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Crimped bullets

Old 03-15-2015, 03:16 PM
  #1  
thepiper92
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Default Crimped bullets

I'm slowly getting my Gaui X3 finished, just waiting for the motor batteries and blades. The motor I'm using will have proprietary bullets, and does not come with the female esc ends. I went to my Lhs, and they do not have the bullets I need...or 360mm blades, a 6s spec motor, and pretty much anything I need, just Blade products, of which I vow to never go back to. I went to Canadian Tire and came across some bullets, much cheaper than what they would be at the hobbyshop. I crimped them on with a pair of pliers, pushed the plastic pieces over the ends. I gave a few tugs, and I'm sure the wire would rip out of the esc before the crimp. Is the connection of a crimp as good as a solder connection though?
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Old 03-15-2015, 03:25 PM
  #2  
birdDog
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I would have to say no. They would be prone to corrosion, mechanical failure and most likely won't be a good contact.
Soldering irons are relatively cheap and this way, you know the contact is solid. It's simple, fast and 100% reliable (when done properly, watch a few videos). ESPECIALLY for helis with the costs and risks involved.

You can do it!

I'm sure some of the resident pros wil be along soon with a better breakdown of things.
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Old 03-15-2015, 04:41 PM
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It's a split camp .... you will find devotees of Crimping and devotees of Soldering.

If Crimping - then you need to make sure you use good quality Bullets and proper Crimping tool - NOT pliers.

The common mistake in crimping is to crush TWICE and therefore cause damage to the crimp itself. It may look OK - but is weakened and can fail dramatically. It is why you should use the proper crimper for the job.

Personally - I am a Solder person and have never had a good solder bullet / connector fail of mine yet.

Nigel
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Old 03-15-2015, 05:38 PM
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thepiper92
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Well the wires are long anyway, so cutting and soldering on new ones is no issue. It is a small area, so pliers seemed fine, just one crimp was done, so they won't be weak. I gather I could run solder into the area as well, making it a crimp and a solder. I do have soldering irons, a lot of solder, etc. The crimp connectors I bought do seem good quality, rating for 100 something volts.
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Old 03-16-2015, 01:48 AM
  #5  
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Default crimp

For connections in an environment where there is motion - as in vibration and shock loads from less than greasy landings etc - crimping is the preferred electrical connection. BUT one must use connectors designed for crimping AND use a proper crimping tool. Pliers just squash and that is not a crimp.

All that said, all my connectors, including bullets, are designed to be soldered so solder I do, adding a shrink tube for strain relief of course.
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Old 03-16-2015, 02:11 AM
  #6  
thepiper92
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Well the particular connectors showed for pliers to be used. The crimp is compressed in the center. Should I stick with soldering or add soldering into the area.
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Old 03-16-2015, 03:08 AM
  #7  
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ALL crimps have a Crimper ...... they may show pliers - but even cheap auto crimps have a specific Crimper. Usually looks like a large set of wire stripper's ... with various functions : Wire gauge, stripper, cutter and crimper.

If there is no strain on the joint - then if it's secure and you cannot pull bullet of - then it should be fine. But I would pay a dollar down on table that after a few connect / disconnects that bullet comes away !

Proper crimped is fine, if not then I prefer soldered. I do have cheap 'Auto' crimp bullets but stopped using them a long time ago as they were unreliable and failed after the repeated connect / disconnect .... They now get used for non-model stuiff .. ie on my yacht etc.

Nigel
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Old 03-16-2015, 03:53 AM
  #8  
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FAA specifies crimped, not soldered connections because done right the crimp will survive 50+ years. The soldering will create a weak point in the wire right beside the solder joint and be subject to failure from vibration.

But most of us don't have the quality of crimper required to do the crimp right. so for most of our home made connection purposes soldering is better.

All of your servos have factory crimped plugs and they have been known to be fine for over 30 years.

Inadequate crimp pressure and the wire will slip out. Excess pressure and you will damage the wire leading to it breaking. There's not a lot of difference between too loose and too tight.
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Old 03-16-2015, 04:09 AM
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Fh mentions servo leads ........ I have the HK lead crimper and servo cable / ends .....

It's one of the best tools and items I have. For years I 'managed' with thin nose pliers and persuading pins into plug bodies. Then saw the light and bought the crimper. The difference is Black to White ....

