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Soldering: what am I doing wrong?!

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Posted by tomikawaTT on Wednesday, June 18, 2008 9:28 PM

Tom, you hit on a key point.  Brand-new, fresh from the box rail is frequently coated with the dregs of oily drawing lubricant.  If it isn't removed, it makes soldering almost impossible.  That's what I was had in mind when I said that all oil must be cleaned off the metal to be soldered.

As for heat transfer, it isn't the wattage of the soldering tool, it's the size and temperature of the copper.  A 25 watt iron with a hefty chisel tip will be more effective than a 100 watt tool with a needle tip.  If the tool is a gun, the tip must be allowed to come up to temp BEFORE touching the work.

Just because I overkill my hand-laid specialwork doesn't mean that everyone should rush out and buy the biggest gun Weller sells (250 watt, I believe.)  The key for me isn't the big transformer in the handle, it's the big chunk of hot, tinned copper that heats the joint.  A 25 watt iron can have just as big a tip.  It just takes longer to come up to temperature.

Chuck (modeling Central Japan in September, 1964)

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Posted by loathar on Thursday, June 19, 2008 10:04 AM
 Rotorranch wrote:

 

I've scratch built many slot cars from spring steel plate, steel piano wire, and brass. No issues soldering any of the material, even to dis-similar materials.

Rotor 

That's how I learned to solder too. A couple NS rails ain't no big thang after doing slot car chassis!

 

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Posted by Gazoo on Thursday, June 19, 2008 12:11 PM

 TomDiehl wrote:
Then, bend the wire so it presses into the web and stays there without clamipng, a drop of liquid flux (the A-West dropper bottles are great for this), a bubble of solder on the iron tip, touch it to the joint area, and faster than you read this sentence, it's done.

This is something that still doesn't make sense to me.  On the one hand I hear that the solder should never touch the tip, and here I've read from several people that they put the solder on the tip of the iron and let it melt off into the joint.  How would I even do that??  Won't the solder just drip off if I try to apply it to a hot tip?

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Posted by rolleiman on Thursday, June 19, 2008 12:20 PM
 Gazoo wrote:

 TomDiehl wrote:
Then, bend the wire so it presses into the web and stays there without clamipng, a drop of liquid flux (the A-West dropper bottles are great for this), a bubble of solder on the iron tip, touch it to the joint area, and faster than you read this sentence, it's done.

This is something that still doesn't make sense to me.  On the one hand I hear that the solder should never touch the tip, and here I've read from several people that they put the solder on the tip of the iron and let it melt off into the joint.  How would I even do that??  Won't the solder just drip off if I try to apply it to a hot tip?

Solder is your iron tip's best freind. If your tip is clean, it shouldn't 'drop off' (unless you flood it). Go back, and read the recommendations on cleaning and tinning the iron.  

Modeling the Wabash from Detroit to Montpelier Jeff
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Posted by Anonymous on Thursday, June 19, 2008 1:25 PM
I don't have a soldering gun or the funds to but one at this time. Is there another way to insure good contact between rail sections? I'm goint to be using rail joiners and thiught that if the joiner was on tight that would be good enough?Thoughts? Bob
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Posted by desertdog on Thursday, June 19, 2008 2:14 PM

 FoulRift wrote:
I don't have a soldering gun or the funds to but one at this time. Is there another way to insure good contact between rail sections? I'm goint to be using rail joiners and thiught that if the joiner was on tight that would be good enough?Thoughts? Bob

 

Bob,

Soldering is the only way to assure that the joiners are tight.  They will loosen up over time and there is no mechanical means (e.g. squeezing them with a pliers) that will work for sure.

Moreover, if you paint the rail or put down ballast with diluted glue, the liquid will flow into the joiner and act as an insulator.

The best way to assure electrical continuity is to connect every section of track, including turnouts, with a pair of feeders.  For the sake of rendundancy, I both solder the feeders and wire every section of track and have absolutely zero problems with stalling engines. 

John Timm

 

 

 

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Posted by jeffrey-wimberly on Thursday, June 19, 2008 2:15 PM
Don't have the funds to get one? I just bought a new Weller 100/140 watt soldering gun from Radio Shack a month or two ago. It cost about thirty bucks.

