Crimping just one or two 25mm2 copper tube terminals - how?

[tinnews]

I have proper ratchet crimp tools for everything up to 16mm2 copper tube terminals but no larger.

I need to crimp some 25mm2 copper tube terminals, probably only four or so of them, can anyone suggest a reliable way to do this? I can't really justify the price of a crimp tool that does this size.

I have seen an illustration (in a boatowner's book) of a simple jig for large cable sizes which you used a hammer on to crimp the cable, I do have a vice available where the wires need crimping so might be able to use that with a suitable jig or former.

Any ideas anyone?

[Nick Odell]

I crimp similar sized tubes over similar sized steel cables when making up a tailwire for a double-bass.

grip the crimp in the rod-gripping section of a pair of very old pliers tightly, then rest it on my bench vice and hit the head of the pliers once with a very large hammer to complete the crimp.

No complaints of tailpieces flying off - yet! (But I've only been doing this for forty-odd years so it's early days :)

Nick

[Andrew Gabriel]

Can you solder them into the crimp terminals?

[Tim Watts]

Is this for carrying large currents in conductors or simply something mechanical not related to a circuit?

If it's electrical, use the correct crimps or solder. A badly done crimp is asking for trouble.[1]

If it's just something mechanical, pliers in a vice should do it.

Electrical crimps of that size usually (the ones I've seen) punch a prong into the side and seriously deform the copper cable underneath with some considerable pressure. Being half arsed about such a joint is just going to lead to oxidation of the conductor and increasing resistance of the joint until it starts heating.

With solder, I'd perform a basic mechanical crmp first with a vice and/o pliers until the cable is held securely then solder that which will ensure a low resistance and stable joint.

[tinnews]

I suppose I could, I have solder etc. here though only a little soldering iron, I could get it hot enough to solder using the gas ring I guess, or there may be a blow torch around somewhere.

I'd be happier if I could crimp them though.

[tinnews]

It's electrical, wires from big boat batteries to bow propeller, big inverter, etc. I'm doing quite a lot of re-wiring etc. and need to add some proper protection for these circuits, hence the need to terminate a few more big fat cables.

Which is why I asked the question.

OK, that's certainly a possibility.

The jig/tool I saw in my book is essentially the jaws part of a proper crimp tool with a simple pin hinge. As shown in the book it was squeezed by using a hammer but could equally be done using a vice. It looks ideal for doing the occasional large crimp and would surely be cheaper than a ratchet crimp tool for large crimps. Correct crimp is ensured simply by making sure the jaws have closed completely.

It's an american book though and I can't find anything similar over this side of the Atlantic.

[Andy Wade]

Crimp tools for the larger sizes can usually be hired from electrical wholesalers. Ring round your local merchants and see if any can help.

[tinnews]

That's an idea, I have an account with Denmans. I'd have to plan well though as the connections are on a boat in Belgium whereas most of my acquaintance with elecrical wholesalers is in the UK. :-)

It's doable though as I'm pretty sure the cables I want to make up are 'standalone' lengths with a copper tube terminal crimped on each end, I just need to measure carefully what lengths they need to be.

[Andrew Mawson]

can't

Where are you. If you happen to be local you can borrow mine. I'm TN33

AWEM

[cynic]

Have you looked at hydraulic crimp kits on ebay? A low priced kit may be cheaper than hiring one from a wholesaler.

[Rick Hughes]

That means high current .. any dicky crimp will cause local heating, and lose power.

Undercrimp - lose power, overcrimp - premature failure.

Why not 'buy a tool' go do the 2 crimps and then take tool back and hour later for refund ....

[John Rumm]

Yup it would work if you can find/make such a thing. Otherwise crimp it by whatever other means you can to get a mechanical fix, then flux it up and solder with a blowtorch.

[John Rumm]

How about buying the right tool, and then ebaying it once you are done? Might be cheaper than hiring.

[Andy Champ]

Talurit splicer in the chandler next to the boat. Used for rigging wire.

Andy

[Tabby]

If crimping and soldering, I'd stic some thin strands of solder around the cable when inserting it. Crimping will squash it out the way, then a useful amount of it will flow and wet when the whole joint is heated up. If you've not blow-lamp soldered before, its a very different art to iron soldering, and not something thats likely to work well first time. But if the crimp's shiny & spotless, this way some of that solder will wet everything.

NT

[Dave Plowman (News)]

If you get it properly hot, solder will be drawn into the terminal as happens with a pipe joint. If it's not heated properly, you won't have a satisfactory joint.

[Andrew Gabriel]

I would be tempted to do some pre fluxing (and possibly flux-less plumbing solder), but it wants to be non-corrosive flux, because it will run up the conductors inside the sheath where it can't be washed away. It will be difficult to get the parts well enough fluxed quickly enough if you rely on flux cored solder alone.

[Dave Plowman (News)]

Of course it has to be clean - but I've done lots like this using ordinary lead multi-core electronic solder, and capillary action does just what you'd expect. Or rather I'd expect. But things need to be hot enough for it to flow - probably not possible unless you use a blowlamp.

[The Other Mike]

I've some huge diameter multicore, maybe 4 or 5mm diameter that is ideal for really big cable lugs to give the right volume but getting the balance right in heat input from a blowtorch to ensure adequate heat and not excessive heat is difficult. Charring of the insulation is easy to achieve.

Fortunately a bit of adhesive lined heat shrink makes it look like a professionally finished job :)

[Dave Plowman (News)]

I wrap a wet cloth round the insulation. Use plenty of heat and don't hand about with it.