how do you solder smd leds??

[ghostman11]

i have seen theese **broken link removed**

on fleabay and was wondering how on earth you solder them??
no particular reason other than curiosity

 

[Speakerguy]

You solder them just like any SMT resistor or capacitor, you just have to make sure it's soldered down in the right direction

Seriously though, good tweezers are an absolute must. Microscopes are helpful with 0603 components but not necessary. I prefer the dry tack method where you have a tin plated PCB and place the component on the pads, touch the soldering iron to one pad just enough to heat up the tin plating and get that side of the component to stick, then solder the other side normally, come back and touch up the original side with more solder.

And in case you couldn't tell by the picture on eBay, the ends are metallized and the cathode marking is usually on the underside.

**broken link removed**

There are some good videos on YouTube by solderinggeek showing various SMT soldering techniques. A very good place to learn from.

https://www.youtube.com/watch?v=qs7rSM731gk

 

[ghostman11]

thanks for the link speakerguy was most useful!! still dont think my eyes are upto that!!

 

[DirtyLude]

Get some cheap reading glasses. The 3X ones from the drugstore.

 

[Sceadwian]

I wouldn't recommend 3X reading glasses, (I have a pair) their focus depth is crap, which means you'll get heavy eye strain and near and close objects will be painfully blurry. 1.5 or 2X at most. Plenty of magnification to help without too much, giving you a broader range of distances you can be and still get good focus.

 

[ke5frf]

The toaster oven/solder paste reflow method is one way but I personally have no experience with it. I'll mess with exclusive SMD only when there is no other alternative. Until then the few occasional components I have to work with will be with tweezers and magnifying glass as long as my vision permits.

 

[ghostman11]

i would really like to use some theese led's but i already wear glasses and strugle to see them on my mother board!! what size soldering bit would you use?? mine seems way bigger than the component itself

 

[mneary]

I use reading glasses only slightly stronger than I use for reading. I read with 1.25 and solder with 2.0.

 

[mneary]

A tip that's about 2/3 of the solder pad size is recommended. 0603 should have pads 0.040 wide, so an ideal tip would be 0.025" to 0.030".

In practice, my smallest tip is 0.040".

 

[Sceadwian]

You just want a fine conical point, and with stuff that small it is especially important to use tinner/cleaner and that it's just slightly wetted. Solder tends to wick all by itself to any bare metal surface so it tends to do the work for you as long as everything is clean and heated. The thing you need to avoid is solder bridges if you use too much solder it will wick inbetween fine pitched package leads and can be a royal pain to fix.

 

[ghostman11]

my six month old daughter absolutely loves small flashing led's she will watch and bable excitedly at the little hard drive active light on my computer.
in the pic you can see a very old hard drive i have, what i want to do is drill thru the top plate of the disk and fit those led's thru it so they shine thru the top of the disk. i would also mount a couple on the arm.
as i have finaly ordered a june bug from bill i thought i would slowly spin the disk and move the arm with a pic while flashing the leds. when put in a perspex case it would keep her happy for hours lol.
is hard to see in the pic but the whole hard drive mechanism is realy pleasing to look at (well is to me ). maybe i am being over ambitious for a complete noob

 

[DirtyLude]

I wouldn't recommend 3X reading glasses, (I have a pair) their focus depth is crap, which means you'll get heavy eye strain and near and close objects will be painfully blurry.

I have two pair. They work fine.

If the depth of focus on yours is too shallow, then don't hold your work so close.

 

[ghostman11]

thanks for the info guys. maybe i will wait till i have alot more experiance at desoldering first lol

 

[Speakerguy]

I use a 1.5mm (0.060") chisel tip for almost all my SMT soldering needs. The other one I use frequently for SMT is a drag hoof. Between these two I can do practically anything, so long as it has leads. QFN's and such are still beyond me. I'll have to buy a hot plate or a hot air station to tackle those.

Personally I do not recommend a fine point tips for anything. I have found no need for them and they don't transfer heat very well. Small chisel tips are a better choice IMO. At work I will even do 0402's with a drag hoof because I'm too lazy to change the tip. But at work I have the microscope which helps a lot.

Edited to add: Added liquid flux is the secret to SMT soldering. It makes a profound difference. I use it so liberally that I actually went and bought a gallon of the stuff for myself to use, it was only $25 plus hazmat shipping fee. Should last me a loooong time Also, the alcohol based fluxes are much easier to use/less sticky than rosin based fluxes. We use rosin at work because rosin is more heat stable and we have alcohol baths to clean the boards with, but at home I find using a no-clean alcohol based flux much simpler.

 

[creakndale]

I use one of these $20 Harbor Freight Desktop magnifying lamps. It contains a circular lamp that shines on the work piece. Plus, your eyes are shielded by the magnifier for solder spatter protection. It works great for all sorts of projects, not just soldering.

creakndale

 

[ghostman11]

i will have to get one of thos lamps!! looks ideal

 

[BrownOut]

I use a microscope, it makes things so easy for my aging eyes. Of course, I do this at my employer's facility ( or at least I did when I was employed ) I don't know what was paid for the micro, but I'm sure It would not pay for me to buy one, unless I begain to do ALOT of smt work.

 

[schmitt trigger]

I use one of these $20 Harbor Freight Desktop magnifying lamps. It contains a circular lamp that shines on the work piece. Plus, your eyes are shielded by the magnifier for solder spatter protection. It works great for all sorts of projects, not just soldering.

creakndale

I have a similar one. I also sincerely recommend it.
The big plus is the attached light. When your are soldering very close to a component, like you do with SMT work, your body will produce a shadow.

 

[maxxypane]

Check the documentation for the soldering and make sure the temperature is applicable to the type of solder is used. For example, the melting point of lead-free solder Sn99 is 440 degrees Fahrenheit, but the SMD components and the PCB pad is also heated to the temperature. Because of the heat transfer and dissipation of iron should produce more than 440 degrees Fahrenheit.

https://www.soldertools.net/products/SMT-Prototype-Stencils.html

 

[alec_t]

One thing you probably will need to do is find a way of temporarily holding the component in place while soldering, otherwise the surface tension of solder on the iron is enough to pull the component out of position. In professional set-ups glue is used, but a clamp (springy wire, etc) can be improvised..