What solder do you use?

[Gordo]

Just wonder what electrical solder is the best to use, silver bearing, 60/40 lead bearing. I have silver bearing and it just seems a SOB to solder 8 wire with.

 

[djrahbee]

I use this and seems to be good.

 

[RC-Dude]

With silver you need lots of heat. Like 400+ deg Celsius. And 50 Watts is not enough. If silver is soldered well it looks like lead solder that is broken. There is a real danger of damaging lipos when you use silver and don't have enough heat and you need time to get the solder hot.

 

[djrahbee]

you need lots of heat.

Yup!

 

[Gordo]

That's what I thought, I just received my onyx 4s 6500 lipos and have to solder my connectors on and did purchase some 60/40 solder, I think it will work out a lot better. I've been a plumber since 1985 and solder probably over a million joints but I struggle with soldering wire, go figure. Never f-ed with rc wiring because I always had gas vehicles but since I got my felony and limitless it's been no stop connectors. Thanks

 

[Diem Turner]

Best solder, imho, is Kester 63/37 leaded solder. 63/37 has a distinct advantage over 60/40 due to its non-eutectic properties. What that means, in real world use is, when using 60/40 the solder joint needs to remain absolutely still during crystallization of the solder once heat is removed, otherwise you run the risk of producing cold solder joints. 63/37 does not incur this penalty and can be moved right up until the moment of crystallization without issue. Other than that they're very similar in terms of melting point (I believe 63/37 is a couple of degrees lower than 60/40 if memory serves) and how it flows.

 

[Mikeeeeeeeeeeeeeeeal]

 

[RC-Dude]

Totally back to 60/40 lead. Tried different silver brands. Not for me.

 

[slick2500]

Best solder, imho, is Kester 63/37 leaded solder. 63/37 has a distinct advantage over 60/40 due to its non-eutectic properties. What that means, in real world use is, when using 60/40 the solder joint needs to remain absolutely still during crystallization of the solder once heat is removed, otherwise you run the risk of producing cold solder joints. 63/37 does not incur this penalty and can be moved right up until the moment of crystallization without issue. Other than that they're very similar in terms of melting point (I believe 63/37 is a couple of degrees lower than 60/40 if memory serves) and how it flows.
View attachment 301610

I think it was @Notorious J that had issues with this melting on his speed run cars. He said he switched to silver and hasn't had a problem since. I could be thinking of someone else though so don't quote me on that.

 

[razorrc]

Best solder, imho, is Kester 63/37 leaded solder.

100%. 63/37 0.8mm rosin core will have you soldering like a pro.

 

[Diem Turner]

I think it was @Notorious J that had issues with this melting on his speed run cars. He said he switched to silver and hasn't had a problem since. I could be thinking of someone else though so don't quote me on that.

At some point in the future I plan on re-doing all of my power connectors and replacing all of the QS8 with 8mm bullets and using 50-55% silver solder for better conductivity. I haven't had any issues with melting solder despite 500-600A pulls, though I can't rule out that it won't happen at some point. FWIW, I'm pretty strict on just making single passes and then heading back to home base so that might be a factor.

 

[Cereal_killer]

Best solder, imho, is Kester 63/37 leaded solder. 63/37 has a distinct advantage over 60/40 due to its non-eutectic properties. What that means, in real world use is, when using 60/40 the solder joint needs to remain absolutely still during crystallization of the solder once heat is removed, otherwise you run the risk of producing cold solder joints. 63/37 does not incur this penalty and can be moved right up until the moment of crystallization without issue. Other than that they're very similar in terms of melting point (I believe 63/37 is a couple of degrees lower than 60/40 if memory serves) and how it flows.
View attachment 301610

what I have been using!

 

[kreeg]

Best solder, imho, is Kester 63/37 leaded solder. 63/37 has a distinct advantage over 60/40 due to its non-eutectic properties. What that means, in real world use is, when using 60/40 the solder joint needs to remain absolutely still during crystallization of the solder once heat is removed, otherwise you run the risk of producing cold solder joints. 63/37 does not incur this penalty and can be moved right up until the moment of crystallization without issue. Other than that they're very similar in terms of melting point (I believe 63/37 is a couple of degrees lower than 60/40 if memory serves) and how it flows.
View attachment 301610

Thanks for the info. I just ran out of solder and needed to order more.

 

[Avyn Nix]

60/40 rosin core solders is the best I’ve found i solder at 850 degrees.

 

[Diem Turner]

60/40 rosin core solders is the best I’ve found i solder at 850 degrees.

63/37(I always assume rosin core solder so I don't state this explicitly every time) is better because it doesn't have the potential to produce cold solder joints if moved during cooling/crystallization. 60/40 will do the job too, of course, but 63/37 is easier to work with and a lot more forgiving. Use whichever suits your fancy, it's just a well intentioned tip from one RCer to another.

 

[RC-Dude]

replacing all of the QS8 with 8mm bullets

You might want to consider hammering the bullets out of the QS8 and you have the 8mm that way. I also cut the QS8 plastic in the middle between the connectors to make them connect easier.

Soldering AWG 12 or 10 with silver does take some time and the electronics get dangerously hot. I've had silver connections become loose when I used a 45 Watt soldering device and it took a while to get everything melted. Hard to see if a joint is well done or not. With 60/40 lead you can see if the solder joint is not OK, i.e. a cold solder joint. It's just frosted / dull.

