I know how to solder a y or t joint with conventional size wiring, plenty of working space, and a means to hold the wires in position. My question is, how to do solder this joint with fine 30 gauge wire used in a decoder install and limited space? Can someone explain their process for making y/t joints? Anyone know of a Youtube video that shows/teaches how to make this joint while installing a decoder wiring? Thanks for any help you can provide!
It is difficult to make a good joint with wire this thin unless you have a long, thin, well-tinned tip you can position under the length of wire youāre joining to. If you donāt have a āthird handā stand to allow 3D positioning of the wire to be attached, I recommend you buy or make one, with suitable jaw material to grip the wire without deforming or nicking it. USE A GOOD NO-CLEAN FLUX, and a good eutectic solder (I use leaded; you may not care to).
I use paste flux and a small āchipā of solder stuck on top of the joint; the heat melts this; capillary action pulls the liquids into the joint, the eutectic āfreezesā promptly to hold alignment. You can take a couple of cigarette-style turns around the wire, but youāll want to keep the joined wires as co-axial as possible. A āTā joint can be wrapped once to opposite sides of the ābase of the Tā but this fine wire doesnāt like repeated flexing or bending much.
In my opinion this is an ideal application for resistance soldering if you care to invest in the equipment.
1 Like
Thank you for your reply Woke_Hoagland! Good information!
I am a DCC neophyte and have locomotives with NMRA 8 pin sockets. Thus far, Iāve converted three locomotives by using a 9 pin JST to 8 pin NMRA harness and TCS T1-LED decoders. Quick easy conversion to add the decoder (after replacing the headlights with LEDās). Some are very critical of this approach, suggesting that one will have greater reliability if all of the existing wiring is removed and new wiring installed. My locos performed flawlessly on DC and the same post-DCC conversion.
I am investigating a complete rewiring when installing more āmodernā decoders with added features and more functions. Y and T joints may be required. Iāve practiced making Yās with decoder wire. I create a V by stripping and soldering two wires with a pigtail joint. The tail of the Y is added by soldering a third wire to end of the V. Finally I cover the Y joint with shrink tubing. Easy to do on the workbench with my helping hands stand. I could easily pre-fab Yās on the workbench and then install on the locomotive.
Is this procedure a good idea or is there better options. Iām neophyte and open minded.
In my opinion, the thing to watch in making these joints with fine wire is not to make the soldered joint too heavy ā that causes stress where the wire runs into the āblobā. You want just enough to wick into the pigtail turns and ācementā them. The heatshrink on a āyā would further add bending strength to the joint.
I am tempted to recommend multiple light coats of āliquid electrical tapeā to insulate a āTā joint where you donāt want a piece of heatshrink holding the stem of the T parallel to one leg of the continuous wire.
1 Like
There is no reason to make the connection an actual T or Y. Twist the the three wires together and solder them. Then insulate them. The electrons do not care.
Sheldon
Hi Sheldon!
My Aristo Craft throttle failed and a replacement was hard to find + expensive. Thus the move to DCC. I miss the simplicity of the AC throttle but now enjoy the greater options with my TCS throttle.
About the Y./T joint, I am not concerned about the electrons getting confused, theyāll figure it out just fine! 
I am discussing a situation where there are three wires that need to be connected, say the RF pickup wire, the RR pickup wire, and the wire to the decoder. A Y joint would reduce wire length and reduce the size of the blob covered with heatshrink compared to wrapping the three ends together. I need a Y if I am hardwiring my T1 decoder since there is only one wire for the right side pickup.
The more modern flat decoders make it easy to solder the two pickup wires together and then solder the paired connection to the decoder. I will change decoder style after I deplete my T1 supply.
DCC newbies like me tend to overthink thingsā¦ I really miss Randy Rinker, he was always very helpful and a great teacher for all MR projects. He never steered me wrong and always added knowledge.
I am lucky. I still have an Ungar Princess soldering iron from my Heathkit building days. It has a tiny tip and I use a very small rosin core solder.
1 Like
If you say so. I just canāt picture it being that hard to arrange the wires differently.
What is āexpensiveā for a replacement 10 channel Train Engineer? I have purchased 6 additional ones, NOS or in very good condition, in the last 18 months. I think $190 was the highest price, most like $150, and few duds for even less that yielded useful parts.
Sheldon
1 Like
Sheldon,
I think the Y is the way to go. Others can have their own opinions, perfectly fine by me. I was merely asking others for any tips they may haveā¦ Woke Hoagland provided excellent insight, Thanks Woke.
My previous unit was a single channel AC Basic Train Engineer, purchased for $30 in late 1990ās. Served me well for many years! When it failed, the decision point was stay DC or go DCC? I could not find find the single channel ACTE and the 10 channel unit requires a base station as well as the throttle. I was able to find a complete system when I searched in January but did not record the web address or amount. . Comparing systems, I was able to purchase a starter DCC system + RRCirkits LLC buffer Bus and five non-sound decoders for $285. The DCC system provides more operational options than a 10-channel ACTE + base station. I was ready for a change and feel a DCC system was the right long range choice for me. YMMV and obviously does! Take care Sheldon!
I get it, I was just curious. What brand/kind of DCC system? One of my non starters is using a phone as the throttle, but other like that.
Sheldon
I purchased a TCS LT50. It is a tethered system with a long enough tether for my switching layout. My ACTE spoiled me with a walkaround throttle. I can easily upgrade to a wifi throttle in the future. Cell phone āthrottlesā result in mixed reviews. Iāve not used one but I suspect they have higher acceptance by road operators with minimal switching tasks versus operators with heavy switching duties. Someday Iāll give it a try but Iām not in a big hurry.
We will be moving in the next year or so. At my age, a small switching layout will continue to be my future rather than a large marvelous layout like yours. Iām a solo operator at home. Now that Iāve switched to DCC, I can take some locomotives to local MR club and experience running on a large layout! Take care!