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Posted by howmus on Thursday, June 19, 2008 2:16 PM
 Gazoo wrote:

This is something that still doesn't make sense to me.  On the one hand I hear that the solder should never touch the tip, and here I've read from several people that they put the solder on the tip of the iron and let it melt off into the joint.  How would I even do that??  Won't the solder just drip off if I try to apply it to a hot tip?

A little theory.....  Heat is transfered to the joint mostly where the metal of the iron is contacting the metal being heated.  Remember that air is an insulator. A dry iron has very little contact area, so the heat is transfered slowly allowing a lot of the heat to travel down the track melting and bending ties as it goes, but won't easily get hot enough where the joint is to melt the solder or if it does you may get a cold solder joint.  Having a small drop of solder on the tip of the iron increases drastically the contact surface allowing heat to be transfered quickly from both the drop of solder and the entire (very hot) soldering iron.  The result is a lot of heat right where you need it.  You are done quickly and before the heat travels away from the joint to do damage.  That phenomenon is the reason several people have recommended a larger and flat tip on the iron.  More contact area, quicker, better, and safer results.

Ray Seneca Lake, Ontario, and Western R.R. (S.L.O.&W.) in HO

We'll get there sooner or later! 

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Posted by jeffrey-wimberly on Thursday, June 19, 2008 2:20 PM
If you do it right, you should be able to solder a rail joint in four seconds.

Running Bear, Sundown, Louisiana
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Posted by howmus on Thursday, June 19, 2008 2:24 PM

 jeffrey-wimberly wrote:
If you do it right, you should be able to solder a rail joint in four seconds.

Or less!  I usually am in and out in 2 seconds. 

Ray Seneca Lake, Ontario, and Western R.R. (S.L.O.&W.) in HO

We'll get there sooner or later! 

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Posted by selector on Thursday, June 19, 2008 2:24 PM

Gazoo, after dipping your hot tip in a tin of flux occasionally, just a quick dip and back out, you can then tin the tip by rubbing the end of the solder over it for only as long as it takes for the tip to become silvery again...no more.  That solder is now devoid of any resident flux, so you will have to lightly wipe the surfaces to be joined with just a kiss of flux before you touch the hot, silvery tip to the items to be joined.  It should all just take that long.

I do agree that a chisel tip, about the size of a smallish flat-tipped screwdriver, is best for getting heat transfer between surfaces.  The pointy ones have much less surface area and therefore contact.

FoulRift, Bob, if you can't solder, there are two things to do, and in order.  First, make good darned and sure that your tracks are well supported where they lie so that they don't dip and twist when trains pass overhead.  That splays and weakens joiners like nobody's business.  Secondly, you can take needle nosed pliers and pinch closed the flanges on the joiners.  That will help a lot, but it tends to ruin the joiners.  It raises the risk of damage outright as you do this.  You could mistakenly lift the rail out of its little tie head retainers, although the risk should be slight.

Of course, as has been stated, it would really help if the rail feet and web were cleared of any oils first.  Perhaps a Q-tip dipped in acetone and scrubbing the metal of the rail would be a good idea before you slip the joiner into place.  Just try to keep the acetone away from any plastics such as adjacent ties.

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Posted by C&OLION on Thursday, June 19, 2008 2:49 PM
I'VE SEEN A LOT OF INFO HERE ABOUT SOLDERING BUT THE ONE AND MOST IMPORTANT THING HAS NOT BEEN MENTIONED! YOU MUST TOUCH THE FLAT OF YOUR IRON TO THE FLAT OF THE RAIL TO GET THE BEST HEAT TRANSFER. If you touch the sharp tip of your iron to the rail you will have a minium of heat transfer. TRY IT. yOU'LL SEE THE DIFFERENCE.
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Posted by bnobob on Thursday, June 19, 2008 4:42 PM

Having been in the electric/electronic business for fourty

years in both the USAF and USPS. the best flux I have found

Supersafe Superior No. 30. It is a water soluble flux that doesn't

really need to be cleaned afterwords, but it won't harm any thing

if you do. It is available from H&N Electronics, 10937 Rome

Beauty Drive, California City Ca 93505 and they do have a web

site you can visit. Called the manufacturer on this and H&N is the

only place that sells it in less than gallon containers. A 2 ounce

bottle lasts me for several years and it works right now. I use an

emptied small squeeze bottle that had lens cleaning solution in

it and can place one drop on the rail joint I am about to solder,

it flows into the joiner and its a quick joint. Nice and shiney.

