Using high melting point solder.

[Leon Crampin]

HMP solder is specified for some jobs such as dropper tags and, in my case, alternator slip ring connections where the mechanical strength of the HMP alloy is needed.

The problem is that an ordinary mains powered soldering iron will not readily melt HMP and a special bit for a "Weller" type of thermostatically controlled iron is not justified for the occasional job.

Variac to the rescue. Applying 270V to a 230V iron will give about a 38% increase in power - sufficient to do the job easily. A short term overload is unlikely to damage a soldering iron - I used a cheap one.

Leon.

Backgound heat from a hot air gun also helps, HMP solder is not to be confused with lead free 'solder', which is a work of the Devil.

[XTC]

A useful tip.

I bet HMP solder could also be used with a soldering gun type iron. The first time I used mine I wasn't used to the action, held down the trigger for too long, and the tip glowed red.

Soldering guns are a bit awkward and not ideal if you have a lot of soldering to do, but for the odd job like speaker tags or soldering to dropper tags, they're very convenient.

Pete.

[Restorer79]

I normally use a 100 watt soldering gun when making off dropper tags with HMP solder, does the job a treat.


Andy

[Philips210]

Hi

I use an inexpensive 60W iron when using HMP solder for ballast resistors.

When I came across a corroded dropper section (rusty tags) that was otherwise ok, I didn't think that the solder would adhere to the tags but after cleaning them, I was rewarded with a first class result. This solder sticks extremely well and may be useful in other areas of engineering where normal solder won't work. I did a repair on some glasses frames using HMP solder on one occasion.

The appearance of the joint always looks duller than normal 60/40 solder.

On the reel of Multicore HMP solder that I have, there is a warning about not overheating the solder. I wonder if that is concerning the hazard of the flux fumes.

Regards
Symon.

[Nickthedentist]

Originally Posted by Philips210

I wonder if that is concerning the hazard of the flux fumes.

Or, burning the flux off prematurely, before it's done its job, maybe.

BTW, am I the only one to routinely use normal solder on radio droppers? I've never had any problems yet, but then my sets don't see as much use as they would have done when new.

Nick.

[Sideband]

Originally Posted by Nickthedentist

BTW, am I the only one to routinely use normal solder on radio droppers?

Hi Nick.

No probably not! I generally use normal solder and so far I've not had problems. However what I usually do is put the wire through the hole in the dropper tag and wrap it round at least once and crimp it tightly before applying solder thus making a good mechanical joint as well. My DAC90A gets quite a lot of use and the solder on the dropper is still good after three years.


Rich.