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Author Topic: New soldering iron, will not tin, repelles tin.  (Read 1217 times)
OH2KEN
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Posts: 27




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« on: November 05, 2017, 09:13:39 AM »

I'm clueless. This year my hobby has been at a stand still, my father was very ill and he died in my arms two months ago. Now I am starting to look at my ham shack again, it has all needed except for the wiring really. Today I went through my boxes with connectors and coax. Took a nice SSB Electronics uhf pro connector, followed the installation instructions and got the connector assembled on the Aircell7 coax to the last point when all that remains is to solder the tip. I had previously, over a year ago, purchased a Stannol 200W soldering iron, rosin core 40/60 tin, flux, a copper "sponge" for soldering connectors. Previously I had not been successful in soldering the tips with a gas powered soldering iron. It tinned ok, but the insulation in the coax melted before the tin on the tip to be soldered. Now I am clueless, I have never encountered this before, the tip of the soldering iron repelles tin! I have tried to flux it and wipe it in the copper sponge, but the tip just gets worse. Now the surface of it has become rough and there is a copper coloured layer on top of the factory new tip. Still repelles tin like the plague. I have looked on numerous very informative videos on how to tin a tip and how to clean it. I have no steel wool at home for the moment, but have tried using the normal damp sponge as well as the copper sponge. I don't want to try soldering the tip of the male uhf connector before having a tinned soldering iron tip. What should I do? I feel really stuped and clueless right now.
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K0BT
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« Reply #1 on: November 05, 2017, 09:26:52 AM »

Have you tried using lead-containing solder for the initial tinning?  The lead-free stuff is terrible for tinning.

Also, the tip may becoated with silicone or another chemical from storage, such as plasticisers used in cables.  Cleaning it with laquer thinner might help if that is the cause.

 If the tip was initially iron-coated and you now see copper, the tip will wear quickly even if tinned. Copper corrodes fast and the iron coating protects it.  You may need a new tip, even if its only been used a few times.

73,
Bob

https://www.elexp.com/Images/Weller_Coping_with_Lead_Free.pdf
« Last Edit: November 05, 2017, 09:45:29 AM by K0BT » Logged
KG5AHC
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Posts: 77




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« Reply #2 on: November 05, 2017, 09:35:53 AM »

Sorry for the loss of your father.

I have found that temperature is most critical for an iron tip to accept solder. I was also so frustrated with soldering until I realized the iron was too hot.  I resolved this by getting a soldering iron with a temperature control dial. (A Weller WLC100 which can handle up to 300 watt irons). Start it up hot and then adjust downward until the solder stops boiling off the tip.  if the tip is already damaged/pitted, you might also need to replace the tip.

73's
Jeff KG5AHC
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K4SAV
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« Reply #3 on: November 05, 2017, 10:01:38 AM »

A 200 watt solder iron will get too hot if you do not do something to control it.  Even my 100 watt iron will do that.  If an iron get too hot, the solder won't flow on it.  The flux will burn immediately and prevent the solder from flowing onto the tip.  The solder will usually just turn into little balls.  Sounds like the plating is already worn off the iron tip and copper is showing.  That will make soldering even worse.  Time for a new tip.

Soldering the center pin can be tricky with some coax.  If it has foam dielectric, the melting temperature will be less than for solid dielectric, and the melting temperature of the foam varies with the manufacturer of the cable.

Jerry, K4SAV
« Last Edit: November 05, 2017, 10:04:20 AM by K4SAV » Logged
K3GM
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« Reply #4 on: November 05, 2017, 12:23:31 PM »

Sal Ammoniac.  It sounds like a great screen name, but it's actually the archaic name for ammonium chloride.  Its great for cleaning and retinning a dirty tip.  Its non-abrasive.   Just rub the hot tip on the block of sal ammoniac, while adding a little solder to the tip at the same time.  It will hiss and smoke as it works, then its ready to go.
« Last Edit: November 05, 2017, 12:29:58 PM by K3GM » Logged
W6EM
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« Reply #5 on: November 05, 2017, 05:55:59 PM »

I have an old Weller gun.  Either 200W or 250W, not sure which.  The tip is solid copper.  Higher power guns use a copper tip.  Small pencil irons in the 20-60W range usually have iron tips.  Yes, copper tips tend to pit over time, but over years, not so quickly in intermittent use.  I've probably changed tips a dozen times in 50 years.  As to tinning, first clean it.  Steel wool and  sandpaper work. 

