Solderstick vs Crimp vs Solder: Which Wire Join Is Best?

Solder seal vs crimp vs solder is one of the most argued-about topics in 12V wiring. Ask on any 4x4, caravan or boating forum and you will get strong opinions on all three. The honest answer is that each join has jobs it does best, and the right choice depends on the wire size, where the join lives and whether you will ever need to undo it.

This guide compares Solderstick connectors, crimped connections and hand-soldered joins side by side: how each one works, where each one shines and where each one is the wrong choice. Yes, we sell them, and we will still tell you when a crimp or a soldered lug is the better option.

Quick answer:

• Solderstick connectors are the easiest way to make a soldered, sealed and inspectable splice on 0.25 to 6.0mm2 wire, with only strippers and a heat gun.
• A quality crimp, made with a matched terminal and a ratcheting tool and covered with adhesive heat shrink, is the better choice where wire flexes or vibrates constantly, and for plugs and terminals you need to disconnect.
• Crimped or soldered lugs are the right choice for battery cables and anything heavier than 6mm2.
• Hand soldering suits bench work and electronics, but needs skill, an iron and a separate seal.

The three wire joins in plain terms

Solderstick

A clear heat shrink tube with a ring of low-temperature solder in the centre and a coloured sealing ring at each end. You put the stripped wires inside, heat it with a heat gun, and the solder flows through the strands while the tube shrinks and the end rings seal against the insulation. One step gives you a soldered, insulated and sealed join. Our Solderstick guide explains the construction in detail.

Crimped connection

A metal barrel, in a butt splice, ring terminal, spade or connector pin, that is squeezed onto the stripped wire with a crimp tool. A good crimp deforms the barrel and the strands so tightly that they become one solid mass with no air gaps, often called a gas-tight crimp. Many terminals also have a second crimp on the insulation to hold the wire and reduce strain on the conductor crimp.

Hand-soldered join

The wires are twisted or laid together, heated with a soldering iron and joined with solder and flux. The join is then covered with heat shrink, ideally adhesive-lined so it is sealed. It is the traditional method, and done well it is a good electrical join, but the result depends heavily on the person holding the iron.

Solderstick vs crimp vs solder: the comparison table

Where Solderstick connectors are the better choice

They have real strengths, and they are not just about convenience.

• Consistency without special tools. The amount of solder is already measured into the connector, and the heat gun does the rest. You do not need a matched crimp die or soldering skill to get a consistent join.
• Sealing in the same step. The end rings seal the join as it shrinks, so you do not need a separate piece of adhesive heat shrink. Solderstick connectors are IP67 rated: dust tight and able to withstand temporary immersion.
• You can see the join. The clear tube lets you check the solder has flowed through both wires and the ends have sealed. With a crimp, you cannot see inside the barrel.
• Slim, tidy splices. A Solderstick splice is only slightly bigger than the wire, which helps when you are feeding a loom through a grommet or into tight conduit.
• Roadside repairs. A small kit and a heat gun can fix a cut trailer light wire or a chafed accessory feed in a few minutes. Our roadside 12V repair kit guide covers what else to carry.

Independent reviewers including Big Clive, Electronics N More, Ross Lukeman and Samcrac have tested Solderstick connectors on video if you want to see them put through their paces.

Where a crimp is the better choice

A properly made crimp is the professional standard across much of the automotive and marine world, and there are jobs where it beats a solder sleeve.

High-vibration and high-flex runs

A crimp leaves the strands flexible right up to the barrel, while any soldered join turns that section of wire into a stiff, solid piece. Under constant vibration or bending, stress concentrates at the point where the stiff section meets the flexible wire, and that is where strands can fatigue and break. For engine bay wiring that moves with the engine, wiring on a vibrating mount, or anything that flexes every time a door or tailgate opens, many auto electricians prefer a supported crimp covered in adhesive-lined heat shrink.