Difficult to see with silver as the joint might be liquid at the surface but not melted next right in to the wire. The only workaround I am aware of is to have a very hot soldering device and see the solder melt when applying to the wires. Like little portions of silver added after each other. With lead you just add heat and know it's hot when the lead starts dripping out at the bottom. You do that with silver it forms a lump in a splitsecond, you can't work it up again and you start over again. Does take some practice.

I find the main difference between soldering lead and silver is that you need to apply the silver in layers where you can just melt the whole soldering area with lead. With silver you sometimes have to add some more wire to make the existing material on the soldering joint melt again. You add over 400 deg Celsius and it won't melt unless you add more wire / flux in the wire. Soldering grease just melts and drops at those temperatures and creates a mess. Just applying the soldering device at high temperature is too much heat for connectors and ESC. The capacitors on the ESC should not be above 135 deg Celcius to not be somewhat damaged. The wires bring just so much heat away from the soldering joint when using the high temperatures silver needs.

If one of the three wires going from ESC to motor has a bad solder joint and it melts as the real connecting surface area is too small - the ESC almost instantly fries as the energy has no where else to go. Seems to me that melting solder joints are the result of too little connecting area having to take too much Amperage. That is the real danger of silver - not soldering hot enough, creating a cold joint and not beeing able to see it right away.

 

[Diem Turner]

You might want to consider hammering the bullets out of the QS8 and you have the 8mm that way. I also cut the QS8 plastic in the middle between the connectors to make them connect easier.

Soldering AWG 12 or 10 with silver does take some time and the electronics get dangerously hot. I've had silver connections become loose when I used a 45 Watt soldering device and it took a while to get everything melted. Hard to see if a joint is well done or not. With 60/40 lead you can see if the solder joint is not OK, i.e. a cold solder joint. It's just frosted / dull.

Difficult to see with silver as the joint might be liquid at the surface but not melted next right in to the wire. The only workaround I am aware of is to have a very hot soldering device and see the solder melt when applying to the wires. Like little portions of silver added after each other. With lead you just add heat and know it's hot when the lead starts dripping out at the bottom. You do that with silver it forms a lump in a splitsecond, you can't work it up again and you start over again. Does take some practice.

I find the main difference between soldering lead and silver is that you need to apply the silver in layers where you can just melt the whole soldering area with lead. With silver you sometimes have to add some more wire to make the existing material on the soldering joint melt again. You add over 400 deg Celsius and it won't melt unless you add more wire / flux in the wire. Soldering grease just melts and drops at those temperatures and creates a mess. Just applying the soldering device at high temperature is too much heat for connectors and ESC. The capacitors on the ESC should not be above 135 deg Celcius to not be somewhat damaged. The wires bring just so much heat away from the soldering joint when using the high temperatures silver needs.

If one of the three wires going from ESC to motor has a bad solder joint and it melts as the real connecting surface area is too small - the ESC almost instantly fries as the energy has no where else to go. Seems to me that melting solder joints are the result of too little connecting area having to take too much Amperage. That is the real danger of silver - not soldering hot enough, creating a cold joint and not beeing able to see it right away.

Oh I fully intend to remove the connectors from the QS8s to use as bullets. They're much longer than all other bullets giving them superior contact surface area and it would be an awful waste of all of the QS8s I have between all of my batteries, chargers, etc. The wire is all 8AWG though I'm considering going the extra step and swapping everything over to 7AWG on all my batteries. I have some ONYX packs that came standard with 7AWG and I have to admit, I find that bit of extra meat on the bone appealing.

I won't be using a soldering iron as silver isn't fully liquid until about 630-650°C (depending on silver content) and my soldering iron "only" goes to 500°C and you don't really see soldering irons that go much higher than that (if at all). Normal soldering flux/grease/paste is of little to no use at those temperatures as it just vaporizes and isn't really intended for use with silver. I'm going to use a propane torch to achieve adequate temperatures of the connector, flux the connector and begin to boil off the water content adding the wire to the cup relatively late so that I'm just heating the last cm or two and not giving it a whole lot of time to travel to the other end and then hit it with the silver, flow it out briefly so that it wets the wire fully and done. That's my plan of attack anyways. I'll be doing some test fittings before moving on to the "live" objects to work on my timing because, as you rightly point out, I don't want to cook the crap out of the caps and other components on the ESC. I'm probably going to use SSF-6 rods and lean on the techniques used in this video. I appreciate the heads up though.

 

[djrahbee]

I use this and seems to be good.
View attachment 301600

@Diem Turner Went to look for some of the 63/37 and it's on backorder, so it must be popular

 

[Diem Turner]

@Diem Turner Went to look for some of the 63/37 and it's on backorder, so it must be popular
View attachment 301924

Don't make it so complicated

These are 1lb. spools. Depending on how much you solder it'll last you anywhere from 1-5 years (possibly even up to 10 years if you only solder on occasion). Kester is among the best (some would argue it is the best and I would have nothing to rebut if someone did state as much) solder. You'll never use anything else again and wonder how you ever put up with lead-free solder (if you've ever had the aneurism inducing displeasure of using that accursed garbage). Don't get me started on how much I hate lead-free solder...we'll be here 'til the new year.

Kester 63/37 Ø = 0.031" https://amz.run/6ie2
Kester 63/37 Ø = 0.040" https://amz.run/6ie6

These are probably the most useful gauges for soldering RC related stuff so, take your pick. I like the 0.040" personally, it helps shorten the lengths of solder needed when filling the cups of QS8 connectors, but that's just me. YMMV.

 

[MAVERICK@2]

I use this for the rc hobby and at work almost daily. I personally prefer having a small diameter like 0.6mm due to it melts quickly
Also adding flux to the wiring helps a lot