• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.

Help! I Need Help With Soldering

#1
I got an FT Twin Sparrow speed build kit recently. I’ve never built or even had a plane, so I’m a total newbie. I’ve also never soldered, which is where I’m having problems. I have a Weller WLC100, 60/40 rosin core solder and a small tub of flux. When I was trying to solder, I simply couldn’t get the solder to flow onto the wire. It just sticks to the tip of the iron. Anyone have suggestions on what I might be doing wrong?

Thanks
 

FDS

Well-known member
#2
Did you “tin” the tip of the iron before use? New ones need to be coated in solder to help transfer it from the tip, look at Youtube videos on how to do this, it’s easy. There’s also lots of how to solder vids.
Next up how to apply the solder to the wire. When you have the bare end of wire, apply a little flux (I dab my wire end in the flux tub) to the exposed wire. You can then “tin” the wire, either by applying a bit of solder to the iron tip and placing it on the wire, or heat the wire until the flux sizzles then apply the solder onto the hot wire.
With some solder applied to the wire it’s ready to join, put the two tinned wires together, heat, add a dab of solder, cool, then it’s joined! Apply heat shrink BEFORE making joints so you can shrink wrap the exposed wires.
 

makattack

Winter is coming
Moderator
Mentor
#3
Great advice from @FDS. I'm assuming you're soldering the battery wires to the esc. Are you using the thicker/bigger soldering tip? That will hold heat better while transferring more of it quicker to the beefier parts you're soldering. You should have the temperature set to 3 or 4 on that station. No need to max out.
 

Kendalf

Well-known member
#6
@LemonyBiscuit I've been learning soldering by trial and error these past several weeks. I was having a very hard time at first until I realized that my solder was lead free. But looks like you're using 60/40 leaded solder.

Perhaps the wire that you're trying to solder is already tinned with lead free solder, and isn't getting hot enough to fuse with the lead solder that you have? Are you heating the wire itself and seeing the solder flow onto the wire? There are several Youtube videos to help with soldering; I would suggest practicing with non-electronics until you get the hang of it.
 

FDS

Well-known member
#8
Get some SCRAP wire and practice, any multi stranded cable will be fine. Speaker wire is in most homes somewhere, that will do for practice.
Chop the end off the wire and start with a clean piece. Are you applying FLUX to the wire first?
Flux helps draw the solder into the spaces between strands by capillary action and removes oxides from the wire.
It shouldn’t matter if the wire ends are already tinned, but try a fresh bit.
You can usually tell if it’s pre tinned, if the wire is fused together so you can’t separate individual strands and is a dull silver, it’s pre tinned.
 
#9
Ok. I’ll look for some old electronics to scrap and practice on. Thanks for the help. Probably not going to do anything tonight, but I’ll start practicing tomorrow if I can find some wire. Thanks for all the help.
 

FDS

Well-known member
#10
Like any other skill it’s less than 40% technique, rest is practice.
Hope you find a solution. That iron should be great once you get a method that works for you. If you just want to test all your electrics and you have a 30A or less motor on there, you can use yellow 30 amp crimped INSULATED automotive bullet connectors or the yellow auto crimp single piece joiners to test it. Remove before flying and solder on a proper connector or make a permanent join.
Only plug/unplug motor wires with your battery DISCONNECTED when testing the ESC, keeps the magic smoke IN.
 

Bricks

Well-known member
#11
When I learned to solder my BIGGEST mistake was not keeping my soldering iron tip clean if the tip does not look shiny it is dirty. When you tin the tip watch if the solder flows across the tip and is very shiny or balls up if it balls up it is dirty. I have had to take sandpaper and clean the tip until it was shiny again then retin and it worked great. Now after just about every solder joint I wipe the tip on some steel wool to clean it.
 

FDS

Well-known member
#12
You can also get brass pads for solder stations that are like a scourer for the tip. They don’t wear the tip away like sand paper can but are better at removing oxidation than a sponge.
 

makattack

Winter is coming
Moderator
Mentor
#13
I think we are all assuming you are something the esc wires that are already on the esc. Is that so? Or, are you something the three motor wires? Maybe to put bullets onto? If you have cut those wires down in size, there's a chance that you have enamel insulated motor strands that need to have the enamel insulation removed first. A lot of heat, sanding or solvents are required for that.
 
#15
How hot do you have your iron set? I've found that if I get things too hot, some really wacky stuff starts happening - especially with rosin core solder. I get really poor adhesion or the solder balls up and doesn't wick in. Your iron is rated at 40w on it's highest setting with temps up to 900 degrees Fahrenheit. That's sedulously hot! My iron is digital with a heat sensor in the tip and I run it 300-350 Celsius (572-662F). I'll bump to 400c (752f) for very thick (10-12 gauge) wires. 60/40 solder should melt at 188 °C (370 °F), so if you have your iron on it's highest setting, you have it WAY too hot. The pics of the wlc100 that I'm seeing have a knob of 1-5 - try running it on 2 or 3 and see if you have any better results.
 

Headbang

Well-known member
#16
Solder rolling off means the wire is not enough. Using a small amount of solder to transfer the heat, hold the iron on the wire until it gets very hot. You know it is hot enough if solder flows into it. I usually set my iron to around 700F. It can take 2 or 3 mins to heat up 12 gauge wire hot enough to flow solder.
 

PsyBorg

Wake up! Time to fly!
#17
This video should help you out a bit. I have been in and out of the electronics industry since the late 80's. I have worked on things from navigation sub assemblies, to pcb hand soldering and rework on military spec radios, to complete refurbishment on British Telecoms automated directory assistance.

Ignore anyone telling you to crank up the heat specially when working on pcb's. Wire work is a little different but methods are the same.

If you are having trouble tinning wires more then likely you have wire that has been coated in schelac. This is older wire or wire meant for motor or transformer use.

The easiest way to tell is to strip some where you have enough exposed wire to be able to apply flame and burn off that coating.

Hit it with a lighter for a few seconds to char the coating. THEN you can dip the wire into flux and tin it. If the wire now takes solder it will have the charred remains mixed in the solder.

You can work with this but it is better to replace it with proper wire meant for electronics not electrical supply or motor works.


Less heat is best for any electronics. The trick is making the solder work for you NOT excessive heat.
 

buzzbomb

I know nothing!
#20
I got an FT Twin Sparrow speed build kit recently. I’ve never built or even had a plane, so I’m a total newbie. I’ve also never soldered, which is where I’m having problems. I have a Weller WLC100, 60/40 rosin core solder and a small tub of flux. When I was trying to solder, I simply couldn’t get the solder to flow onto the wire. It just sticks to the tip of the iron. Anyone have suggestions on what I might be doing wrong?

Thanks
What are you trying to solder?