I got my 0603 SMD LEDS, Now I have to Solder Wires to Them - Page 1
Forum section: electronics / projects

author: xrunner
author_rank: Super Contributor
timestamp: May 23, 2013, 09:06:57 pm
content: LOL - they're tiny. I have red, yellow, and green. I have 36 AWG wire and I need to make traffic lights for an N scale Model Railroad. I need tips on soldering wires to these tiny LEDS. These will be controlled via an Arduino that I already have a program written for which is being tested with larger LEDs.Any tips are appreciated.

author: c4757p
author_rank: Super Contributor
timestamp: May 23, 2013, 09:10:53 pm
content: Glue them to a piece of thin paper to keep them from moving around. Add a spot of flux, hold the wire against it, and touch with a soldering iron with some solder already on the tip. Repeat for the other side. Just rip it off the paper when you're done, and you can get the rest of the paper off with water and a brush.You might have a hell of a time getting a good mechanical connection, though. Personally I'd have had a bunch of tiny PCBs made.

author: Paul Price
author_rank: Super Contributor
timestamp: May 23, 2013, 09:24:15 pm
content: For testing and working with SMD parts off a PCB:(1) Use 3M a double sided tape piece to hold the little thing in place on top of a bench vice.(2) Give the pins a swab with water soluble flux.(3) Strip silver plated wire-wrap wire #28 to #32 for leads.(4) With a solder temp just above melting point and with a steady hand solder the WW wire leads to pin after pin.(5) Clean the finished work with another Q-tip dipped in denatured ethanol.

author: xrunner
author_rank: Super Contributor
timestamp: May 23, 2013, 09:42:15 pm
content: Quote from: c4757p on May 23, 2013, 09:10:53 pmQuote from: Paul Price on May 23, 2013, 09:24:15 pmOK I'm starting to get the idea.What I'll need is to have all the cathodes wired together and each R-Y-G LED with it's own wire, so that's four wires going down to the controller. Also need to glue the three LEDs to ... something ... to make it look like a traffic light but that's another issue.

author: Paul Price
author_rank: Super Contributor
timestamp: May 23, 2013, 09:51:54 pm
content: Try wiring the LED's with two wires instead of one.You can buy plastic transparent sheets at some artist, architecture supply or paper stores to create the traffic light lens effect. You can easily create a traffic light using paper to form a tube and fashion sun visors from paper as well and spray paint them to match their traffic pole. Architects often need to create scale models of their designs so architect supply places will offer all types of rods and foam etc. Never underestimate the utility of GOOP, Superglue, or silicon rubber to creating castings. Plaster can then be poured into molds made from wax or silicon rubber.

author: millerb
author_rank: Regular Contributor
timestamp: May 23, 2013, 09:54:35 pm
content: An 0603 will fit right between the pads on a 2.54mm (0.1") piece of veroboard which you can get cheaply from Radio Shack. Here's a photo of an 0603 resistor on one next to a buck converter I put together.I'd just cut a piece of board and tack them down on there instead of trying to solder wires onto them.

author: xrunner
author_rank: Super Contributor
timestamp: May 23, 2013, 09:56:11 pm
content: Quote from: Paul Price on May 23, 2013, 09:51:54 pmYea I'll have to carefully plan all that so I can get the wires going in the right direction as soldered, if possible. You said to have the iron just above the melting point of solder? Not up at ~650 F or so, but near, say 200F?

author: Paul Price
author_rank: Super Contributor
timestamp: May 23, 2013, 10:08:50 pm
content: For the sake of your lungs and that of the little poor device you are momentarily torturing with heat, keep the heat to a point that will make the solder just flow as a bright shiny liquid, you need hotter if the solder is like almost melted ice-cream soft in viscosity, and if you see a lot smoke you are hot enough to make trouble and toast. Heat the joint of wire and device first and as you see the flux evaporate touch the joint, soldering tip and device pin all at once to add a tinsey widdle bit of solder.

author: andyturk
author_rank: Frequent Contributor
timestamp: May 23, 2013, 10:23:45 pm
content: Quote from: millerb on May 23, 2013, 09:54:35 pmI bet soldering that QFN was a barrel of fun.