Anything you need to unplug

Plugs, sockets and terminals are crimped. If you are wiring a light bar, trailer plug, fridge or any part that gets removed for service, the disconnect point needs a proper crimped plug and socket. Our Deutsch connector guide covers a popular sealed option. You can still use Solderstick connectors on the permanent side of the loom.

Boats wired to marine standards

The US-based ABYC marine wiring standard, which many boat builders and surveyors refer to, is widely quoted as saying solder should not be the only means of mechanical connection, and that soldered joints should be supported so the conductor does not flex at the joint. If your boat needs to meet that kind of standard, crimped terminals are the safe choice for anything structural. See our marine wiring connections guide for more on salt-water wiring.

Crimp quality matters

A crimp is only as good as the tool and terminal. A ratcheting crimp tool will not release until it has completed a full cycle, which prevents half-made crimps, and the die must match the terminal. Cheap non-ratcheting crimpers and poor terminals give inconsistent results, and a loose crimp with air gaps lets moisture in, which raises resistance and heat over time. If you do not have a good crimp tool, a Solderstick is often the more reliable option.

Where a soldered join or soldered lug makes sense

Hand soldering still has its place.

• Electronics and bench work. Circuit boards, small components and fine wire under a magnifier are soldering territory.
• Battery and heavy cable lugs. For battery cables and anything heavier than 6mm2, use crimped or soldered lugs, not splice connectors. A heavy-duty lug crimper is the common choice, and some people solder lugs as well. Either way, keep the solder in the lug barrel, not wicking up the cable, and finish with adhesive-lined heat shrink.
• Odd joins. Joining wire to a component lead, a switch tag or a terminal that was designed to be soldered.

The downsides are that it needs an iron and power, takes more skill to get a good joint every time, and still needs a separate seal. A poorly heated joint, often called a cold joint, can look fine and still have high resistance.

Solderstick vs crimp under vibration and flex

This is the core of the solder seal vs crimp debate, so it is worth being clear about.

When solder flows into stranded wire, it wicks along the strands by capillary action and makes that section rigid. Every soldered join, whether by iron or by solder sleeve, has a point where stiff, soldered wire meets flexible, unsoldered wire. If the wire bends or shakes at that point, the strain concentrates there.

That does not mean soldered joins fail on vehicles. It means they need support, which is good practice for every type of join:

• Cable tie or tape the wire to the loom or a solid mount a short distance either side of the join, so the join itself is not flexing.
• Do not leave a join hanging in free air between two mounting points.
• Keep joins out of sections that move, such as across hinges, near steering or suspension parts, or on the engine side of an engine-to-chassis loom.
• Run the loom in split conduit where it could rub.

With good support, they are well suited to most chassis, cabin, tray, trailer and caravan wiring. For the high-vibration exceptions, a supported crimp under heat shrink is the more conservative choice.

Solderstick vs crimp vs solder for waterproofing

Water and dust are what kill 12V joins on 4x4s, trailers and boats. Corrosion creeps into an unsealed join and up the strands, resistance rises, and eventually the circuit stops working.

• Solderstick: sealed in the same step by the adhesive end rings, and IP67 rated.
• Crimp: not sealed on its own. Use heat shrink butt splices, sealed connectors, or cover the crimp with adhesive-lined dual wall heat shrink.
• Hand solder: not sealed on its own. Cover it with adhesive-lined heat shrink. Plain single wall heat shrink insulates the join, but it does not seal it.

For what IP67 actually means, see is Solderstick waterproof? and our IP rating explainer.

Tools, time and skill

The tool kit you need for each method is quite different.

• Solderstick connectors: wire strippers and a heat gun. A cordless heat gun makes them practical away from power.
• Crimping: wire strippers, a crimp tool with the right die for each terminal type, the terminals themselves and adhesive heat shrink. Different terminal families, such as insulated terminals, open barrel pins and heavy lugs, often need different tools.
• Soldering: wire strippers, an iron (and power for it), solder, flux and heat shrink, plus practice.

