Oxidisation of solder joints

D

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I am soldering a lot of jump leads etc to my LGB track outdoors. Any useful suggestions to protect the soldered joints against oxidisation? Should I be concerned?
Cheers,
Sandy
 
Dob some paint on the solder. Won't stop it but will slow it down
 
I'd have said that as long as you don't have any dry joints it doesn't matter, unless you think it looks out of place.

A dab of silicon grease on the cable end (after soldering) might help stop any corrosion from creaping under the insulation, I've seen it travel several inches.
 
bobg said:
I'd have said that as long as you don't have any dry joints it doesn't matter, unless you think it looks out of place.

A dab of silicon grease on the cable end (after soldering) might help stop any corrosion from creaping under the insulation, I've seen it travel several inches.
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I was going to ask about the corrosion with cables. I used some heavy duty speaker cable for my track feeds when installing about 18 months ago and although heavy gauge cable it wasn't particularly expensive so I'm guessing has a poor copper content. Now last week I took some up while remodelling the track plan and found the corrosion had creeped up to a foot along the cable, turning it black. Will this affect the conductivity of the cable?
 
As Neil says, neutralise the flux, a brush and metho is good to remove the residue if resin flux, if you did use an acid base flux then bicarb soda in water brushed on works. MOST IMPORTANT for electronic soldering use only resin cored flux, never use an acid base flux. Also for exterior work its best to cover the joints with something that will prevent the ingress of moisture to prevent dendritic growths. Dendrites are a bit like stalagmites, the current and moisture combine and you get a sort of electro plating process that creates shorts and erodes soldered connections. I found that the liquid electrical tape is excellent, it sticks like the proverbial and shrinks as it drys.... Heat shrink is a waste of time if you want to keep water out.....
This is the stuff: though I bought mine at Jaycar. http://www.ebay.com.au/itm/Black-Li...ng_Materials&hash=item27c15012df#ht_500wt_724

Speaker cable is good for this use, sposed to be "low Oxygen copper'
 
Interesting :thinking: I never suspected that anything would come between the brass rail and the solder, if done correctly. I can understand the surface of the solder getting dull with oxidation however.
 
Dan, the operative words being "if done correctly".... I spent some considerable time during my career very heavily involved with HRHS ( High reliability hand soldering) this is the sort of soldering needed to do repairs to aircraft and other areas where human lives are at risk of death due to a cold joint or bad workpersonship. Initially I did a course with NASA ( wow what a bunch of......) then another course with the RAN and I had to complete annual requals..... I even have my last requal certificate hanging on my wall. Anyway the specs for an acceptable joint on a PCB are just amazing and for really critical work eg spacecraft the joints are xrayed and critiqued at length which is why things cost so much and why I as 1 of about 5 civilians in Australia at the time with the qualififications could demand such extortionate salaries.... I was a younger chap then and the work was mentally exhausting working all day thru a microscope and if I was having a good day I could make a passable joint every 2 minutes. You had to cut the melted end of the solder, wipe the solder with Isopropyl alchohol, check the soldering iron temp, then solder the joint..... then a real challenge would surface just to ruin the day, a 7 or 9 layer board out of a Hughes Aircraft computer would land on the desk as being faulty and then after finding the fault it was out with the dental drill and excavate the board down to the track that was burnt away and solder a new bit of track in the refill the board with epoxy finally finishing t it off and sending away for inspection ( usually with a mark somewhere you had not worked on ) for inspection.....
Of course today if I'm building a Jaycar kit I work under a magnifing lamp simply to see the damned board :rolf::rolf::rolf: and I dont have a QC chap there measuring the radius of each joint...
Where the difficulty lies here is that one is joining 2 different metals e.g. Copper and brass and its the (oh I love this word) interstital alloy ie the alloy made when the solder melts and bonds to the base metals and that's where all joints fail add an atom of moisture to form an electrolyte and its game on... Mind you in a dry environment problems rarely surface... But moisture is the bane of all outdoor and marine soldering and electronics.....
A trick to slow down oxidation is to use silver bearing solder.....
 
