I have a need to kit bash a signal to make a signal bridge. I can't justify $60 for a signal bridge, so I want to take two $7.50 signals and take the heads off and mount them on styrene plastic beams.
I was able to carefully take off the head and found that regular wires were soldered to magnet wires inside the signal post. Of course I will need to resolver in order to remove the wires from the original post.
How to solder to magnet wire? What care should I take to work with magnet wire?
NP.
NP,
You should be able to heat the existing solder joint to loosen it. Presuming you've tinned the new attachment point, just heat and they should stick together, maybe adding just a touch of fresh solder if needed.
Magnet wire solders just like any other. The trick is getting the thin insulated coating off. The best way to do that is to turn the heat of your soldering iron up all the way, then get a blob of liquid solder going. Pass the magnet wire through the solder blob and it will burn off the coating. Then tin and fasten like any other wire. Since you're dealing with magnet wires that have already been soldered, probably no need to to do that, but it's a good trick to know if you start installing LEDs with it in the future.
Also, when running the magnet wire through the model, whatever it is, be cautious about sharp edges that can scrape off the coating, which can lead to a short. You can use skinny heat shrink or liquid electrical tape for insulation, usually a good idea if the model is metal.
Mike Lehman
Urbana, IL
Yes, using a hot iron and "dipping" the wire into a big drop of hot solder is the best way to both clean and tin the ends of magnet wire. I bought an Oregon Rail Supply signal bridge kit and a package of LEDs from my LHS, and some magnet wire from Radio Shack. All were very reasonably priced.
The kit comes with a top catwalk, which was not yet installed when I took this picture so the wiring would be visible.
I also used some thin stranded wire on this project, but I used magnet wire for the tight spots. I used shrink tubing and paint-on insulation to protect the connections.
This signal bridge has 10 LEDs on it, all operating. It's used as a turnout-position indicator, for both the turnout it's close to and the next one down the line. If you are wiring LEDs together on the same circuit, wire them in series, not in parallel, so all will get the desired current.
It takes an iron man to play with a toy iron horse.
Thanks team! I will try this ... hopefully my almost scratchbuilt signal bridge will be ready by the weekend.
My signals are going to an SE8C for occupancy and switch indications, so I will need to wire in parallel (common anode). I don't have bipolar LEDs, I have three separate LEDs so it's going to be 4 x 2 = 8 wires. Not looking forward to that bit of delicate work.
I looked at Oregon Rail. I wanted a "leaner" signal bridge (I don't know why signal bridges of the past were that "heavy duty"). So I am going with a 1/8" styrene tubes for posts and a 1/2" lattice beam. The signal heads are mounted on the beam and the magnet wire will go into the tube, where it will meet real wire.
I will share a photo if/when I complete the structure.
NP
Can you not wire the LEDs with a single common wire to reduce the number of wires you need to run through the tubes?
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
Dave,
NP didn't say what this magnet wire went to, but I presume it's surface mount LEDs. That's where I deal with it. They're tiny, so it's much easier to run the fine wire leads to a common point and tack in there. That's sort of what you're suggesting, but I've found it's better to work with the long leads and let them take me places I need to go, rather than trying to get them wired into common nearby the LEDs. It really depends on the specific installation, so it's always good to consider all the options before deciding how to proceed. The leads are actually fine enough they can represent electrical cables in HO, so that can also be put to advantage by the modeler.
The LEDs are already assembled in signal heads which I broke off from signal posts. I ended up with 4 magnet wires per head, common, R, Y, G. these go to 4 conductors in a phone cable. I use phone jacks for plugging my signals o the se8c.
Hi Mike
I wasn't thinking in terms of SMDs although I work with them all the time and I have used lots of magnet wire. I will agree that because the magnet wire takes so little space it would be much easier to run individual wires for each SMD LED. I made the common lead suggestion simply because the OP seemed to indicate that he thought he had a lot of wires to deal with, and I was thinking of 3mm LEDs instead of SMDs at the time. Trying to install a common lead on SMDs is not the way to go particularly with a styrene structure. My bad!
I would add a suggestion for the OP and others doing the same sort of work. That is to go to your local hobby/art supply store and buy a selection of various colours of Sharpie paint markers. The paint markers make it easy to identify which wires are which when they come out of the other end of the conduit. In my (somewhat limited) experience I have found that if you want to feed several wires through a small tube they have to be done all at once or subsequent wires will simply jam in the tube. Even if they don't have to go through a conduit, having a bunch of unmarked magnet wires hanging out of the bottom of a project is a sure recipe for frustration.
Last, DON'T FORGET THE DARNED RESISTORS!!!!!! Been there, done that
Mike,
Just my thinking,,,,,I would have made the main structure,out of brass tube and had the structure itself,be the common connection..Made many of my own street lights that way..
Cheers,
Frank
NP01
You are way ahead of us! (Pardon the pun - signal 'head' - way 'ahead' - OK, again - too obvious!)
Now I understand why you have eight wires with six LEDs!
Please show us some pictures when you have it done.
I was going to make the same suggestion re a brass bridge but I decided not to because the OP indicated that cost was a concern. If it were me I would consider the brass option for the reason you stated, but it might be a draw between the complexity of soldering all that brass together vs the ease of gluing styrene and hiding a few more wires. I am still a bit of a klutz when soldering.