I also use the " Little Joe " aluminum clips to prevent tie melting,

these are available from Micro-Mark. 

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Posted by dinwitty on Thursday, June 19, 2008 6:02 PM

 jeffrey-wimberly wrote:
Don't have the funds to get one? I just bought a new Weller 100/140 watt soldering gun from Radio Shack a month or two ago. It cost about thirty bucks.

guns? omy, they work, I use an iron. 19 bucks or less at radio shack, widely sold everywhere really. Solder a wire to a joiner, connect your tracks then solder the joiner on. Guns are heavy to hold, irons are heat ready when heated up, just keepem in the holder when not in use. Do get a good iron holder. Dont use the cheapie lay down on the table holder.

 

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Posted by TomDiehl on Thursday, June 19, 2008 6:54 PM
 Gazoo wrote:

 TomDiehl wrote:
Then, bend the wire so it presses into the web and stays there without clamipng, a drop of liquid flux (the A-West dropper bottles are great for this), a bubble of solder on the iron tip, touch it to the joint area, and faster than you read this sentence, it's done.

This is something that still doesn't make sense to me.  On the one hand I hear that the solder should never touch the tip, and here I've read from several people that they put the solder on the tip of the iron and let it melt off into the joint.  How would I even do that??  Won't the solder just drip off if I try to apply it to a hot tip?

Ray's answer to this one above should have had the Mythbusters "Warning Science Content" plate at the beginning.

The technique is one I learned years ago in the Air Force, their High Reliabilty Soldering course. That little bubble of solder on the iron tip acts as a heat transfer, remembering that the metals being joined have to get hot enough to melt the solder. The bubble of solder, being molten, will shape to the joint and make the heat transfer faster by bringing the heat source into contact with a larger area of the joint. Once the flux vaporizes (don't breathe the fumes) the solder flows into the joint area. Just before touching the iron to the joint, I usually start a slow exhale across the joint, that way the flux fumes blow away from me.

Solder does have to touch the tip. What you remember hearing was probably just a small part of the rule for making large solder joints. Tinning and cleaning the tip are also important to keeping the soldering iron in good shape and ready to go. Most soldering iron stands and all soldering stations have a small tray for a sponge. This sponge is to be kept wet while you're working with the iron, and after each joint, I do a quick wipe of the tip over the sponge to remove any flux residue from the tip. While working, the tip should ALWAYS be a shiny silver color of clean, melted solder. When tinning the tip, you may have noticed that a small bubble of solder will hang there, any more and it would drip off. Most wire joints like we're discussing here take very little solder to do properly.

Smile, it makes people wonder what you're up to. Chief of Sanitation; Clowntown
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Posted by Capt. Grimek on Thursday, June 19, 2008 7:28 PM
Any particular recommendations for using soldering guns instead of irons? Tip recommendations for HO code 83? I've got a couple of guns I inherited from my father but some local folks have told me that an iron is
easier to solder track due to it's size. I've used an iron so far on a friend's layout...
Thanks.

Raised on the Erie Lackawanna Mainline- Supt. of the Black River Transfer & Terminal R.R.

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Posted by Anonymous on Thursday, June 19, 2008 10:34 PM
Selector-Thanks for the tips. I appreciate it. Bob
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Posted by Rotorranch on Thursday, June 19, 2008 10:48 PM
 howmus wrote:
 Gazoo wrote:

This is something that still doesn't make sense to me.  On the one hand I hear that the solder should never touch the tip, and here I've read from several people that they put the solder on the tip of the iron and let it melt off into the joint.  How would I even do that??  Won't the solder just drip off if I try to apply it to a hot tip?

A little theory.....  Heat is transfered to the joint mostly where the metal of the iron is contacting the metal being heated.  Remember that air is an insulator. A dry iron has very little contact area, so the heat is transfered slowly allowing a lot of the heat to travel down the track melting and bending ties as it goes, but won't easily get hot enough where the joint is to melt the solder or if it does you may get a cold solder joint.  Having a small drop of solder on the tip of the iron increases drastically the contact surface allowing heat to be transfered quickly from both the drop of solder and the entire (very hot) soldering iron.  The result is a lot of heat right where you need it.  You are done quickly and before the heat travels away from the joint to do damage.  That phenomenon is the reason several people have recommended a larger and flat tip on the iron.  More contact area, quicker, better, and safer results.

