1000 thanks Marine!
I just read all this thread and learned many things from you.

Here are my comments and questions:

- I read that the rosin in the Kester 44 is "non-conductive".
Maybe all rosins are non-conductive or mildly conductive... but, isn't it bad for our application? Isn't its electric resistance an issue? Isn't it better to avoid, if unnecessary, the use of rosin flux because of this?
I know that some rosin evaporates with the heat of soldering but what about the residue?

- Kester states that "Flux cored solder wire has a limited shelf life determined by the alloy used in the wire. For alloys containing > 70% lead, the shelf life is two years from date of manufacture. Other alloys have a shelf life of three years from date of manufacture". What happens after these 3 years? and how can we be sure to buy recent solder wire? where do you suggest to buy it online to be sure that it's recent?
I live in Europe and tin/lead wire is forbidden here therefore I must find a trustable source online extra-UE.

- I would suggest to add more videos

- I read that RMA means "rosin mildly activated" while you wrote "rosin medium activated"

Yes, flux can leave residue, plus any that drips will still be around, that is why you must clean after you solder. There are downsides to flux, and that is that you need to clean connections after you solder, because it can corrode or cause some shorting. The benefits are worth the extra time. Besides, if you use cored solder, you will still have flux residue left over, and non-cored solder will not flow without adding flux.

Shelf life, metals corrode over time, and flux speeds the process. The corrosion makes the solder not flow as well. It will still work for years on end, but will not be as easy to use as fresh. Just seal any extra up in an airtight container and you can even throw in some moisture absorbing material to make it last for practically forever. I have some that is near 10 years old that was factory sealed in plastic, it still works great.

I usually get my solder from work... :lol: so as for a an online source, I can't help you. I would try to find an online electronics supply site, one with a contact email that you can ask questions through. I also suggest getting 63/37 solder.

Yeah the lead free crap over there sucks, a mandatory electronic recycle law would be better for all I think. Less lead in the landfills and better quality connections in the products.

I will see if I can find some more good videos, If I get time, I may make my own. It may take a while though.

RMA, it can be said either way, its the same thing in the long run. :D

I absolutely love this thread. I wish there were more informative threads like this about other aspects of RC racing.

A big thank you marine! :nod:

I suggest a video clip is just good enough for beginners. As many will be blur when reading the texts.

I read that the rosin in the Kester 44 is "non-conductive".
Maybe all rosins are non-conductive or mildly conductive... but, isn't it bad for our application? Isn't its electric resistance an issue? Isn't it better to avoid, if unnecessary, the use of added rosin flux because of this?
Afterall in the video of the Tekin RX8 he solders easiliy without added flux.
I know that some rosin evaporates with the heat of soldering but what about the residue that remain mixed in the alloy or, even worse, between the alloy and the connector, that cannot be cleaned?

I tried to post the link to the video where Traxxas shows how to solder Traxxas connectors but this forum don't let me post URLs because I'm don't have enough posts...

Funny, when I was taught to solder this was the exact method that was taught. It has served me very well with everything I have needed to solder.

One problem now seems to be availability of lead solder. Here you cannot find lead solder in shops. I have had to use silver solder and it is ok to work with. Requires a hotter tip though. Doesn't always provide nice joints either. I need to order my 63/37 solder online.

Flux is acidic, (this is where the RMA comes in, it is mildy/medium acidic) and it removes the impuritys and oxide layers from metal when heated. That helps the solder flow better and stick to (wet) the joint. Solder actually forms a metallurgical bond with the metal, so flux can not "mix" in the solder. This means that there will be less resistance in the connection due to a better bond.

I have seen people try to solder on old equipment and the corrosion being really bad and the solder not sticking well if at all. The solder would stick to the wire but not the contact area. In that case there is a layer of flux between components, but its not the fault of the flux. It just means that the connection is very dirty/corroded and this is unlikely to happen on new components. The components I seen this happen on were off of helicopters built in the 70's.