I understand,,just thought I would mention it,,,,cost wise,,probably few cents more,,hollow squares and tubes,,more robust,,,but that's my opinion...
I am unfamiliar with magnet wire. Is it bare wire or coated with some kind of insulator?
Rich
Edit Note: Oops, I just read Mike's earlier post, and I see that the magnet wire is coated.
Alton Junction
OH yeah, never forget those resistors. I, too, BTDT.
Good idea on the markers, although that may still require the Optivisor to sort them out.
Frank,
Good idea with the brass structure, especially if one is starting from scratch. With the signal heads already assembled, it does get trickier to deal with shortening the wires.
Another factor at work may be the form of the magnet wire. I usually come across a rather loosely twisted magnet wire pair when I get my SMD LEDs from Ulrich. The last order I got was a bit different, as the coiling of the paired leads was much tighter. Still easy enough to uncoil; that always involves lots of delicate untwisting to disentangle the pair if you do want to shorten one lead over the other, which is why I'm a bit leery of after doing that myself. The tighter twist also made the twisted together leads look more like a cable in HO scale than the older less tighter twist. It also seems like there are a lot more turns to make in untwisting the more tightly coiled leads if you do come across it.
When the pair is twisted together, it has a little more heft to and less likely to snag, etc. Once it's untwisted, the single wire leads are considerably more delicate. Although in a very tight install this could be used to one's advantage, it usually is trickier when dealing with single wires. Also, sorting then bundling the needed leads and then soldering all at once into the main signal wiring together may be easier than attaching to multiple points.
This stuff is tricky to work with, so once you get experience with it, it's easier to decide what will work best for you in each install.
Da*n resistors!
I installed two signal heads on the silver spray-painted bridge. Looked great! I tested them- my LED test jig is a 9V battery with a resistor soldered to one terminal. Great ... But! I accidentally touched the non-resistor terminal to RED of one of the heads. Puff ... The REDs are super sensitive, I think the Green survived. Do you guys have similar experience? Delicate work is so frustrating.
I am also finding that soldering is hard on this delicate structure. I might have to get new tips for the soldering iron ...
Tonight will be another try. I will try to upload progress pictures- you will see it is a very simple signal bridge, but it looks ok actually.
Here are the materials:
Two posts and the bridge lattice beam cut to size and with notches added for mounting signals. Two signals: one is prepared with the head off and one is still in the as-purchased state.
Here is the bridge with signals mounted. I was pleased with ths until I took out the RED from one of them and the soldering part got frustrating.
Are you positive,that the signal lights are LED's and not,1.5 volt bulbs??
Yes. The only work in one bias and everything about the lens and the light pattern is LED.
The reason why I asked,was that you said,the Red one went poof,when you touched the lead without a resistor with a 9volt Batt....12volt or 3volt,LED's in the signal head??
By the way,in your pic,is that Warren Truss Girder you show,,is that from,Plastruct??
If they are,those surely,are not cheap,,,,how well,I know that..I spent more money,detailing a interior roof,on a Machine shop,,than I paid for the whole kit..
NP01Do you guys have similar experience?
Breathes there the man with soul so deadWho never has dispatched a LED,Who with his own, his very handWhose wire hath crossed and thereby burned,...
Yeah. Turning a Light Emitting Diode (LED) into a Darkness Emitting Diode (DED) is an old tradition, dating back at least to the days of Sir Walter Scott.
You know I read up. Lower frequency LEDs drop lower voltage in forward bias. Red is 1.8v But Blue is 3.3V. Now I can see how Red will be the first one to die when accidentally applying a 9v battery.
I am going to make a current limited 3v supply with two 1.5v AA cells taped together in series with a resister soldered. That's much better than burning up $7.65 signals, of which I now have burned 2 out of 8. Ok the first one came burned.
Indeed the truss beam is Plastruct, was $2.40 and I can get one signal bridge and one cantilever signal out of it. So I thought it was a nice little scratch building project.
The lyrics make me feel OK. I was pretty *** Wednesday night when I did that.
NP01I am going to make a current limited 3v supply with two 1.5v AA cells taped together in series with a resister soldered. That's much better than burning up $7.65 signals, of which I now have burned 2 out of 8. Ok the first one came burned.
Yeah, I was going to suggest that, as it's what I use. Much less likely to let the smoke out.
Glad to hear,,you are on your toe's,,you beat me to the batt.hookup..
By the way,,the Plastruct Truss's I bought were,two in a package,,just a tad under,9 inches long,for,9.25 and I used,7 in the Machine shop..I thought that was high,but the detail,you can't beat........Good Luck,on Your project,,,,,,,try not to make anymore,DED's..
Ok so I put on my patience hat and spent 2 hours hunkered down last night with careful use of scotch tape to hold down the assembly and wires so I could solder one by one. Success! I will post pictures as soon as I attach some reinforcements to the post-bridge attachments and finish adding the phone jack wire harness for connecting to the signal drivers.
The bridge is up! And what a difference the phone jack method made to under table body contortions. I have written the Logix's as well ...