Re: Heat Sink Clip Suggestions

[K3yPr0gg3r]

Hi,

I'm in the process of taking a soldering class, (J-Standard), and today we were discussing, among other things, using a heat sink with diodes. Does Mouser or any other of the "suggested"  component companies sell the "roach clip"/alligator clip type?
Also, I have seen videos where a component is soldered then the lead is clipped afterward. Just wanted to give a heads up that this technique can cause what's called "exposed base metal" which can lead to fractures in the solder, and shorts in the circut board. Just passing on information given to me by my instructor.

Thanks

[K3yPr0gg3r]

Hi Again,

Found something called Goot Clips at Amazon. Should do nicely...

Thanks again,

[klonisgayjplay]

on muffwiggler theres a NASA standards document on proper soldering techniques full with pictures and explanations. Which makes you think, some practices of soldering are implemented because there are projects are at the expense of millions of dollars and or peoples safety.

Its really interesting, but i think for our purpose's this method of "solder then cut" is fine especially considering we can always go back and touch up broken or cold solder joints.

[galaxiex]

In all my years of soldering/building circuits I have used a clip-on heat sink maybe 3 times....

Of the potentially 1000's of solder joins where soldering directly on the lead of a semiconductor or other device,
I cannot think of any one instance where the heat from soldering could be blamed for the project not working or the part failing.

That said... I do use sockets for IC chips and have directly soldered an IC chip right to the board maybe 6 times....
Never had one of those fail from the heat either, but a socket sure makes changing the IC easier when you *oops* reverse the supply voltage. 

Edit; I do use a very HOT soldering iron (750 degrees) and get on-off the solder join very quickly.

Also when you consider the big manufacturers use wave soldering and NONE of those tiny SMD parts have heat sinks on them just for the soldering process... and they basically get immersed in molten solder... well... (shrug)

...and that said.. if you were soldering a "relatively" expensive hard to get Ge part, it might be prudent to use a heat sink clip. 

[davent]

I have a few pairs/sizes of locking forceps/hemostats that would do in a pinch but i can't recall ever using them for heatsinking. They can be found for very little money.



dave

[culturejam]

I got the little cheap one from Radio Shack years ago:
https://www.radioshack.com/products/soldering-heat-sink-clip-tool?variant=5717595077

I think I've used it twice.

[Betty Wont]

I have a few pairs/sizes of locking forceps/hemostats that would do in a pinch but i can't recall ever using them for heatsinking. They can be found for very little money.



dave

This^, and they make great clamps, helping hands, and roach clips.

[wgc]

Edit; I do use a very HOT soldering iron (750 degrees) and get on-off the solder join very quickly.

Also when you consider the big manufacturers use wave soldering and NONE of those tiny SMD parts have heat sinks on them just for the soldering process... and they basically get immersed in molten solder... well... (shrug)

...and that said.. if you were soldering a "relatively" expensive hard to get Ge part, it might be prudent to use a heat sink clip. 

The only time I've used a heat sink clip is soldering germanium transistors.

Not intending to argue or poke anyone, but there are some wrong assumptions in your post, and you seem like you'd be interested to know more.

The main issue isn't so much the temp or the time in most cases. It's actually thermal shock from getting too hot too quick.

Wave solder has preheating zones that ramp from low temps to close to the wave temp, over a minute or so. The wave is actually about 500-600 deg, much less than 750. Too hot too soon and the pcb will warp, flux cooks off before it can do its job, and you get solder bridges and tons of dross. 

Same process with smd reflow in ovens that have a conveyor and about 7-12 zones. The even temp change is consistent and avoids hot or cold spots. Just slightly hotter than solder melting point.

Your 750 iron is imho just a little too hot, but workable for most things. Meaning you can shock a part and cause internal issues if you're not careful. It may not fail right away but will likely have a shorter life span.

We're splitting hairs but probably better to be a little cooler and shoot fora temp that allows 2-3 sec per joint. I spent years optimizing these parameters for electronic production in mil spec factories.

If you think about baking a pizza it's a similar thing. Too hot, uneven heat leaves some parts cooked too much and others less so.

[galaxiex]

Edit; I do use a very HOT soldering iron (750 degrees) and get on-off the solder join very quickly.

Also when you consider the big manufacturers use wave soldering and NONE of those tiny SMD parts have heat sinks on them just for the soldering process... and they basically get immersed in molten solder... well... (shrug)

...and that said.. if you were soldering a "relatively" expensive hard to get Ge part, it might be prudent to use a heat sink clip. 

The only time I've used a heat sink clip is soldering germanium transistors.

Not intending to argue or poke anyone, but there are some wrong assumptions in your post, and you seem like you'd be interested to know more.

The main issue isn't so much the temp or the time in most cases. It's actually thermal shock from getting too hot too quick.

Wave solder has preheating zones that ramp from low temps to close to the wave temp, over a minute or so. The wave is actually about 500-600 deg, much less than 750. Too hot too soon and the pcb will warp, flux cooks off before it can do its job, and you get solder bridges and tons of dross. 

Same process with smd reflow in ovens that have a conveyor and about 7-12 zones. The even temp change is consistent and avoids hot or cold spots. Just slightly hotter than solder melting point.

Your 750 iron is imho just a little too hot, but workable for most things. Meaning you can shock a part and cause internal issues if you're not careful. It may not fail right away but will likely have a shorter life span.

We're splitting hairs but probably better to be a little cooler and shoot fora temp that allows 2-3 sec per joint. I spent years optimizing these parameters for electronic production in mil spec factories.

If you think about baking a pizza it's a similar thing. Too hot, uneven heat leaves some parts cooked too much and others less so.

Thanks for your input, and no offense taken!    (or intended)

I have just enough knowledge to be dangerous.... 
Appreciate the additional info from someone that's been there, done that.
Did not know about the preheat on SMD parts, but it certainly makes sense.
I get the pizza analogy too. 

As for the temp of my iron, the 750 degrees is what the temp readout on my solder station says...
Not sure how accurate or even if it can be trusted but that's what it says.
I arrived at that setting after some experimentation.
I started low-ish at around 600 and worked up to where I felt comfortable with how it "works" for my method of soldering.
I do like to get on-off the part very quickly.

I re-read my above post and realize that it may have come across as slightly arrogant.
Hope it was not taken that way.
Simply trying to tell of my experience with soldering and what works for me.
Cheers!

[wgc]

sweet, I love pizza.    No offense here either, and really, its a hobby for most of us.

Most here are soldering mylar caps, metal film resistors, and wires to lugs.  There's a lot more tolerance to thermal issues than semi-conductors have, so if you're socketing those, very little risk of heat damage. 

It becomes a little more important with smd ceramic caps, but they're still fairly tolerant.  Probably the biggest risk for most of us here with a too hot iron is lifting a pad or screwing up a footswitch.

If my post helps even one person avoid the head scratching of a failed part a few years out, then I can sleep easier.   

In all sincerity, I did not detect any arrogance, none more than mine.  I figured at the least, the info might be interesting, and its a great discussion.

Just a few friends trying to help each other out.