If you glob on a big glob of solder, and make that a habit, that big blob can hide the bad connection underneath because you can not see it. That is why I said in the post that you only need a good fillet of solder flowing between the components. A good fillet also reduces resistance. I have seen many pics of guys cars on this forum where they do not glob on too much or use too little, but they do not have a good even solder fillet, or the wires look bird-caged (the wire stands are separating from each other like the bars of a cage) and that causes resistance as well.

In the video, he did not use flux, but he did pre-tin the wire and post, so the fresh solder on them helped the solder flow pretty well without flux. Pre-tinning helps prevent "bird-caging" as well. the strands of wire should be running smoothly just like they are in the un-stripped areas for the best connection. Also, high quality multi-core solder has quite a good bit of flux inside, and larger diameter solders have a good amount of flux as well.

You can buy a "flux pen" which is a felt tip pen that applies flux like an ink marker. They are far less messy, and work great on new components or well maintained/clean components. Just be careful not to bird-cage the wire when applying the flux for pre-tinning. You still must clean up after though. :lol:

nothing a little motor cleaner or electronics cleaner won't cure.

a little wipe with a treated rag, and nobody will know you used flux and they'll be asking you how you got your solder joints so smooth and professional looking

And also...

Thanks for the compliments and feedback guys. This forum has helped me out quite a few times, so I wanted to contribute where I can.

:lol:

Here is what I have in mind: img51.imageshack.us/img51/7204/screenshotjv.jpg (again unfortunately this forum doesn't allow me to show it as image because it says that I don't have enough posts...)

How can that non conductive flux residue, along with oxide and impurities that remain inside it, be an advantage in the electric conductivity of that?

how can you remove that residue if it remains between the tin and the bar, incorporated within the soldering?

marine, could you please elaborate on the "bird-caging" term? Never heard of it.

That example can never happen, (on new components) the only time I see something like that is when the component is VERY dirty, and the flux can not do its job. In those cases, the solder doesn't even begin to stick to the components and the wire would not make a connection and when you clean the sticky flux away it comes loose. Trust me, you WILL know if the wire is not connected. To get so much corrosion that you have that problem, you would need to soak the connector is salt water for months.

Flux can not mix with metal, there will never be a mixture of flux and solder. Flux will remove the oxides from the metal surface and leave fresh clean metal for the solder to stick to. The solder creates a molecular bond with the metal, that can not be separated again. When solder gets put on that shiny gold connector, it will forever remain silver looking, the solder will remain on there unless eroded away with something like sand paper. If you can see the solder flowing and sticking to the component, then you are fine. There is a reason why solders come with flux cores, flux is good.

Simply put: Flux will do its job and then get out of the way.

When the solder starts to stick to the component the flux will not get in the way. The molecular bond is much much stronger than the physical stickiness of the flux.

Bird-caging is when the individual wire strands of multi stranded wire (like that used in RC) separates from each other.

Take a piece of wire and strip an inch of insulation off the end, then twist the wire end the opposite way the strands are twisted together, they will start to separate and leave gaps between them, like the bars of a bird cage. It disturbs the natural "lay" of the wires and requires more solder to fill the gaps, this is a less efficient connection.

While solder is less conductive than copper, a solder connection (which is molecular) is far less restrictive than a mechanical type of connection. (crimp type like terminal lugs and splices or contact type like in battery/bullet connectors) Besides, the short distances we need the power to flow in an RC car means the difference in conductivity of different metals is not so important as it is in other areas, like power grids and precision equipment.

I missed your post in amidst the others... sorry about that... now for a reply :lol:

I find it funny that they have such a fit over lead solder, but still allow silver solder. One of the components of silver solder is just or more poisonous than lead.

how do you get the tip out of a soldering iron after they have fused together??

I still don't understand well a thing: where does all that flux (that you apply with the pen between the connector and the tin) go? does a layer of rosin (or a little residue of it) remain under the tin/lead? if not, why not and how can I be sure that it does not? I can't see under the tin/lead and I can't clean it if it's there.

...but solder comes with 0%, 1.1%, 2.2% or 3.3%... so why?

