AC Soldering Iron heating element?

[BigBrother]

A few months ago I acquired a small 30W adjustable soldering station:

(the hood is off because I was curious)

but the output is 15V AC! what's worse, it came with these odd heating elements with soldering tips that slide on:



...but I just tried to remove a soldering tip to place another on and the entire metal shaft came off and with it, the heating element's wire! fsck. This was my first soldering station and I kinda like it. The "pens" (heating element) aren't clunky and they fit in my hand just right and they don't get hot. I tried looking around for a replacement but I keep finding these more common ones where the soldering tip goes in a hole and locks in place with a nasty bolt. I need a bit of help here, to say the least.

[IanB]

Those look like Antex style tips. Normally they would have a brass clip over the split to help the tip stay on firmly.

The tips do have a tendency to get "stuck" on the heating element if left in place too long. To remove a stuck tip try twisting gently while gripping the base of the heater and don't pull too hard. Once you get a tip free clean the outside of the heater of any dirt and corrosion to help prevent new tips from sticking.

By the way, what is wrong with using AC to run a heating element?

[nanofrog]

IF it is an Antex, take a look here: http://www.antex.co.uk/prodtype.asp?strParents=180&CAT_ID=198&numRecordPosition=1. Not sure of the model you have (might be too old, but they offer others as well, such as a 12V, 25W, user specified length.

They have a US site, but the heating elements aren't listed, so I used the UK site.

[T4P]

All hakkos are AC, what's your issue? 

[BigBrother]

All hakkos are AC, what's your issue? 

the output from the base is 15V AC. Hakko irons are AC?

[IanB]

An Antex iron and tips for comparison:

[T4P]

All hakkos are AC, what's your issue? 

the output from the base is 15V AC. Hakko irons are AC?

They run on 24VAC

[IanB]

the output from the base is 15V AC. Hakko irons are AC?

AC is what comes out of the mains, and is what comes out of transformers. If not AC, what are you expecting?

[BigBrother]

the output from the base is 15V AC. Hakko irons are AC?

AC is what comes out of the mains, and is what comes out of transformers. If not AC, what are you expecting?

...DC. Everyone that I've talked to find it absolutely strange that the output is AC.

[SeanB]

All low voltage irons run on AC, easier to switch in the controller. Heater does not care if it is fed AC or DC, it just makes heat.

As to the stuck bits, on the next one you clean the element and then smear heatsink compound on the shaft before you slide the bit on. Use the common white one, and it will smoke for a few minutes after you power it up, then it will stop. This enables the tip to slip off easily when you want to change it.

[vk6zgo]

Looks like a nice iron,at least it has a transformer!

When my old Weller croaked,I bought an "El Cheapo" from Jaycar,with a "temperature control" on the front with no markings.
It would solder,but never worked all that well,so when I bought a secondhand WTCP Weller at a Hamfest,I retired the "cheapie".

One day,out of curiosity,I opened the case:

What felt like a transformer was a weight glued to the bottom,& the "temperature control" was a light dimmer,which drove the element directly.
When I find where the digital camera is hiding,I'll post a few pictures.

[G7PSK]

Put coppereaze on the shaft before you put the tip on that will stop the tip sticking. Any good car/automobile spares supplier will stock it or similar as it is used to stop parts seizing up on things like disc brakes and exhaust manifolds.

[amyk]

Did you get it used? The construction of that station looks really old.

The 2-pin connector for the iron means that it's not ESD-safe nor temperature controlled. Keep that in mind when working on sensitive electronics.

[T4P]

1) Extra BOM costs for rectifying commonly 2amps
2) why do you need DC for?
3) What's wrong with AC
4) It's not that easy to just use a SCR as a switch
5) DC requires thicker gauge wires

[IanB]

...DC. Everyone that I've talked to find it absolutely strange that the output is AC.

So think about this logically. Where would the DC come from? It doesn't come out of the transformer or mains supply so it has to be made. At a minimum you need rectifiers. Rectifiers add to the parts cost, they sap power reducing efficiency, they generate heat so additional cooling and ventilation is required, they reduce reliability as there are more parts to go wrong, and the heat they produce will be a problem for nearby components. So making DC adds costs and problems in many areas.

Now ask what benefit DC would have in a heating element? I can't think of any myself.

Now I may have missed something you have in mind, so what is it that makes you believe the output should be DC?

[SeanB]

DC in a heater which is cycled and picks up atmospheric moisture means corroded leadout wires on one side, and a dead heater much sooner than the same unit run on AC.

[IanB]

DC in a heater which is cycled and picks up atmospheric moisture means corroded leadout wires on one side, and a dead heater much sooner than the same unit run on AC.

Ah, I thought there might be a specific disadvantage to DC. Thanks for that.

[BigBrother]

looks like the consensus on this is that soldering irons are AC. the reason I said DC is because two good reasons: the guy I buy bits from has been in business for about 35 years now and another guy who(m) I trust also found AC to be odd as well. Not sure if they were simply mistaken on the matter or not... but I'm still not sure what type of heating element to buy. this more open type where the tip sits in fastened by a bolt seems common but I feel that having the tip directly on the heating element itself is more efficient.

[IanB]

but I'm still not sure what type of heating element to buy. this more open type where the tip sits in fastened by a bolt seems common but I feel that having the tip directly on the heating element itself is more efficient

The one where the tip sits in a recess fastened by a bolt is usually associated with low end "cheap and nasty" irons. The better quality irons usually have the heating element in the middle and the tip covering the outside. This causes all the heat from the element to flow directly into the tip rather than escaping into the surroundings.

[BigBrother]

OK, the fine tip has likely fused the to the heating element itself. I have about 40$ and I need a couple tips as well. How screwed am I?