Same goes for 'auto-crimps' etc. There is no substitute for proper crimper.

But in our hobby - soldering serves us well ... and I have yet to see any cable or plug fail in a model due to soldered end fracturing.... that includes high vibration 4 stroke models as well.

Nigel
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Old 03-16-2015, 05:26 AM
  #10  
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Originally Posted by fhhuber View Post
FAA specifies crimped, not soldered connections because done right the crimp will survive 50+ years. The soldering will create a weak point in the wire right beside the solder joint and be subject to failure from vibration.

But most of us don't have the quality of crimper required to do the crimp right. so for most of our home made connection purposes soldering is better.

All of your servos have factory crimped plugs and they have been known to be fine for over 30 years.

Inadequate crimp pressure and the wire will slip out. Excess pressure and you will damage the wire leading to it breaking. There's not a lot of difference between too loose and too tight.
Is a pair of pliers that bad though for a crimp area with a fairly thin wire (actually surprised how thin the wires on the Talon 35 is)? I can understand a very large gauge wire, where if you use pliers, you would naturally be left with unequal area of crimping. Has anyone done both crimping and soldering, meaning crimping a connector on and running solder into it.
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Old 03-16-2015, 08:05 AM
  #11  
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Originally Posted by thepiper92 View Post
Is a pair of pliers that bad though for a crimp area with a fairly thin wire (actually surprised how thin the wires on the Talon 35 is)? I can understand a very large gauge wire, where if you use pliers, you would naturally be left with unequal area of crimping. Has anyone done both crimping and soldering, meaning crimping a connector on and running solder into it.
I have soldered AND crimped but that is because of damage to the crimp.

Pliers BIGGEST problem is not the unequal crimp - it's the damage they do to the crimp and possibly wire .... The Crimp is designed for a uniform compression to the cable inserted. Pliers do not g'tee that and often - user will double or multiple squeeze the crimp to get a visually uniform crimp. This often causes crack or mechanical damage to the crimp structure - which causes reduced compression and grip on the cable. It can also lead to fracture of the crimp area itself or in really bad crimps - failure of rthe cable.

A trip to a boat shop where they make mast stays will show exactly what I mean. The Talurit - often mistakenly called a Swage - is a composite metal tube that is used to create eye's in wire rope ends. The eye is formed and tube slid over the standing and running part of wires and then hydraulically pressed at great uniform pressure to grip the two parts of cable. It is only pressed ONCE ! If the pressing is bad or failed - it should NEVER be re-pressed ... it should be removed and a completely new Talurit used. This also applies to Swage terminals.
Unfortunately a lot of Boat shops do not 'educate' their operators and you end up with sub-standard fittings ... because they press twice !

It may seem extreme to compare a mast stay to a model bullet - but the principle and effects are same.

The internal damage to a crimp by improper crimping can destroy all advantage of it's use.

Nigel
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Old 03-16-2015, 08:48 AM
  #12  
Larry3215
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Those automotive bullets are not designed for higher current applications and the "crimp" you can do with pliers is going to be way sub-standard for what we do.

Those bullets are for tail lights, turn signals and other low power applications where connection quality doesnt matter all that much and the power level is low - a few watts at most.

They are also pretty hi resistance compared to gold plated bullets, so may heat up quite a bit under load. They might also cause you esc sync issues if one is even slightly worse than the others in crimp quality/resistance.

You would be much better off just soldering the wires directly together than using those low quality bullets.
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Old 03-16-2015, 10:36 AM
  #13  
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Originally Posted by Larry3215 View Post
Those automotive bullets are not designed for higher current applications and the "crimp" you can do with pliers is going to be way sub-standard for what we do.
+1.. They are designed for low amp use. It's not really an issue of crimped vs. solder, it's a issue of the overall quality and rating of the connectors in question. The RC versions are gold plated for better conducting and lower resistance, those automotive ones are just cheap steel, fine if wiring up a new car radio but totally inadequate for the purpose of powering an RC heli motor. I'd not even think about using them, not for a moment.

You can get suitable solder bullet connectors online for pennies, eBay has lots of them.

IMHO do the job right or dont bother.