What kind of soldering iron is it? You can try to use a pair of pliers to remove the tip while the iron is still hot. If its a cheap iron, I would say just go get a new one, preferably a quality one with variable temp. (more than low and high)

The flux will float to the top of the solder. No flux will remain under the solder, as long as the solder is flowing and sticking to the components. I attached a picture to help. As long as the solder looks like the first two sections, then there is a connection. Too much solder, while not ideal, still makes a connection. What you are describing is De-wetting, that is when the solder does not stick to one or both components. In that case flux will remain in between the solder and component, but it is not caused by the flux. The flux is there simply because its available space to be in. If you have de-wetting, it will be obvious, and the components will pull apart easily. Like I said before, the only time that you would have that problem is with old components that are not clean and there is too much corrosion for the flux to remove. The parts would look discolored and obviously dirty/corroded before you even try to solder them. Unless you are trying to use battery connectors you found from 20 years ago or sitting in salt water for months, you have nothing to worry about with flux getting under the solder. It simply can not happen, If the solder is not sticking properly, then you have other issues, like oil, corrosion, or some coating preventing the solder from sticking.

Ok, this explanation reassures me, thanks Marine!

New question: why do you write "too much" solder in those examples in your drawing?
I thought that "too much" were only when it's too much between the post and the wire, but in the case of your two examples it's seem to me to have only the effect of fortifying the result. Am I wrong?

its a cheap one that I keep in my track bag....

I read on the page of "W.S. Deans Racing Silver Solder 1 oz." on Towerhobbies' site that "Silver or Gold plating requires a special solder. Ordinary solder causes a chemical reaction which will degrade the joint. Deans Racing Solder is 2% silver with high activity ProFlux. [...] The Best Solder for Silver and Gold Plated Surfaces."

Marketing or truth?

I'm glad to help.

Too much solder... More solder is not better for the connection, it does not make it stronger or electrically superior. Having too much solder can hide bad solder flow problems, is can also weaken the connection by having extra solder flowing into the un-stripped section of wire, making it break easier. Its best to use just enough solder to make a connection, it has less resistance and holds up better.

Well if you can not get it out with some pliers with the iron on high, you may need a new one.

Yes, gold dissolves and reacts to tin and lead. Silver has issues as well. The joints are far less strong than they should be.

But the issue is not a big problem because gold and silver plated electrical components are designed to be used in mechanical/contact type connections like plugs and bullet connections. This is because gold and silver do not corrode as easily, and the addition of electricity and two types of metals causes a lot of corrosion, the gold plating stops/slows that process. Any normal part designed for solder will not be gold plated. (at least the solder tab area) So don't worry about that, Gold and silver plated parts cost a lot more than normal ones, a set of deans plugs would cost near $10 instead of $4.

Silver solder is harder to use and is actually more poisonous than lead solder. To me, unless it is absolutely needed, its benifits are not worth its problems.

It also has a higher acidic flux, with is harsher on components and iron tips, meaning it is even more important to clean up after. In the real world, there is no such thing as No-clean flux.

Look at this new drawing: img707.imageshack.us/img707/5607/screenshotfg.jpg
Can we say that, once we obtained a successfully result like that on the left, adding solder to reach the result on the right adds mechanical resistence without decreasing electric resistence?

The question is: is Sn63Pb37 + RMA flux the best for gold and silver plated parts too?

By the way, I notice that some RC wires appears externally grey instead of reddish like copper. Why? what material are they done of?

No, that would not actually add any benefit. While, if the solder is flowing well, it would not be very bad, it is not better. So, if you get a little too much solder on the connection, there is no need to overly worry, it just is not needed. The standards for soldering have been developed for as long as soldering electronics has existed. It has been poked, prodded, and even x-rayed, to figure out the best combination of strength, resistance and reliability. The standards I was taught to use are for aviation and spaceflight, they are the toughest and strictest standards around, and the most reliable. While such strict standards are not needed in RC, striving to reach them is never a bad thing. So long as your connections are smooth you will be fine. The techniques I provided will help even novice solderers make reliable connections, even if they are not perfect.

