, 2020 12:52 PM

RR_Mel
I use heat shrink when I pig tail connections.

Same here. I have some that is about 1/8" diameter and shrinks nicely around 30 ga. wire.

 LL_E8_DCC2 by Edmund, on Flickr

 IMG_2856 by Edmund, on Flickr

You can see several joints in the examples above. 

Good Luck, Ed

 

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Posted by tstage on Sunday, May 24, 2020 1:14 PM

Solder the pigtail for best electrical continuity then insulate it with heat shrink.

Tom

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Posted by rrinker on Sunday, May 24, 2020 1:15 PM

  Depending on the loco, I'll either have the 3 wire pigtail, with heat shrink, or maybe use 2 different wires - one to link the front and rear pickup points, and then another from either the front or rear, whichever is closest, to the decoder.

                                    --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by John-NYBW on Sunday, May 24, 2020 2:17 PM

I have no experience with heat shrink so I went out to YouTube and looked at a number of videos. All of them used solder-and-shrink connectors rather than heat shrink wrap. Most of them suggested using  a heat gun to melt the solder and the insulation. I don't own a heat gun so I checked the pricing and the cheapest one was $23 and I don't know how good that would be. One of the videos did show how an open flame could be used as long as the wire doesn't get any closer than one inch from the flame. He used a candle but said you could also use the long charcoal lighters like Bic makes although he didn't demonstrate with that. Regardless, of the heat source, some of these connections are going to be made fairly close to the decoder. Is there a risk of damage to the decoder from either a heat gun or an open flame?

One other question. The smallest connector I could find was for #24-26 wire and I am using #30 in my decoder intallations. Will those work with the smaller wire. 

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Posted by tstage on Sunday, May 24, 2020 2:24 PM

You don't need a heat gun, John, or a connector.  Just use the hot upper portion of your solder iron (away from the tip) on the heatshrink and it will work just fine.  That will shrink the heatshrink tubing around the pigtail; covering it, as well as keeping your soldering tip clean.  Just remember to put your heatshrink on the wire BEFORE soldering or attaching it to the decoder.

Tom

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Posted by mvlandsw on Sunday, May 24, 2020 2:32 PM

Solder the wires with a pencil type soldering iron and use heat shrink tubing to insulate the joint. The heat shrink is not wrapped around the joint. The tubing must be slipped onto one of the wire before you make the splice. Keep it about an inch away from the joint while you solder or it will begin to shrink and you won't be able to slip it over the joint.

Once the joint is soldered slip the tubing over the joint and hold the hot soldering iron near the tubing to shrink it. No need for a heat gun.

Mark Vinski

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Posted by jjdamnit on Sunday, May 24, 2020 2:44 PM

Hello All,

Yes, heat shrink tubing is the preferred option to insulate solder joints.

As you are discovering, the investment in tools can be more expensive than the actual part(s) being installed.

MicroMark has an assortment of heat shrink tubing and an inexpensive heat gun.

I picked up a "heat embossing" tool from a craft store for less.

NTE Electronics, Inc., sells a great assortment of heat shrink tubing. I use the "Thin Wall" type.

You can activate the heat shrink tubing with an open flame but I would not recommend this. Go ahead and get an inexpensive heat gun.

Do some practice shrinking on a blank piece of wire to see how the product works.

Another option that doesn't involve the investment in tools is Liquid Electrical Tape; available at hardware and big box stores.

This is a brushable- -think contact cement- -product that, when dried, provides electrical insulation.

No tools necessary. It cleans and thins with acetone.

I use this product to insulate the frames on older Athearn Blue Box re-motor projects.

Compared to the cost of other methods of insulation and the requisite tools, it is probably the cheapest option.

Hope this helps.

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Posted by mbinsewi on Sunday, May 24, 2020 3:48 PM

I do what Tom does, solder the twisted wires, and cover with heat shrink tube, which I use my solder iron to shrink the tube.