Last edited by JetPlaneFlyer; 03-16-2015 at 11:02 AM.
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Old 03-16-2015, 02:36 PM
  #14  
thepiper92
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From my understanding, the only purpose of gold plating is the resistance to corrosion. I guess I'll buy some from the hobbyshop
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Old 03-16-2015, 04:53 PM
  #15  
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Originally Posted by thepiper92 View Post
From my understanding, the only purpose of gold plating is the resistance to corrosion. I guess I'll buy some from the hobbyshop
Much better to buy a bagfull from Hobby King or online ... you can even get ones that have plastic cases like EC connectors !
I buy them in bags .... have a divided plastic case that has the different sizes in ...

I also buy my Deans and XT60's that way -- sorry to say it - but I get 2 - 3x as many for my money and that incl. shipping.

eBay has hundreds of sellers all selling same products.

The gold is to stop corrosion - which in turn assists in keeping good contact over time. It is not just for initial storage or contact.

Nigel
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Old 03-16-2015, 05:00 PM
  #16  
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Originally Posted by solentlife View Post
Much better to buy a bagfull from Hobby King or online ... you can even get ones that have plastic cases like EC connectors !
I buy them in bags .... have a divided plastic case that has the different sizes in ...

I also buy my Deans and XT60's that way -- sorry to say it - but I get 2 - 3x as many for my money and that incl. shipping.

eBay has hundreds of sellers all selling same products.

The gold is to stop corrosion - which in turn assists in keeping good contact over time. It is not just for initial storage or contact.

Nigel
I only use xt60 connectors, but them in bags. I don't feel like waiting another 3 weeks for just a few connectors, or fork out $30 for US shipping.
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Old 03-16-2015, 05:15 PM
  #17  
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Originally Posted by thepiper92 View Post
From my understanding, the only purpose of gold plating is the resistance to corrosion. I guess I'll buy some from the hobbyshop
Corrosion resistance is a big part of it for sure, but the other part is that the gold is an excellent conductor which is meant to reduce the resistance at the points of contact.

If your hobbyshop doesnt have them in stock i'd just order them online. In fact I did just that today for some big 5.5mm bullets for my new Goblin heli.... No chance of my local shop having those in, it's not even worth calling them to find out.
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Old 03-16-2015, 05:32 PM
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Originally Posted by JetPlaneFlyer View Post
Corrosion resistance is a big part of it for sure, but the other part is that the gold is an excellent conductor which is meant to reduce the resistance at the points of contact.

If your hobbyshop doesnt have them in stock i'd just order them online. In fact I did just that today for some big 5.5mm bullets for my new Goblin heli.... No chance of my local shop having those in, it's not even worth calling them to find out.
I may have to order online. I should have ordered my blades online too, would have been cheaper. I try to support them but they seem useless. All they carry is the Apple of RC helis, Blade. I got my 250 DFC through them...and they have one or two parts. They have bullets, not the align ones though. It's not easy supporting a place that is huge, tons of parts, but so little brand selection.

I was thinking though, what would be great is a connector for brushless motors, three prongs. If it turns the wrong way, turn the connector around.
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Old 03-16-2015, 07:27 PM
  #19  
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Something a lot like this?: http://www.hobbyking.com/hobbyking/s...airs_bag_.html
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Old 03-16-2015, 07:30 PM
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...Well now, seems they do exist.

I ordered these puppies: http://www.hobbyking.com/hobbyking/s...arehouse_.html

And these, considering some reported failures of the Gaui X3 plastic blades: http://www.hobbyking.com/hobbyking/s...ail_Blade.html

I should receive everything before the motor and batteries arrive, as banggood is extremely slow; the batteries were shipped out on the 25th, and NL post still only says "Ready for Shipment" when I track the item.
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Old 03-18-2015, 01:04 AM
  #21  
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Though tI would chime in because I see some good and bad info being stated here. Not picking on anyone OK.

I have worked with battery plants all my professional career as a PE and worked with many battery and connector manufactures, and set on NEC code panels.

Start with gold. Gold is used primarily for its resistance to oxidation and corrosion. Gold is a good conductor but ranks 3rd to Silver and Copper, with Aluminum being 4th.