Very well said! Tip mass is the issue with most irons. You need mass to transfer heat. Square chisel tips have the best mass. The rail will suck heat out of the iron. A low mass (pointed tip, pencil tip) iron will melt ties before solder flows between the rail and the joiner.

The flux helps transfer heat, while as well as cleaning the material to be soldered.

The bit of solder on the tip can help to transfer heat, as well as add contact area (mass), to the work to be soldered.

Rotor

 Jake: How often does the train go by? Elwood: So often you won't even notice ...

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Posted by loathar on Thursday, June 19, 2008 11:17 PM

 COLION wrote:
I'VE SEEN A LOT OF INFO HERE ABOUT SOLDERING BUT THE ONE AND MOST IMPORTANT THING HAS NOT BEEN MENTIONED! YOU MUST TOUCH THE FLAT OF YOUR IRON TO THE FLAT OF THE RAIL TO GET THE BEST HEAT TRANSFER. If you touch the sharp tip of your iron to the rail you will have a minium of heat transfer. TRY IT. yOU'LL SEE THE DIFFERENCE.

Must not have read my earlier post then...Whistling [:-^]

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Posted by tgindy on Thursday, June 19, 2008 11:41 PM

Just after a joint is soldered, I like to do a quick wipe with a damp rag, to clean the "now dirty" flux residue before it has time to set-up, and the soldered joint also cools a little quicker. You may hear a small "sizzle" on the wet rag.

It is a little trick adopted from soldering copper plumbling and stained glass.

Conemaugh Road & Traction circa 1956

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Posted by dstarr on Friday, June 20, 2008 10:14 AM

 Capt. Grimek wrote:
Any particular recommendations for using soldering guns instead of irons? Tip recommendations for HO code 83? I've got a couple of guns I inherited from my father but some local folks have told me that an iron is
easier to solder track due to it's size. I've used an iron so far on a friend's layout...
Thanks.

A solder gun heats in seconds and cools down just as fast.  You can set the gun down on the layout without risking burns.  An iron takes minutes to reach soldering temperature and stays hot, so you need a heat resistant fire proof stand to set it down upon, unless you like burn marks on the layout.   Once hot, the larger tip of a big iron holds more heat and will heat a joint to soldering temp faster than a gun.  

   A gun is somewhat more convenient, a hot iron is a bit faster.  Good solder joints on rail can be acheved with either tool.

 

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Posted by PhilCPR on Saturday, June 21, 2008 12:29 PM

Hi Gazoo - wow - you have so many good suggestions and many yrs of experience to tap into

I must confess - I have only been doing this for the past 4 yrs but I did learn a lot from the Weller web site - since these people make a fine product that most of us use and they have the knowledge on how to care for the soldering gun and useful practices as well.

see Weller.blog.com for starters

at our Club - Waterloo Regional Model Railway Club in Southwestern Ontario, -we solder 22 gauge feeders onto the under side of each and every single piece of rail in the visible area of the layout -the rail is all hand laid on wooden ties so less concern for plastic melting. I make sure to clean the under side with a fine strip of sandpaper, as you have learnded one of the key and most important principles to remember is that both surfaces must be as clean as you can make them.

I find the hotter the gun the faster the job -and that is generally the story you gather from all these other fellows and fast is best - so I use a 150W Weller gun ( I don't have a hotter one )  and the tip about not using an extension cord is so important as well. ( I must remember to do that more myself - I confess some times I plug into the extension cord near where I am working and then it takes  longer to heat up as well ) 

we do  not tend to solder the rail joiners as we found we prefer not to depend on them for conductivity between rails - thus we solder every piece of rail - yes I agree it takes more time but this ensures no loss of power on the rails - this also permits for expansion and contraction with the extremes of temperature and humidity we find up here. 

on the  hidden track - we use Flex track and I solder onto the outside of the rail  - I actually clean the soldering tip and hold onto the top of the rail here and tin the outside of the rail 1st then apply heat to the this spot again when I press the tinned wire to the same spot - works great for me .

wishing you all the best !  and practice - it took me ages before I felt comfortable as well.  

