For a few years, on and off, I've been using one of those cheap, yellow soldering irons that cost about £9. The problem is that it has one of those 45 degree flat tips, but apart from that it woks great. Never needed cleaning or anything.
I spent a bit more (£30) on a solder station with interchangable tips, but the tips seem to be getting coated in carbon really quickly. This means the solder just balls up on the tip or on the length of solder.
I'm fairly sure that this is not uncommon, but I can't work out why it's happening, given the tips seem to be fairly good quality. Too hot? Too cool? I'm using lead-free.
If anyone has any suggestions, they'd be much appreciated!
Most likely the iron is too hot or you are not keeping the tip coated in solder. I keep my tip at 650F (340C or so) which is plenty hot -- some suggest even lower. There is a mistaken tendency to crank the heat up for lead-free solder which is just not necessary.
Ugh...soldering irons without actual temperature numbers are like speedometers without actual numbers.
Not meaning to insult your iron choice, but a "step up" soldering iron with actual temperature settings is a good investment.
It's probably not worth going lower than 50% on a 40W iron but I would stop using the sponge, especially a wetted sponge. Water just accelerates oxidation. I would suggest using brass shavings instead, something like this:
Ha, feel free to insult my iron choice, I'm well aware it isn't amazing! I just needed something with a finer tip. Aside form that the old one worked fine.
Will look into wet sponge substitutes, thanks for the idea!
Lead free can be murder to soldering irons if it's not good stuff. I destroyed a soldering iron very quickly after I (temporarily for testing it) switched to lead-free.
I've now got a Kg of the stuff that I'm not going to use... But it was free.
I know people who use lead free and that special tinning stuff to coat their iron after use. Never tried it though.
I keep my tip at 650F (340C or so) which is plenty hot -- some suggest even lower.
Then they are nuts.
Too low a temperature results in part damage due to increased heat transfer to the part. Turning the temperature up can decrease the heating of the part, because you can get the solder joint up to temperature more quickly and remove the heat source.
There is a mistaken tendency to crank the heat up for lead-free solder which is just not necessary.
Not necessary? Even though it has a higher melting point?
Too low a temperature results in part damage due to increased heat transfer to the part. Turning the temperature up can decrease the heating of the part, because you can get the solder joint up to temperature more quickly and remove the heat source.
Right. It's about selecting the "right" temperature, but all too often people turn the heat up when what they should be doing is using a bigger tip to transfer more heat.
Not necessary? Even though it has a higher melting point?
Not necessary. Consider that 650F is about 340C which is about 100C hotter than the melting point of lead-free solder, and even 5-20C higher than leaded solder, so as long as you use the right-size tip and a sufficiently powerful iron, the heat gets transferred and the solder melts. In theory you can turn the heat down to 1C above the melting point of the solder if you have an infinitely efficient tip and heating element to back it up. The higher the quality of your iron and tip, and with the right tip choice, the lower your temperature can be.
Consider that "pro" version soldering irons have a temperature lockout -- only the "boss" can change the temperature by using a special key or other security device. This is to prevent the soldering tech from cranking up the heat to make things go faster. The soldering iron manufacturers know that tip selection is the thing to think about, not so much temperature.
--
The Rugged Motor Driver: two H-bridges, more power than an L298, fully protected
In theory you can turn the heat down to 1C above the melting point of the solder if you have an infinitely efficient tip and heating element to back it up.
Out here in the real world we have this variable called "time". You're back to the heat transfer problem again.
I say again, 650F for lead free is nuts. I've removed lead-free solder from parts that required 800F to melt the stuff. No, the tip wasn't new, but it was a good quality well maintained tip on a quality soldering station (Hakko).
If you are an experienced soldering technician with very good equipment you might be able to get away with this. If you are a hobbyist with average or below equipment and skills, do not try to solder at 650, especially with lead-free solder.
I use lead solder at 750F (which is a bit hot) and do not damage parts. 750F allows me to get the solder joint made and get off the part so I stop transferring heat into the die via the lead (that's "leed", as in pin/wire/etc).
Well, regarding the temperature, I think it depends on how large your target component. In other words, if there is a large heat spreader like ground plane where you want to solder or a thick terminal, you need to increase the temperature. That's the beauty of using temperature adjustable soldering iron. In my experience, it varies from 650F to 750F.
Also, as already mentioned by others, if the soldering iron's temperature is relatively high, you can reduce the time for the iron to contact with the component. With this trick, at about 750F, by brief touches can solder small parts quickly and safely.
ArduKu:
I just needed something with a finer tip. Aside form that the old one worked fine.
For years, when I needed a very fine tip, I took a chunk of 12AWG solid copper wire and wrapped it up the body of the iron and the tip and had it poke out straight for a few mm from the tip. When needed, I would sand it up, tin it and use it. When done with it, I would slip it off and set it aside for next time. It worked a treat and cost nothing.
Now I have a fancy-pants station and fine interchangeable tips, which is great, but not actually a lot more convenient than the old copper coil.
gardner:
......a chunk of 12AWG solid copper wire and wrapped it up the body of the iron and the tip and had it poke out straight for a few mm from the tip......
For years, when I needed a very fine tip, I took a chunk of 12AWG solid copper wire and wrapped it up the body of the iron and the tip and had it poke out straight for a few mm from the tip. When needed, I would sand it up, tin it and use it. When done with it, I would slip it off and set it aside for next time. It worked a treat and cost nothing.
But it was free.