How to Know When to Crimp vs Solder – Holley Tech

How to Know When to Crimp vs Solder – Holley Tech


I get asked a similarly simple question often
and it rivals, “what came first, the chicken or the egg?”. The debates on this question can get pretty
interesting and that question is simply, should I crimp, or should I solder? My quick answer is almost always going to
be to crimp. There are pros and cons associated with each
and I’m going to cover some of the highlights that are associated with them. Any connection should start with quality components
and the correct tools for the job starting with your wire strippers. Stripping wire with your pocket knife, a pair
of side cutters, or the wrong gauge slot in your stripping tool can cause breaks in the
conductor that can result in excessive resistance as well as frayed conductors that can cause
failure over time. Let’s start with crimp connections. Crimped electrical connections have been around
since they were introduced in the early 40’s, over the years technology as well as materials
have improved since the early days. Most people think that a crimp connection
just crushes the contact in the wire as you can see in this cross section of a poorly
executed crimp connection. In reality when done properly as you can see
in this cross section crimp, the pressure involved causes the metals to flow, resulting
in a wielding of the metal surfaces, that’ll produce a gas tight as well as a connection
with minimal resistance that will not allow oxenisation over time. It’s a good idea to pull test your connections
once you have made them. You shouldn’t be able to pull the wire out
when applying a reasonable amount of force to that connector. In most cases the stress to it’s failure point,
the wire should actually break before coming out of the connector. Over crimp connections are just as bad as
under crimp connections as it will make it brittle and prone to failure. In short proper crimp connections create a
weld between the connector and the wire creating an environmentally resistant long lasting
connection without creating a brittle, failure prone joint. The key to proper crimp connections are simple,
use high quality materials that are designed to work together utilizing quality connectors,
the proper gauge wire and the proper crimping tools and techniques. In front of us you see a broad assortment
of crimping tools. What you’re going to find you do not want
to use, that are not acceptable, is going to be a hammer, channel locks, lineman pliers,
things like side cutters. You want to make sure that you use the proper
crimping tools every time. There’s several crimping tools available on
the market that can range from the basic, essentially a hard ware store type of crimping
tool, which I really don’t recommend, to professional, quality crimpers. They can range any where from a standard,
compound leverage manual crimper, all the way up to some high end hydraulic crimpers. The key is again to use the proper crimping
tools. If your crimping ECU pins for Holley EFI,
it’s going to be important to make sure that you use the correct crimpers, Holley part
number 567-100 is a crimper that’s available for that. We also have a crimping tool that has interchangeable
anvils, it’s available through MSD, to cover a lot of your other crimping needs, and the
key is making sure that your using the proper connectors. When it comes to applications with sub harnesses
that require you to disconnect and re-connect your connections, I like to use commonly available
weather pack as well as metro pack connectors for those applications. Again one of the keys to that is making sure
that when you make those connections, and your crimping the terminals, that you use
the proper crimping tools that are designed for the job. When it comes to eyelets, spades, and buck
connectors, I personally like the non-insulated type. When your buying these connectors you want
to go for a good quality connector, preferably that is either a seamless or a braised seem
type of connector. Once you get done crimping these connectors,
it’s important to make sure that you put a little bit of shrink wrap over it and I prefer
the adhesive lined shrink tube. One of the keys to properly crimping these
type of connectors is to look at the connector in the orientation, look for the seam and
you always what to do what they call, saddle the seam, in which case you make sure that
your, D10 on the crimping tools is properly aligned opposite the seam. Once properly crimped with your connections,
one of the things you are going to find is that it should give you a good, solid, secure
joint that can take actually quite a bit of abuse in order to separate. Oh, so people that thing that crimped joints
are not a secure solid joint, probably haven’t been doing it properly. One of the keys to that again is making sure
that you you use the right crimping tools. Generally I would use this pair of Thomas
and Bett’s crimping tools or this ratcheting style crimper, either way just make sure that
you are using the proper crimping tool and your crimping it in a proper place, provide
the required bell mouth for the correct strain relief. A few companies offer a nice selection of
quality crimp connections, that have the adhesive lined shrink tube built into those already. These connectors are pretty nice and I always
keep a few of those in my wheel house, but I usually prefer to shrink non-insulated connections
because it allows you to visually inspect your connector a little bit easier. Holley offers connector kits for popular engine
applications in an ever expanding line of high quality wiring components and solutions
to fit your needs. Next we’re going to talk about soldering. So we talked about crimp connections so now
let’s talk about soldering, soldering seems simple enough doesn’t it? You strip, you twist, you heat, you melt,
you repeat. Well it’s really not that as simple as it
