ColdHeat

[Sceadwian]

I received a ColdHeat soldering tool this Christmas, I was wondering if on sensative devices if a small grounded clip was placed above the tip of the lead being solder that was grounded would keep dangerous voltages/currents from developing further on past the clip? Anyone have any experiance with these things and using them without hurting chips?

 

[Andy1845c]

I've never used one, but i'm interested to hear how well it works. Does it work as well in real life as it does in the TV commercial?

 

[dknguyen]

I heard it's no good for real solder jobs. Then again, it's supposed to be a portable quick fix field tool rather than a workshop tool like if you notice a couple loose joints in the field. But for longer field soldering jobs, a butane iron is still better.

The act of clipping the lead might cause a spark which would destroy whatever you are soldering. There has to be enough resistance on the line for it to be dissipative rather than conductive. Removing static charge from a ESD sensitive device is pointless if you make a spark while doing so. Do you do this with your other soldering? Or are you jsut worried because the part is ungrounded? In which case wouldn't it be more effective just to ground the tip of the tool before you used it?

I forget how cold head works, but it involves passing high currents or something so the tip is probably electrically conductive. If there is charge built up and you touch it onto the lead and the ground wire is conductive and not dissipative, you'll still destroy the chip.

 

[Marks256]

I would think that they would have some protection build in, wouldn't you?

 

[Sceadwian]

There is no built in protection, there can't be, the voltage and current at the tip are what make it work. I'm just wondering what exactly it is that would cause IC damage? I'm mainly thinking about what will happen if I use this to quick tack solder on a couple generic transistors or FET's. What is the exact method that it can damage IC's and how do I prevent it? If I can't ground the lead near the IC to prevent a voltage/current from going into it can I connect all the leads of the IC together with a clip to prevent voltage differentials on the pins?
I checked the tip on a meter and it's just raw battery voltage. I'll update this thread later after I take it apart and look inside.

As near as I understand it the tips are nothing more than a alloyed form of graphite. They're light enough for it. I'm going to take the extra tip I got with it and stick it on our X-ray flouroscope at work and see what it comes up with, not expecting much as they're really designed to check metals.

 

[audioguru]

It takes a lot of current to make the tip heat to solder melting temperature and the battery doesn't last long. So I think if a base-emitter junction or little diode got across the gap in the soldering iron's tip then they would blow up.

 

[Sceadwian]

I took it apart and looked around inside, there's nothing to it, the tip's halves are connected to the on/off switch and then directly to the battery voltage. There's a tiny IC in the back (14 pin soic) with a handful of surface mount bits on it about 1cm square, they only connect to the LED's, the IC's markings are obscured. The only thing I could make out was HP 9<something>, all the IC seems to do is control the LED's, the wires are too thin to have anything to do with power. I can see an acidental brushing of the tip across the legs of an IC accidentally causing the 6 volts to appear on two pins, and the current is obviously high if that happens. But there shouldn't be any real problems if the only thing that shorts is the tip itself and the work lead?

 

[Oznog]

I think the real problem comes about if you have 2 nearby pins and the 2 sides of the tip (one connected straight to the battery + and the other to battery -) touch different pins. More often than not that will kill the chip.

No you won't have any current if the 2 sides of the tip ony touch the single lead.

Awhile back a guy said he wanted to use a wall wart transformer instead of the batteries. Turns out that thing takes a buttload of current- more than any common consumer transformer will put out.

 

[Sceadwian]

The tip does arc when you touch it to something, and if you try to solder for more than about a second the LED's dim to nothing, I'm asuming the battery is going into 'shock'. I looked up Energizers alkaline application manual and it says the short circuit current for a AA is about 10 amps. With four fully charged AA's that's about 60 watts of power for brief periods. I am a bit disapointed in the internal simplicity, the least they could have done was add a super cap or two, as it would increase battery life a good 50+% Especially at those current loads. You could probably use the wallwart idea if you had a few 10 volt high value super caps, but that would likley cost more than the entire ColdHeat tool in the first place, you're better off just buying yourself a decent soldering iron at that point. It's a nice gift, a simple quick and simple way to solder, or heat up any conductive object, and worse comes to worse it's a 6 volt battery pack. The tip's are relativly open on the outside, and will easily let you put 6 volts across a standard pair of jumper pins, or you could just as easily tap the battery directly, once the tip is removed the contacts are easily accesable.

 

[Nigel Goodwin]

From the many previous threads about these, they appear to just be a cheap gimmick, and useless for soldering!

 

[Overclocked]

How stuff works has a nice view inside the thing..
https://electronics.howstuffworks.com/cold-heat1.htm

 

[audioguru]

I wonder if its little battery cells get as hot as its fragile tip. No, the battery won't get too hot because it will be dead before it gets too hot.

I wonder what the IC is for.

 

[mramos1]

I bought one when they came out, returned it 2 days later. The tip chipped as I could not get it on small flat objects and I pushed to hard.

Cheap junk for me.