Solder diameter

[rdonahue]

Today I started soldering up my first build, a Crack. I am taking it slow and have only done the first few steps. I am noticing that the solder I am using, Kester 44 .020 seems to be too thin. I am having to apply a lot of solder and it is still not filling the holes of the terminal strips. Also, since I have to keep the iron on the component longer to apply more solder the wire insulation is melting. With stripping the wire 1/4" and hooking it through the hole the insulation is right up to the hole to be soldered so it is melting. Do I just need to get some thicker solder?

[Doc B.]

.031 might work a little better. But you could also practice feeding that skinny solder into the joint much faster once it starts to flow.

[rdonahue]

Sounds good. I'll give that a shot before I buy more solder. That 1 lb. spool wasn't cheap!

[Deluk]

Thin solder does give YOU more control over the flow and build up. There is no need to fill the hole in the strip. The idea is to make a neat, smoothly meniscused (curved) joint around where the wire wraps round and touches the metal tag. A big blob of solder doesn't make it more reliable or efficient.

[Rocketman248]

I've been using 1mm diameter solder for the majority of my kits.  When that ran out, I ordered a spool of 0.5mm accidentally.  It works great on the PCBs, but it gets a little tricky on terminal strips and components.  My main issue with it is that it's very pliable.  With the 1mm stuff, when I touch it to the part, it stays where I want it, and I can put a little bit of force behind it.  With the thinner solder, it bends too easily, making it difficult to push it into the work.

[Deluk]

If you're having to force it the joint isn't hot enough. When hot, the tip of the solder should melt in with no resistance. The solder is actually a heat sink and is trying to cool the joint. If you have a variable temp iron an extra 20º with the thicker solder should help. Forcing it makes me think of trying to get the spaghetti to bend into the pot when adding to boiling water. The bundle of spaghetti takes the water off the boil.

[Doc B.]

Let us also mention that one does not want to overheat components either. We hear of faulty switches and jacks and other bits that are due to overheating. One needs to get the hang of finding the right balance of dwell time for the tip against the work to get the solder to flow thoroughly into the joint while at the same time not melting the switch or jack.

Over the years I have found that turning the iron up to max temp gives me the best balance regarding this melt solder/don't melt parts scenario. But that is after a lot of years doing this stuff. For newer builders I would suggest getting a temperature controlled iron and keeping the temp around 650F. Practice getting the tip in good contact with both the wire and the terminal it is being soldered to, so the heat gets into all the parts you want the solder to flow onto in the most efficient way. Use a eutectic blend (i.e. 63/37), as they flow better than non-eutectic blends. All of that will make the diameter of the solder less important.

http://bottlehead.com/smf/index.php?topic=8457.msg80679#msg80679

[Paul Birkeland]

There is no need to fill up the holes in the terminal strips.  Bend the lead up against the body of the t-strip, then apply the solder so that it flows between the component lead and the terminal strip.  That's all that's required to get the job done. 

I have done a lot of repairs where the builder applied solder endlessly until all the holes were filled, and every time I would run through with a solder pump and suck it all out before affecting repairs.