With respect to overheating, yes, you easily can if you squeeze the gun trigger constantly.  Just bring it up, say for 15-30 seconds, then let it cool slightly.  Repeat over and over.

Buy a can of soldering paste.  Dunk the end of the tip into the paste.  Then, as the just-cleaned tip warms up, slowing apply 60/40 or 63/37 alloy resin core solder to tin the tip.  Let it cool and wipe the tip to check to see if it tinned properly.  If not, clean it again and repeat the dunk into the paste can.

When you get ready to solder the tip of the PL-259, get the tip hot, then hold against the pin and start applying solder to the pin, not the tip of the iron.  The pin needs to get hot and melt the solder.  It will wick the solder up inside.  And use a resin core solder.  Some of the electronic solders these days don't have flux cores.  Or, liquid flux which can evaporate.

Just remember, you don't have to continually pull the trigger.....to accomplish a good solder joint.
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OH2KEN
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« Reply #6 on: November 06, 2017, 12:02:28 AM »

Thank you all for your kind advice. The soldering iron is of the pen type, 200 W, I don't know how the heat is regulated if at all. Yes, the tin is of the kind with rosin core flux and has lead in it. The tip when unused had a steel or nickel looking plating and a blue lacquer looking transparent protective coating on the very end of the tip. This melted away when I heated up the iron for the first time.  From that first moment on it expelles tin, it just won't stick to the tip at all. At the very "best"  the tin would form one big pearl and sit on the tip, immediately rolling off it. Almost as if it was magnetically pushed away from the tip. I will get that cleaning stone and try it, also some steel wool. Maybe the tip is too hot, but the tin doesn't boil, it makes pearls that refuses to contact the tip. I also own a Stannol welding gun, it's 100W. A year ago tried welding N and UHF connectors with it, was not successful at it, took too long to heat the centre pin with it so the dielectric melted resulting in the centre conductor touching the coaxial copper shroud of the cable shorting it out. I also have a Portasol P-1K butan gas powered old soldering iron pen I usually use in the outdoors, but again, it doesn't heat up the tip fast enough to get the solder melting before the heat has started damaging, melting, the dielectric of the coax. It is great for soldering smaller stuff, not these connectors though.
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G3RZP
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« Reply #7 on: November 06, 2017, 01:42:53 AM »

An alternative to sal-ammoniac is the old "killed spirits". This is zinc dissolved in hydrochloric acid until the acid is neutralised. A very effective but corrosive flux. Or in the UK, one can still buy 'Baker's Fluid' - which is much the same thing - or the proprietary paste flux 'Fluxite'. Again, they are both corrosive, which a flux needs to be - but these stay corrosive and need washing away when the job is done. Rosin based fluxes are only active when hot, which is why they can be used for general soldering. These more active fluxes are more likely to be found at suppliers of materials for model engineers than of electronic components.
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N1LO
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« Reply #8 on: November 06, 2017, 04:26:39 AM »

That translucent blue coating on the new tip sounds kind of suspicious to me. I do not have experience with non lead-containing solder but I have seen the phenomenon you describe when a soldering iron tip becomes contaminated by touching plastic that has melted onto it and turned black.

When the iron cladding on tips of my iron wears through I get out a file and file a new chisel tip into the copper and re-tin it while the copper is still bright as soon as it is warm enough to melt solder using tin lead solder with rosin core.