If you already own good crimp tools and do a lot of plugs and terminals, crimping is efficient. If you do occasional repairs and accessory installs, Solderstick connectors need the least gear and the least practice to get right.

Which should you use?

• If you are splicing a cut or chafed 12V or 24V wire between 0.25mm2 and 6.0mm2 in a cabin, tray, chassis, trailer or caravan, use a Solderstick and support the wire either side.
• If you are joining wire in a high-vibration engine bay run or a section that flexes constantly, use a crimp with a ratcheting tool, covered with adhesive-lined heat shrink, and support it.
• If you are wiring anything that gets unplugged, such as a light bar, trailer, fridge or removable accessory, use a crimped plug and socket at the disconnect point.
• If you are joining battery cable or anything over 6mm2, use crimped or soldered lugs and adhesive-lined heat shrink.
• If your boat must meet a marine wiring standard, use crimped terminals and check what the standard requires.
• If you are working on circuit boards or component leads, use a soldering iron.
• If the job involves 230/240V mains wiring, none of these is a DIY job: call a licensed electrician.

Whichever join you use, size the cable and fuse for the load first. No connector fixes undersized cable. Our wire gauge guide covers how.

Frequently asked questions

Are solder seal connectors better than crimp connectors?

Neither is better for every job. They are easier to get right without special tools, sealed out of the box and easy to inspect, while a quality crimp handles constant vibration and flex better and is the only option for plugs and terminals.

Is crimping or soldering better for car wiring?

Factory looms rely mainly on crimped terminals, because a correctly made crimp is repeatable in production and keeps the wire flexible. Soldered joins, including solder sleeves, work well on car wiring when the wire is supported either side so the joint does not flex.

Do Solderstick connectors hold up to vibration?

They hold up well when the wire is supported. Like any soldered join, they make a short section of wire stiff, so tie the wire down either side of the join. For runs that move with the engine or flex constantly, a supported crimp under heat shrink is the more conservative choice.

Should you crimp and solder a connection?

Some people do, especially on battery lugs. If you do, keep the solder inside the terminal barrel and do not let it wick up into the cable, and support the cable so it does not flex at the lug.

Can you use Solderstick connectors on battery cables?

No. For battery cables and anything heavier than 6mm2, use crimped or soldered lugs. The largest Solderstick connector, yellow, covers 4.0 to 6.0mm2.

Are Solderstick connectors OK for boats?

They are sealed and IP67 rated, which suits damp areas on a boat. If your boat has to meet a marine wiring standard such as ABYC, which is widely quoted as not allowing solder as the only mechanical connection, use crimped terminals where the standard requires them.

Do Solderstick connectors need a crimp tool?

No. You only need wire strippers and a heat gun. The solder, insulation and seal are all built into the connector.

What to use

For splices from 0.25 to 6.0mm2, an assorted Solderstick kit covers every size. The connectors are ISO 9001 and CE certified and IP67 rated.

• 50PCS kit: 10 white, 22 red, 13 blue, 5 yellow.
• 100PCS kit: 25 white, 35 red, 30 blue, 10 yellow.
• 250PCS kit: 40 white, 100 red, 90 blue, 20 yellow.
• 500PCS kit: 80 white, 200 red, 180 blue, 40 yellow.
• Bulk 100 packs of a single colour.

For crimped joins, lugs and battery cable, use adhesive-lined dual wall heat shrink. The 3:1 and 4:1 dual wall tubes suit most crimps and lugs, and the 6:1 heavy wall black tube (33mm to 5.5mm) suits large lugs and heavy cable. All are rated 600V, with a working temperature of -45 to 125 C.

For fitting instructions, see our step-by-step guide. We ship Australia wide by Express Australia Post with free express shipping, and orders placed by 1pm are dispatched the same day.