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soldering - what am I doing wrong?

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So, I'm trying to solder some motor wires to connect my brushless motor to my ESC and things aren't going well. 

I've finally managed to get some solder to tin the post on the ESC but now I can't seem to be able to heat it up enough to get it flow so I can solder the wire to it. I've tried both my (admittedly cheap and cheerful) soldering iron and my not so cheap and cheerful Dremmel gas torch/iron and had zero success with either.

Can anyone help with advising what I'm doing wrong please?

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If your iron is less than 60watts that can make things difficult. 
My soldering was less than average with an el cheapo iron but improved immensely with a stronger wattage iron. 
Keeping the tip clean and dipping into a pot of flux then wiping it on some steel wool also helps. 
 

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I have always had trouble soldering,  and then like @Re-Bugged says, I got a decent solder station and it suddenly became easier. I bought the Hakko FX888D and it changed my life. Its not just the watts, its the type of element. The cheap ones heat up but can't maintain the temperature when you start using it. The expensive ones have *magic* and maintain the temperature. Also, get a big tip, around 5mm will hold the heat on big wires and solder tabs.

My friend has a gas one and gave up on it, now just uses it to shrink heat shrink.

Another issue is the ambient temperature. I tried soldering one night in winter in my garage. It didn't go well. Tried again during the day and it was easy.

There is a really good 'how to' on rctech which is worth a read.

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2 minutes ago, Jonathon Gillham said:

My friend has a gas one and gave up on it, now just uses it to shrink heat shrink.

My wife’s hairdryer is my go to now for heat shrinking. More so when I remember to put the heat shrink on BEFORE soldering 🙄

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3 minutes ago, Re-Bugged said:

My wife’s hairdryer is my go to now for heat shrinking. More so when I remember to put the heat shrink on BEFORE soldering 🙄

That is soul destroying (because I'm a rubbish solderer-er) when you realise you have to unsolder something because you forgot it. The other day I had to swap a bullet for a low profile one to fit in the car properly and it was actually ok, simce I have my new solder station. I would probably have bought a different car before that could take the bigger bullet!

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There are so many little things that effect soldering. it sounds like not enough heat in this case.

Even having a good iron will not always work,i have about 5 , from 5w upto 100w.

I have to judge the job size to iron. Then you have the cleaniness of work and a good tip tinning.

Soldering is a really black art

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I find my soldering results can go from no clean solder at all, to working but ugly, to functional and beautiful, with absolutely no appreciable reason why.  I just have good days and bad days, I suppose.

However, these are some things that I have learned over the years, and have massively helped:

For big things like motors and battery terminals, you need a high wattage iron.  It doesn't have to be expensive.  I have a cheap mains-powered 70W iron that is my go-to for this sort of stuff.  It takes a long time to heat up, so be patient and wait until it's properly scorching before starting or you'll get frustrated.  Trying to work with a cool iron (or underpowered iron) means you will spend longer working heat into your join, which gives more time for the heat to transfer into whatever you are soldering, so you risk damaging your expensive new ESC or melting your new Deans connectors before you've even started.

If your iron is dirty, solder won't flow.  I used to use a wet sponge but recently have discovered brass wool: this is abrasive enough to polish your iron tip but not enough to remove the hardened coating.  Using water will cool the tip of the iron and cause expansion/contraction issues which can crack the coating.

If solder wants to bead up and run off the tip, it is dirty.  If wool doesn't help, either replace the tip (they are cheap) or buy some tip tinner.  This is an acid paste that cleans the tip.  Apply the hot iron to it, then rub it off with the wool.  Solder should now flow onto it nicely.

If the tip is pitted, it's likely the coating has worn off and the mild steel underneath is oxidising.  The long-term fix is to replace the tip but you can use it in short bursts by repeated use of tip-tinner and wool.

Solder on the iron tip will oxidise quickly.  I always dip my iron in the brass wool to clean off the old solder before tinning it for every join.

Tin both the terminals and the wires with solder before you start.  You don't need much, just enough to encourage more solder to flow.

For things like motor and ESC terminals I use a flux pen before tinning.  It's like a felt tip but for flux.  The flux cleans the contact area and encourages the solder to flow where you want it to go.

Use a good set of helping hands (soldering clamps).  You can't solder if you're trying to hold the motor, wire, iron and solder at the same time.  Bear in mind the plastic insulation will soften when you apply heat to the wire, so the wire might move - I tend to clamp from a fair way up the wire to reduce this and stop the insulation melting through completely.  Position the clamps so the tinned wire is touching the tinned terminal.

Always solder with a wet tip.  Having solder on the wire and terminal isn't enough, the heat transfers faster through liquid.  Think of the difference between slapping your hand on a motorcycle exhaust header at 350*C or splashing your hand in a saucepan of water at 95*C.  One will have you going "ooh, that's hot" and the other one, well, just don't do it.  Touch the bulb of molten solder on your iron against the tinned wire.  It should melt fairly quickly.  If you watch the join closely, you'll see when the solder on the terminal melts.  You may need to feed in more solder to encourage it, but if the solder won't feed in you don't have enough heat - either wait longer or get a hotter iron.