Nice one Trev, and I don't just mean the "word" (though it is a good 'un)!
 
bobg said:
Nice one Trev, and I don't just mean the "word" (though it is a good 'un)!
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Yes, though its the sort of word one would get challenged on in Scrabble....I can still remember having to submit samples of the interstital alloy to the melalurgy lab for "analysis".....
Using a lead free solder though is the best possible way to go.
I use this stuff: http://www.ebay.com.au/itm/Furutech...nectors_RL&hash=item35b7f900fa#ht_3240wt_1132

I also use lead free paste in a syringe....
 
Amazing Trev. I really do learn something every day. Only problem is finding where I stored it up there. :rolf::thinking:
 
Well yes... I only remember because, well I don't know....I just remember the strangest things at times, dont ask me what I had for breakfast today but I could tell you what I had 30 years ago....
 
tramcar trev said:
Well yes... I only remember because, well I don't know....I just remember the strangest things at times, dont ask me what I had for breakfast today but I could tell you what I had 30 years ago....
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So true :thinking:
 
tramcar trev said:
Yes, though its the sort of word one would get challenged on in Scrabble....I can still remember having to submit samples of the interstital alloy
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Got to ask... Is there not an "i" missing from the word?
I thought it was "interstitial", certainly in medical science applications.
 
MRail said:
tramcar trev said:
Yes, though its the sort of word one would get challenged on in Scrabble....I can still remember having to submit samples of the interstital alloy
Click to expand...
Got to ask... Is there not an "i" missing from the word?
I thought it was "interstitial", certainly in medical science applications.
Click to expand...

I was thinking the same thing, and surely the extra "i" in interstitial would make it score more in Scrabble? :D
 
I totally agree with Trev's comments about soldering having held HRHS quals myself. One suggestion for soldered joints outside is instead of using plastic sheathed wire consider using solder wicking braid this stuff is copper, prefluxed and flexible. It is similar in appearance to the braid wire that the full size railways use. Another suggestion is to use a conformal coating, the same as is used on printed wiring board circuit card assemblies, over your joints to prevent moisture ingress a polyurethane varnish from the local paint shop will suffice and being relatively cheap it can be used to repair deteriorated joints during your regular maintenance inspections. The most inportant thing about obtaining a good solder joint is cleanliness of the jointed area, mechanical cleaning (with a fine wire brush or sandpaper to get a shiny surface) firstly followed by chemical cleaning (using some type of alcohol), applying some flux then soldering is the way to go, after soldering removing the excess flux with alcohol is important and then applying the conformal coating this method should should reduce the corrosion.
 
One more suggestion that may be of some interest is to drill a hole through the web of the rail, insert your jumper wire, then solder. I did it that way on most of my rail, and it has held up nicely. I feel that it gives the wire just alittle more bite into the rail. Now that I have converted to battery power, it doesn't matter any more. But that's a whole 'nother topic for a different heading.
 
ROSS said:
ntpntpntp said:
MRail said:
tramcar trev said:
Yes, though its the sort of word one would get challenged on in Scrabble....I can still remember having to submit samples of the interstital alloy
Click to expand...
Got to ask... Is there not an "i" missing from the word?
I thought it was "interstitial", certainly in medical science applications.
Click to expand...

I was thinking the same thing, and surely the extra "i" in interstitial would make it score more in Scrabble? :D
Click to expand...

In the school I went to 70 years ago you would have been "duffed up" in the air raid shelter using a word like that ...:rolf::rolf:
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Hmmm duffed up?? presumably in your interstitial orifice???
 
Strewth... I hope there's no Kiwis on this forum..... They have sheep with cliff edge function for that
 
It's only soldering, how hard can it be. :bigsmile:

Done many an outside joint with no problem.
Have soldered joints from tiny surface mount to hundreds of kilowatts, no problem.
Just do it right and you'll have a stress free life.

As to Scrabble......how much would you get for eutectic, liquidus and Capillary :laugh:
 
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