Soldering big connectors

[Raptorapture]

Originally Posted by smsodhi

Just wondering...is all 63/37 solder eutectic? or do we have to look specifically for a eutectic 63/37 solder. Would you recommend to get one with a rosin solder core, for the solder to be used for the iron, not the pot?

Sorry for these basic questions. Thanks

Pretty sure not so. I'll double check later but I'm pretty sure mine has a flux core. Most likely the bar is the differentiator without flux vs a spool.

[Ace Dude]

Originally Posted by smsodhi

Just wondering...is all 63/37 solder eutectic? or do we have to look specifically for a eutectic 63/37 solder. Would you recommend to get one with a rosin solder core, for the solder to be used for the iron, not the pot?

Sorry for these basic questions. Thanks

Eutectic means that for certain ratios of the alloy (tin/lead/etc.) the solder melts at a single temperature rather than a range. As a result it goes through the pasty state and solidifies very quickly compared to non-eutectic solders. There are other ratios besides 63/37 that are considered eutectic solder, but for our application 63/37 is the most popular. Because of this, all 63/37 would be considered eutectic.

I use rosin core solder, Kester #44 63/37, for all my electronics soldering. You don't want to solder without rosin core solder here.

The only place I use solder w/o rosin is in the solder pot itself. However, when tinning wires with the solder pot you still have to apply a tiny amount of rosin to the very end of the wire (there are a few tricks to using a solder pot too). I use liquid rosin here. Without rosin the solder will not bond to the wire. If you can find it, you can use non-rosin core wire solder in the solder pot. Might be easier than dealing with bar solder too. Depends on the sire of the solder pot. I got a very small one just for tinning wires.

I don't want to hijack this thread. We can move this soldering discussion to a new thread if folks would prefer.

[smsodhi]

Thank you for clearing this up, I am sure many others have benefited from this discussion and your knowledge too.
This thread is a general discussion thread, all sorts get discussed in here.

[smsodhi]

Originally Posted by Ace Dude

I prefer to insert the tinned wire into a tinned bullet connector and have the wire held in place with a jig. It's important that the wire is in contact with the edge of the bullet connector to get the lowest resistance connection possible. I also make sure the wire is fully seated in the bottom of the bullet connector as well. Then I heat the bullet connector with a soldering iron and feed in solder until the bullet connector is full. I like to have the wire held in place with a jig while soldering because if the wire is not held perfectly still during the soldering process you can end up with a disturbed joint.

I was rereading the posts and was wondering about the statements in bold. "A tinned bullet connector". What I think off as a tinned bullet connector is putting some solder into the base of the connector filling by about 1/3. By doing this you cannot place the tinned wire on the bottom of the bullet.

Originally Posted by Ace Dude

Also, get some wide (e.g., 5mm+) rosin desoldering wick. You can use this to tin the bullet connector as well as remove the solder from the bullet connector to practice on the same connector over and over again (that's what I did).

Now after reading this am I correct in understanding that you put some solder into the base of the bullet, then remove it using the desoldering wick, leaving an empty bullet with solder lining the sides and base, now you can place the tinned wire on the base, have it touch the whole side of the bullet. Heat up and feed in solder to fill.

[Ace Dude]

A friend who is certified to solder for NASA explained that's the way they're required to do it. Completely fill the cup with solder and then remove all the solder using desoldering wick. Now you have a perfectly tinned bullet connector. After doing it that way I will say it's a pain. It takes some time and a lot of desoldering wick to remove all that solder from a big 6.5mm bullet connector, hence the recommendation to use the largest desoldering wick you can find. I cleaned the inside of the bullet using IPA and added a drop of liquid rosin flux to the connector before starting the process.

Whether it's absolutely necessary or not I can't say, but if it's good enough NASA I'll heed their advice.

[jimsair]

Originally Posted by Ace Dude

A friend who is certified to solder for NASA explained that's the way they're required to do it. Completely fill the cup with solder and then remove all the solder using desoldering wick. Now you have a perfectly tinned bullet connector. After doing it that way I will say it's a pain. It takes some time and a lot of desoldering wick to remove all that solder from a big 6.5mm bullet connector, hence the recommendation to use the largest desoldering wick you can find. I cleaned the inside of the bullet using IPA and added a drop of liquid rosin flux to the connector before starting the process.

