The Solder Won't Melt

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I have been trying unsuccessfully to solder a ring tongue terminal onto the ends of each of the DC power cables for my radio.  So far I have not been able to get the solder to melt.  The power cables that came with my new Kenwood TS-480HX did not yet have connectors on the end of the wires that connect to the power supply.  My power supply is an Astron RS-50M power supply.  It uses nuts and washers to fasten the connectors to a lug.

I went into one of the local Radio Shack stores and after showing them my cables and connectors, I asked them which soldering iron and solder they would recommend for that task.  The salesman recommended a 15-Watt soldering iron and a tube of their .062 diameter lead-free silver-bearing solder.

I tinned the tip of the soldering iron. The power cable appeared to already be tinned, so I skipped that. I then tried to tin the connector, but could not get the connector hot enough to to melt any solder.  So I just went ahead and tried to just solder the parts together.  For about 5 or 10 minutes, I kept applying heat and trying to get the part and the wire hot enough for the solder to melt, but the solder never did melt.  When I finally gave up, I was surprised at how hot the fuse holders, on the cables, had become, even though they were 8 inches away.  I hope I did not damage them.  Over the years, on several different projects, I have run into the problem of not being able to get solder to melt.

Do I need a higher Wattage soldering iron or a soldering station to be able to perform that task?  If so, does anyone have any recommendations of what I should get?  I have seen soldering iron recommendations in an earlier eHam discussion, but it was not for this specific task.  I will also need to solder a PL-259 connector onto the end of a coax cable.

Another concern of mine is that the ring type connectors that came with the power supply seem to fit quite loosely onto the end of each power cable.  Should I try to crimp it first, or do they make tighter fitting connectors that would still be a large enough for my power supply?  The hole where the wire is inserted into the ring type connectors appears to be threaded, why is that?

I also need two additional connectors but the local Radio Shack store only has the crimp-on type.  The Kenwood TS-480HX radio is the 200 Watt version which requires the use of two power cords, with two wires each, even when using just one power supply.  That is why I need to find two more connectors.  Where could I get something like that? Perhaps, I could order them over the phone from the HRO store where I purchased the radio and power supply.

I also ordered a 1.8KHz filter and a 500Hz filter, but just recently realized that I may need to solder them in.  I may try to hire someone to do that.  I have thought about possibly ordering the inexpensive Learn to Solder kit from Carl's Electronics and practice with that first.  I also planned to read up on what anti-static precautions might possibly also be needed. But, I probably won't do that myself, now that I am discovering how difficult soldering is.  I will probably just hire someone to do that, because I would would not want to risk ruining the new transceiver.

This will (hopefully) soon be my first time on the air with an HF rig.

You need a (much) larger iron. Something on the order of 100 watts or so. Solder should flow in seconds not minutes. The longer it takes to solder a joint, the more heat transfered to other (surounding) componets.

Dennis Zabawa:
Since the environmentalists have gotten lead-free solder banned, we have been saddled with vastly inferior substitutes.  The silver-bearing solder needs a higher temperature to flow and has extremely poor wetting action.  I still jealously guard my stash of Kester brand, tin/lead solder.

The soldering iron is way too small for your application (at Radio Shack, you got questions, we got lousy answers - how about a cell phone?).  You are not getting enough heat quickly enough into the work area to melt the solder properly.   You need a larger iron or a soldering gun if you decide to accomplish that task.  The bigger iron/gun will also be needed for PL-259 connectors, etc.

The "threads" are in the crimp-type ring connectors are  intended to make the crimped connection more reliable and secure.  While many will argue this point, a properly crimped connector NEVER needs solder.

Crimp connectors are sized for a particular range of wire gauges.  You need to get the connector appropriate for the power cable wire size.

As far as soldering your filter in, this is way above your skill level at this time.  Your radio is way too expensive to risk damaging.  Definitely get some help with this!

Dennis KG4RUL

Philip Camera:
Your soldering iron is too small.

Get a Weller 125

Bob Lewis:
Tin/Lead solder is still available at places like DigiKey and Mouser.

You need different wattage irons for different sized jobs. Your 15W iron is too small to solder those connectors. On the other hand, it's about right for soldering small components on a printed circuit board. Use too small an iron and the solder won't melt properly. Use too large an iron and you can damage components and printed circuit boards.

I find a soldering gun to be quite handy for soldering connectors and power wiring - but never use one with a printed circuit board.

The connectors you are trying to attach are probably designed for crimping rather than soldering. You need to right sized connector for the size of wire you have. When soldering wires to those connectors the solder tends to wick up the wire, making it brittle at the connecting point. That can result in broken wires at the connector over time if they move at all. Crimp is a better idea for that particular application.


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