best solder

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Tommy Levescy

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Mar 29, 2014
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341
what is everyone using for high amperage setups? i keep desoldering 8mm bullets on 4s lol.
 

Martin Hamilton

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Mar 7, 2008
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Are you using 60/40 or 63/37 solder ? 63/37 flows better in the joint, 60/40 does not flow as good & can result in cold joints. 60/40 is best suited to plumbing.
 

Mike Hughes

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Feb 23, 2003
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First question, what do your solder joints look like after you are done. They should be smooth and shinny. If not, then there is not enough heat and flux being used. Second, what size bullets are you using? Some are having trouble with 5.5. Move up to 6 or 6.5.
Mike
 

Hydro Junkie

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8mm bullets are desoldering on 4S? What kind of process are you using to solder the the bullets on? I've never had a joint fail using the following method:
  1. Clean the wires with flux and then tin the exposed end of the wire. The solder should run up the wire to just inside the insulation if done properly. Clean off any remaining flux with alcohol after the solder cools.
  2. Clean the inside of the bullets with flux and then tin, again cleaning off any remaining flux with alcohol
  3. Solder the tinned wires into the tinned bullets, making sure the joints are shiny and that you have a slight fillet of solder at the end of the bullet's cup around the wire
I've done this for years in aviation on wires from 24 gage up to 8 gage and, as I said, never had one fail. That being said, however, I also haven't had to do this on a circuit that runs the amperage some run in their boats. Where I've seen solder joints fail is when the wires weren't tinned properly, not enough heat was used(a cold joint) or the solder cup end of a connector pin wasn't filled. What must be remembered is any time a wire is terminated into any kind of connector, if it's not done correctly, the joint will heat up due to resistance. If a solder joint gets hot enough, the solder will melt, allowing the wire to fall out of the bullet and completely open the circuit
 
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Tommy Levescy

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Mar 29, 2014
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341
First question, what do your solder joints look like after you are done. They should be smooth and shinny. If not, then there is not enough heat and flux being used. Second, what size bullets are you using? Some are having trouble with 5.5. Move up to 6 or 6.5.
Mike
I follow almost the same method that hydro junkie posted. and its 8mm bullets in a P-sport hydro. Now don't get me wrong im pulling a **** ton of amps. I have a very high amperage combo in the boat. So maybe it was just a bad connection. but i was curious if anyone were using some sort of special high temp solder or is everyone just using like 60/40 or 97/3 or one of the other commonly found stuff.
 

MarkScott

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Oct 5, 2014
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This is what Mike Ball suggested to me over the weekend race at Cincy.


Spool is now on it's way to me.
 

longballlumber

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Apr 17, 2003
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IMO if your de-soldering 8mm connectors; solder type is the least of your concerns! Already mentioned but...
* Cold solder joint
* poor connector surface area contact. 8mm connectors should be a b**ch to connect and pull apart
* If it's amps; I would argue you prop, motor, and boat set up isn't optimized

Question - are all connectors desoldering, just motor side, just battery side?????

Typical 60/40 solder has an estimated melting point of 375F

I have been using 96% Tin 4% Silver and it's melting point is 422F. Be warned it's not as user friendly.


just my 2 pennies worth
 

RaceMechaniX

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I use 60/40 rosin core solder from Kester. It sounds you might have too much gap between the wire and connector cup. If you are trying to fill a large gap, the solder will reflow and the wire will come. You want the smallest gap possible when inserting the wire into the back end of the connector. If you need to build up the wire diameter try using some small diameter solid copper wire and wrap it tightly around the multi-strand wire. Tin the solid wire to the multi-strand before soldering the built up wire into the connector.

You can also fold the wire back on itself to build it up, but I prefer the above mention technique.

Silver solder is for mechanical joints not electrical ones so I don't recommend it. It also takes considerably more heat to flow and you can damage brass connectors by tempering the material to a dead soft condition especially on the male connectors.

It goes without saying the male and female plug connection needs to be tight. Loose connections will generate a ton of heat.

If you want the best connectors, invest in the Schulze 6mm plugs.
 