Whether it's absolutely necessary or not I can't say, but if it's good enough NASA I'll heed their advice.

I tin the bullets as well. But instead of using a solder wick to remove the excess solder, I use a solder sucker. Much quicker. Probably not NASA approved, but i only go up a few hundred feet..... not into orbit The whole point of tinning is to form a solid molecular bond between the solder and the the wire or bullet material.

[Raptorapture]

Man, you guys are thorough. Interested in your feedback on the following procedure:

1. Place bullet connector in socket drilled out of wooden base (home made jig) sized to allow only the contacting portion to enter.
2. Wipe gel like flux all around inside of soldering portion of connector, using liberal amount but removing major excess.
3. Strip or cut wire to have exposed length equal to depth of connector plus 1-2mm.
4. Apply gel like flux to wire, ensuring fully coated but removing any excess.
5. Tin soldering tip
6. Tin wire ensuring ensuring all portion to be immersed is covered yet not wicked past exposed portion.
7. Apply heat to connector while filling with solder to the point it will not overflow once wire inserted.
8. Insert wire using a fixable arm into bullet while applying heat to bullet ensuring wire contacts and remains in contact with bottom of connector adding solder if necessary
9. Remove heat once wire starts wicking solder
10. Let cool while ensuring wire continues to remain immobile in place contacting connector
11. Apply additional solder if connector not fully filled or contact with wire is not conical while applying heat to both connector and wire.

The goal is to ensure the bonding with both connector and wire is demonstrated as strong via the shape of the edge of contact with both. Challenges that I have are whether I should let connector cool and reheat before inserting wire? Depending how quick I am, it does cool sometimes to the point no longer liquid. Is this considered a form of tinning since a bond is created and is it necessary to cool since it will anyway? Answering my own question, I can see that by removing the excess solder from the connector, the remaining portion will only stay if bonded demonstrating success in that regard. But I'd rather not do the NASA thing if not necessary. The next question is how poor is it to add solder post some cooling to complete or ensure outer contact points are good? Lastly, when and if contact is necessary between iron and wire before final removal of heat from connector? The trouble being that the connector needs more heat than the wire so the earlier there is contact with the wire the more it wicks. It appears to be a balancing act to get the right amount of heat to each surface where they require differing amounts. Additionally, even if that were achieved, I have trouble placing the wire, adding additional solder and applying heat to both connector and bullet once wire is inserted all at the same time. I think I need some more appendages or maybe a robot

Finally, one portion of the procedure that bothers me is the need for the solder to contact the iron to run in the connector. Should it not by virtue of heat and flux be able to become liquid with direct contact with iron. I believe I have achieved this in the past when soldering electronics. Additionally there is always some excess to clear if too much on outer edge of connector as the iron, seriously big, does not fit inside connector.

Apologies for the lengthy post on what should be a simple procedure but this has been bothering me for a while and I have been fortunate enough not to suffer a cold or broken joint but wish to increase my confidence in that continuing and take any necessary steps. Thanks for reading.

[Ace Dude]

If you want to use the heat and insert method this video from JR demonstrates that process well.

Master the secrets of soldering! (8 min 24 sec)

[Raptorapture]

Cool! Pretty much the way I used to do it until my fingers got blisters
Anyway, looks like my issue is size of chisel being too great to fit in bullet connector to get solder to flow from the inside as well as being able to stay around in there during insertion of wire to contact both. Thanks.

[Ace Dude]

I have the same issue so I've only been heating the connector from the outside with the chisel tip.

[Steve_JR]

Anything and everything you could ever want to know about soldering. Watch the entire series, you will learn a lot!

Basic Soldering Lesson 3 - "Cup Terminals" (4 min 20 sec)

[Ace Dude]

The Pace series is excellent, I watched them quite a few times. Those cup terminals must be quite small since they can solder them so quickly in the video. My Elmer informed me has a resistance soldering station. Plan to try it someday to see how well it works.

[smsodhi]

This is a nice one on tinning the cup

Lead Free Gold Cup Preparation | B.E.S.T Corporation (5 min 30 sec)

[Luvmyhelis]

Originally Posted by smsodhi

This is a nice one on tinning the cup

Lead Free Gold Cup Preparation | B.E.S.T Corporation - YouTube

Good stuff guys, I have seen most of these. Great info!