A good solid connection.

Mike.

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Posted by John-NYBW on Sunday, May 24, 2020 7:11 PM

mbinsewi

I do what Tom does, solder the twisted wires, and cover with heat shrink tube, which I use my solder iron to shrink the tube.

A good solid connection.

Mike.

 

 

Isn't there a possibility you will melt a hole in the tubing which would expose the wire or do you not touch the soldering iron directly to the tube.

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Posted by BigDaddy on Sunday, May 24, 2020 7:28 PM

Like hand grenades, close is good enough, but at the temps I use, I have not melted any holes in touching the shrink wrap.

Henry

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Posted by tstage on Sunday, May 24, 2020 8:17 PM

John,

Heatshrink is made to withstand high temperatures; just don't leave it in one place for say, 5 or 10 seconds.

I set my soldering iron around 650F and move the non-plated portion of the soldering iron back 'n forth along the heatshrink until it shrinks down around the wires/wire junction.  And I actually make contact with the heatshrink over its entire circumference for uniformity.  Just be mindful of your soldering tip if it's close to other wires.

If you're feeling nervous about using heatshrink, John, make up a sample set of pig-tailed wires and practice shrinking the heatshrink around the wire junction.  It's not that difficult.  You'll get the hang of it in no time.  You also want your heatshrink to be slightly longer than the wire junction so that it overlaps and is snug with the insulation of the wires.

Tom

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Posted by rrinker on Sunday, May 24, 2020 9:24 PM

 Another advantage of a temperature controlled soldering station - I just turn mine to the minimum temperature and it shrinks the heat shrink without melting it. Not touching the heat shrink with the tip, but further up. Most heat guns intended for the purpose are the size of hair driers and even with a fairly small nozzle, there's still a chance of melting anything plastic laying around the work area - like the shell of the loco you are installing the decoder in. They are also meant for the large sizes of heat shrink - for fine decoder wires you need some really small heat shrink.

 I've considered getting another soldering station that has a hot air tool, intended for soldering surface mount parts, but with a fine nozzle and turned down, they work great for heat shrink, and aren;t nearly as bulky as a heat gun. But I've had no problems using my soldering iron, so I think I'll save my money for more decoders.

 A regular solding iron, this trick doesn't work very well with - accidently touch the heat shrink and you will have gooey plasticy gunk on the iron, and it's nearly impossible to clean off. If it's on the tip, just replace the tip.

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Posted by John-NYBW on Monday, May 25, 2020 12:53 PM

The problem with investing in all the things I'll need to heat shrink is my loco roster is fairly complete and I only have few second hand DC locos to convert. The heat shrink isn't that expensive but it comes in bundles of hundreds of tubes of different sizes, way more than I would ever use. Then I'll have one more item cluttering my shelves that I never use. I don't see myself using a soldering station enough to justify the cost. I might be able to figure out how to do it with my basic soldering iron but the idea of using liguid electrical tape might be the best solution for my situation. I was unaware that there was such a product until another poster suggested it. If I was just starting out and planned to do dozens of decoder installations, it would probably be worth it to buy the tools needed but for the few I am going to do, the liquid tape seems like the best option. 

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Posted by tstage on Monday, May 25, 2020 1:34 PM

John-NYBW
The heat shrink isn't that expensive but it comes in bundles of hundreds of tubes of different sizes, way more than I would ever use. Then I'll have one more item cluttering my shelves that I never use. I don't see myself using a soldering station enough to justify the cost.

You can purchase single-size heatshrink from vendors like Litchfield Station in 1-yd lengths:

https://www.litchfieldstation.com/?s=shrink+tubing&post_type=product&type_aws=true

And it comes coiled in a 4 x 6" ziploc bag for easy storage.  Postage is also very reasonable at a flat rate of $4.00.

If you only have a "one-speed" soldering iron, just get the tip close to the heatshrink (w/o touching it) and the heat from the iron will shrink the tubing.