author: Paul Price
author_rank: Super Contributor
timestamp: May 23, 2013, 10:44:48 pm
content: Damn, Millerb, your soldering sho' looks nasty! Even Lincoln looks fried.

author: xrunner
author_rank: Super Contributor
timestamp: May 23, 2013, 10:51:38 pm
content: Quote from: Paul Price on May 23, 2013, 10:44:48 pmWasn't that millerb's soldering? (it was a quoted pic)In any case using that board would end up with a traffic light that was too big for N scale.

author: millerb
author_rank: Regular Contributor
timestamp: May 24, 2013, 12:35:22 am
content: Quote from: xrunner on May 23, 2013, 10:51:38 pmThis is too big?

author: Paul Price
author_rank: Super Contributor
timestamp: May 24, 2013, 12:41:13 am
content: Damn, Millerb, your soldering sho' looks nasty! (On the right side of the LED pictured.) Left side looks great.

author: xrunner
author_rank: Super Contributor
timestamp: May 24, 2013, 12:42:18 am
content: Quote from: millerb on May 24, 2013, 12:35:22 amNo ... I said using the pads on thatboardto make up a traffic light would be too big.

author: Paul Price
author_rank: Super Contributor
timestamp: May 24, 2013, 12:45:24 am
content: Xrunner, that picture has been magnified! Is isn't really that big.And taking a second look, Damn, Millerb, your soldering sho' looks nasty! Looks like you nearly fried this LED's both pads, surprised it still lights. You are not going to get a NASA Certified Soldering merit badge with this kinda work.Hint: turn down the heat a little, man...and flux around a bit.

author: xrunner
author_rank: Super Contributor
timestamp: May 24, 2013, 12:50:11 am
content: Quote from: Paul Price on May 24, 2013, 12:45:24 amThat's not the issue though. It's the spacebetweenthe pads. Traffic lights have (proportionally) not nearly that much spacebetweenthe lights. I understand that the 0603 LED can be soldered onto the pads as shown, but that's not the only concern with regards to my modelling application.

author: DavidDLC
author_rank: Frequent Contributor
timestamp: May 24, 2013, 12:57:20 am
content: Can you provide the separation between the LEDs ?I have a PCB LED matrix with 0603, maybe I can cut something for you depending on the distance.David.

author: TerminalJack505
author_rank: Super Contributor
timestamp: May 24, 2013, 01:16:54 am
content: Get a cheap piece of balsa wood and cut a shallow grove in it for the wire and a small area for the LED. Hold the piece of wood down to the bench with mounting putty (Fun-Tak, for example.) Tin the wire, put it and the LED in place. Use some flux and put a small amount of solder on the tip. Steady the wire with your free hand, touch the tip to the LED and wire and Bob's your uncle. Use a stereo microscope if you have one and you can hardly go wrong.

author: andyturk
author_rank: Frequent Contributor
timestamp: May 24, 2013, 01:44:02 am
content: Quote from: xrunner on May 23, 2013, 09:06:57 pmIf you put 3 LEDs on a tiny board, you can probably get OSHPark to make them for pennies. A 2-layer board is $5/square inch (including postage).

author: ConKbot
author_rank: Super Contributor
timestamp: May 24, 2013, 01:53:12 am
content: Quote from: Paul Price on May 24, 2013, 12:45:24 amNot like the nasa hand solder standard covers any real SMD work besides the goofy old gull wing packages you have to run though a $5000 lead former first.

author: Paul Price
author_rank: Super Contributor
timestamp: May 24, 2013, 01:58:54 am
content: Xrunner: Layout your parts positions and wiring using some free layout software such as PCB123 or equiv. Then print out a copy of the PCB onto film and place it over any substrate you wish (even balsa wood or paper might do the trick.) Then drill the holes and assemble the thingy using your own teensy-weensy wires to make ends meet and you've got watcha want.

author: pickle9000
author_rank: Super Contributor
timestamp: May 24, 2013, 03:32:55 am
content: Here is how I'd do it.

