some basic de-soldering info

[jcoffin1981]

You all have seen me post several questions as a newb.  I'm de-soldering a polker 3 and cleaning it and replacing the switches.  This not something that comes natural to me.  Better quality tools would help, but that's neither here nor there.

My question is WHAT TEMPERATURE should I set my iron on to desolder switches.  In the past I've been concerned about damaging PBC components.  I've gotten through halfway and there are no damagaed components as far as I can see.  Videos only help so much .  It's really hands on that helps.  Too cool a temp and it cools too fast before the solder sucker can do it's job.  This is probably subjective, but any imput would be appreciated.   Thank you.

edit: the new POkers have ABS keycaps, probably because of the LED's.  I probably would not have gotten it if I knew this.  If I brick my old one I'll be transferring the keycaps.

[TalkingTree]

Theoretically, the same temperature for soldering should work for desoldering, and the temperature you need depends on the solder composition as, usually, more lead need higher temperatures.

You can empirically determine the temperature you need by raising it progressively and see when the solder around the pin melts. Start atop of the pin so you won't lift pads on the PCB.
Also, a drop of flux should help you desolder at lower temperatures.

Lastly, from my experience, when you can't completely desolder a pin, solder it back and then desolder. That would remove all the residues around the pin and the pad.

[hKing]

My question is WHAT TEMPERATURE should I set my iron on to desolder switches.

I am using 350 degrees, works good!

[appleonama]

My question is WHAT TEMPERATURE should I set my iron on to desolder switches.

I am using 350 degrees, works good!

I use 350 as well

[jcoffin1981]

I find desoldering a nightmare.  I wish I had one of those machines where you just  pump a gun and it comes off.   I'm mechanically  inclined and most things I am good at, but this gives me a hard time.  I have damaged several switches in the processs, so if  my board is 100 percent working I'll have  to buy some extra switches.

[TalkingTree]

I have damaged several switches in the process

I'm curious, what kind of damage to the switches?

[kekman]

350-400 works fine for me in most scenarios. More importantly is keeping everything both mechanically and chemically clean. Makes soldering a breeze.

[appleonama]

350-400 works fine for me in most scenarios. More importantly is keeping everything both mechanically and chemically clean. Makes soldering a breeze.

I clean the area with paint thinner then add flux

[jacobolus]

My question is WHAT TEMPERATURE should I set my iron on to desolder switches.

The important thing is not the temperature per se (and note, the temperature sensors on cheap soldering irons are very very inaccurate), but the heat flow.

The right temperature to use depends on the type of joint you’re soldering/desoldering, the size of your soldering tip, the condition of the tip (e.g. make sure you keep the tip tinned), and the heat capacity of the tip/iron. You want to use a temperature such that all the solder in the joint melts within a couple of seconds.

Try watching these PACE instructional videos:
https://www.youtube.com/watch?v=vIT4ra6Mo0s&list=PL926EC0F1F93C1837

Specifically, start here at 12:10 in the first video, and watch the next few minutes, http://www.youtube.com/watch?v=vIT4ra6Mo0s#t=12m10s

If you have a Soldapullt and a decent soldering iron, desoldering is easy and fast, and there shouldn’t be any damage to switches even if you desolder dozens of full keyboards. (A $500 desoldering iron is obviously even easier, but by no means essential.)

[xtrafrood]

My question is WHAT TEMPERATURE should I set my iron on to desolder switches.

The important thing is not the temperature per se (and note, the temperature sensors on cheap soldering irons are very very inaccurate), but the heat flow.

The right temperature to use depends on the type of joint you’re soldering/desoldering, the size of your soldering tip, the condition of the tip (e.g. make sure you keep the tip tinned), and the heat capacity of the tip/iron. You want to use a temperature such that all the solder in the joint melts within a couple of seconds.

Try watching these PACE instructional videos:
https://www.youtube.com/watch?v=vIT4ra6Mo0s&list=PL926EC0F1F93C1837

Specifically, start here at 12:10 in the first video, and watch the next few minutes, http://www.youtube.com/watch?v=vIT4ra6Mo0s#t=12m10s

If you have a Soldapullt and a decent soldering iron, desoldering is easy and fast, and there shouldn’t be any damage to switches even if you desolder dozens of full keyboards. (A $500 desoldering iron is obviously even easier, but by no means essential.)

