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February 22, 2020, 06:05:01 PM

Author Topic: Solder blobs are not always solder joints ...  (Read 15831 times)

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Offline 2wo

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Re: Solder blobs are not always solder joints ...
« Reply #15 on: July 12, 2012, 07:22:49 PM »
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   
John Scanlon

Offline DoS

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Re: Solder blobs are not always solder joints ...
« Reply #16 on: January 29, 2013, 02:32:09 PM »
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 ::)

Offline adamct

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Re: Solder blobs are not always solder joints ...
« Reply #17 on: February 21, 2013, 05:09:47 AM »
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

Offline Grainger49

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Re: Solder blobs are not always solder joints ...
« Reply #18 on: December 14, 2013, 04:01:06 AM »
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.