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Need soldering advice and help with wiring

#1
Hey everyone, I’m new to building my own drone and I’ve started running into a problem. When I’m trying to solder on the wires to connect my LiPo batteries, the solder on the pad never melts no matter what i do. The only way it melts is if i hold it to the hottest part of the soldering iron which is thick and hard to use. Any ideas? Also, I’m getting a little confused on the wiring for the receiver. Here are a couple pics. I have the Matek F722-SE and the Spedix GS45 and a XSR receiver.
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Merv

Well-known member
#2
It took me a while to learn that heat is EVERYTHING when it comes to soldering. To little, solder will not stick, to much and you burn off the flux. The sweet spot is narrow, maybe 20F. The sweet spot changes with the size of the stuff you are soldering, with small stuff like servo wires, 620F, with large stuff like XT60, 710F, with landing gear 800F. Don’t take these temperatures as gospel, they are intended to point you in the right direction.

I started with a cheap soldering iron and my soldering was terrible. I spent $70-80 on a no-name eBay soldering station with controlled heat and a build it hot air rework station. It was like magic, all of a sudden I can solder almost anything.

The other trick is flux, most of the time there is enough flux in the solder but sometimes a dab of flux can Tuan OK joint to perfect.

The controlled heat soldering iron is an absolute need, the hot air rework station optional but is worth it. I have found many other uses for it in my shop. It’s very handy to remelt hot glue and perfect for bending plastic into useful shapes. I use it almost as much as the soldering iron.
 
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ElectriSean

Eternal Student
Mentor
#3
I agree with Merv that a temperature controlled soldering station is essential, but almost as important is having enough power to quickly heat the joint to the correct temperature. You want to be applying the correct temperature for the shortest time possible to make the connection. Extended heating time just damages stuff, especially PCB's. Find a station with 50-60 watts, and you won't believe how easy it can be :)
 

Bricks

Well-known member
#4
Clean your soldering tip constantly using either steel wool or sponge and water and retin the tip each time it is cleaned which for me can be after every soldering joint. Make sure the tip is not wore out as in the coating is gone. For boards and small wire I just have a cheap Aliexpress pencil soldering iron which is adjustable temperature. For larger stuff like XT60`s I use a Weller 325 watts.
 
#5
Thanks everyone, i ended up successfully soldering most of the wires except the xt60 one. no matter what, i still cant get that to work. I have the X-Tronic Model #3020 Digital LED 75 Watt Solder.
 

Merv

Well-known member
#8
The size of solder tip also makes a difference, use a small tip for small stuff & your largest tip for bigger stuff. For XT60, I pretin the wire, then heat the plug, when it starts to take solder, touch the wire to the iron to start heating while keeping heat on the plug. After a few seconds, add more solder to the plug & insert the wire. Keep the heat on for another few seconds, add more solder if necessary. I always have a male & female connector plugged into each other while soldering, this keeps the pins from moving out of place.
 
#9
The size of solder tip also makes a difference, use a small tip for small stuff & your largest tip for bigger stuff. For XT60, I pretin the wire, then heat the plug, when it starts to take solder, touch the wire to the iron to start heating while keeping heat on the plug. After a few seconds, add more solder to the plug & insert the wire. Keep the heat on for another few seconds, add more solder if necessary. I always have a male & female connector plugged into each other while soldering, this keeps the pins from moving out of place.
Thanks I’ll try that. By the way do you know how to bind a X8R to a Taranis x9 lite?
 

outthayr

Active member
#10
I feel your pain. Something that has helped me is counting to three or so. Touch/heat on 1, attach 2, remove 3. If it doesn't happen within those few seconds maybe it's not hot enough - if it happens quickly it's hot and you don't want to apply too much heat for too long.
 

Merv

Well-known member
#11
I feel your pain. Something that has helped me is counting to three or so. Touch/heat on 1, attach 2, remove 3. If it doesn't happen within those few seconds maybe it's not hot enough - if it happens quickly it's hot and you don't want to apply too much heat for too long.
I agree that you need to get into a rhythm. AND never hold the heat on a circuit board more than a 3 count, the heat could damage the components if you do. In my experience small stuff heats much quicker, a 1 count, and large stuff takes longer, a 5-10 count.
 
#12
Hey everyone thanks for answering. I have a new solder iron and i tried putting solder on it first then heating up the Lipo pad but it still wont melt and even if it melts it’s only for a second. Any other things i can try?
 

PsyBorg

Wake up! Time to fly!
#14
Check your iron and see that it is a "fast recovery" type iron. This is where most people struggle with soldering. They go cheap and dont get a fast recovery iron and that is why so many people tell others crank up the heat. WORST idea EVER when working on flight controllers or other sensitive electronics. This aint the stone age and we are not soldering plumbing.

Make the solder work for you. Clean and Tin your tip before every joint you do making sure to make a solder ball on the iron the size of the wire you work with. That will transfer heat fast to a pre tinned wire and that will transfer heat to the tinned pad in turn. No need to press down no need for crazy temperature settings.

Here are two vids I made that show the process for bare boards and actually solder work. Using the proper tip size for the job also makes a big difference.


 

PsyBorg

Wake up! Time to fly!
#16
I just looked that iron up. The reviews trend to the unit being great out of the box but quickly degrading and unable to support higher temps properly. You may be a recipient of one of these defective irons. If you have a digital thermometer you should check what temps the iron actually achieves.
 

ElectriSean

Eternal Student
Mentor
#17
X-Tronic Model #3020 Digital LED 75 Watt Soldering Iron Station - 10 Minute Sleep Function, Auto Cool Down, C/F Switch, Solder Holder, Brass Tip Cleaner w/Cleaning Flux (Deluxe - 5 Extra Solder Tips) https://www.amazon.com/dp/B079VVHPPS/?tag=lstir-20 I’m using that one
I meant the actual solder that you are using with your iron. If it's anything other than 60/40 or 63/37 you're causing yourself grief :)
 
#18
I just looked that iron up. The reviews trend to the unit being great out of the box but quickly degrading and unable to support higher temps properly. You may be a recipient of one of these defective irons. If you have a digital thermometer you should check what temps the iron actually achieves.
i dont have a digital thermometer but the iron doesn't seem to heat up as well as it did when i first got it. if i return this and get a new on is there on that you would recommend?