Really informative video thank you for that 

[quasistellar]

I just desoldered a pok3r myself and the $15 desoldering iron from radio shack worked well.  Just make sure you buy extra tips for it, as they get burnt out fast.

[jcoffin1981]

I have damaged several switches in the process

I'm curious, what kind of damage to the switches?

I have been trying to have the iron contact have as little contact time so as to not damage the board or contacts.  Yes it seems the temperature control makes very little difference, but I have been using 350 degrees.  When trying to remove the switch from the plate/pcb sometimes one of the 2 contacts coming from the bottom of the switch would come off.  I'm debating buying more switches and getting the board back in working condition as I already have a Poker 3 I like better.  This is the LED version which kinda sucks.

[OfTheWild]

I have damaged several switches in the process

I'm curious, what kind of damage to the switches?

I have been trying to have the iron contact have as little contact time so as to not damage the board or contacts.  Yes it seems the temperature control makes very little difference, but I have been using 350 degrees.  When trying to remove the switch from the plate/pcb sometimes one of the 2 contacts coming from the bottom of the switch would come off.  I'm debating buying more switches and getting the board back in working condition as I already have a Poker 3 I like better.  This is the LED version which kinda sucks.

In my experience (for what little thats worth) that would indicate that you are having to leave the heat on the contact for too long. If you rase the temp a bit you should find that you will heat a smaller area faster and thus prevent heating up the whole switch. If that makes sense.

[jcoffin1981]

Actually, I've been trying to leave the heat in contact as little time as possible.  Little tiny bits of solder remaining on the contact caused more pressure needed to remove the switch and that's how  they broke.  But I think I do need a soldering station to give me more control with the temp.

[xtrafrood]

Actually, I've been trying to leave the heat in contact as little time as possible.  Little tiny bits of solder remaining on the contact caused more pressure needed to remove the switch and that's how  they broke.  But I think I do need a soldering station to give me more control with the temp.

The soldering irons with the temp adjustment dial on the handle might work for some. I can't even.

[OfTheWild]

Actually, I've been trying to leave the heat in contact as little time as possible.  Little tiny bits of solder remaining on the contact caused more pressure needed to remove the switch and that's how  they broke.  But I think I do need a soldering station to give me more control with the temp.

The soldering irons with the temp adjustment dial on the handle might work for some. I can't even.

thats what I've been using for years  But then again, my background is automotive - relays, ECU mods, megasquirt systems, etc. Keyboard switches, or at least cherry switches seem to be a bit more delicate maybe? i dunno.

[xtrafrood]

Actually, I've been trying to leave the heat in contact as little time as possible.  Little tiny bits of solder remaining on the contact caused more pressure needed to remove the switch and that's how  they broke.  But I think I do need a soldering station to give me more control with the temp.

The soldering irons with the temp adjustment dial on the handle might work for some. I can't even.

thats what I've been using for years  But then again, my background is automotive - relays, ECU mods, megasquirt systems, etc. Keyboard switches, or at least cherry switches seem to be a bit more delicate maybe? i dunno.

I'm just jaded from using solder irons without the temp adjustment.  )

[jcoffin1981]

Lastly, from my experience, when you can't completely desolder a pin, solder it back and then desolder. That would remove all the residues around the pin and the pad.

This is a good tip.

For the cost a Hakko desoldering gun is just not going to be practical for the  amount of use I will get out of it.  Can anybody comment on the items I have posted here?

1. http://www.amazon.com/dp/B00DZTFLCA/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=2ELFPFM3AEA3Q&coliid=ISN51DMT0V36O

2. http://www.amazon.com/dp/B00KQ6PR6K/ref=wl_it_dp_o_pC_S_ttl?_encoding=UTF8&colid=2ELFPFM3AEA3Q&coliid=I2GK5EQ7GA773S

3. http://www.amazon.com/dp/B00068IJSG/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=2ELFPFM3AEA3Q&coliid=I2CJ175YZGN000

4. http://www.amazon.com/dp/B00DZTI2EE/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=2ELFPFM3AEA3Q&coliid=IFJDFCOKOPGHQ

  Even $150 is more than I want to spend, but if it's  a great working tool than I can bite the bit and swing it.   I hope somebody here has used one of these and can give me  some practical advise.  I don't think I should do anymore desoldering with this cheap Mudder soldering iron.  Thanks for taking the time!

