Bottlehead Forum
General Category => Tech Tools => Topic started by: Paul Joppa on December 27, 2011, 05:40:45 PM
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This is just another take on solder joint repair. Something I saw today made me think it was time to say it again. :^)
Adding solder is not the same as "reflowing" - if the solder joint is bad, it is likely because not ALL the metal involved was heated above the melting point of the solder. Adding solder to the blob does not make the terminal and the wire hotter; usually the iron itself must conduct heat to the terminal and the wires.
The best repair to a bad solder joint is to remove as much of the old solder as possible - you can get a solder-sucker, or use the woven copper tape with flux which wicks it away. Then, when you can see the metal parts, put the iron onto them for a bit before adding solder. Touch the solder to the terminal and/or the wire, not the soldering iron, so you are sure the metal parts are hot enough. When you see it flow onto the parts, then you can take the iron away. One reason this is best it that the flux inside the solder wire will be in the right proportion. The flux that was with the original solder blob has evaporated already, and the excess solder just dilutes the flux in the added solder.
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Paul
Good post.
When I repair kits made by others, poor soldering is usually the problem.
Debra
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It's funny to see people who can't solder try to solder. To a solderer, it seems unimaginable to not be able to do so, and to me, watching an adult do it who can't, just makes them look like a toddler trying to do it. I thought reflowing was a specific type of soldering for SMD components using paste.
Reflowing is indeed a method for SMD attachment. It's also what we call reheating any existing solder joint to the liquid state in order to get it to properly distribute itself through the joint, which is of course exactly what is being done with SMD reflow. It's also called rewetting.
If you think watching a person who doesn't know how to solder is funny, you should watch me try to ice skate. I'll bet there was a time when even you didn't know how to solder.
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I want to note that you need a good mechanical joint first, then cover with solder. I crimp all my leads onto the terminal strips or tube pins before soldering.
I get few bad solder joints. My FP 2 power switch wire fell off after 11 years. The power switch has no hole in it so it was "chewing gummed" onto the switch with solder. It failed.
I should have drilled a hole. I had the same failure in the Paramount I built, the power switch let go of the wire and solder.
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I only try to ice skate if I need a broken ankle.
You should see me solder a BGA with those x-ray glasses I got from the back on the comic book.
I almost always burn myself, probably not enough flux.
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What happened to the wonderful "How To Solder" animation one of the Bottleheads from the old site had somewhere?
That would be great!
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One day the link was 404. I tried to contact the author, but didn't hear back. We seem to be getting a lot of reasons to acquire a decent video recorder these days. I will look into it when we get a breather - things are really hopping these days.
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What I love about this forum is that folks who don't know how are welcomed, encouraged, and taught. The "bad" soldering is a lot better soldering than "not" soldering. With time, the technique improves. A video and some practice is very helpful. As are a nice set of forceps for wrapping/crimping....
John
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Hello,
My first post here, but I've been reading and learning from the forum for several months. I have the Crack kit and tools ready and will soon attempt my first build. I also picked up a couple of small cheap kits that I will use to practice soldering. I would like to ask if most of you here "tin" your wire leads before attaching and soldering?
thanks,
Thom
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I don't tin but instead put a little solder on the tip of the iron to help the heat spread. This tiny bit of wet solder spreads the heat.
I add solder after the small amount on the pen's tip starts to flow onto the terminal and wire.
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I don't normally tin wires before terminating to a terminal unless they are really big or there a specific reason for doing so. For most terminations, I try to get a really good mechanical connection and then use a tiny bit of solder paste (even with rosin core solder). I clean up the excess solder past with rubbing achohol and a soft brush.
A strong mechanical connection will bite you later though if you need to remove it. With practive and experience you can create a nice tight connect without wrapping the wire completely around the terminal:-)
Even on some busy terminal positions like 28, if you take your time and are careful can even make that position look pretty good. IMO, solder flux/past helps prevent blobs by making the solver flow much better. And with a good mechnical connection, it doesn't take much solder to secure/finish the job.
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. . . We seem to be getting a lot of reasons to acquire a decent video recorder these days. I will look into it when we get a breather - things are really hopping these days.
You must have gotten that camera since I have now seen the Tode videos.
