ancient solder troubles

[magnetmaz]

Anybody ever tried restoring some 50's era electronics, and the solder just will not melt off of contacts? I'm working on restoring a heathkit, and i swear the solder on one was just fine.. came off with ease.

On this one, though, i can sit and hold a 100 watt iron to it and it just acts like cement... doesn't budge...doesn't liquify.

I swear, it's like someone used some non-electronics grade solder to build this thing.


Anyone know what it is?

 

[jjblue84]

You really need a soldering gun for some or most of this stuff. Typical pencil style guns will work great on circuit boards but point to point you need a gun, proper ventilation and a solder sucker.

 

[62SY4]

On this one, though, i can sit and hold a 100 watt iron to it and it just acts like cement... doesn't budge...doesn't liquify.


Anyone know what it is?

Just old solder, try flowing some fresh stuff into the old and see if that helps, if that doesn't do it you need more heat.

 

[DanO55]

I have done a couple dozen Heathkits in the last year or so and you are right. Must have been some pretty tough stuff back then. It was very common to use a soldering gun back in them oldendazes.

 

[ConradH]

As above, plus dab on a bit of rosin flux.

 

[gadget73]

yeah, daub a bit of fresh solder on and it will probably liquify quite readily. I use nothing but pencils on old stuff like this, though it is a Hakko FX-888 which I think is 60 watts or something and temperature controlled. Very seldom does it not melt something, and then its usually only stuff soldered to the chassis directly.

 

[Wolverine]

I have had a Roman Legion camped out in my back yard for the past week and nothing seems to get rid of the tough little buggers.

Oh wait you said ancient solder?

Never mind I have a different problem.......

 

[larryderouin]

Wolverine.......Rabid Elephants usually decimate Roman Legions, but you'll have to clean up the mess afterward.

Larry

 

[petehall347]

fresh flux ought to do it .sort of rub it in with the hot tip of your iron .also be sure iron tip is cleanly tinned .

 

[GordonW]

My guess, is that someone used 40/60 (40% tin, 60% lead) instead of the normal 60/40 (the opposite proportions), that's normally used in electronics. There's a warning against that, in most Dynaco manuals- can't remember if Heathkit put in the same warning, or not. It does take a LOT more heat to melt.

In this case, flowing a bit of 60/40 onto the old solder, will sometimes start to "melt away" the old stuff. As it mixes, it decreases the melting point.

In any case, you will want a pretty hefty iron, to get the melting process started...

Regards,
Gordon.

 

[zandru]

Anybody ever tried restoring some 50's era electronics, and the solder just will not melt off of contacts?Anyone know what it is?

Good Morning mag,

Are you actually working on a Heathkit that was built by a hobbyist, or might it be a a factory built device from the
Heathkit assembly plant , where they may have used a different soldering technique than a traditional hobbyist
would have used. Not to be confused with Heath "Brand" Prebuilt equipment. The Heathkit prebuilt products were
manufactured to be used as store demos. Some of with were sold to the public. Manufactured Heathkit products
may have been assembled by using a special handheld soldering device that fed "hard or silver solder" (like
high temp "900˚F-1000˚F brazing temp) up through the heating elements and delivering the molten silver alloy
solder directly to the hook-up wire and the contact point at the blink of an eye, or possibly an off-shoot or a miniature
hybrid version of FCAW welder. However as mentioned in other reply posts; a high temp soldering gun will take
care of business. Tinning the problem solder joint or connection first; will improve your ability to strip away,
creating easy access to proceed and complete your project. I've had a high temp soldering gun around for many
years and their very helpful for may tasks. Even though my soldering gun has a max temp of 1,135˚F , I can push
the soldering guns tip through an 1/8" sheet of aluminum.

 

[for_p1]

I saw few consumer electronic devices from 1950s where welding was used instead of soldering. In that case you have to cut off the whole joint. Regular solder does not even attach to the ball of melted metal left at welding point.

 

[kpaxfaq]

Other then stuff soldered right to the chassis (like can caps) I've never had my 30 watt pencil iron not be able to melt anything in dozens of vintage pieces of gear I've worked on....There have been a few points (the Stromberg Carlson ASR-433 comes to mind) where like 5 to 7 components were all tying to one point but it still melted it, it just took longer to heat it up enough.

 

[Splatter Pak]

You're lucky you get solder joints of any kind! I once saw at a farm auction an old radio so old that the wire consisted of steel rods with eyelet ends, held down by wing nuts! No, really.

 

[Thom]

Also with Soldering guns make sure the tip is tight in the mounts or it may not get hot enough.

 

[jaymanaa]

As above, plus dab on a bit of rosin flux.

Bingo, never unsolder without it.

 

[jaymanaa]

I use the gun type for dismantling to save time, and my good Hako tips. It has two heat settings and two headlights, so it's good for an old blind man like me. For chassis soldering I use a big chisel tip weller pencil. It's amazing what that thing will do.:yes:

 

[jjblue84]

You're lucky you get solder joints of any kind! I once saw at a farm auction an old radio so old that the wire consisted of steel rods with eyelet ends, held down by wing nuts! No, really.

This is some really beautiful work, when you see one in person. I have seen a few, the wire gauge, bend, tube sockets, ancient capacitors. Its really beautiful to see all the hand made labels and wiring. :yes: