Splicing very short AL wires - Page 1
Forum section: electronics / repair

author: soldar
author_rank: Super Contributor
timestamp: October 04, 2024, 09:46:05 am
content: I was messing with an old fluorescent tube fixture and the electromagnetic ballast got loose and pulled from the cables connected to it but due to the very strong gravitational force we have in this area the cables pulled the screw terminal off and the tiny wires from the coil broke off leaving only a few mm exposed and accessible. If they were copper this would not be a problem as I could just solder a copper whisker but, unfortunately, the ballast winding is aluminum or aluminium, one of the two, so no soldering.Using screw terminals is impossible. Twisting is impossible.I can connect to them, barely, using those terminals with a tiny hook at the end but this is unwieldy and not very secure.What would be the best way to connect to these AL wires?I do not need any suggestions to get a new electronic ballast, etc. I know all the alternatives very well. This is just for the fun of it.And, just to digress a bit, and totally unrelated, I have a box full of wall wart SMPS which are not working. I know full well they are not worth repairing as they are so cheap to buy, but yesterday afternoon I repaired three of them just by replacing input or output caps and I felt it was quite an acomplishment to get three out of junk box and into the "available for use" box.

author: Postal2
author_rank: Frequent Contributor
timestamp: October 04, 2024, 10:05:30 am
content: Quote from: soldar on October 04, 2024, 09:46:05 amYou need pure tin, a couple of drops of gun oil and a 100 watt soldering iron. After the aluminum is tinned (usually a couple of tinned spots), roll the copper wire into a tube, tin it with the same tin, and put it on your wire in a molten state.Practice on a similar wire first to avoid damaging the small ends.

author: tooki
author_rank: Super Contributor
timestamp: October 04, 2024, 10:08:39 am
content: How long are the wires? If they’re around 8mm or longer, you could use WAGO splices (221-2401). Ideally with WAGO’s contact grease for aluminum.Can you crimp some kind of splice on?Spot weld it?Smaller screw terminals?

author: RoGeorge
author_rank: Super Contributor
timestamp: October 04, 2024, 11:00:25 am
content: Clamp two alligator clips. Anchor the clips to the box with construction foam or glue-gun plastic so they won't move.

author: soldar
author_rank: Super Contributor
timestamp: October 04, 2024, 11:02:43 am
content: Quote from: Postal2 on October 04, 2024, 10:05:30 amWhat I am getting from the internet is that a tin-zinc alloy works best but it is not worth the trouble or expense of buying such solder. It seems it is mostly the zinc that does the trick. It is not worth buying the special alloy solder and I cannot think of how I could get a drop of each metal and try to make the alloy myself.https://www.belmontmetals.com/popular-uses-for-tin-zinc-solders/I am thinking more in the direction of micro-sized alligator clips or screw terminals. Maybe make myself some kind of crimp terminal.

author: soldar
author_rank: Super Contributor
timestamp: October 04, 2024, 11:07:21 am
content: Quote from: RoGeorge on October 04, 2024, 11:00:25 amI have thought of this but I do not consider the connection reliable or trustworthy. At least with the clips I have.Once I can get a good connection I can glue or epoxy the connection so it does not move.

author: Ian.M
author_rank: Super Contributor
timestamp: October 04, 2024, 11:14:45 am
content: Soldering aluminum with ordinary Sn60/Pb40 solder is not difficult! Seehttps://www.eevblog.com/forum/projects/soldering-aluminum-wires-vs-copper/msg3145590/#msg3145590where I soldered a wire to a piece of thin aluminum from a takeaway container, in less time than it took to write this!Alternatively, get some small bore*brass tube from a modelmaking supplier, cut some very short pieces with a Dremel cutting disc and debur the inside of the ends, squish them to an oval so you can get two wires in it side by side, insert the bare wires from opposite ends, crimp it, preferably in a crimper die it fits in nicely, and sleeve with heatshrink.*an ID of approx 1.5x the wire diameter would work - you don't want it too big or the crimp wont be reliable.

author: Psi
author_rank: Super Contributor
timestamp: October 04, 2024, 11:17:16 am
content: I'd probably just join two small connector crimp pins together at the pin end by soldering.So basically turning it into a crimp to crimp joiner. Then crimp the existing wire to a new wire and then tape the whole thing up to keep it secure.Another option might be a wire ferrule, cut it open at the other end so the hole goes all the way through turning it into a joiner.Then have your existing wire and the new wire running in parallel. The crimp ferrule joins them together.

author: Postal2
author_rank: Frequent Contributor
timestamp: October 04, 2024, 11:18:44 am
content: Quote from: soldar on October 04, 2024, 11:02:43 amI told you what to solder with. I soldered with 99% tin, 90% tin should work. No solder will do, only pure tin. Even a copper tip is specially tinned with this tin. You drip oil, collect tin on an overheated soldering iron and scratch the wire under the oil. You can tin a soldering iron with rosin, but you cannot use rosin when soldering.QuoteDon't do that.

author: Ian.M
author_rank: Super Contributor
timestamp: October 04, 2024, 11:30:53 am
content: YMMV. I've had excellent results soldering aluminum with ordinary rosin flux core Sn60/Pb40 solder and ordinary liquid rosin flux. See link above. It was common practice for jointing thin aluminum in various 20th century amateur science/mechanics magazines, as pre-70's hobbyists with anything other than SnPb solder were pretty rare. I suspect that most Pb-free high Sn solders will work equally well, but I've not tested that. I didn't and will not use the under oil method as I don't like the fumes or the cleanup. I suppose with a high enough temperature-stable oil, it may be your best option if you are trying to use an under-powered soldering iron as a deeper oil pool will exclude more oxygen for longer.Zinc is also notoriously difficult to solder to so although its the major component of those low temperature brazing sticks for aluminum, I don't think its going to be helpful here.

author: Postal2
author_rank: Frequent Contributor
timestamp: October 04, 2024, 11:34:00 am
content: Quote from: Ian.M on October 04, 2024, 11:30:53 amI tried. No wetting. Just pure tin.

author: Ian.M
author_rank: Super Contributor
timestamp: October 04, 2024, 11:42:41 am
content: Well try again, with the biggest meanest bit you've got on your most powerful iron. You *MUST* abrade through the flux pool, then form a solder blob and keep rubbing and scratching it into the surface till it takes. If soldering to thin aluminium sheet, it needs to be hot enough to melt solder next to the solder blob without the solder wire contacting the blob or the tip. You wont get any wetting if the aluminum isn't hot enough or if it takes too long to heat from when you stop abrading through the flux pool till when you get a solder blob over it.

author: Postal2
author_rank: Frequent Contributor
timestamp: October 04, 2024, 11:47:45 am
content: Quote from: Ian.M on October 04, 2024, 11:42:41 amIt pretends to be absorbed, but easily bounces off. Tin, however, is thoroughly wetted.You can solder by dipping in molten zinc, but I have not done this, although I know that this is the standard method for soldering aluminum twists of several wires.

author: hanakp
author_rank: Regular Contributor
timestamp: October 04, 2024, 11:48:50 am
content: I'm surprised nobody mentioned it yet, so I'll bite. There are special fluxes for aluminium soldering, google it. They work by (temporarily) chemically removing the oxide that forms on the metal's surface, thus allowing for wetting by solder. I've been usingone locally produced fluxfor about 15 years now and it works great. Its base component ishydrofluoric acid, so your best bet is to buy a similar one. Be sure to thorougly wash the finished joint in DI water. And don't let the flux touch your skin and don't breathe the fumes.Among other things, I've been using it to solder grounding wires ontopopular Hammond extruded aluminium cases. You need to preheat such big components with hot air gun or hot plate.

author: Postal2
author_rank: Frequent Contributor
timestamp: October 04, 2024, 12:06:25 pm
content: I didn't come up with the idea of ​​soldering aluminum with tin. It's written in the book, and the chemical justification is given. There's also an explanation of why there shouldn't be lead in the soldering.

author: Ian.M
author_rank: Super Contributor
timestamp: October 04, 2024, 12:27:32 pm
content: Quote from: Postal2 on October 04, 2024, 12:06:25 pmCite please, and also quote why there shouldn't be lead.I've just soldered a 4mm2copper wire to the bottom of an aluminum Strongbow cider can using the under oil method. The oil used was actually Petroleum Jelly (Vaseline), which left the bit clean. Solder was ordinary Sn60/Pb40 rosin flux core off an approx 30 year old reel I have knocking around the bench. The label's long gone so I don't know the brand or exact flux core. It did take several minutes scratching through a large blob of solder to get initial wetting. Strength: Pulling on the wire has partially inverted the dome of the can bottom with no signs of separation.

author: Postal2
author_rank: Frequent Contributor
timestamp: October 04, 2024, 12:34:17 pm
content: This is a book for children in Russian, called "Advice for a Beginning Master". I don't even remember where it is.I tried soldering with regular solder, I soldered a thick copper wire to an aluminum ruler and tried to tear it off. I already wrote the result.Of course, I have been soldering electrical wires this way for many years, even those hanging from the ceiling.

author: Ian.M
author_rank: Super Contributor
timestamp: October 04, 2024, 12:53:24 pm
content: You wont have any joy soldering to thick aluminum unless you can get the whole part up to ~ 200 °C (or more like 230 °C for Pb-free) quickly enough not to form a thick oxide layer and hold it at temperature while scraping the solder pool into the surface to break through the oxide layer and start it wetting. The can is ~ 100um aluminum sheet, not much thicker than heavy foil, and even so I can barely get enough heat into it with a Weller 8100D 100W soldering gun. For thicker sheet, I'd need to assist with a hot air tool or a pencil blowtorch or put it on a PCB preheater.

author: Postal2
author_rank: Frequent Contributor
timestamp: October 04, 2024, 01:08:23 pm
content: Quote from: Ian.M on October 04, 2024, 12:53:24 pmBut it's weak, no good. I solder with something like the one in the photo, only the handle is plastic.Buy Weller as in the second photo - it will fit.

author: RoGeorge
author_rank: Super Contributor
timestamp: October 04, 2024, 01:09:24 pm
content: I did solder on Al sheet with normal 60/40 solder for electronics. The trick is to solder underneath a thick drop of motor oil, so the air don't get to the Al and oxidize it. Cooking oil might work, too. Scratch the Al while it is covered with oil, then solder with a powerful enough soldering gun. It needs a lot of heat. Never tried that with Al wire, maybe it works, but practice first on another wire.

author: Ian.M
author_rank: Super Contributor
timestamp: October 04, 2024, 01:15:13 pm
content: Incidentally the glassfibre pencil brush ishttps://cpc.farnell.com/unbranded/10191/fibreglass-pencil-4mm/dp/SABU10191or similar. If its working right you can see the oil or flux turn black with abraded aluminum particles. Getting the brush clean afterwards is a PITA - I just burnt off the Vaseline with a lighter then used switch cleaner and its discoloured but at least not greasy - so it may be better to keep a brush insert just for this job.The problem with soldering wire will be keeping the oil and solder there. Try making a shallow depression near the edge of a piece of pine wood with a very small V notch up to the edge for the wire, and clamping it at the right height for the wire to be level.However the last time I needed to get a solder joint to aluminum magnet wire I crimped a duPont pin terminal to it (use a tiny smear of Noalox) and simply soldered to the pin! Its much easier and is pretty much foolproof.

author: Postal2
author_rank: Frequent Contributor
timestamp: October 04, 2024, 01:41:47 pm
content: Quote from: Ian.M on October 04, 2024, 12:27:32 pmI don't know how you did it. I've always been able to tear a drop of regular solder off the ruler, but with tin the wire itself just comes off. But I've tried both. Why don't you try with tin.

author: Ian.M
author_rank: Super Contributor
timestamp: October 04, 2024, 01:59:19 pm
content: .... because I don't have any SN100C solder handy. I do have a small pack of SAC405 I keep for Pb-free repair work, but at 4% silver that stuff is too pricy to mess about for no reason. I suspect we are in violent agreement that high tin solder will work to tin aluminum. You contend SnPb doesn't - others disagree.

author: Postal2
author_rank: Frequent Contributor
timestamp: October 04, 2024, 02:12:25 pm
content: Tin is a food metal, sold for repairing saucepans. I don't think it's a problem to find it. Try it, compare, and don't forget to tell us.

author: themadhippy
author_rank: Super Contributor
timestamp: October 04, 2024, 02:13:15 pm
content: Quoteit does

author: coppercone2
author_rank: Super Contributor
timestamp: October 04, 2024, 02:17:38 pm
content: the key is to get the aluminum soldering flux that worksI had nothing but problems but someone at work left and they gave me a remains of a jar that wow it soldered foil like copper (NO BS LIKE mineral oil)this one looks correct from memory, I would have to go to my shop to check but the container looks right, and my leg hurts right nowhttps://www.amazon.com/STAY-CLEAN-FLUX-4-OZ/dp/B008FM5JXIbut I have a tiny 1oz bottle. hmm

author: soldar
author_rank: Super Contributor
timestamp: October 04, 2024, 03:12:26 pm
content: The problem is not only making electrical contact with aluminum but also that there are just a few mm showing and very fragile and quite inaccessible. It's not like I have a long end and can easily handle it. I cannot easily hold, scrape, etc. I can hardly get in there. If I handle it any more it's going to break and that will be the end of it. Which may be a good thing.

