Weller Soldering Iron

[Hugh Robjohns]

With the iron in free air, 27W might well be sufficient to overcome the radiated heat.

However, when the iron is in direct contact with components -- especially large, thermally conductive ones -- it probably needs more input power to maintain the tip temperature.

[Martin Walker]

Indeed, your iron could well be like some of us here - working perfectly when doing nothing, but not enough energy to do anything useful when it comes to the crunch

[GRAHAM99]

I know that feeling!
I am still curious to see if I can get it working properly so will look for a correct power supply for it.
Can’t really justify buying a “proper one”.

[ef37a]

I know that feeling!
I am still curious to see if I can get it working properly so will look for a correct power supply for it.
Can’t really justify buying a “proper one”.

Yes the lower 'wattage' might well be the problem and yes, you can use any 24V 50VA transformer. I used a monster 250VA isolation transformer that had several 25V windings to make it up to 110V. I used to run two irons off that with different bits. Also you really do need a #8 bit for general work with a 2mm tip. The very long 'needle' bits wear out PDQ.

Dave.

[GRAHAM99]

Just need to get hold of a suitable transformer!!

[ef37a]

Just need to get hold of a suitable transformer!!

Yes, 12 + 12 V traffs are a very common specification at about 2A but a bit more won't hurt and the transformer will run a bit cooler.

Dave.

[DGL.]

Here's a 24V 50VA Transformer that should be suitable,
https://uk.rs-online.com/web/p/pcb-transformers/7320512
It claims to be of the PCB mounted type but seems to have regular spade terminals
You will need a case for it to go into and some way of getting power in/out.
Personally I would use a "kettle style" connector for input and a 4 pin XLR or 3 pin DIN plug for output, unless anyone has any better ideas.

As for cases, either a standard project box from somewhere like RS/CPC or places like toolstation sell enclosures. A metal toolstation enclosure holds the replacement embedded PSU for my Grans stairlift just fine (noting that you'd want to earth the metal enclosure).

The tip on the soldering iron should also be grounded, I believe via a suitable resistor to mains ground.

[GRAHAM99]

Many thanks for that.
I am going to try rigging up some batteries to the laptop adapter to get enough voltage to make sure the iron gets hot enough before I spend any money on it!!
This is all very interesting!!

[GRAHAM99]

I have found a transformer which was inside CD player.
Is it possible to upload photos on here?

[Kwackman]

Is it possible to upload photos on here?

https://www.soundonsound.com/forum/view ... hp?t=62135

[GRAHAM99]

Can you not just upload a photo from your iPad etc?

[Wonks]

No. No picture hosting on this forum.

[GRAHAM99]

Why not?!

[Drew Stephenson]

Copyright liability, hosting space, probably other reasons too.

[Mike Stranks]

Here y'go... this will show you how to do it... NB. NO sound

https://youtu.be/s7vVDGTOHW0

[Drew Stephenson]

Thought you'd managed to find a video of some making their own Weller power supply there Mike.

[ef37a]

https://uk.rs-online.com/web/p/chassis- ... rs/0504672*

With a suitable enclosure, 30-35 quid all up? You have the pencil which are about £100 and so even if that proves no good you could get a new one which I assure you will work on that transformer thus saving you another £100 or so.

"One has to speculate..."

*N.B. I am assuming you have the necessary knowledge to work on and make safe 'mains side' equipment? If not your transformer options are much more limited.

Dave.

[Mike Stranks]

https://uk.rs-online.com/web/p/chassis- ... rs/0504672

I am assuming you have the necessary knowledge to work on and make safe 'mains side' equipment? If not your transformer options are much more limited.

Dave.

Not so sure on that Dave... Ohm's Law had to be explained earlier in the thread...

[GRAHAM99]

Thanks for all the input on this!!
I have never put anything together involving mains voltage so perhaps it is best left alone.
I will have a think about what to do.

[MarkOne]

I hadn't ever thought about this until a few days ago, I'm looking at building a bench PSU for lab projects and looking through a few YouTubes (Yes, not the best source of advice when it comes to legal/regulatory matters) I noted a couple of comments about making mains powered kit and where you might stand in the event it blew up/burned your house down/killed someone

So I'm thinking, in this world of regulation, health and safety, etc, where does that leave the ardent DIY-er?

If you make something with a donor supply like an ATX supply or a laptop brick and you don't modify that in any way, it comes complete with a CE mark (or a UL mark if you are Leftpondian) and has been certified as fit for purpose. Conversely if you cobble something together with a Toroidal, a rectifier, and a regulator from RS and some strip board, even if you know what you are doing, and sometime later it er... burned down your house, would an insurance company see that as a big get out for not cutting you a cheque for a new one (house that is)

Over the years I've designed and built supplies for all kinds of things, both as a DIY-er and in a professional capacity for my job on everything from HiFi kit to bits for fighter jets. But I'm not sure I'd do that any more without using a certified module to convert the killer-watts to the benign ones that run my logic board

[GRAHAM99]

I don’t give up easily!

[GRAHAM99]

There are laptop adaptors on Amazon for about £17 stating 25v and 2a.
I think this would work and be a safer than cobbling something together?
Does the output voltage have to be ac or dc?

[Hugh Robjohns]

...even if you know what you are doing, and sometime later it er... burned down your house, would an insurance company see that as a big get out for not cutting you a cheque for a new one (house that is)

Insurance companies will try all sorts of crap to avoid doing what they charge you lots of money to do!

But legally I think it comes down to 'competence'. You need to show that you have sufficient competence to do what you did. Obviously an appropriate qualification or professional experience would demonstrate competence. Without a qualification, you'd have to indicate that you are knowledgable in the subject, aware of the dangers, and took appropriate and adequate precautions to mitigate those risks.

So demonstrating that you selected an appropriate size of mains cables, calculated the correct fuse ratings, used appropriate insulation around live connections, mounted components in a safe way, etc etc....

[ef37a]

I agree with Hugh, depends on the person and the experience they can prove.

In my case I think 45 years or so fixing TVs, radios, audio and microwaves should prove ability. Then I was working on live chassis for a guitar amp company past my retirement age. I hope they would give me a glowing reccy!

I would not however be 'qualified' to do certain works to my house wiring*, the regulations are very stringent. I HAVE of course! Fitted the odd extra 13A outlet. Some years ago I had to replace a switch unit in the meter cupboard so I was working with one live wire straight out of the company fuse. Nitrile gloves, insulated pliers and ensured that nothing 'earthed' was anywhere near me. Very stressful but in practice just getting one thick wire in a terminal block and screwing it tight. Some people do that every day!

The 'kids' will get the bungalow (or the local council? ) so they can sort out the rewire and the accumulation of 53 years of electronic junk.

*Who here has all the wiring qualifications?

Dave.

[Folderol]

There is this:
https://cpc.farnell.com/ideal-power/59r ... 20supplies

Depends on whether your iron can work on DC. That's down to how the thermal control is managed. If so, all you meed to do is arrange a suitably plug/socket combination. It's possible there are also slightly more beefy PSUs which would give you a bit of extra margin.