may sound. For my experience over the years, finding
properly executed non-factory solder connections in automotive wiring was a lot like buying
a lottery ticket, sometimes you get lucky but unfortunately most of the time you don’t. It’s starts with clean, oil free, non-corroded
materials and a soldering iron that’s set to the proper temperature with the proper
tip for the materials and connector being soldered. I prefer solder with about a 30,000ths diameter
with a 60/40 rising core, 60% being tin and the 40% referring to the lead content. I prefer it due to it’s low melting point. What you don’t want to do is use one of these
while your soldering your wires. Now there’s a time and a place for this, if
your soldering a large gauge battery cable and for example you would generally, a lot
of times end up utilizing a torch if your going to do that. You want to make sure that you do have that
right solder, you never want to use a acid core solder with electrical wiring and you
don’t want to use a very large diameter, large gauge solder VS the 30,000ths because you’ll
have to apply way too much heat, which is going to cause you to have some issues with
a poor connection. So we’re going to show you how to properly
solder a joint, when I solder connections in the case of this buck connector, I like
to interlace my conductors with each other, kind of fan them out a little if you need
to. Interlace them through and twist the conductors
opposite of each other, which itself will give you a semi secure joint, and it also
doesn’t effect the overall diameter as much as some other twisting techniques. Over the years I’ve found that these little
helping hands can actually be quite the helping hand when it comes to soldering your connections
because it allows you to free up your additional hands. You want to make sure that your soldering
iron set at the proper temperature, with a clean tip, and again using the proper solder. You want to apply heat through the back side
of the conductor, you don’t want to apply the heat directly to the solder. It’s ok to put a little bit of solder on the
tip to help it conduct heat a little faster to your wire, but you actually want to heat
the wire, and get it hot enough where it melts and it gives you good penetration. By putting the heat on the back side of the
conductor and the solder opposite, it will actually pull the solder towards the heat,
which will allow it to flow completely through the joint giving you a nice solid connection. You want to avoid applying too much heat and
too much solder as it can cause some other issues that is associated with the joint. As I had mentioned, you never want to touch
the solder to the iron in order to start the flow into the joint. Doing so will result in a cold solder joint
that is porous, can be brittle and prone to resistance. A properly soldered joint should be smooth
and shiny, it should never be dull, if it’s dull or it looks like solder is just globed
on, it’s probably a cold joint. On a short side note, if you use lead free
solder it’s generally going to look duller than a lead based solder is going to look. The most common mistake that we see in the
field is wicking, and that’s actually when there is too much heat, and too much solder
that’s physically applied to the joint and it causes it to wick underneath the insulation. We look at our nice flexible multi-strand
wire here, we can see that it’s quite flexible, and it can take quite a bit of movement. We go to this particular joint, I intentionally
wicked this joint, and if we apply some pressure to the outside edges of the conductor, we
can actually see where it’s become ridged out underneath the insulation. What happens with too much heat and too much
solder is actually wicks the solder out into the insulation, and what happens is it takes
our joint, and unfortunately, it makes it quite brittle and prone to failure. It’s one of the reasons that crimp connectors,
a lot of the times, are better and why I generally go with them is as you saw on the earlier
video on crimps, the connection that I crimped took a lot more abuse. I strongly advise against soldering connections
on small gauge wire, generally if your in the 20 gauge or smaller, 22, 24, 26 gauge
wire and it’s always better to crimp that connection. If your soldering bud splices it’s a good
idea to create a strain relief using 2 over lapping layers of adhesive line shrink tube. When creating a strain relief with shrink
tube you want to use 2 different lengths, that way it over laps and gives you an additional
amount of relief. Go ahead and we’re going to shrink the first
layer on, make sure that it’s centered up and I like to use adhesive lined shrink to
give me a good tight seal. We’ll go ahead and we’ll put our secondary
layer on and make sure that you over lap the ends of the first layer. Applying the overlapping edges gives you a
nice strain relief, especially once this cools down a little bit. It will allow it to be resistant to damage
to that solder joint due to flexing. Most of the time I crimp, but depending on
the application I will solder or crimp and solder the connection. The cost of crimping tools can be high, and
if your going to preform quality crimps then they really are a required investment and
well worth the cost. Maybe you are lucky and you have a buddy that
owns them and he’s kind enough to let you use those and borrow them from time to time. If you don’t have access to the proper crimping
tools for your connection, but that connection can be soldered, by all means PROPERLY solder
and shrink those connections. What ever method you choose just remember
a couple of simple things and that’s to do it properly. Leave your wire nuts in your house, your T
taps in the trash can and your twist and tape methods to your competition. For more recommendations and tips on wiring
your vehicle, check out our other great Holley tech videos.