FWIW...

Tom

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Posted by gmpullman on Monday, May 25, 2020 2:11 PM

John-NYBW
The heat shrink isn't that expensive but it comes in bundles of hundreds of tubes of different sizes, way more than I would ever use. Then I'll have one more item cluttering my shelves that I never use.

Send me your address in a PM and I'll send you some of the heat-shrink I have. Two sizes, about 1/8 and 3/16. My former employer was tossing out thousand-foot rolls because it was past its "expiration date" and some of it came home with me.

I also use it as kind of a "strain relief" on wiring such as where the wire attaches to the truck:

 Truck-wire by Edmund, on Flickr

Good Luck, Ed

Regards, Ed

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Posted by Bayfield Transfer Railway on Monday, May 25, 2020 3:00 PM

Note that there are different quality levels of heat shrink.  Radio Shack is very thin and will indeed melt away if you touch it with a soldering iron.  Better heat shrink will not and is much to be preferred.

The "liquid electrical tape" works too.

 

Disclaimer:  This post may contain humor, sarcasm, and/or flatulence.

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Posted by UpNorth on Thursday, May 28, 2020 10:03 PM

"  The "liquid electrical tape" works too.  "   

Expensive stuff. Over 15$ for 4 Oz.    

Get a small can of  Plasti dip for 5$.  Takes a little long to cure but works great.

Marc

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Posted by rrinker on Friday, May 29, 2020 7:25 AM

 Don't install block detection on your layout then - the silver paint that is the best thing to use is about $80 for 1/4 oz. But I did 100 axles and didn't use even 1/4 of the paint. Unfortunately now that it's been sitting for close to 8 years it's probably no good.

 Actually, just looking around, seems a bit cheaper these days since the price of silver is quite a bit lower than what it was back when I bought it. There seem to be some really cheap sources that claim to be 60% silver for as low as $10 on eBay, but I wouldn't trust them when all the scientific chemical suppliers want about $50 for the same thing. It's used mainly for scanning electron microscopes, to attach specimens to the slides.

 Anyway, 4oz of liquid electrical tape will last a LONG time, probably do 1000's of locos, although I only use it for track bus and feeder connections - it takes way too long to dry and I wouldn't want to put a loco shell back on unless the stuff was truly dry and not outgassing any more. Heat shrink is much faster (instant, really) and you can go on with finishing the work instead of having to set it aside for a day to dry.

                                       --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by John-NYBW on Friday, May 29, 2020 8:03 AM

UpNorth

"  The "liquid electrical tape" works too.  "   

Expensive stuff. Over 15$ for 4 Oz.    

Get a small can of  Plasti dip for 5$.  Takes a little long to cure but works great.

Marc

 

https://www.amazon.com/gp/product/B000FPAN2K/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

This is what I bought.

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Posted by wrench567 on Friday, May 29, 2020 10:21 AM

Loco roster almost complete?

Ha. I said that about 40 locos ago. The old philosophers saying  "All I want is a little more than I will ever have" And I don't even have a home layout yet.

   Pete

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Posted by woodone on Friday, May 29, 2020 10:35 AM

I just hope the OP does not go broke with that purchase-

putting in a decoder requires good tools and related material to do the job right.

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Posted by John-NYBW on Friday, May 29, 2020 11:20 AM

wrench567

Loco roster almost complete?

Ha. I said that about 40 locos ago. The old philosophers saying  "All I want is a little more than I will ever have" And I don't even have a home layout yet.

   Pete

 

I can't imagine a reason I would buy any more locos than I have now. I already have more than I need to run all the trains in my ops session. I have every type of loco I want. The only reason I can see spending several hundred dollars on a new loco is if so many of my current roster died and I needed to replace them. I'm at the same point with my rolling stock although with that I rotate part of the fleet off and on the layout. If there is a car that grabs my interest, I still might add a piece here or there. I did that just this week when I saw a banana reefer from Accurail. 

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