Silver = 15.9 p(Ohms . m)
Copper = 17.1
Gold = 22.1
Aluminum = 26.5

On to Bullet Connectors like EC3 and EC5. Bullet connectors offer the most contact surface area. Surface area contact directly relates to current capacity and resistance between the two contact surfaces. The larger the contact area, the lower the resistance is. Thus the ability to pass more current with less heat build up and lower power losses.

Now to the controversial subject of Solder vs Crimp. This will upset some but hear me out.

Generally speaking Crimping is superior to Soldering both mechanically and electrically.

Solder is a weak mechanical bond. It is not thermal welding forming an alloy between two metals. From a laymen point of view it is conductive hot glue. It also forms a weak point in the wire where the metal wicks up the solder causing the wire to loose flexibility. With mechanical stress will cause the wire to fracture and break from mechanical fatigue from vibration. Many industries like aviation, marine, and automotive prohibit it use in wiring. Even the NEC limits it use and where used has to have mechanical reinforcement to take all stress off the solder joint.

Electrically solder is not a good conductor of 150 p(Ohms . m) or roughly 6 times higher than aluminum.

Crimped connectors on the other hand if done with approved and listed connectors and tooling is far superior. A compression connector when properly compressed mechanical strength is stronger than the wire. If a pull test the wire will break before being pulled out.

Electrically assuming you use the right size connector on the right size wire with a listed tool will apply enough pressure to homogenize the barrel of the connector to the wire essentially welding the two together making them one, thus no meaningful resistance.

No before you go beating your chest and yelling at me hear me out. In this hobby you cannot get the quality crimp I just spoke of. None of the connectors and tooling are approved or listed to any testing standard. It is cheap Chi-Com hobby grade material. The compression connectors materials or heavy enough or the right material to stand up to the pressure required. Approved small gauge wire connectors like #12 AWG up to 8 AWG use 6 and 8 ton compression tools, Larger gauges from #6 AWG to 750 MCM use hydraulic 15 ton tools like this.



So here is my take. If the connectors you use only allow for soldering, use a silver solder and take your chances. It is a bit expensive but a small roll will last you a life time. For those that use crimp connectors use the correct tool for the connector to get the mechanical strength, and then finish with a dab of silver solder to get the connection resistance down. Just a dad on the end where the wire protrudes.
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Old 03-18-2015, 01:18 AM
  #22  
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So the crimps I used, are they actually not capable of the amps of the system? Is there any way to know if they are good? These are the ones I have used http://www.canadiantire.ca/en/pdp/ga...l#.VQjEqueRvIU

Like I said it is no issue using soldered ones instead.
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Old 03-18-2015, 02:00 AM
  #23  
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Originally Posted by thepiper92 View Post
So the crimps I used, are they actually not capable of the amps of the system? Is there any way to know if they are good? These are the ones I have used http://www.canadiantire.ca/en/pdp/ga...l#.VQjEqueRvIU

Like I said it is no issue using soldered ones instead.
Common low amp rated automotive crimp connectors. Generally fail in automotive use after about 3 to 4 years if applied "right" (there really is no right way to crimp these things)

they are galvanized steel with plastic (generally crimped through the plastic...)

Might be OK to 5 amps but don't trust em to keep your RX working.

Note that expected use of these in a car is for them to be crimped to the wire then plugged in and NEVER disconnected. Disconnect and reconnect life is very few cycles.
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Old 03-18-2015, 02:23 AM
  #24  
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I am not sure if you can find a supply house like Graingers, Cesco, or Graybar to buy small quantities but Thomas and Betts makes really good quality Bullet Connectors in their male and female connectors.

If you did, then you have a problem getting the right tool to terminate them like this one.

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Old 03-18-2015, 02:30 AM
  #25  
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Originally Posted by dereckbc View Post
I am not sure if you can find a supply house like Graingers, Cesco, or Graybar to buy small quantities but Thomas and Betts makes really good quality Bullet Connectors in their male and female connectors.

If you did, then you have a problem getting the right tool to terminate them like this one.

These bullets look identical to the ones I have though...the metal looks to be the same, the dull silver. Same design and everything. The description states brass with copper sleeve. Isn't brass a poor conductor? Is there any way to check the composition of the bullets... I have a few extras, so if a have to damage one to check it is not a big issue. I can pick up soldered bullets...but now I am really curious if these bullets are good or not. Amps will not be exceeding 35, and 6s will be used.
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