100 thoughts on “How to Know When to Crimp vs Solder – Holley Tech

  1. I have 8 years of soldering experience, and usually the best joints are when you flow the solder on your iron… Not on the wire cause then thats when the flux stays on the wire and cant burn off.

  2. From an Electronics Technician…….. Great video. Most of the time, I watch these "how to" vids for a laugh, the advice provided here was spot on.

  3. One of the best concise tutorials on correct crimping. So many otherwise excellent professionals on youtube spread a lot of bad info on this topic.

  4. I admit I skipped around a bit but did this video actually address 'when' to crimp vs solder? If so I must have missed that.

  5. I'm curious. Do americans pronounce sold as sodd. "Just sodd my old bike" Becaue they sure as hell fuck it up when they pronounce "solder"

  6. $260 for a basic crimp tool? You could at least include some KY with it. At what point are you taking advantage of your customers just because of your brand name?

  7. Best connection is crimp with water tight shrink tubing over joint. Emphasis on water tight, as not all shrink tube is water tight. The good stuff always costs more. As the demonstrator instructed, you should always use the connectors for the application and the correct crimper for the purpose.

  8. LMAO. You can get a great joint by applying solder to any side. The wire just needs to get hot enough so it wicks into the wire.

  9. Thank you! can't tell you how often i see soldered on small gauge wire and they say "hasn't failed yet" but they never have the cars for more than just a few years vs a decade or more. Not to say that i have not soldered smaller gauge, but when i do i make sure to apply multiply stages of relief just like you did as solder will create a stress point in the wire that i've seen a few times when soldered then just wrapped in tape. Have yet to solder anything on any clients cars, just my own as a shortcut lol because i will know where it is and know not to stress it as much.

  10. Haven't you seen the crimper that hit with a hammer to set it? BTW, where are your hydraulic crimpers… you know, the 10 ton closing force ones with interchangeable dies? My favourite crimper for small lugs and links are a pair of Vicegrip linesmen's pliers with a crimping tool built into the pliers, just behind the pivot. When you are wiring up a switchboard, you don't have time to pick up and use a pair of strippers, put them down and pick up a crimping tool, use it two or three times and put it down and then repeat the whole process all over for every cable coming in to the switchboard. It might get you good marks for the practical exam but you are likely to get a kick in the pants from the boss for being too slow. When soldering lugs on to cables, the solder lug has no inspection point and the easiest and quickest way to solder them on is use a solder pot and liquid rosin based flux. You can't do the subject of crimping or soldering links, lugs or splices justice in 12 minutes.

  11. A western union splice that is then soldered is described in NASA manuals. The Wiki page on western union splice has the link to the NASA Workmanship Technical Committee page describing the process and applications. This union, when used as specified, is very reliable and easy to do.

  12. I have to disagree with what he said about crimping opposite from the seem. Crimping opposite from the seem can cause the seem to open up and result in a connection that loosens over time causing problems that can be a nightmare to diagnose. if you look at any Automobile company and likely Holley's own ECU terminals they are crimped the exact opposite of what he said. in fact, the female spade connector that they show in the video at 5:13 is an OE style connector that can only be crimped at the seem.