 

 

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Posted by Capt. Grimek on Saturday, June 21, 2008 2:43 PM
Dstarr, thanks. I could see there'd be times when you want to solder a lot of track at once and the iron could indeed be handier/faster. I kind of wanted to use my late Dad's guns, but I think I'll use them for something else instead of track soldering maybe. What size tip do you like for your gun? I have two, a larger and smaller but I can't access them to see what sizes they are right now... (big enough and plenty! though.)

PhilCPR, If you solder all rail joints together how does that allow for expansion/contraction? Was that a typo and did you mean to say every other rail joint or something of that sort? Thanks/

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Posted by dstarr on Saturday, June 21, 2008 9:54 PM

 Capt. Grimek wrote:
Dstarr, thanks. I could see there'd be times when you want to solder a lot of track at once and the iron could indeed be handier/faster. I kind of wanted to use my late Dad's guns, but I think I'll use them for something else instead of track soldering maybe. What size tip do you like for your gun? I have two, a larger and smaller but I can't access them to see what sizes they are right now... (big enough and plenty! though.)

PhilCPR, If you solder all rail joints together how does that allow for expansion/contraction? Was that a typo and did you mean to say every other rail joint or something of that sort? Thanks/

With soldering guns you don't get a choice of tips.  There is one tip that fits your gun and thats the one you use.   This probably comes from the fact that the  electrical resistance of the tip must be just right for the gun to work.  If the length or thickness of the tip is changed the electrical resistance changes and that isn't allowed with guns.  In fact, after a lot of use, enough metal burns off the tip to change the resistance and that's when you replace the tip with a new one.  

   Guns last a long time.  I have two, one of which I got in high school, and the other comes from the Safeguard anti ballistic missile program, which was a long time ago.  Your father's soldering gun[s] will most likely work just fine.  You might treat them to  new tips. 

As far as soldering all the rail joiners, I don't, for fear that shrinkage or swelling, warp or wind of the wooden bench work could throw the track out of gauge.  Train room humidity changes a lot when heating season arrives, and a change in humidity will make wood shrink or swell.  I don't rely on rail joiners to carry electricity, I run a power bus wire under the layout and solder feeders to the track every so often.  In principle you solder feedes to every piece of track.  In practice, the layout will run well with a lot fewer feeders.  I haven't soldered any feeders to my main line yet, but the train runs well, clean around the 10 by 13 foot train room, with just rail joiners carrying the juice.  Feeders are coming, but soon as I got the track down, I had to run a train just for the pleasure of it.  

 

 

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Posted by Gazoo on Friday, June 27, 2008 9:42 AM
 TomDiehl wrote:
 Gazoo wrote:

 TomDiehl wrote:
Then, bend the wire so it presses into the web and stays there without clamipng, a drop of liquid flux (the A-West dropper bottles are great for this), a bubble of solder on the iron tip, touch it to the joint area, and faster than you read this sentence, it's done.

This is something that still doesn't make sense to me.  On the one hand I hear that the solder should never touch the tip, and here I've read from several people that they put the solder on the tip of the iron and let it melt off into the joint.  How would I even do that??  Won't the solder just drip off if I try to apply it to a hot tip?

Ray's answer to this one above should have had the Mythbusters "Warning Science Content" plate at the beginning.

The technique is one I learned years ago in the Air Force, their High Reliabilty Soldering course. That little bubble of solder on the iron tip acts as a heat transfer, remembering that the metals being joined have to get hot enough to melt the solder. The bubble of solder, being molten, will shape to the joint and make the heat transfer faster by bringing the heat source into contact with a larger area of the joint. Once the flux vaporizes (don't breathe the fumes) the solder flows into the joint area. Just before touching the iron to the joint, I usually start a slow exhale across the joint, that way the flux fumes blow away from me.

Solder does have to touch the tip. What you remember hearing was probably just a small part of the rule for making large solder joints. Tinning and cleaning the tip are also important to keeping the soldering iron in good shape and ready to go. Most soldering iron stands and all soldering stations have a small tray for a sponge. This sponge is to be kept wet while you're working with the iron, and after each joint, I do a quick wipe of the tip over the sponge to remove any flux residue from the tip. While working, the tip should ALWAYS be a shiny silver color of clean, melted solder. When tinning the tip, you may have noticed that a small bubble of solder will hang there, any more and it would drip off. Most wire joints like we're discussing here take very little solder to do properly.