No, lead solder is not ideal for gold or silver plated parts, but silver solder also has tin in it, and that is not good for plated parts as well. True gold/silver safe solders are not readily available and are harder to use and need higher heat. But like I said, plated parts are usually not designed for soldering. The parts that are plated are the parts designed for physical contact connections, like CPU sockets and PC board connections or High end audio/visual plugs. Deans plugs are not gold plated, or they are not listed as such. I will check up on that and the traxxas connectors. If they are, I would suspect that they are not plated at the solder area.

The thin plating on the connectors would not really cause much problems though. It takes a 5% concentration of gold in the solder to negatively impact the connection to any real degree. There is not all that much gold in the plating.

Some wire is coated in tin or other metal for corrosion resistance. Some is even silver coated, but that type is costly, and needs special solder or crimp type connections. Since the special solders are hard to get and use, and crimp type connectors are rare in RC the use of the silver coated wire is not needed or its benefits are negated by the use of improper solders and connectors.

I don't know about anyone else, but I would love to see you put a video on youtube!!! Please.

I will when I can, my Iron is burn out so I need a replacement. With the holidays its been low on the list of things to spend on. :lol:

Marine,
Any advice on soldering the tabs of Li-Poly batteries. I'm not sure what the tabs are made of but soldering them sux.

Unless they are copper tabs, you'll need zinc solder and a compatible zinc based flux and its corrosive. Be careful, the fumes are said to be toxic.

More solder does not make things better. If you are running on brushless modified motor.. Excess solder will melt causing short to motor & ESC. The wiring to the motor just melt & disconnects.

Hence when solder you need to ensure each every strand of the wires stick properly to the terminal with enough solder.

what are some iron's yall are using, besides the team checkpoint? I'm thinking about upgrading my single temp iron now that Im actually starting to use it some.

You mean the individual cell tabs?

If the tabs are large (contain a lot of metal/surface area) then they act like a heat sink and you need a very good iron and large tip to solder them well. You may also need to up the temp about 50*, no higher than 750* though.

The Checkpoint is just a re-branded Hakko. It is a good Iron, and I pick it over the actual Hakko because the graphics skin for it does not cover the temp markings. Weller makes some decent Irons for around the same price, but their quality ones, comparable to the Checkpoint and Hakko will cost around $150. The LPR station is thoroughly kick a** but is over kill for hobby use, it is basically a high end unit used for electronics repair, and you pay that high end price as well.

Thats a lot of amps!

If your solder connections are melting and coming apart when running the electronics you have other issues to worry about...

Personally I like the Lead Free Novak Silver Solder.

Try Kester 63/37 you'll change your tune and save a lot of $ too.;)

Thanks, I will give it a try. I have a feeling I will like it better than the Novak SS.

Yeah it takes a lot of amps to heat up solder connections that much.

Lead free sucks, and silver solders are more poisonous than the leaded stuff. 63/37 is the best solder you can use.

No doubt about it ;)



Yea I wasn't gonna say the over priced rc solders suck but you pretty much took the words outta my mouth on that one. :lol:

Excellent thread Jar Head...I thought I was decent at soldering but learned some good things in reading this that I will apply right now as I solder up my new ESC and motor!!! Thanks for taking the time to write this up.....Devil Dog!!!

Semper Fi!!!!

1st Mar Div

OORAH!

Hello again Marine!

Quick question... I can't seem to find my stash of "good" leaded solder...

So I think I'm gonna order some off Ebay...

I just wanted to verify that I'm getting the right stuff.

I realise it's a little thin, but I do work on electronics as well, so the small wire works better for that... I can twist it to double up the thickness in R/C applications.

I just need to verify that its the correct stuff..

http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWAX:IT

Unfortunately there is no right stuff on eBay. All have a D.O.M. (date of manifacture) older than 3 years or unknown.
This one has an (intentionally?) damaged D.O.M.