On smaller pencil irons that have a round tip I file on four sides to make a pyramid chisel tip. Once the copper becomes pitted with repeated use I just file again and can make a tip last a long long time.
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KG4RUL
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« Reply #9 on: November 06, 2017, 06:07:38 AM »

When you are using sal-ammoniac to clean the tip, make SURE you are in a WELL-VENTILATED area!  Or, better yet, do it outside.
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N7EKU
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« Reply #10 on: November 06, 2017, 07:34:27 AM »

That translucent blue coating on the new tip sounds kind of suspicious to me. I do not have experience with non lead-containing solder but I have seen the phenomenon you describe when a soldering iron tip becomes contaminated by touching plastic that has melted onto it and turned black.

When the iron cladding on tips of my iron wears through I get out a file and file a new chisel tip into the copper and re-tin it while the copper is still bright as soon as it is warm enough to melt solder using tin lead solder with rosin core.

On smaller pencil irons that have a round tip I file on four sides to make a pyramid chisel tip. Once the copper becomes pitted with repeated use I just file again and can make a tip last a long long time.

Hi,

I was think the same thing about that blue coating.  It sounds to me like it burnt onto the tip and now needs to be removed.

Yes, it's not the end of the world if the plating comes off.  I did the exact same thing with a file on my old radio shack cheap iron (filed a pyramid shaped tip and re-did it when it because pitted).   You just need to replace the tips more often.

For cleaning stubborn deposits on my tips, I usually just put the tip in jar of plumbing flux as the iron is heating up.  Eventualy it will start to boil the flux and become clean.  Wipe it on a damp cellophane sponge or cotton cloth to check it, then tin it with regular rosin core solder.

Often, non-temperature controlled irons need some way to manager their heat.  You can easily and cheaply control the wattage the iron receives by using a light dimmer:  http://www.instructables.com/id/10ish-DIY-Variable-Temp-Soldering-Iron-Controller/

For soldering UHF connector tips, I certainly have never needed so many watts.  With my Hakko 65W iron on its highest setting, I can solder the braid (that is for the smaller coaxes that use the adpater, I haven't tried soldering the braid on large coax to a UHF connecter with this iron yet), and for the tip I usually turn the iron down some . 

73,


Mark.



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Mark -- N7EKU/VE3
KD0REQ
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Posts: 2018




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« Reply #11 on: November 06, 2017, 08:32:17 AM »

plumbing flux is zinc chloride, the same thing as "killed spirits."  it is also corrosive to electronics work.  it may be the only thing to get the blue oxide off the tip, but then you need to drown the tip in rosin flux and wipe on a damp sponge to neutralize it. green slop on copper plumbing comes from zinc chloride.

there are a LOT of coax connectors out there that are plated with a chromium mix, and that stuff does not take solder worth a darn.  silver-plated connectors, not as common as in the 60s, solder up nicely.  the rest, file gently and flux and hope your bird-warming fairy is with you.
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K8AXW
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« Reply #12 on: November 06, 2017, 10:48:27 AM »

To start with, a fixed 200w soldering iron is too big.

Second, if the tip is copper grind the time until you see nothing but copper.

Third, heat the iron up and melt the solder all over the tip, letting it run off onto something it won't hurt, like a rag.

Fourth, wife the tip clean with the rag and it should be shiny silver colored.

Fifth, if the 200w iron is at full temp and you use very small diameter solder, it will have a tendency to "roll off" as one pointed out.  It's actually boiling off.

It has also been pointed out that the copper tip will corrode or wear down .  But rest assured this will take a long time and it will take some cleaning on occasion.

You should get a 15-25w pencil soldering iron and a 150w Weller soldering gun.

Your 200w iron may come in handy later.....  I have one I use outside where the moving air creates a soldering problem.

BTW, being unfamiliar with your brand of connector....let me insult your intelligence and suggest you remove any plating over and around the braid soldering holes with a small round file.  Underneath is brass which is much easier to solder.  Your 200w soldering iron should do a good job here if you grind the tip down to fit into the solder slot on the PL-259.
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