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Electronics => Beginners => Topic started by: Dantali0n on March 06, 2014, 09:31:51 pm

Title: soldering iron creates sparks
Post by: Dantali0n on March 06, 2014, 09:31:51 pm
Hello,

Im new to electronics so I dont have any proffesional gear. I have a rigal ds1052e osciloscope and an multimeter from the local hardware store. However those work fine the problem is with my soldering iron. I got it at an local supermarket and it was about 10 euro ( 15 dollar ).

Recently i noticed it sometimes creates sparks across the board when i am using it to solder.
Now that's probably very bad ? and that is also my question,

* How can that happen I cant imagine soldering irons are designed to do so ?
* what can I do to prevent it ?
* and finally how bad is it for my circuits ?

Hope this helps.

PS: I also included an image of the soldering iron as attachment.
Title: Re: soldering iron creates sparks
Post by: IanB on March 06, 2014, 09:36:49 pm
It's maybe bad, but if your board is sitting on an insulated workbench then sparks shouldn't happen. You are not working on a live or energized circuit board by any chance?
Title: Re: soldering iron creates sparks
Post by: IanB on March 06, 2014, 09:38:16 pm
You can do a simple test with your multimeter. Unplug the iron and let it cool down, then do a continuity test between the tip of the iron and the connections of the mains plug. Ideally there will be continuity to the earth connection and infinite resistance to the live or neutral pins.
Title: Re: soldering iron creates sparks
Post by: Dantali0n on March 06, 2014, 09:42:47 pm
No the circuit is not live. But my working surface could be the issue since its an wooden surface. If just tested your multimeter test and the tip is only connected to earth so that's not the problem.

Seems I need an better working surface.
Title: Re: soldering iron creates sparks
Post by: electronics man on March 06, 2014, 11:57:38 pm
Do you have any charged caps in your circuit sometimes if u try to solder a charged cap you gat a spark.
Title: Re: soldering iron creates sparks
Post by: Dantali0n on March 07, 2014, 12:18:00 am
I always make sure caps are discharged when I solder, I short them with a screwdriver before I use them.

The most strange part was that it did not stop after one spark. It was like sparking every second, I could even see the arc.
Title: Re: soldering iron creates sparks
Post by: Psi on March 07, 2014, 01:00:08 am
Are you absolutely sure your circuit was completely unconnected to power/ground while you were soldering?

If your circuit had any connection to some other device, like from a psu or from a USB plug or anything like that you can get a small voltage difference between "soldering iron tip ground" and your "circuit ground"

It's uncommon when the house ground wiring is good but in old houses ground can get broken and if things start floating the earth connector will pickup mains and produce small sparks when touched to the actual ground.
Title: Re: soldering iron creates sparks
Post by: SoundTech-LG on March 07, 2014, 05:21:12 am
The other possibility is ESD. If you are wearing highly insulated shoes, and have a polyester, or nylon carpet, you are probably generating hundreds of thousands of volts as you walk or move on it. Discharge yourself to ground before you touch your soldering iron (spark might be unpleasant but will not hurt you. Get a wrist strap to prevent ESD. Happens here in the lab at work all the time.

http://www.ebay.com/itm/like/370790580505?lpid=82 (http://www.ebay.com/itm/like/370790580505?lpid=82)
Title: Re: soldering iron creates sparks
Post by: Dantali0n on March 07, 2014, 10:22:54 am
ESD is very possible the ground is nylon which i mostly sit on without shoes on.
I think our house wiring is very decent, we never have problems with it and our house is only 15 years old.
also my circuit boards are on a wooden bench together with my psu.

So I guess I should move my psu get an anti static wrist wrap and maybe some kind of rubber mat for on my working surface.

Thanks everyone for all the help and replies.
Title: Re: soldering iron creates sparks
Post by: Joule Thief on March 07, 2014, 10:57:30 am
Do you receive a shock if you walk across the nylon floor carpet and touch a door knob or grounded appliance?
Title: Re: soldering iron creates sparks
Post by: amyk on March 07, 2014, 11:40:03 am
The most strange part was that it did not stop after one spark. It was like sparking every second, I could even see the arc.
If this is really a continuous thing and not just once or twice after you do a big movement (and wearing static-generating clothes), I don't think it's ESD.
Title: Re: soldering iron creates sparks
Post by: Dantali0n on March 07, 2014, 12:33:49 pm
Do you receive a shock if you walk across the nylon floor carpet and touch a door knob or grounded appliance?

sometimes I do but this is pretty rare occurance, Most times I dont.

The most strange part was that it did not stop after one spark. It was like sparking every second, I could even see the arc.
If this is really a continuous thing and not just once or twice after you do a big movement (and wearing static-generating clothes), I don't think it's ESD.

Thats why I thought it couldnt be ESD at first, but I cant figure out another reason.

Would it be a good idea to connect the tip of the soldering iron to the board and test if there's an voltage going across it, While its plugged in of course.
Title: Re: soldering iron creates sparks
Post by: SoundTech-LG on March 07, 2014, 06:11:04 pm
Not a bad idea to connect your iron to the board ground you are working on. I'm not sure I like your barefoot technique though...  :palm:
Title: Re: soldering iron creates sparks
Post by: Yago on March 07, 2014, 06:36:37 pm
A faulty iron and no proper earth to the bench mains supply?
Title: Re: soldering iron creates sparks
Post by: Nerull on March 07, 2014, 10:32:59 pm
Wrap a wire around one of your multimeter probes and use it as a lead and you can measure any voltage on the tip of the iron to ground without damaging your probes.
Title: Re: soldering iron creates sparks
Post by: Dantali0n on March 09, 2014, 01:53:21 pm
Wrap a wire around one of your multimeter probes and use it as a lead and you can measure any voltage on the tip of the iron to ground without damaging your probes.

I tested this it said 0.2 volts. Or if i disconnect the ground lead it said 26 volts.

I used a wire to connect the board i am soldering on to the earth of my wall outlet this seems to remove the problem.
( at least it did not happen in the past day anymore )
Title: Re: soldering iron creates sparks
Post by: Joule Thief on March 09, 2014, 02:08:33 pm
a few random thoughts ...

Bring the soldering iron up to temperature.
UNPLUG the iron or station from the AC power.
Try to solder a small connection on the PC board - does it still spark with the iron unplugged?

Does the spark occur only when soldering this particular PC board? Can you reproduce this same issue with a different PC board or a scrap board ?