 

Oh what a difference a little advice and practice makes.  I soldered a few test joints and a few actual joints last night and it was a breeze.  They practically soldered themselves with the advice here.

I have a couple of follow up questions, one of which you hit upon:

1.  When I first tried to tin my soldering gun with the little metal container of Radio Shack substance, I had my face right down next to it.  I got a pretty deep whiff of some nasty fumes.  Do I even want to know what I inhaled?!  That was a quick lesson learned about exhaling as you use the soldering iron.

2.  I went to Lowes and they had "acid free flux," "acid flux," and another container of "petroleum jelly based flux".  If it doesn't SAY "acid free" on the container, is it acid free?  I got the petroleum jelly based container.  It's dark brown.  Can I use this or should I get rid of it?

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Posted by TomDiehl on Friday, June 27, 2008 10:10 AM
 Gazoo wrote:
 TomDiehl wrote:
 Gazoo wrote:

 TomDiehl wrote:
Then, bend the wire so it presses into the web and stays there without clamipng, a drop of liquid flux (the A-West dropper bottles are great for this), a bubble of solder on the iron tip, touch it to the joint area, and faster than you read this sentence, it's done.

This is something that still doesn't make sense to me.  On the one hand I hear that the solder should never touch the tip, and here I've read from several people that they put the solder on the tip of the iron and let it melt off into the joint.  How would I even do that??  Won't the solder just drip off if I try to apply it to a hot tip?

Ray's answer to this one above should have had the Mythbusters "Warning Science Content" plate at the beginning.

The technique is one I learned years ago in the Air Force, their High Reliabilty Soldering course. That little bubble of solder on the iron tip acts as a heat transfer, remembering that the metals being joined have to get hot enough to melt the solder. The bubble of solder, being molten, will shape to the joint and make the heat transfer faster by bringing the heat source into contact with a larger area of the joint. Once the flux vaporizes (don't breathe the fumes) the solder flows into the joint area. Just before touching the iron to the joint, I usually start a slow exhale across the joint, that way the flux fumes blow away from me.

Solder does have to touch the tip. What you remember hearing was probably just a small part of the rule for making large solder joints. Tinning and cleaning the tip are also important to keeping the soldering iron in good shape and ready to go. Most soldering iron stands and all soldering stations have a small tray for a sponge. This sponge is to be kept wet while you're working with the iron, and after each joint, I do a quick wipe of the tip over the sponge to remove any flux residue from the tip. While working, the tip should ALWAYS be a shiny silver color of clean, melted solder. When tinning the tip, you may have noticed that a small bubble of solder will hang there, any more and it would drip off. Most wire joints like we're discussing here take very little solder to do properly.

 

Oh what a difference a little advice and practice makes.  I soldered a few test joints and a few actual joints last night and it was a breeze.  They practically soldered themselves with the advice here.

I have a couple of follow up questions, one of which you hit upon:

1.  When I first tried to tin my soldering gun with the little metal container of Radio Shack substance, I had my face right down next to it.  I got a pretty deep whiff of some nasty fumes.  Do I even want to know what I inhaled?!  That was a quick lesson learned about exhaling as you use the soldering iron.

2.  I went to Lowes and they had "acid free flux," "acid flux," and another container of "petroleum jelly based flux".  If it doesn't SAY "acid free" on the container, is it acid free?  I got the petroleum jelly based container.  It's dark brown.  Can I use this or should I get rid of it?

1. It depends on what that "Radio Shack substance" is. Get the name of it from the container, go to Google, type in that name followed by "msds" (Material Safety Data Sheet). You'll find out more than you really wanted to know about it. Or you may not want to know.

2. "Acid free flux" simply means that it has a different type cleaner in it, probably a strong alkali, which can be just as corrosive as acid. Follow the same advice in my first answer and look up the MSDS through a Google search.

Smile, it makes people wonder what you're up to. Chief of Sanitation; Clowntown
  • Member since
    August 2006
  • From: Franconia, NH
  • 3,130 posts
Posted by dstarr on Friday, June 27, 2008 12:14 PM

 Gazoo wrote:
 

 

I have a couple of follow up questions, one of which you hit upon:

 

2.  I went to Lowes and they had "acid free flux," "acid flux," and another container of "petroleum jelly based flux".  If it doesn't SAY "acid free" on the container, is it acid free?  I got the petroleum jelly based container.  It's dark brown.  Can I use this or should I get rid of it?