Edit- I've realized that the desoldering guns are designed to go with the  entire desoldering station, not stand alone, so this  is not an inexpensive option.   The only  inepensive option would  be  the irons with the bulb vaccuum pump.  If these  are absolute crap it's not worth  my time or money either.

[spanyam]

So I also need some input here. I see a lot of recommendations for 350 or 375 degrees, but I'm confused if that's Farenheit or Celcius. Here's the source of my confusion:

When I first tried desoldering last week, I had set the temperature between 350 and 375 celcius (since my iron's temp range was 200c to 400c). But I had a ton of trouble using it at that temp, as the solder refused to stick to the tip (for tinning). It would simply fall off, and the desoldering process was rather a mess.

Then I looked up the melting point for the solder I was using (Kester 44) and found this chart: http://www.kester.com/kester-content/uploads/2013/06/Alloy-Temperature-Chart-15Feb11.pdf. For 60/40 solder, the melting point was 183 to 190 celcius, so on the next try, I dropped my iron to the lowest temp setting (200c).

Immediately, I found that I was able to perfectly tin the tip and still melt the solder. By this point, I had moved from desoldering to soldering, and everything seemed to work quite well. I even had to desolder one switch after I found it wasn't working, and that temperature allowed me to do it quite cleanly.

So, what I'm wondering is, am I right to think that 200 celcius is the right temperature? Or have I kept it too low and risked cold soldering the entire keyboard?

[jcoffin1981]

I too have difficult times desoldering.  Most people seem to recommend 350 degrees which is above the melting point of the solder.  The idea is the heat is in contact with the board for less time and can cause less damage (I think).  The composition of  the solder you are using will also affect the melting point, so you will want to do some research on that.

[jcoffin1981]

I  have gone with the Yihua  936 which is a Hakko desoldering clone which costs about 5-10% of the real Hakko machine.  Those who have used it I have heard claim that it is somewhat near enough in quality to the original Hakko.  I'm sure they had to cut some corners to distribute it at this price.  Does anybody have any experience with this machine?

[spanyam]

I too have difficult times desoldering.  Most people seem to recommend 350 degrees which is above the melting point of the solder.  The idea is the heat is in contact with the board for less time and can cause less damage (I think).  The composition of  the solder you are using will also affect the melting point, so you will want to do some research on that.

Oh I see, I guess that makes sense. Maybe I can set the tip to 200 to get it to tin properly and then up to 350 for the actual soldering work. I'll see if that ends up working out.

As for having soldered everything at 200 already, I'm hoping it's safe to leave it like that since it's already above melting point of the Kester 44 that I used (i.e. no risk of cold solder joints). The joints look normal without any obvious deformities.

[jacobolus]

You folks should really watch the series of Pace videos I linked above.

[kekman]

I too have difficult times desoldering.  Most people seem to recommend 350 degrees which is above the melting point of the solder.  The idea is the heat is in contact with the board for less time and can cause less damage (I think).  The composition of  the solder you are using will also affect the melting point, so you will want to do some research on that.

Oh I see, I guess that makes sense. Maybe I can set the tip to 200 to get it to tin properly and then up to 350 for the actual soldering work. I'll see if that ends up working out.