Hydro Junkie

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Oct 2, 2006
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From what I've heard, silver solders can build up resistance from electrical current polarizing the solder, never seen it personally so can't say for sure. The 96/4 silver solder may be fine as most silver solders I have seen have other metals added for strength.
I have to agree with Tyler's comment about gap filling. I know we have three ways to fill a gap that are "legal" in the aviation world:
  • add filler wires
  • folding back the conductor
  • add a spacer to make the opening smaller
These are actually for crimped on terminations but the first two would also work for soldered ones. One thing to be aware of is a folded back wire will require twice the space of a straight one and, depending on the size of the wire and bullet, should be too large to fit into the solder cup. If you can fit a folded back wire, you're probably using too large of bullets to begin with
 

Kris Flynn

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Mar 11, 2002
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4,190
Tylers comment of connector "FIT" is one of the more important things to look for. Most cheaper connectors only touch on the tip of the male plug (so at the bottom of the female hole when connected). I go through all my plugs when I get a batch and assemble them and see how much 'slop' they have once inserted. There shouldn't really be any slop, or the contact area of that 8mm plug is wore than a good 5.5. hope that makes sense :)

I have only used OSE 5.5mm plugs and Novak solder (3%? silver) with very good results when using method above. The plugs have never been that hot in my SAW stuff... but I do know that Oval racing is a little different as heat can build up a lot more.
 

donaldhuff

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Feb 13, 2017
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Here is what I have been using for connectors since I started rewinding. On most motors the rewinding does not
increase the power, but rather it allows you to prop up some and not burn it up, which gets the motor closer to it's horsepower peak, which typically occurs at 50% of it's UNLOADED max RPM. This produces a lot more heat in the whole system and especially in the connectors.

After switching to this solder, and finally learning how to use it. I don't de-solder connectors anymore.

You'll have to use a butane torch with this stuff because of the 580* melting point, and tin everything it touches with regular 60/40 because it DOES NOT FLOW!
 

Kris Flynn

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Mar 11, 2002
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Here is what I have been using for connectors since I started rewinding. On most motors the rewinding does not
increase the power, but rather it allows you to prop up some and not burn it up, which gets the motor closer to it's horsepower peak, which typically occurs at 50% of it's UNLOADED max RPM. This produces a lot more heat in the whole system and especially in the connectors.

After switching to this solder, and finally learning how to use it. I don't de-solder connectors anymore.

You'll have to use a butane torch with this stuff because of the 580* melting point, and tin everything it touches with regular 60/40 because it DOES NOT FLOW!
Hi Don,

Did you forget to add in the details of the product you use? :)

Thanks
Kris
 

HTV Boats

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Nov 8, 2006
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Interesting. I looked up melting points of metals and here is what I found.
Lead - 621 F
Tin - 449 F
Silver - 1761 F
From Mcmasters specs.
Dons solder is 1% Tin 97.5% Lead and 1.5% Silver = 580 F
60% Tin 40% Lead = 375 F
Lead free electrical 96.5% Tin, 3% Silver, .5% copper = 420 F
Draw your own conclusions. How does 60/40 have a lower melting point than Tin or Lead. Chemical engineers speak up.
Mic
 

HTV Boats

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Nov 8, 2006
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Reading further rosin residue vs acid residue.? Opinions on how it affects joints.
Mic
 

Daniel's Racing

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Apr 14, 2008
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1,380
Interesting. I looked up melting points of metals and here is what I found.
Lead - 621 F
Tin - 449 F
Silver - 1761 F
From Mcmasters specs.
Dons solder is 1% Tin 97.5% Lead and 1.5% Silver = 580 F
60% Tin 40% Lead = 375 F
Lead free electrical 96.5% Tin, 3% Silver, .5% copper = 420 F
Draw your own conclusions. How does 60/40 have a lower melting point than Tin or Lead. Chemical engineers speak up.
Mic
Most all alloys have lower melting points than the pure elements they are made of.

Why is the melting point of solder lower than Lead or Tin. - Heat Transfer & Thermodynamics engineering - Eng-Tips
 

donaldhuff

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Feb 13, 2017
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Alloy metals always have a lower melting point than the pure metals that they are made from.
In pure metals, the atoms are arranged in a very uniform manner, but in the alloy, this pattern is all messed up because of the different size and arrangement of the blended metals. Thus making the bond holding the atoms together, come apart more easily.
 

Hydro Junkie

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Oct 2, 2006
Messages
4,999
Reading further rosin residue vs acid residue.? Opinions on how it affects joints.
Mic
It really depends on the flux. Acid flux needs to be cleaned off(isopropyl alcohol works well, it's also what we use at work to remove flux residue so I can verify to that being the case) or it can corrode the joint anywhere it's left, or so I was told in soldering class at NAS Whidbey Island back in January 1983. On the other hand, the rosin in rosin cored solder is supposed to be safe to leave since its not nearly as acidic as the acid in acid flux. With that said, I've never left flux on a joint so I can't say from personal experience whether any of the above is true or not
 

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