Hi all. Decided to get back into drone flying after a longish break. My old quad was looking a bit sad and the FC was AWOL. Bought a Speedybee F7 mini stack but boy that thing does not want to take solder.
Advice needed so I searched the web and this seems the place to be!!!
Kind regards
Phill

Welcome to intoFPV!

What wattage iron are you using, what tip, and what solder? Are you using flux?

Some reading:
https://oscarliang.com/soldering-guide/
https://intofpv.com/t-how-to-solder-prin...chnics-etc

(12-Oct-2023, 06:54 PM)Lemonyleprosy Wrote: Welcome to intoFPV!

What wattage iron are you using, what tip, and what solder? Are you using flux?

Some reading:
https://oscarliang.com/soldering-guide/
https://intofpv.com/t-how-to-solder-prin...chnics-etc

Hi Lemonyleprosy, wow great name.

Thanks for the welcome and the advice.
I´ve put the board aside for a while pending some new larger tips.
I have 30w, 60w and 120w irons plus an old weller which I think is about 90w. Solder I´ve tried is 60/40 and Eutectic. Bad I know but haven´t tried any zero lead. I´ve also tried OLK solder paste with it`s own flux, which worked well on an UNO project board.
I usually use MG 8351 no clean flux. The reason I´m waiting for new tips on the 120w is that on another project I used RMA 223 flux (smt) and it greyed the tip. They clean ok and then grey again. Maybe it´s just for hot air soldering.


My criticism of the Speedybee is that to me, for motor wire connections the castellated slots just don´t have enough meat to solder to.

I suspect I´ll probably end up killing the ESC board and then have to buy some other make. As a trial I soldered onto a (very) old Matek esc board  and had no problems.

Kind regards and best wishes to all.

I’m a fan of 63/37 solder, and I prefer Kester. Lead free is crap.

MG 8531 is good flux, apply it liberally.

Motor pads and battery pads need quite a bit more heat- so use a higher wattage iron and a larger tip, and tin the pads first- you can get away with a smaller tip if you lay it on its side on the pad.

If you post a picture of one of your failures, we can tell you what you did wrong.

(16-Oct-2023, 02:41 PM)Griffin Ucos Wrote: Hi Lemonyleprosy, wow great name.

Thanks for the welcome and the advice.
I´ve put the board aside for a while pending some new larger tips.
I have 30w, 60w and 120w irons plus an old weller which I think is about 90w. Solder I´ve tried is 60/40 and Eutectic. Bad I know but haven´t tried any zero lead. I´ve also tried OLK solder paste with it`s own flux, which worked well on an UNO project board.
I usually use MG 8351 no clean flux. The reason I´m waiting for new tips on the 120w is that on another project I used RMA 223 flux (smt) and it greyed the tip. They clean ok and then grey again. Maybe it´s just for hot air soldering.


My criticism of the Speedybee is that to me, for motor wire connections the castellated slots just don´t have enough meat to solder to.

I suspect I´ll probably end up killing the ESC board and then have to buy some other make. As a trial I soldered onto a (very) old Matek esc board  and had no problems.

Kind regards and best wishes to all.

Hi Phill,

Regarding the soldering. I use a 60 Watt AC unit with the adjustment wheel taped
at 425 C degrees. Except for irons less than 60 Watt, it is less about the iron and 
more about the temperature setting. The wire or pad absolutely MUST get hot.

If the solder is not melting then either the pad or wire has not yet reached the 
solder's melting point which is somewhere between 183 C and 190 C degrees
depending on the solder and the quality. I use Kesler solder and flux. So, if the
solder isn't melting or is not "bonding" to the pad (or wire) then the material is
likely not hot enough resulting in a cold solder joint; turn up the temperature. 

What the wattage does for an iron is keep the temperature up when working 
with larger material since the iron actually cools as it heats the material. 

Some of the cheaper solder seems to be problematic likely due to inconsistent
mixes or maybe little to no flux. 

For a more detailed explanation of soldering you might want to take a look at
TUTORIAL - How To Solder - Principles, Technics, Etc.

About those cut out "C" motor pads. I actually like those really well. When the 
board is set on its edge with a set of pads on the top edge. The pads look like
"U"s and are easy to fill with solder. In fact, they sort of "hold" the solder.
Here is how I solder them:

Tin the pad.

1) Stand the board on it's edge with the "C" holes the top edge so that they
    look like valleys and secure the board. I use that blue tack stuff.

2) Set the tip of the iron in the bottom of the hole.

3) Appy solder from the top, above the iron. 

4) The solder will melt and fill the hole. 

Connect the pre-tinned motor wire.

1) Set the pre-tinned motor wire on top of the solder that is in the valley of the hole.

2) Set the iron on top of the wire with light pressure.

3) When the solder melts the wire will sink into the valley.

4) As the wire sinks, remove the heat.

5) Done.  

6) Trim any excess wire (I leave the wire a bit long, then trim it).

Flip the board and repeat on the other set of pads.


NOTE: I use reverse tweezers to hold the wire.

Later, iFly  

Many thanks for the excellent advice guys. I'll give the vertical method a try once I've finished replacing the processor on this FS-TH9 board I have.

BTW somehow my reverse tweezers have found their way into my wife's sewing basket!

Welcome back to FPV
If the solder pads don't want to take solder, apply a small amount of solder paste on the pad first will make it a lot easier

Thanks Oscar. Alas the self fulfilling prophecy got me. Managed to solder the wires on with the board in the vertical plane. Quite pleased with myself until I realised I had got a small amount of solder in the slot between a small smd chip and a row of components that look to be 1x2mm. Couldn't clean it out and long story short managed to remove an smd in the process. Ordered a V7 stack! I'll put the mini FC in the parts bin for another day.