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  • Author Author: ntewinkel
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Soldering a tiny LED using a Digital Microscope

ntewinkel

In an earlier blog post, I mentioned my new tech toy: a relatively affordable little 7" digital microscope I bought on Amazon.

 

A few people were curious as to how effective my new little digital "Koolertron" microscope would be for soldering.

As some people in the past have mentioned, digital microscopes can have a bit of lag which can make doing anything like soldering impossible or at least terribly annoying.

I've actually found it to be quite nice to use. Now, I'm no expert, so others with quicker reflexes might feel lag that I don't notice image

 

So I took some video of my very shaky attempt at soldering a tiny smd. I think it's 0402 ? it's smaller than the 0603 ones that were marked. In any case, at one point I obviously thought it was a good idea to buy some impossibly tiny smd LEDs for some future impossibly tiny projects. Life lessons abound.

 

Here are a few more learning opportunities that I will share right now, as I made several mistakes in this soldering project that made things very difficult:

1. solder flux. sigh. don't forget the flux, even on those little parts. especially on those little parts

2. find a way to secure the little parts, or else they will just stick to the solder on the iron.

 

That explains the burnt look on the finished LED image

 

In any case, I eventually saw the folly of my ways and life got easier. I'll spare you the very frustrating parts, and just share a few short videos so you can kind of see it in action.

 

The result worked out well enough, though it wasn't pretty image

image

 

I use magnet wire with smd LEDs for use in art type projects, as the wire is much thinner than regular type wire, and the lacquer coating keeps it from shorting out.

I find it easiest to just burn off some of the lacquer at the spots you need to solder or connect to battery.

 

Bit of an intro/overview first:

 

Here is my messy attempt. it's cool to see how much messier things are when they are enlarged with the microscope image

I think this might have been try number 5 or so, after the forgotten flux and the silly attempt at loose soldering.

 

And finally, showing the LED actually working - success!!

 

Cheers,

-Nico

  • Nico,

     

    Thanks for this, these were very helpful videos. It is good to see how clear the video seems to be while actually trying to solder. I still think your soldering is pretty good - compared to mine on some pin through hole components. I'm not too bad with 60:40 solder but I do find anything else just doesn't seem to work as well. Not sure why.  I have some 63:37 solder and it just seems so much more difficult to use. Maybe the internal flux is different, or something.

     

    However, the idea of using a magnifying camera system does seem to be something I will have to look into for soldering and maybe other things as well. The magnification and clarity seem just great.

     

    Dubbie

  • in reply to shabaz

    I had an orthodontists modify a pair of dental tweezers from his toolbox, to make these flat tip babies. The tip is normally closed, pinch to open. They are super thin and have a smooth surface. They actually close to hold one side of the 402 LED to enable soldering the other side.

     

    I appreciate your commentary on misplacing your tweezers. These were at one site and I was at another. I carried the material to the other side to use the tweezers:)

    image

  • in reply to ntewinkel

    Hi Nico,

     

    The tweezer style below seems reliable to me, although some might prefer angled ones, etc.

    I don't think I have any 0402 LEDs, but I had 0603 and 0402 capacitors, as shown in the photo below, the 0603 is gripped with it.

     

    It is >10 years old, I don't think these particular ones (VOMM brand) are made any more, but are labelled "PSF SA" which might be (not 100% sure) a general tweezer size/shape code that other manufacturers make too.

    image

    They have a squared-off flat end that is about 0.8mm wide measured with calipers. Each time I misplace them, I feel totally lost trying to do surface-mount, so from my perspective they made a big difference to me.

    image

  • in reply to colporteur

      wrote:

     

    Great update. I have soldered the 402 LED freehand. I watched a few Youtube videos to get an idea. Yes, securing the LED is import and your realization of the need for flux.

     

    I use the 402 LED often in HQ scale model railroad. Car lights or vehicle obstruction lights are typical. Using the lacquered winding wire. 0.1mm is what has proven best for me. 

     

    I tip my hat to you for your mad soldering skillz! image

     

    Those tiny LEDs open up a world of hobbyist/artist options don't they?

     

    How do you remove the lacquer from the wire for soldering? I tried fine sandpaper, nail polish remover, paint thinner, but ultimately the big hammer approach of fire seems to work most reliably, even if it's not very accurate, followed up with sandpaper to remove any soot.

    It could also be that I'm reusing wire from old transistors... that might be harder to work with.

     

    Best,

    -Nico

  • in reply to geralds

      wrote:

     

    One idea: fix one tinned copper wire on the board-desk then lay the pin of the LED on this wire and melt them by heating the wire. The LED will sinking into the tin.

     

    Oh that's a good idea.. you mean like add a bit extra solder tinning to the wire, and then heating the wire further up with the iron will re-melt the solder that's on the wire onto the LED?

     

    >If you use a tin wire (<=1mm_dia) with rosin, you do not need extra rosin, because this "explode" and the parts will jumping away.

    I never thought of that effect. I think I do have some thinner solder wire I can try too.

     

    I also bought some smd solder paste a while ago... I wonder if that might work well too.

     

    Thanks for the tips!

    -Nico