Blind soldering with an Instant Heat Battery Soldering Iron

I've been doing hobby electronics since I was first old enough to be trusted with a soldering iron and not to burn myself, or burn the house down.

So, after I lost my sight, soldering became a problem and a very upsetting loss.

I have only recently felt very strongly that I wanted to find a way of doing some sensible soldering and hobby electronics again.

I acknowledge that I am not going to be soldering QFP surface-mount SoC chips or MCUs any time soon. But I have found some techniques which mean I can now manage most of the typical old 0.54mm (0.1 inch) pitch through-hole components and boards.

I recently got an RSPRO battery soldering iron from RS Components here in the UK.

This iron is billed as being 15 Watts. The body of the iron is square in section, and about one inch on a side. Overall it is about ten inches long, from the very tip of the soldering bit to the top of the handle.

It is sufficiently lightweight that prolonged use should not make your arm or your fingers ache.

There is a rotary control to lock the power button, so that it cannot accidentally set fire to your rucksack if you take it out and about.

Most importantly for me, the power button is so light to the touch that, again, you are not going to find your finger aching after a couple of hours soldering.

Also very importantly, the tip heats up very quickly indeed. So, having once placed the tip against the joint you want to solder, by using touch while the tip is cold, you are not going to have to wait so long for the solder to melt that there is an excessive transfer of heat to the work.

The thing came supplied with some little LED constructions that I can only guess clip on to the iron somehow, but I cannot discover how.

I have no idea yet how long the iron will be usable between eight-hour charges.

Now, the negatives. The cost. It is a very expensive iron, and the charger has to be ordered separately, and that is also not cheap. So this iron will be out of reach for a lot of people. I think I have blown my 'toy budget' for about the next twelve months.

But this is a seriously lovely piece of kit.

In testing it today, I have discovered another technique for helping the placing of the solder.

Some years ago it seemed as if Europe was going to outlaw the use and the selling of leaded solder. I don't know the status of that ban today, but because lead-free solder is, in my opinion, far inferior and very hard to use, I bought a few very large rolls of leaded solder back then, thinking it might soon be unavailable.

The solder I bought was very fine in gauge.

Today I discovered that, if I wind two lengths together very tightly, I can then cut of the end with a sharp modelling knife, and then use a thumbnail to make the end into a tiny fork, like the tongue of a very, very small snake.

What this does, is to make it easy to offer this 'fork' up to the work, on the opposite side ofg a component lead or the pin of a through-hole chip, placing the legs of the fork either side of the wire component lead or chip leg.

Doing this means it is far less likely that the solder is going to slip off the target before the iron has reached the temperature to make a good joint.

I am totally blind, but having soldered a number of scrap chips into scrap Veroboard today to practice with the iron, my fingernails seem to tell me the joints are every bit as good as those I would have made before, when I could see.

Of course things have to proceed more slowly, because I cannot just jump along the pins of an IDC header, or along the legs of a chip or chip socket. But slow and steady wins the race.

I'm also not going to be able to build things as small as I used to. Soldering components into holes in Veroboard hard against the chips in the matrix is probably going to be out of the question.

So things will just have to be bigger.

De-soldering is likely to be another challenge. I will just have to be very careful about component placement, and make no mistakes.

And of course, this 15 Watt iron is not the kind of tool you can use to solder the centre pin of a coaxial plug, like a PL259. For that I have the good old Weller soldering gun. Which also gets very hot very fast. But which is too big and cumbersome to use on small circuitry.