Remove the solder before you remove the iron, or you may end up with the solder stuck to the join (which gives you a sharp edge that can poke through heatshrink).

If the wet solder wants to follow the iron when you remove it, you took a little too long to solder the join.  Flux in the solder should form a bubble around the solder that stops it from oxidising, however it burns off fairly quickly.  Once this happens, an oxidised skin forms on the outside, just like when you leave your custard out too long.  This skin stretches when you remove the iron and solidifies into an ugly spike.  Either learn to work quicker, or use more flux.

As soon as you're done, dip the tip into the brass wool to clean it, then add some fresh solder to the tip.  This will protect the tip while it's waiting for you to set up your next join.  Remember, this solder will oxidise, so clean it off with the wire wool and add fresh solder before starting again.

When you're completely finished, clean the tip in wire wool, then coat the tip in solder, then switch off the iron.  This will protect it while it cools and while it's in storage.

If you are soldering on an old surface, clean the old solder off first.  Use new solder to melt old solder.  A solder sucker is another useful bit of kit to suck wet solder off a join, revealing a (hopefully) clean terminal underneath.  Use flux before soldering the terminal again.

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19 minutes ago, Re-Bugged said:

My wife’s hairdryer is my go to now for heat shrinking. More so when I remember to put the heat shrink on BEFORE soldering 🙄

You too, huh..? :( 

25 minutes ago, Jonathon Gillham said:

My friend has a gas one and gave up on it, now just uses it to shrink heat shrink.

I have a 120W Iroda Solderpro gas iron and it's one of my fave pieces of kit.  It wasn't cheap - IIRC over £100 in the pack with the carry case - but I've had it well over a decade and only replaced the tips once.  On full blast it will do motor terminals with ease.  It also gets up to full temp in under a minute.  Unlike a mains iron, which stays switched on oxidising its tip throughout the session, the gas iron will go on and off as I need it.  Just recently my cheap 70W iron has stopped working (it's probably around 6 years old..?) so the Solderpro has done all my heavy-duty soldering.

Plus I can take it to the track - it's saved my skin a few times, especially at scale crawler meets which take place in the middle of nowhere with no electricity supply.

The exhaust port is great for heatshrink.

It has its drawbacks - the 'throttle' setting doesn't account for atmospheric conditions, so at full chat it will flood and spit and lose temp.  A little bit like a pilot finessing the mixture lever on this throttle quadrant, it's about finding the position where it gives max heat without flooding.  And just recently it's been a bit temperamental about starting, so maybe it's due a rebuild or replacement (most of it is rebuildable but the spark mechanism seems to be hidden inside the casing).  It also burns through its gas supply really quickly.  The box said something like "5 hours use per charge" but I doubt I would get more than 5 minutes continuous use at ESC terminal temps.

I also bought a mains solder station for lightweight stuff.  It's brilliant for discreet components like LEDs, resistors, capacitors etc.  Especially as LEDs and capacitors can be damaged by heat, I can set the temp so I can join quickly and get the badword out of Dodge.

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have you used solder flux?,  I see you have got a dremel gas iron, I have one to and I use that most of the time because it is really easy to solder thick wires and connectors with it, yesterday I soldered extension wires and connectors with it and it was an easy job with the dremel. 

I have a normal solder station to but I use that only for thinner wires now, because it is a pain to solder thick wires and connectors with it.

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Ok guys - thank you very much for all your advice and help.

I think the iron I've got is only 40W, so it might've been a bit under powered for motor wires. The Dremel gas iron would probably work better for this if it didn't have the vent hole (I guess it's for heatshrinking?) as the way it tightens up it was blasting hot air right at the ESC body which meant it was getting pretty hot :( I seriously hope it's still working ok :unsure:

I've bought some flux paste, brass wire and a 100W iron, so if this doesn't work at least I can blame better quality tools :P

Will give an update when I've tried again - thanks again everyone :) 

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5 hours ago, Re-Bugged said:

My wife’s hairdryer is my go to now for heat shrinking. More so when I remember to put the heat shrink on BEFORE soldering 🙄

There is a formulae for this.

[How good is the solder] x [Urgency to use] / X = [Likelihood of having put the heatshrink on]

Essentially the better the job you do and the urgency to use said job, the less likely you are to have put the heat shrink on .

 

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Pre-tin the wiring helps (pre-solder the wire tips first always) 600-900 degrees, a soldering tip at least the size of the wire AWG size, if i use silver solder it has to have flux, rosin core then no,

unless it's something larger. and putting more solder is not necessary,  higher heat =less time for heat build up down the line thus quicker soldering.

Gas soldering unless it's like the one Mad AX had,

for me is a no no unless it's copper pipe.

 

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My soldering improved dramatically when I bought some flux cored lead solder. The lead based solder melts far quicker and doesnt seem to clump into balls of silver rubbish over everything except the end of the wire like the lead free stuff did.