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I'm jumping in late here but here's my 2 cents:
What I notice about soldering say wire to a binding post is it takes so long to heat the post such that the insulation (teflon in this case) begins to pull away. I realize if you have room teflon tubing may be used or even a quality heat shrink to repair the connection. But space can severely limit ones ability ensuring a solid connection. I end up tinning the iron tip a little to create a quicker heat transfer but I also tend to put the solder on the tip to get a flow going. I also notice this when soldering to PCB's. I that case the "heating period" is quicker because the substrate is thinner and thus heats more quickly and I suspect more evenly. That IMHO makes for a more reliable joint that will be much less likely to degrade sonics. Of course I could just be full of it......thoughts?
John
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You must have gotten that camera since I saw the Tode videos.
Actually the Tode videos were done at 720p with a Microsoft Lifecam Studio webcam I borrowed from my son Colin. Amazing bang for the buck, but required me to haul my workstation up to the listening room to capture the video thru the USB port. I have since acquired a Nikon D5100 from our own dbishopbliss (thanks David, lovin' it!) that does very nice 1080p video. I'm still learning how to use it but plan to start shooting some more videos once I feel confident with it.
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John,
After PMing you I finished reading your post and think you need more power. (Tool Time reference here) An additional 25% to 50% "wattage" on your iron would heat the terminal up quicker allowing you to flow solder onto the terminal and wire(s).
Since the terminal and bare wire will be soaking up the heat through the liquid solder the insulation won't get too much heat. Solder joint will go quicker.
Dan,
Great to hear. I know the video(s) will be the same high quality of all Bottlehead products.
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Hey John, I'm with you. When faced with a good sized connection, I lay my iron on the connection and add a bit of solder to the iron side of the joint, just a little to prime the pump so to speak. That little bit greatly increases the surface area and heat transfer to the joint...John
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There isn't anything wrong with reheating a solder joint if nothing immediately attached or near it will be damaged from heat; because it may a decent amount of heat. I use Kester 44 solder, and it is lenient for this practice.
The important thing to do when soldering to begin with is keep a careful watch for the solder to cling to both surfaces. If it isn't, we call it a cold solder joint; because one piece did not heat enough. In fact blobs are often a sign that the solder did not run onto the piece you are connecting. It takes an incredible amount of solder to look like a blob without a cold joint, most of the time.
Even if you don't tin wire, you can heat wire up before trying to attach it to anything. The idea isn't that you have to heat it a LOT, but the solder is harder to see running onto it than it is a terminal/rca/etc, so it is a little reassurance. Plus typically the wire will dissipate some heat on the run to the starting location, and what you solder to may be more heat sensitive.
SMD's are tricky stuff. You can blob solder on, and suck it up, to get attachments. But you want to quickly touch each pin that doesn't have a CLEAR non-cold joint. If it looks like a mini blob at all, it mostly likely need to be heated in order to run a non-cold attachment to both pad and pin. The pins usually will take on a decent amount of solder (it'll wrap all the way around them). Careful, careful, careful, SMD parts don't like heat. Reduce the working time as much as possible or come back to it if you had trouble. Personally when I want to remove a bad SMD chip, I cut the legs with a razor blade and flick them off the pads with a soldering iron (wish I had a needle nose soldering iron). It is way less of a headache and only take a couple moments.
The future might be SMD's, but my future only involves a hot air soldering station or the rare hole mount kit ::)
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What I love about this forum is that folks who don't know how are welcomed, encouraged, and taught. The "bad" soldering is a lot better soldering than "not" soldering. With time, the technique improves. A video and some practice is very helpful. As are a nice set of forceps for wrapping/crimping....
John
John,
What forceps do you use? I've been using various tweezers that just aren't up to the job. I need something stiff enough that I can really grab onto/crimp stuff as needed. Preferably something with a non-slippery tip...
Best regards,
Adam
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I recently sent this to a new Bottlehead. I think it may help others:
I've been soldering for a long time. Every so often I sit back and analyze how I do it. I'm an engineer and help a number of people with these kinds of things.
Usually in a Bottlehead kit you solder a component lead or wire to a terminal or tube socket pin. You have two pieces of metal that should be mechanically joined already. I mean you should have crimped the lead or wire onto the terminal or pin.
Using a dry soldering tip to heat both metal pieces at the same time is hard. I put a tiny bit of solder on my tip and use the liquid solder to transfer heat into the other two pieces. After a few seconds I put the solder on one of the pieces, the larger and see if the solder melts. If it does I add enough solder to cover the wire. You do not have to cover the whole terminal or pin with solder.
After the solder is applied I remove the solid solder and wait 2-3 seconds for everything to become the same temperature and remove the soldering tip.
This should give you good solder joints.