author: andete
author_rank: Contributor
timestamp: May 24, 2013, 05:04:57 am
content: There's actually a webshop called ledbaron on ebay  that sells among things nicely wired SMD LEDs.http://stores.benl.ebay.be/ledbaron

author: hlavac
author_rank: Frequent Contributor
timestamp: May 24, 2013, 08:21:27 am
content: My hands are too shaky for this stuff so i cheat, tin both ends, hold it together with tape or something, and use hot air gun to reflow the solderLooks much better than when I beat it with soldering iron tip...

author: xrunner
author_rank: Super Contributor
timestamp: May 24, 2013, 12:44:19 pm
content: Quote from: pickle9000 on May 24, 2013, 03:32:55 amYes, that's what I think I will need to do. I looked around on Ebay last night and found a seller of red, green, and copper colored magnet wire in many gauges -Magnet WireI have some red 30 AWG solid wire and I twisted 4 wires together and it's small enough to look good - either as the type of hanging traffic light (one that hangs above the street on a cable) or to run down a small copper tube. Not only that, but as I've done with other single LED lights I've made by hand, the copper tube acts as the cathode wire, so all you have to do is solder the cathode of the LED at the top and a wire at the bottom of the tube (which can't be seen since it's below grade) and you eliminate one wire.The three colors make it easy to wire up at the other end. The stuff is dirt cheap (391 ft for $4) so I think I'll get that and I'll be OK. The hanging twisted wires can simply be painted flat silver or black - I'll have to go look at a traffic light today.

author: pickle9000
author_rank: Super Contributor
timestamp: May 24, 2013, 05:16:08 pm
content: So here are my bits.- I used 1mm lead solder (Kester) and pretinned everything.- Iron temp was 310deg and the tip was a 3mm chisel.- I soldered on top of a piece of MDF (medium density fiberboard) and used paste flux (the solder was rosin core).- The common wire was a single strand of 16 gauge wire pretinned made taught and screwed to the board.- I marked the back side of the leds with a marker (red and yellow) to indicate the colour in case thy slipped.- I used a scalpel blade to place and hold each led while soldering, make sure you have metal to metal contact as flux or paste may prevent it from taking. You need to hold it by the substrate not the lens.- My eyes are poor so I did use a microscope.- The actual soldering time (per connection) was well under a second. The action was wipe tip, retin tip, wipe tip, touch to connection, done.- The image looks as if everything is melted (lens) but that is just the flux and it will clean up fine.- After the first led was in place the rosin from the solder kept the other one there.- Use as little solder as possible and the fastest soldering time, if you don't the leds will blob together.- I did not use glue or tape mainly because everything is so close together it would just get ugly. If you do use something try the sticky stuff off of a post it note.For your application you could turn the wire 90 deg after the common wire is soldered. That will lessen the profile, if you do that place the common wire in a large metal clip (aluminum would be best) and make sure the actual solder touches the aluminum. This will act as a heat sink an prevent the joint from melting.How are you going to do the crossing lights? I know of a trick with a 4011 that would work perfectly.

author: xrunner
author_rank: Super Contributor
timestamp: May 24, 2013, 10:00:02 pm
content: Quote from: pickle9000 on May 24, 2013, 05:16:08 pmThanks for the suggestions. I put together a small mockup (see attachment). I'm thinking of running the wires out the back through tiny holes I can drill in the mounting block. I have strip styrene I can use for these parts which welds together very easily with plastic welder cement.QuoteThe RR crossing lights? Hadn't thought about it yet, but if these work out OK with the 0603s I will try to use red ones on the crossing signal models I have, because they have tiny lenses that are clear. I could put them behind the lens.A 4011 NAND gate? Whatcha got in mind?

author: xrunner
author_rank: Super Contributor
timestamp: June 04, 2013, 10:18:15 pm
content: Here's the rig I set up to help me solder the 0603's. I'm soldering to 30 AWG magnet wire. The red and green magnet wire doesn't require stripping because the insulation melts and the manufacturer says it actually acts as flux. However I pre-tinned it anyway before soldering to the LED.Funny thing is, the amber magnet wire they sell has enamel insulation that has to be stripped off by hand. I don't understand why they can't make that insulation like the red or green.BTW - the company isTemCo