For model railroading work you want rosin flux.  It's a dark brown greasy  stickum, comes in little metal cans.  Kester and NoCorrode are two brand names.  It's intended for electrical and electronic work.  The active ingredient is dispersed in the rosin and only activates and bites into the work when the rosin is melted by the heat of the soldering iron. When cool and solid it's inactive.  The flux makers claim that rosin flux residues are non corrosive and don't need to be cleaned off.

In the printed circuit business we always washed the flux off the boards after soldering.  The only solvent that could cut rosin flux was Freon.  Some years ago it was declared that Freon was destroying the ozone layer and the raw sunlight, unfiltered by the ozone layer, would kill us all.  So, with a lot of grumbling, the industry went over to "water wash" fluxes, which don't flux as well, but you can  get them off with hot water and soap.  

  I don't bother to de flux model railroad joints, and I have never had a joint corrode on me.  But I do use flux sparingly, just enough to get the joint to solder well.

   Plumbers used to use acid flux (often liquid, came in glass jars) for soldering copper tubing.  Acid flux is too strong for electrical work, it eats too much copper, and it keeps eating it.  The standard rule was never ever use acid flux for any kind of electrical work.  

  Then the anti lead activists convinced  us that tin lead soldered joints on copper water piping was giving us all lead poisoning.  My hardware store now only carries lead free solder (mostly silver, which makes it expensive)  and a new paste flux for it.  The "lead free" flux is a pale yellowish grease, much lighter in color than rosin flux.  I don't trust it much, but it probably will work with tin lead solder. 

  Solder itself usually is made hollow, and the hollow core was filled with flux.  Usually rosin flux, but they also make acid core solder for plumbing.  On nice new clean work, the rosin from the rosin core solder is enough to get a good joint, maybe.  Me, I add dab of rosin flux from the can, just in case.  When buying solder, read the fine print and make sure it says "rosin core" or "solid core" but NOT "acid core" .  Also it should say 60-40 tin-lead.  Thats the lowest melting temperature solder.  Avoid the 50-50 solder, that's  for plumbing, not electrical work.

   When in the big box stores like Lowes or Home Depot, believe the markings on the package and be wary of anything the clerks tell you.  If the guy really knows anything, he can get a better job than clerking at a big box.  Most of them are nice people and all that, but they don't know much about what they are selling.  

  
 

  • Member since
    September 2006
  • From: Dayton, OH
  • 84 posts
Posted by Gazoo on Friday, June 27, 2008 12:28 PM

http://support.radioshack.com/msds/msd64-020.pdf

 

Found it.  Thanks!  It's "just" lead and formaldehyde. 

  • Member since
    December 2004
  • From: Finger Lakes
  • 10,198 posts
Posted by howmus on Friday, June 27, 2008 12:40 PM

For flux, I have been using the rosin flux pen available at Micro-Mark.  Seems to work very nicely.  My Father in Law gave me a small tin of No-Corrode 40 years ago.  I had been using that until last year and have done several thousand solder joints with it so, yes, a little goes a long way.

Rosin Flux Pen

Ray Seneca Lake, Ontario, and Western R.R. (S.L.O.&W.) in HO

We'll get there sooner or later! 

  • Member since
    April 2007
  • From: Lilburn, GA
  • 966 posts
Posted by CSXDixieLine on Tuesday, July 15, 2008 2:56 PM

Everyone, Thanks to reading the responses on this thread, I tackled a soldering job this past weekend with renewed confidence. A soldered track joint had become misaligned vertically and was causing locos to stutter as they crossed it. I desoldered the joint, realigned it and crimped the rail joiner, then resoldered it with excellent results. The joint is smooth, trains run great, and visually I can tell this is a better soldering job than the ones I did last year.

I also switched from a 25-watt pointed tip iron to a 40-watt chisel tip iron--wow what a difference! The joint heted up immediately and the solder flowed beautifully. I did not need to use any flux, but I did discover that a desoldering wick works nicely for this kind of job.

Jamie

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