[Ace Dude]

In addition to the Pace series posted above, I found these helpful while studying and practicing.

*EXPERT LEVEL* Soldering Tutorial #2 TTC Avionics (3 min 8 sec)

*EXPERT LEVEL* Soldering Tutorial #4 TTC Avionics (10 min 46 sec)

[crash at 42]

Hey guys lots of info but lots of aspirin.
Just my $.02 but if your like me and buying your solder from a home depot big box store the solder is 60/40 lead silver rosin (flux impregnated). Solder travels to the heat so heat the lower portion of the cup (I use a torch) you can control the heat by waving the flame from direct to indirect. To much heat is no good but its a feel between liquid solder and flaming. Melt enough solder in to cup (1/2 full) and its ok to let cool just heat cup enough to melt the solder you need. Reheat and Lower the wire slooooowly into the cup maintain your heat waving the flame on the off the cup directly until wire is fully seated, remove heat and allow to cool (10 seconds) you can actually see it change. Voila done takes about 2 minutes. I've seen many joints fail and ALL where done with a solder iron most likely caused by low heat.
Remember the solder travels to the heat so heat at the BOTTOM.
Note this is for large bullet type connectors we use between batts and esc. I let my buddy whos great with an iron for small 20awg wire connections
Rich

[Luvmyhelis]

Originally Posted by crash at 42

Hey guys lots of info but lots of aspirin.
Just my $.02 but if your like me and buying your solder from a home depot big box store the solder is 60/40 lead silver rosin (flux impregnated). Solder travels to the heat so heat the lower portion of the cup (I use a torch) you can control the heat by waving the flame from direct to indirect. To much heat is no good but its a feel between liquid solder and flaming. Melt enough solder in to cup (1/2 full) and its ok to let cool just heat cup enough to melt the solder you need. Reheat and Lower the wire slooooowly into the cup maintain your heat waving the flame on the off the cup directly until wire is fully seated, remove heat and allow to cool (10 seconds) you can actually see it change. Voila done takes about 2 minutes. I've seen many joints fail and ALL where done with a solder iron most likely caused by low heat.
Remember the solder travels to the heat so heat at the BOTTOM.
Note this is for large bullet type connectors we use between batts and esc. I let my buddy whos great with an iron for small 20awg wire connections
Rich

I love it! best description about all this is hidden in the middle of this post. "Its a feel".

Good equipment, good technique, and practice till you get it is what I am seeing come together in this discussion. There is some serious talent represented with this group!

[smsodhi]

Originally Posted by Luvmyhelis

Good equipment, good technique, and practice till you get it is what I am seeing come together in this discussion.

100% agree..I have received my new Weller Station today and I have been practicing today. Over 20 connectors done ..over and over. Starting to get a feel for tinning the wire now, using just enough to tip the end of the wire. Also getting a feel for the amount of solder to put in the cup and the technique for placing the wire in the cup and holding against the back wall. I am starting to get a concave fillet as per the videos, only in the last couple of attempts. So progress is there. I am starting to get better control with wicking now. As for tinning the cup, I put solder in and then hold the connector with a pair of pliers and shake it off in a box. OK, I know health and safety.... much quicker and good results.

I am using the butane torch to heat the connector, this gives good heat and keeps the solder molten when I put the wire in. I am waiting to get the 37/63 solder to see how this performs in comparison to what I have. I dont think I have been using a good quality solder so far.
I have learned quite a bit now and have a new found respect for soldering, I may actually start to enjoy it....

[Raptorapture]

I have been tempted to add a torch to the mix. Especially after reading about making sure the bottom of the cup is hottest which makes a lot of sense to avoid a cold solder joint where you can't see it. It is the one location that is furthest away from an iron and most difficult to heat. Did you also tin the bullet with the torch?

[Ace Dude]

I tried a Butane Mirco-Torch but decided to stick with the iron. With the torch you need to be careful you don't overheat the solder/connector as too much heat can ruin the connector/joint as well. The butane torch can reach ~2,500F+ while a good temperature controlled iron is good for ~800-1,000F max.