  13. People crimp because they probably dont know how to solder correctly. Crimping is faster also. Solder is always best. It will always give a positive corision proof connetion. I received solder training at work many years ago. One of the comments the teacher made was that when manufacturing satellites they dont crimp they solder. Soldering is always better in hostile environments. Learn ho to solder correctly and you are golden!

  14. What I don't get is your comment on wire nuts, and I know other mechanics feel that way. If they are good for voltage that could kill you or burn your house down how can they be bad for cars. They could be easily sealed with a dab of silicone .They take up space and don't look good where you can see them, but how are they a bad way of doing it other than that?

  15. Can’t complain about those crimp jobs; i’ve never seen such high quality versions of what usually is horrid crap. The trouble I’ve experienced at the hand of the usual crimp method is very numerous, compared to hardly ever with soldering.

  16. I like that.. "Do it properly. Leave your wire nuts in your house, your T-taps in the trash can and the twisted tape methods to your competition". Good stuff. Thanks for the info.

  17. I guess butt splicing small gauge wire is ok if the system you are doing it on doesn't matter if the resistance is higher bc I have found control circuits with 22 or 20 gauge that trying to crimp them caused the system to fault out

  18. After 40 years of experience I use almost exclusively solder and heat shrink. Less money spent, less tools to buy that you can't find in auto or hardware stores, less connector sizes and types to fiddle with and keep on hand, better overall results in most situations.. I can't remember a single soldered connection of mine that ever failed, but I have had crimp connections fail mostly due to corrosion over time and poor quality crimp connectors.

  19. Soldering should be left for PCBs and thats it.
    When using good quality crimping tools and connectors, crimping is the best method.
    Solder joints can become brittle and crack over time, as well as too much heat will damage the wire insulation.

    Boeing and Airbus and other aircraft manufactures only use crimped connectors, it's quicker and easier to make a good strong connection, and far less likely to damage wiring.

  20. LOL this guy is lecturing about having quality connections, yet he chooses to use weatherpack?!?!?! What a joke. Otherwise, a decent video.

  21. Soldering is not used to connect wires in Commercial Aviation, Soldering only occurs in the Computer Boxes on bread boards

  22. Crimping reuires the right tools, real crimpers are expensive (most consumers will not spend $100+ for them). No matter the cost of the crimps or thier quality, not using the correct crimpers will render the connection inadequate. Soldering does ensure complete current connections but as with crimps heat shrink must always be used (waterproof shrink wrap is best). DO NOT use the cheap crimpers being used in this video.

  23. Crimp…yeah, back in the 1970's I worked for a big machine tool company, 30"-60" panels with 100's of relays and stuff…I probably crimped several thousand terminals daily #20 up to #8……top quality stuff T&B, Burndy and nylon insulated, not the cheap vinyl.

  24. Solder is for the tight ass backyard butchers .
    You shouldn’t find solder in marine or earthmoving.
    Chances of failure much higher due to corrosive environments.
    Get me a deutz connector anyday .

  25. Been crimping wires wrong for ages, wasn't taught properly to begin with and have likely wicked more soldered joints than I care to admit thinking I was doing it properly. Strain relief w/ heat shrink, never even entered my mind. Guess I have a lot more homework to do than I thought!

  26. Good stuff. FAA prefers aircraft wiring repairs to be made with crimp connectors, partly because it's an easier skill to master than a good soldered joint. If it's good enough for work on aircraft, it's good enough for cars. But as you say, it's imperative to work carefully, using quality materials and the correct tools. I build a lot of custom harnesses for high-end hot-rods, and some of the horrible work I've seen under the dashes of expensive custom builds is just plain scary.

  27. Great video! This covers pretty much everything I’ve learned over 20yrs working in installations and electronics manufacturing. The only thing I would add is the addition of a separate flux during soldering, especially for splices, as it ensures good solder flow through the strands. As for the common style crimps, I prefer to crimp on the split as I’ve found it allows for the “V” to bite better into the strands. For marine connections I solder after crimping, making sure to leave a 1/16” backspacing with the insulation before adding meltable wall heat shrink.