Im working on the basis that a few minutes of lead fumes twice a year at the most are probably not hurting me anymore compared to any of the other things in life that might. Its not like im in a sweatshop soldering pcbs for ten hours a day every day.

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22 minutes ago, Gazzalene said:

Regards the vid above.

I can not take anyone seriously who says "Soder"

That's how i say it. My dad taught me to solder when I was a very young lad. That's how he said it so it stuck. He's from Boston so there are plenty of words I pronounce wrong.

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1. Keep the tips clean.

2. Get better quality solder. Not all solders are created equal.

3. Flux - use it.

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Really helpful this thread, I’ve been procrastinating about soldering for years. 

Got the kit, no excuse now not to try it! 

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7 hours ago, Gazzalene said:

Regards the vid above.

I can not take anyone seriously who says "Soder"

lol... yeah, I've noticed some people from UK or Australia saying "Sol-der."  He even said that "I know a lot of people say 'Soder' but I say 'Sol-der,' so there."    

Living in US, I've never heard anybody saying "solder."  It was always "soder."  But it's weird.  Why is it like Salmon?  Even the US version of Webster says "So-der."  https://www.merriam-webster.com/dictionary/solder 

Looking up the origin...

It's from Latin; Solidaire; to make solid.  So it had L sound in it.  But more recently, it was from French, "Soudure," modern "Souder."  During Renaissance, people re-Latinized it to "Solder," but they kept pronounced it the French way.  So I guess people in US say it the spoken way, and people in UK say it the written way.  Who knew.  By definition, language has to go with the majority use, if more people pronounce L, I'll go with that too.  Either way, it is shorter than; "the whatchamacallit method of melting tin to put wires together."  At least it means the same thing.  

For Aussies, please be mindful of the word "thongs" when visiting USA.  Old ladies might have an heart attack if your child yells across the pool, "Dad, can I take your thongs? Jacob stole mine."  These are definitely not called 'thongs' in USA.  

y7q8nxP.jpg

=================================

 

Anyway...  

 

As many members experienced already, a weak soldering iron makes things difficult.  

But even a $12 soldering iron (60w) made me a decent enough of a solderer.  Also, don't heat it up to crazy temp, it could damage stuff.  

z1SAyCf.jpg

If you are going to solder more than a couple times a year, I would recommend getting a tip tinner.  I always tinned manually, but it's just so much easier to just dip it.  It prevents oxidation of the tip, so the tip stays sharp. Also, prepped for the next use.  This way, I get to be lazy without compromising anything.  

aYtKh8V.jpg

 

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6 hours ago, Grumpy pants said:

Really helpful this thread, I’ve been procrastinating about soldering for years. 

Got the kit, no excuse now not to try it! 

It’ll come in handy if your going LiPo to change those Tamiya plugs to XT60 or Deans 👍🏻. Welcome to the next chapter in your RC career 😉

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13 minutes ago, Juggular said:

If you are going to solder more than a couple times a year, I would recommend getting a tip tinner.  I always tinned manually, but it's just so much easier to just dip it.  It prevents oxidation of the tip, so the tip stays sharp. Also, prepped for the next use.  This way, I get to be lazy without compromising anything.  

aYtKh8V.jpg

 

Wow didn’t know that was a thing 👍🏻

Brilliant. 
 

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14 hours ago, Gazzalene said:

I can not take anyone seriously who says "Soder"

Especially when they mean "braze"

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8 hours ago, Juggular said:

lol... yeah, I've noticed some people from UK or Australia saying "Sol-der."  He even said that "I know a lot of people say 'Soder' but I say 'Sol-der,' so there."    

Living in US, I've never heard anybody saying "solder."  It was always "soder."  But it's weird.  Why is it like Salmon?  Even the US version of Webster says "So-der."  https://www.merriam-webster.com/dictionary/solder 

Looking up the origin...

It's from Latin; Solidaire; to make solid.  So it had L sound in it.  But more recently, it was from French, "Soudure," modern "Souder."  During Renaissance, people re-Latinized it to "Solder," but they kept pronounced it the French way.  So I guess people in US say it the spoken way, and people in UK say it the written way.  Who knew.  By definition, language has to go with the majority use, if more people pronounce L, I'll go with that too.  Either way, it is shorter than; "the whatchamacallit method of melting tin to put wires together."  At least it means the same thing.  

For Aussies, please be mindful of the word "thongs" when visiting USA.  Old ladies might have an heart attack if your child yells across the pool, "Dad, can I take your thongs? Jacob stole mine."  These are definitely not called 'thongs' in USA.  

y7q8nxP.jpg

================================

 

A G-string is still a G-string though - so if you hear Jacob stole someones G-String, you have some problems ahead.....

If you find this sort of thing interesting (the English language - not items of underwear) I can highly recommend Bill Bryson's 'Mother Tongue.' I have to say I had never appreciated quite what a tough job people learning English as a second language have when there are so many inconsistencies in it. 

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