author: hanakp
author_rank: Regular Contributor
timestamp: October 04, 2024, 05:02:28 pm
content: Like I wrote earlier, forget brushing, oil etc. Just get aluminium flux with hydrofluoric acid, then it will solder almost like copper wire.

author: Psi
author_rank: Super Contributor
timestamp: October 07, 2024, 08:35:31 am
content: Has anyone tried pointing a TIG torch at some aluminum electronics just with the gas on, then cleaning and soldering the aluminum part? Does it work well?

author: 5U4GB
author_rank: Super Contributor
timestamp: October 07, 2024, 12:03:48 pm
content: I've never tried it at this (tiny) scale but could you try brazing, a.k.a. "aluminium welding", it?

author: soldar
author_rank: Super Contributor
timestamp: October 07, 2024, 01:58:32 pm
content: At this point it does not seem to me there is any practical way of soldering or brazing worthwhile for this unimportant project.I am thinking I might try to find the tiniest screw terminal I can find, epoxy in place with the screw loose, and once it is held firmly in place tighten the screw. I think trying to tighten the screw with the terminal loose would most probably result in a broken AL wire.I also think epoxy is safer then hot glue which is really not so rigid.I could even solder a thin copper wire to the screw terminal.

author: mikerj
author_rank: Super Contributor
timestamp: October 07, 2024, 02:03:03 pm
content: Quote from: Postal2 on October 04, 2024, 11:47:45 amAll I can say is you are doing it incorrectly. Like Ian I have made strong, well wetted connections to Al with regular rosin cored flux, it's all in the technique. If you have ever used the Al brazing rods it's a very similar method, abrading the oxide layer through the molten pool to allow the solder to wet the raw Al.

author: Greybeard
author_rank: Frequent Contributor
timestamp: October 07, 2024, 07:01:50 pm
content: Quote from: hanakp on October 04, 2024, 05:02:28 pmI would never use anything containinghydrofluoric acid.It's highly dangerous!https://en.wikipedia.org/wiki/Hydrogen_fluorideQuote

author: jpanhalt
author_rank: Super Contributor
timestamp: October 07, 2024, 07:30:44 pm
content: Quote from: Greybeard on October 07, 2024, 07:01:50 pmThen don't. Presumably, you understood that your reference was to the pure gas. Most people probably know that (EDIT: the flux) reference is to HF in dilute solution. In such instances, it has many uses. In the US, for example, Whink Products sells a rust stain remover for sinks and toilets in grocery stores (https://web.faa.illinois.edu/app/uploads/sites/6/2021/05/WHINK-Rust-Stain-Remover.pdf). It also works on blood stains on clothes, if all else fails.(It looks like Whink was acquired by Rustoleum. I don't know whether current products are the same.)

author: tooki
author_rank: Super Contributor
timestamp: October 08, 2024, 07:18:49 am
content: Quote from: jpanhalt on October 07, 2024, 07:30:44 pmOn theproduct page, in the Technical Information tab, there is the download for the technical data sheet:https://www.rustoleum.com/-/media/6111FC40699C4F82811A045EFD907995.pdfIt still lists HF as the active ingredient.It also lists Bitrex as an ingredient, which makes total sense from a safety standpoint, but man do I hate Bitrex in cleaning products, because of how Bitrex residues then spread everywhere and ultimately end up on your fingers, and then face. (In the case of this product, the relevant situation would be carpets, since all the other applications involve thorough rinsing.)I once made the mistake of using alcohol that was denatured with Bitrex to clean my bathroom. It took weeks to get that damned bitterness gone. It’s actually a fascinating way to demonstrate how bacterial/viral cross-contamination works…

author: Greybeard
author_rank: Frequent Contributor
timestamp: October 08, 2024, 11:32:13 am
content: https://www.anmeldestelle.admin.ch/dam/chem/de/dokumente/infoblatt-flusssaeure.pdf.download.pdf/infoblatt-flusssaeure-de.pdfGoogle translation:QuoteSorry for the loss of text structuring.