  28. For me its been based on if I want it to be easy to take apart and how much I’m getting paid. If I’m using crimp butt connectors it’s because I’m not getting paid enough to care. There is a time and a place for crimp connections like when your making $10 an hour or building a harness where you want to be able to take apart or take parts off without cutting wires…

  29. Thank you, great, down to earth video. Good advice for most people, including me, IMO. What I find most surprising is the dislike rate. At the time I am posting (Nov 5, 2018) this comment, it is 75 dislikes and approximately 1200 likes. So, of those that responded, 6.25% did not like the video. What controversial thing was suggested to bring in a response like that? I didn’t see it. Usually when I find myself posting a dislike, I feel obligated to tell the poster why I feel that way. I had a quick look at the comments and did not see anything substantive there IMO. The suggestion about the alligator clips piercing the insulation seems ridiculous to me. In normal circumstance you apply heat, apply solder, allow penetration and pull back in 2-3 seconds – hardly enough time for the insulation to get warm, let alone soften.

  30. When you used the 'helping hands' to hold the insulted part of the wire, it is best NOT to have the teeth biting on the insulation. Get a pair of helping hands and double heat-shrink the teeth.

  31. I've learned more useful tips from this video than all the other crimp videos I've watched on YouTube. Triple thumbs up!!!

  32. always crimp if you can. don't interlace when soldering as you won't be able to undo that connection if you needed to remake it.

  33. Yep thought so, that butt joint was wrong and you do not solder crimps. There are military and national standards for this stuff, when will you people bother to read them.

  34. Commercial Aviation Crimping on wires is used exclusively , soldiering is not used for wire repairs or for production splicing , Soldiering used for micro chips for on board computers is used but in protected and controlled environment. Butt splices should be used with shrink tubing. Butt Splices (environmental Splices) called “Ray Chem” the butt splice joint is tin plated for Boeing and nickel plated for Airbus Aircraft with a slip over heavy shrink rap than heated . they are used in Commercial Aircraft in Unpressurized areas that withstand the elements of 35,000 ft 450 knots at below – 50 deg temps. Soldering has its limitation. Look up Ray-Chem on google !

  35. At 2:25, those basic crimp tools that are "not recommended" do have one very valid use, which is for the threaded bolt/machine screw-cutting feature or function, which allows you to shorten the Fastener without totally bugging up the threads at the end where you cut it. It's handy to have one for metric fasteners as well as one for SAE standard fasteners.

  36. Thank you for this excellent video! So hard to find good information on these subjects, especially this much in one place. Not to mention there wasn't any bad or incorrect advice I saw. I now have a new video on the topic of wiring I can add to my small collection of those worth sharing.

  37. Good video, I used to solder all my connection for 30 years. I now I do a lot more crimping, it's even faster then letting the iron heat up.

  38. I've always been told the staking, where you press an indent, like you did, is not a strong uniform joint like a proper crimp, which is uniform compression, no punches. Cable lugs are also made to slightly different sizes, on production lines they buy the lugs and tools from the same vendor, so the dimensions are matched. That's how milspec production lines run. Is it bunk? Maybe.

  39. I wish there were more ‘adult education’ classes on subjects like this. I’ve had formal education in the military and in civilian factories. Have seen too much of what appears to be self taught soldering and crimping… scary work out there on boats, cars & rv’s. “Good enuf” really…. isn’t.

  40. Shrink butts work ok, but I have seen so many crimped with a non insulated crimper. It blows a hole in the side of it rendering shrink tube useless. I like the non insulated ones with shrink tube. I haven't soldered much in a long time. If corrosion has wicked it's way up the wire and it's orange or black, solder won't stick anyway.

  41. Hi and thanks for this video (I searched for it). I'm an HVAC tech installing a new condensing unit. I have to terminate #10 solid copper wire under terminal screws that are just barely big enough. I wrapped the wire clockwise around the screw but it just doesn't fill me with confidence. Can you recommend a solution? TY

  42. Was always taught by record holder engine builder to use crimp and solder all connections tires shake can be hell on everything electrical.btw he has seen two tenths better et just by doing a good wiring job with solder all connectors🤷‍♂️

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