R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Radio and Electronics

Like Tree6Likes
Reply
 
Thread Tools Search this Thread
Old 12-21-2009, 11:06 AM   #46
Tech Fanatic
 
Hide's Avatar
 
Join Date: Sep 2007
Location: London
Posts: 931
Trader Rating: 8 (100%+)
Default

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.
__________________
Losi 8ight-E 2.0, LRP Shark, Xray M18T custom extended, Traxxas VXL Revo
Hide is offline   Reply With Quote
Old 12-21-2009, 12:25 PM   #47
Tech Regular
 
marine6680's Avatar
 
Join Date: Feb 2009
Posts: 465
Trader Rating: 2 (100%+)
Default

Quote:
Originally Posted by Imbuter2000 View Post
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
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.
marine6680 is offline   Reply With Quote
Old 12-21-2009, 12:36 PM   #48
Suspended
 
Join Date: Oct 2009
Location: FLA
Posts: 415
Trader Rating: 2 (75%+)
Default

Quote:
Originally Posted by Imbuter2000 View Post
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?

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
justanotherdude is offline   Reply With Quote
Old 12-21-2009, 12:44 PM   #49
Tech Regular
 
marine6680's Avatar
 
Join Date: Feb 2009
Posts: 465
Trader Rating: 2 (100%+)
Default

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.
marine6680 is offline   Reply With Quote
Old 12-21-2009, 12:49 PM   #50
Tech Regular
 
marine6680's Avatar
 
Join Date: Feb 2009
Posts: 465
Trader Rating: 2 (100%+)
Default

Quote:
Originally Posted by justanotherdude View Post
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
marine6680 is offline   Reply With Quote
Old 12-21-2009, 03:14 PM   #51
Tech Initiate
 
Join Date: Dec 2009
Posts: 33
Default

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?
Imbuter2000 is offline   Reply With Quote
Old 12-21-2009, 03:47 PM   #52
Tech Regular
 
bluechucky's Avatar
 
Join Date: Aug 2009
Posts: 453
Trader Rating: 4 (100%+)
Default

marine, could you please elaborate on the "bird-caging" term? Never heard of it.
bluechucky is offline   Reply With Quote
Old 12-21-2009, 07:37 PM   #53
Tech Regular
 
marine6680's Avatar
 
Join Date: Feb 2009
Posts: 465
Trader Rating: 2 (100%+)
Default

Quote:
Originally Posted by Imbuter2000 View Post
How can that non conductive flsolderux 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?
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.

Quote:
Originally Posted by bluechucky View Post
marine, could you please elaborate on the "bird-caging" term? Never heard of it.
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.
Attached Thumbnails
How to solder correctly (a not so brief lesson)-solder.jpg  
marine6680 is offline   Reply With Quote
Old 12-21-2009, 08:03 PM   #54
Tech Regular
 
marine6680's Avatar
 
Join Date: Feb 2009
Posts: 465
Trader Rating: 2 (100%+)
Default

Quote:
Originally Posted by Hide View Post
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.
I missed your post in amidst the others... sorry about that... now for a reply

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.
marine6680 is offline   Reply With Quote
Old 12-22-2009, 06:04 AM   #55
Tech Champion
 
whitrzac's Avatar
 
Join Date: May 2008
Location: WI
Posts: 5,750
Trader Rating: 96 (100%+)
Default

how do you get the tip out of a soldering iron after they have fused together??
whitrzac is offline   Reply With Quote
Old 12-22-2009, 07:06 AM   #56
Tech Initiate
 
Join Date: Dec 2009
Posts: 33
Default

Quote:
Originally Posted by marine6680 View Post
Flux can not mix with metal, there will never be a mixture of flux and solder.
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.

Quote:
Originally Posted by marine6680 View Post
There is a reason why solders come with flux cores, flux is good.
...but solder comes with 0%, 1.1%, 2.2% or 3.3%... so why?
Imbuter2000 is offline   Reply With Quote
Old 12-22-2009, 12:47 PM   #57
Tech Regular
 
marine6680's Avatar
 
Join Date: Feb 2009
Posts: 465
Trader Rating: 2 (100%+)
Default

Quote:
Originally Posted by whitrzac View Post
how do you get the tip out of a soldering iron after they have fused together??
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)

Quote:
Originally Posted by Imbuter2000 View Post
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.
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.
Attached Thumbnails
How to solder correctly (a not so brief lesson)-solder.jpg  
marine6680 is offline   Reply With Quote
Old 12-22-2009, 02:00 PM   #58
Tech Initiate
 
Join Date: Dec 2009
Posts: 33
Default

Quote:
Originally Posted by marine6680 View Post
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?
Imbuter2000 is offline   Reply With Quote
Old 12-22-2009, 02:36 PM   #59
Tech Champion
 
whitrzac's Avatar
 
Join Date: May 2008
Location: WI
Posts: 5,750
Trader Rating: 96 (100%+)
Default

Quote:
Originally Posted by marine6680 View Post
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)
its a cheap one that I keep in my track bag....
whitrzac is offline   Reply With Quote
Old 12-22-2009, 02:51 PM   #60
Tech Initiate
 
Join Date: Dec 2009
Posts: 33
Default

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?
Imbuter2000 is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
Some rules for soldering marine6680 Rookie Zone 15 12-21-2014 10:48 PM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 04:51 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net