how in the world am i going to solder this?? - RC Groups
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Mar 09, 2006, 06:50 PM
No more nicotine for me!
micro_builder's Avatar

how in the world am i going to solder this??

soldering isnt a big deal for me, been doing it for quite some time. but, i think i've hit a wall.

i got my .3 gram RX from Nick Leichty, and have been getting the rest of the parts together for my 5" proxflyer. Nick also sent me some caps for the motors (i was getting lots of glitches). i guess i dont really know what i was expecting, but when i looked at how incredibly small these things are, i was floored. my Weller soldering iron is a 60W, so i'll be looking for a new iron, and the tip i've been using that i thought was so small now looks monsterous.

how am i going to solder these to the motor wires? any suggestions or ideas? i really have no idea how i'm going to go about this.


edit: had an idea: CA the cap to the bell of the motor, strip a tiny portion of each motor wire and solder to the cap. would this work? i know the caps are supposed to be as close to the motor as possible, but is there such thing as too close?
Last edited by micro_builder; Mar 09, 2006 at 07:02 PM.
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Mar 09, 2006, 07:42 PM
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caseyjholmes's Avatar
clamp whatever it is you are soldering it to down and grab it with a tiny tweezer, hold your breath, and hope the solder lands where you want it!
just joking. Try a drop of glue to hold it to the back of the motor while you solder it. Thats how I did it with my micro flier radio rx
Mar 09, 2006, 07:43 PM
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caseyjholmes's Avatar
lol, just saw your edit. You got the right idea =)
just be careful of heat
Mar 09, 2006, 08:50 PM
Registered User
Saw the dots {LOL} on your finger in the pic.....guess i need a better mag-glass to play with this new micro stuff...getting smaller and lighter all the time....but that is good just hard on old eyes lol Jeff
Mar 09, 2006, 09:00 PM
Registered User
The Fonz's Avatar
Hey Micro,

Get one of these suction cup dodads. I use it all the time and notice the other size suction cups. It is indispensible for holding small parts.

You squeeze the bulb to hold, then squeeze again to let go............COOL

The Fonz
Mar 09, 2006, 09:02 PM
Registered User
merc-blue's Avatar
when you get this size i would suggest getting a good weller or Goot solder station with adjustable temperature and a few small tips
Mar 09, 2006, 10:12 PM
Realtired User
mharms's Avatar

That looks like a 0402 size cap (or is it smaller?). I almost always need to work under a microscope for this size. Definitely you need a small tip that's in good condition, and tiny diameter solder. If you have some super sharp tweezers (basically needle-sharp), you can also hold the body of the cap down while you solder. However, if you don't press straight down on the center of the cap, you may send it flying and you'll never find it.

I find it convenient to cut little bits of solder ("caterpillar poop" size) and place them on the pcb pad next to the cap terminal, then I just quickly hit it with the iron. If you aren't soldering to PCB pads, you could use a bit of flux to hold the tiny bit of solder where it needs to be. Also, since you use only a tiny bit of solder, this helps control the effect of capillary action that will grab the cap and attach it to your tip.

Good Luck!

Mar 09, 2006, 10:16 PM
Gravity is a harsh mistress.
Tim Wolff's Avatar
Might be a case where a good conductive epoxy is the best solution.
Mar 09, 2006, 11:16 PM
why wont it fly
have you considderd hot air and solder paste approach?
Mar 10, 2006, 12:09 AM
Good Better Best quest.
olmod's Avatar
select a piece of bare copper wire and wrap around your iron tip and one end can be shaped and tinned to form a tiny tip
Mar 10, 2006, 02:21 AM
relaxr's Avatar
5-8 W soldering gun, microtip - magnifier headset or binocular microscope - microscissors fixed to three hands - calm hands - GO!!!
Mar 10, 2006, 08:59 AM
Stupid ground....
Why so small??? It is to go from the can motor terminals to ground, isn't it? Just get the appropriate value leaded cap from Radio Shack and use that. Will cost you pennies vs $100.00 for a soldering station you'll rarely need. Parts like that are meant for high density applications where you have very little room and lots of parts to put in there. Be careful about the superglue thing though... Superglue puts off some of the most obnoxious fumes I've ever seen when heated.

Jarod Matwy
Winnipeg, Canada
Mar 10, 2006, 10:08 AM
Registered User
fumes have cyanide in them - not too healthy
Mar 10, 2006, 10:30 AM
I crash A LOT
Those ceramic caps are really only meant to be soldered on to a PCB. The way the metal solder points are bonded to the ceramic provides a fairly weak mechanical interface. Be careful wit those things.

Anyway, tweezers are the way to go when you want to place them. The suction deal is most likely too big. When I place 0402 sized components with a vacuum tip I usually do it with a 30 gauge syringe tip.

BTW: 0402's are a pain to solder without a microscope. You never know if you got a good solder joint. 0201's (about half that size) are a real pain.
Mar 10, 2006, 11:18 AM
Sticky Shepherd
Graham Stabler's Avatar
it looks like 0603, no big deal.

You need good tweezers, spend some cash get pointy non magnetic ones.

Tin both ends of the cap, tin the wires you intend to attach it to. Hold one end to one wire and dap with the iron as soon as it melts its soldered. Then do the other end, be quick, just a dab. You don't need an expensive soldering station you can do this with a hot nail.

These things are VERY cheap so buy a load if you want and you can play till your hearts content.



cyno will burn
suction cups will melt if used during soldering
so small because a leaded one will weigh as much as his RX

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