The New And Improved Unofficial R65 Forum V2
Technical Discussion => Misc. Technical Discussion => Topic started by: Bob_Roller on July 10, 2007, 03:40:45 PM
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I'm involved in making up a modification kit for adding a switch and additional wiring to my employers 737 aircraft. I have to make up 1,200 switch assemblies for the cockpit sliding window anti-ice system, they supplied me with .020 in. diameter solder, and I am amazed how much easier soldering is using this small diameter solder, as compared to using the standard 'thick' solder from a source like Radio Shack . This is using a run of the mill Weller 40 watt soldering iron, like you would get from Radio Shack or other retail outlet.
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I have never used thin (I assume) rosin-core solder before. Interesting.
I had to buy some silver solder, that came with it's own tube of rosin, for making up my throttle cables. It is very thin, but I had to use a
propane (? plumbing...) torch to get sufficient heat to work it. Those cable tips are still holding... (I forgot to pack my spare cables on my last trip!!! :-/)
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Yeah Rob, it was resin core. It's been my experience with trying to replace components on printed circuit boards, that by the time you got enough heat to melt the thick solder, it usually caused problems with the surrounding solder joints, or worse yet overheated electrical components next to where you are working. Rob, have you ever thought of storing your spare cables in the 'backbone' tube under the tank?
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I think the cables are too long for the backbone.
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I have always used the thin stuff, but I started as an elec. tech back in the early 70s.
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I want to learn to solder. I did some years ago when I got an assembly job making connectors (of some sort - been too long and I don't remember what I was making) but I haven't done any since then.
Is there anywhere on the internet that would help teach that to me? Or one of you can come and teach me? ;) Well, maybe not. Have you got any other ideas about where one can go to learn the basics? I just want to be able to solder wiring for the bike and maybe something else that I don't know about yet. Maybe there's a book?
I was thinking about getting out some wire and trying to solder ends together for practice. Maybe that's the best way to learn. But I do know there is a certain look to the bead that makes it a better connection. I just don't know what that is.
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I don't know if the Heathkit company as still around or not but they used to sell a simple soldering training kit. Just search the internet and I'm sure you can find a lot of pics showing what a good solder joint looks like. Basically it's shiny, doesn't "glob" up, conforms and flows to/through the joint. Get out out some wire, an iron (yes, I said iron, not gun), and some small diameter solder and it'll all come back. Add to this some heat-shrink tubing and you are well on your way to making 100% solid reliable electrical connections.
Hint: Very important to keep the tip clean and tinned, put a little solder on the tip to help transfer the heat to wire/joint, hold under the wire/joint, and apply solder to the top side of the wire/joint. The solder will wick into the wire/joint toward the heat source.
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The tin/lead (and now tin/silver thanks to the RoHS initiative) solders have fairly low
melting points compared to the high silver content solders like what Rob used for the
cable repairs. On the other hand, the higher temp solders are significantly stronger
(and less flexible) when the joint is formed and are much better for joints requiring
more strength, and which aren't susceptible to heat damage.
There are lots of nifty little electronics kits one can buy on the internet that provide
a good opportunity to learn to solder electronics... Less so for soldering/sweating pipe
joints, though !!!!
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Just read an article on installing a high output charging system in an airhead. It required that the old field windings be removed from the cover which gets reused. The writer used compressed air to blow the old solder out of the connections while heated. Egads! A nice desoldering tool or even some desoldering wick is a nice addition to your shop and inexpensive as well!
My current favorite "Iron" is a little butane powered catalytic model that gets real hot real fast and no 'lectric needed.
http://www.portasol.com/docs/Technic.pdf
rich
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Neat tool Rich! It has to be better than the battery operated ones (that I have no personal experience with...).
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In the "field" for small stuff you can't beat a 17 watt Antec pencil and I use a Weller 40 watt iron for heavy stuff. On the bench I have a variable temp soldering station that you can dial in whatever temp you like! ;D I also use a Paladin "solder-sucker" that is small, light, and really sucks - in a good way! ;) When I was a bench tech (in a previous life) we had a vacuum desoldering station that used hollow tips on a special iron, you mashed a foot switch, and the melted solder was sucked out of the joint into a glass tube/reservoir for easy cleanup. That thing was really slick.
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When I was a kid, I once disassembled a complete television set my parents dumped in the basement.
I wonder if all those fumes could explain who I am, today... :o
::)
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I went to a 3 week course on soldering and putting plugs together when I built minuteman missles for GE.very picky about their soldering!!
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Kester and Ersin (from the UK) are the only brands I trust. To do that much work I suggest you jump on Epay and find a good used Weller temp controlled soldering station. Since the EPA weenies took the lead out of solder it doesn't flow as well and needs more heat. Boards "tinned" with the new stuff don't solder as well either. Pointed tips don't transfer as much heat as those with a flat "screwdriver" type end and the thermal mass of the tip is also important. Keep the tip "tinned" with solder and clean it often on a damp sponge. A good joint looks shiney, not dull and grainy. I've built
or repaired a number of the famous Heathkits (aka Griefkits), some
fine old Collins radios, and a bunch aof Japtrack gear. It's getting harder to make a good solder joint to a board. I wish the bleepin' bureauweenies would get OUT of our lives. I'll not be giving up my stash of 63/37 tin/lead stuff anytinme soon.
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Insofar as "tips" go, you heat the joint, not the solder, and touch the
solder to the tip just before you apply it to the joint. The old stuff used to "wick" right into the joint as soon as it was hot enough, the new bleep doesn't do it as well and reqiures more heat. Having a tip coated with shiney solder aids in heat transfer, but you want just a coat, not a blob. NASA QA for solder joints (with the old stuff) was for
a joint where you could still see the outline of the leads and wire, not a huge blob that covered everything. Colllins Radio in the good old days had inspectors who put a red dye mark on every jont they approved so an "unhacked" Collins unit had a red mark on every joint. It was a good telltale, "golden screwdriver and soldering iron" hacks were instantly obvious. There are parts in the 50's gear which have to go at this point to keep the stuff working, but I still hate to disturb a red marked joint.
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I went to a 3 week course on soldering and putting plugs together when I built minuteman missles for GE.very picky about their soldering
Those were the good old days before wave soldering.. I took a NASA course in college...They were a little picky as well...It's nice to be a NASA approved solderer... :D
That was a nice certification to have when things were actually troubleshot and repaired at the component level...Not much of that going on anymore..
John
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Wave soldered through hole components are being replaced by surface mount computer placed bits which are then cooked in an oven to melt the solder/stickum, bring new meaning to the label "no user serviceable components inside". It is so inexpensive to make these boards that the units containing them are serviced by stuffing in a new one. One hopes that someone looks at the dead ones to find any engineering blunders which might result in failures. The boards can be serviced but to place and remove the parts you need a suction device snf s good magnification system.
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but you want just a coat, not a blob
did my NASA approved High reliability Hand Soldering course in the RAAF and we used to joke "the bigger the blob the better the job".
The HRHS habits have stayed with me and even with "no clean" solder I still have to clean away the flux residue so i can inspect the joint correctly. I would never make a good TV tech as I get too perdantic, and wouldn't survive in the world of "time = money"
John
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I've seen a number of cold soldered joints hidden in "big blobs". A lead can run right through one and be held in place only by the flux. This is just a hobby for me, not many getting paid would work on 50 year old tube stuff. Still, even in the newest Japtrack stuff there are a few old fashioned "interfaces".