How to solder little stuff?

S

sofasurferlinux

New Member
I'm trying to make a stop light switch.
I have soldered. Never been good at it but...
How do I solder the little switch pictured? Heres a link to it... Mini SPST 0.5-Amp Momentary Switch (4-Pack) - RadioShack.com
Its only about 1/2 inch long. I tried to solder wires to it and the plastic gets hot, the terminals get loose and its shot. Would you solder it or is there some kind of connectors that can be used? What would you do.
 

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Sofa,
Soldering small electrical terminals is very easy if you have the right stuff. You'll need a small electric soldering iron. A soldering pencil is the best. Clean the wire and the terminal well with a good solvent to remove any grease and allow to dry. Apply a paste flux such as No Corrode to the wire and terminal, and allow the iron to heat. Tinning the iron tip is important. By tinning I mean to melt some solder onto the tip so it appears silver. You can help this along by lightly dipping the heated tip in the flux then wipe it clean. I use a stainless steel brush to clean the tip. Once the iron is hot enough to melt the solder apply a small drop, or ball of solder to the tip then touch the area where the wire and terminal meet with the ball. Allow the molten solder to heat the joint then touch the solder to the connection and watch it flow into the wire strands and the terminal. The heat effected area is small and should not compromise the plastic parts of the switch or the wire insulation. For small stuff I like to use 1/16 or no larger than 3/32" solder, acid or flux core. Hope these tips gets you in the right direction.
Tom
 
VERY good Tom,

sofasurferlinux:

To elaborate a bit on what Tom was talking about, use a 15 Watt iron for fine electronics work. If you are using a weller dual heat gun, it gets too hot! It's like using a blow torch on Aluminum Foil!

Always use rosin core solder for electronic stuff.

Jim
 
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I think that is my problem. I am using a Weller gas soldering iron. I'll get a little soldering iron.
I'm using 95/5 solder marked as "electrical solder".
 
sofasurferlinux said:
I think that is my problem. I am using a Weller gas soldering iron. I'll get a little soldering iron.
I'm using 95/5 solder marked as "electrical solder".
Click to expand...

The Weller butane units are actually really cool...you can throttle it back to a low heat!

As Tom said...get a fine electronics solder...Radio Shack has it.

Try adjusting the heat on your gas iron!

Jim
 
Everything they said is correct. If I was soldering this piece with a hot iron I would strip my wire, put a twist in it and put it through the hole. Then bend it back on itself. Now when you apply heat focus it on the wire and not the terminal. The terminal will get hot enough anyway and the solder will flow to it. As soon as that happens you're done and you can remove the heat.

Soldering is easy and fun when you learn to control the heat. The heat and the flux determine where the solder will flow. The solder will only stick on metal that has been exposed to flux. Either the flux in the rosin core or the flux you apply.

Sometimes on difficult solder joints I will form my wire into the shape I want first then I will remove it and 'tin' the wire. This allows me to make a joint quicker without exposing the terminal to anymore heat than is necessary.

If you get the hang of soldering your experience will apply itself to brazing as well. They are essentially the same thing just with different temperatures and materials.
 
sofasurferlinux said:
I think that is my problem. I am using a Weller gas soldering iron. I'll get a little soldering iron.
I'm using 95/5 solder marked as "electrical solder".
Click to expand...

95/5 would have a much higher melting point. Get some standard 60/40 rosin core solder. The thinner the better. It will take much less heat to melt it.
 
I used those exact switches and I originally sldered the wires....good thing they come in a bag with many.

I ended up using female spade terminals that solder on the wires, but are held onto the pins by tension like those below. Just use the smallest ones you can find. Even those a a tad bigger then they need to be, but mine work well and have not come loose. The advantage is being able to install the switch (screw in) and the pushing on the wires. I used heat shrink tubbing on each spade right up to the end and placed them on the pins so that the flat side of the spade faces to the the middle so they will noy touch each other. It's tough to see in the pic, but maybe you can get the idea.
 

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I put one of those switches inside my brake leaver, its a switch that is reversed, so when you push it is kills the circuit. That way when i apply the brakes even just a tad, the circuit is closed and my brake lights light up.

I use a radio shack iron, does what i need. I let the iron heat up in its stand, tin the wire, and sometimes I may tin the part, if there is plastic that'll melt easy. For those switches, a pair of helping hands is nice, you can clamp the wire and switch down.

I think the hurdle I faced with soldering was heating the part, just sortof figured the solder would just stick there.

This guy seems to explain most of the points I would mention
YouTube - How to Do It: Basic Soldering
 
Id use 60/40 and a 15 watt pencil. 60/40 seems to work good for me when im working on small things and it cools quick.
 
Ok, thank you all for your help. I tried my butane iron again. I turned it down real low. I did a better job this time. My main problem was that I did not tin the iron. That made a big differance. It was still too hot though. I will get a 15 watter tomorrow and some proper 60/40. And a new pack of switches, since I melted all of them.
 
Soldering is very easy.. I can do it with the 95/5 and a cheap $5 soldering iron but the 60/ 40 is easier .. hate the guns. anything for an automotive type application ( I would consider this automotive ).. really shouldn't use an acid core solder.. Rosin core should be used, as it is much more corrosion resistant and usually doesn't require any kind of flux. I did a lot of auxillary wiring to my '67 Falcon I had, all rosin core.. 2 relays triggered 4 circuits, and ended up needing 16 wires solder and shrinked and bundled togther as an extra wiring harness.. Ford didn't design them to take electric fuel pumps and MSD ignitions...
 
Now theres another thing I did not know. I never though of rosin core being any differant than acid core. I just assumed they performed the same function in the same way. I thought that acid or rosin was the same as flux but instead of dipping the solder into it, it was inside the strand of solder. Please explain more about the differance between acid, rosin and flux.
Thanks.
 
the core is the anti corrosion/ adhesion part of solder.. it can be flux, acid core or rosin core, or even solid... you wouldn't use solid core unless you were soldering a copper pipe and then you would also need flux.. Flux actully is a sheilding agent, just as you need in welding.. oxygen will cause a weld or a solder joint to not have good integrity, the flux sheilds and displaces the oxygen... then there are the cored solders.. Rosin core is special for high corrosion enviroments, and acid core can be used on indoor stuff.. not really sure on how to explain it.. they do perform the same function, but there intended applications are diffrent
 
Got my iron and solder yesterday. Radio Shack iron with tool rest, solder, heat sink and ajustable setting from 15-45 watt...about $8. Also got a roll of 60/40 rosin core, .068(?) solder. Now all I need is time to use it. Got called back to work yesterday.
They also had singe temp irons for $9 or $10. Hardware stores were $15. Go with Radio Shack.
 
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