3PDT switches melting....

commathe · Post by **commathe** » 26 Sep 2013, 08:34

Is this normal? I am not sure if I am doing something wrong. My problem is that the epoxy on the lugs melts and the lug falls out before I can heat it up enouhg to get solder on it. My solder seems to need a bit more heat than normal (350C) to melt in the first place though and I'm wondering if that is the problem? Do I just need solder that needs less heat, or do I need new switches? Every one in the batch I got has done the same thing.

Lucifer · Post by **Lucifer** » 26 Sep 2013, 09:18

I've had a similar problem with cheap (ie, Chinese) switches.

I think the 'epoxy' is just cheap plastic.

You have to be really quick on the soldering, so do everything you can beforehand to make sure the soldering process is short - such as scraping or sanding the tags to make sure any oxidation has been removed.

Also, make sure that the sodering iron tip is wiped clean, and put a small blob of solder on the tip, as this helps to transfer the heat quickly and make a good soldered joint.

Good luck.

commathe · Post by **commathe** » 26 Sep 2013, 09:40

Well I live in China... so I wonder if that has something to do with it? I'm going to try another supplier. I spent the afternoon practicing on bust ones. I found putting quite a chunk of solder on my iron and a really high heat to be most effective. Kind of just throw it on there and if I am quick enough I can get a big, splatty, but secure solder joint at the top before the bottom heats up. Better switches are the only long term option tbh. My success rate is still only about 25% with that technique...

karul · Post by **karul** » 26 Sep 2013, 17:00

You can help your self a bit if you tin the wires, or other elements you are attaching to the switch.

Take a look here - it's an audio XLR connector, not a 3PDT switch:

http://www.mediacollege.com/misc/solder/tinning.html

If the switch terminals are long enough you may try to use a small crocodile crimp as a cooler.

Lucifer · Post by **Lucifer** » 26 Sep 2013, 17:29

commathe wrote: I found putting quite a chunk of solder on my iron and a really high heat to be most effective. Kind of just throw it on there and if I am quick enough I can get a big, splatty, but secure solder joint

You might get a big splatty joint, but unless the wire and switch tag have both been heated sufficiently by the iron so that the solder can flow smoothly between the items to be joined, you will not get a secure joint. Trust me, I used to be a professional wireman, so I have experience. The joint might hold for a while under the weight of solder, but it will not be a good joint, and it will fail just when you're about to stun the audience with a blistering solo.

The other problem about throwing molten solder around . . . well, it's pretty obvious, I guess.

Be careful. Good luck.

.Mike · Post by **.Mike** » 26 Sep 2013, 19:22

What kind of solder are you using? Lead-free solder melts at a much higher temperature.

For example, 60-40 melts at 183C and solidifies at 190C. 63-37, which is what I use, melts at 182C and solidifies at 183C.

Apparently, two common lead free solders are SAC305 and SN100 (I've never used lead free solder). SAC305 melts at 217C and solidifies at 220C. SN100, or really Sn99.3Cu0.7, melts and solidifies at 227C.

It's just a guess, but if you are using lead free solder, you are likely using a much hotter iron than with leaded solder, and the switch might not be able to handle the heat.

Good luck,

Mike