As for having soldered everything at 200 already, I'm hoping it's safe to leave it like that since it's already above melting point of the Kester 44 that I used (i.e. no risk of cold solder joints). The joints look normal without any obvious deformities.

as long as it looks like a cold join (shiny) it should be fine. Otherwise, it might be worthwhile reflowing in an oven but I don't think it's necessary if you haven't run into any issues so far

[jcoffin1981]

I purchased the Hakko 936 clone, which is a quality soldering station- no more guesswork and damaged  parts from cheap soldering pens (hopefully).   I also purchased a desoldering iron that uses  a bulb that you squeeze for  suction. Is it  really possible to  desolder an entire board with a device like this? I have been looking  at true desoldering vacuum guns and they seem to start aroung $175 and go up from there to $375.  I cannot  damage any more components.  I have to take every switch off a board, clean, and relubricate it.  This is an impossible task with that cheap pen style soldering iron I have now which is why I'm buying these tools.

I'm wondering if for ease of use I should just get a true desoldering gun.  It would be great if I could find something that I could plug into this 936. I also have a few boards I wanna attempt to repair and I won't even try with the cheap cr#$ that I have now.

[spanyam]

as long as it looks like a cold join (shiny) it should be fine. Otherwise, it might be worthwhile reflowing in an oven but I don't think it's necessary if you haven't run into any issues so far

Yeah, no issues so far, other than the fact that I haven't gotten around to cleaning off the flux residue yet. =/

[jcoffin1981]

There is this Tenma 72-6406 that is a replacement for the soldering station it comes with.  It's a vacuum desoldering gun.  Can I use this with the Hakko clone soldering station I'm buying?  It has a 5 pin connector which is what the Hakko uses.   Will it be compatible?

I can't get the image to post, but here is the URL

http://www.amazon.com/Tenma-72-6406-Replacement-Desoldering-72-6340/dp/B008DJS5RK/ref=sr_1_9?ie=UTF8&qid=1459047529&sr=8-9&keywords=desoldering+gun

Edit:  It looks like the station itself may provide the suction in which case this would be a no-go.  Is this correct?

[jacobolus]

Just get an Edsyn Soldapullt. IMO it works better than anything else that you can find for less than a few hundred bucks.

[rpeterclark]

I agree, an Edson Soldapullt is the way to go. I set the iron to 350c, add a bit of solder to each lead,  and I'm able to desolder a 60% with LEDs in about an hour. I'll use solder wick for cleanup, but not for actually removing switches.

[jcoffin1981]

I got the engineer SS-02 which is probably similar in quality.  You add solder to every lead before you desolder, or just the smaller LED's.

[TalkingTree]

You add solder to every lead before you desolder, or just the smaller LED's.

Add solder to every die-hard contact, LEDs are indeed nasty when it comes to desolder.

[jcoffin1981]

Just to clarify, when you say every die-hard contact, you mean EVERY ONE?  If there is already a big mound at the solder joint what is the advantage of adding more solder before desoldering?

[jacobolus]

There’s no reason to add more solder unless desoldering fails the first time.

[TalkingTree]

Just to clarify, when you say every die-hard contact, you mean EVERY ONE?

No, only those which don't melt completely at the first attempt.

If there is already a big mound at the solder joint what is the advantage of adding more solder before desoldering?

I don't know the technical details nor the magics behind it, but if the joint doesn't melt, adding more solder will solve the problem. Maybe you can try with flux.

[Signature]

Just to clarify, when you say every die-hard contact, you mean EVERY ONE?

No, only those which don't melt completely at the first attempt.

If there is already a big mound at the solder joint what is the advantage of adding more solder before desoldering?

I don't know the technical details nor the magics behind it, but if the joint doesn't melt, adding more solder will solve the problem. Maybe you can try with flux.

It is because the new solder makes greater contact with the old solder, than the soldering iron does. Thus resulting in a better transportation of heat to the old solder.

[tp4tissue]

Just to clarify, when you say every die-hard contact, you mean EVERY ONE?

No, only those which don't melt completely at the first attempt.

If there is already a big mound at the solder joint what is the advantage of adding more solder before desoldering?

I don't know the technical details nor the magics behind it, but if the joint doesn't melt, adding more solder will solve the problem. Maybe you can try with flux.

It is because the new solder makes greater contact with the old solder, than the soldering iron does. Thus resulting in a better transportation of heat to the old solder.

Don't use this technique liberally, because it DOES add more total energy to the area, Greatly increasing the likelihood of pad lifting and/or burning traces..

This Goes double for the less durable PCBs.