Copper-coated aluminium isn't just for power cables.. - Page 1
Forum section: electronics / general

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: July 02, 2025, 02:08:08 pm
content: "Copper" air-conditioning pipe set. Copper ends, joined to aluminium tube, with a plastic cover to make it look like copper.Immediate giveaway (apart from suspiciously low price) was it felt way too light.

author: NE666
author_rank: Frequent Contributor
timestamp: July 02, 2025, 02:42:59 pm
content: To be fair, I'm not sure why it was perceived necessary by the manufacturer to disguise it, so long as it was priced appropriately.Aluminium piping (obviously of the correct thickness) is entirely suitable for some compressed air and refrigerant applications. And it doesn't form Verdigris on the outside with condensation etc.

author: thm_w
author_rank: Super Contributor
timestamp: July 02, 2025, 09:06:07 pm
content: It looks like the end is crimped on, but can't really tell.The only issue I can think of is its not going to bend much before it starts to crack? So you'd want to be gentle with it.

author: Someone
author_rank: Super Contributor
timestamp: July 02, 2025, 10:02:50 pm
content: Quote from: NE666 on July 02, 2025, 02:42:59 pmYes, vehicle AC is full of the stuff and has a reasonable history.

author: nctnico
author_rank: Super Contributor
timestamp: July 02, 2025, 10:40:57 pm
content: Quote from: thm_w on July 02, 2025, 09:06:07 pmI'd guess the alloy used also allows to bend it like copper tubing. In my experience it is a good idea to use a proper pipe bending tool when installing an aircon system. Easier and less prone to error compared to bending the pipes by hands only.

author: tooki
author_rank: Super Contributor
timestamp: July 02, 2025, 10:43:18 pm
content: Quote from: mikeselectricstuff on July 02, 2025, 02:08:08 pmPlease delete the inline image tag so it reverts to an end-of-post thumbnail

author: thm_w
author_rank: Super Contributor
timestamp: July 02, 2025, 10:58:07 pm
content: Whats wrong with inline image?

author: KE5FX
author_rank: Super Contributor
timestamp: July 02, 2025, 11:19:11 pm
content: Nothing. I hate clicking on thumbnail after thumbnail to see what someone's talking about.

author: Someone
author_rank: Super Contributor
timestamp: July 02, 2025, 11:28:15 pm
content: Quote from: thm_w on July 02, 2025, 10:58:07 pmInline in this case not being a float, but the image masquerading as a word/character. So instead of a flow of text around the image it not only wastes space but also the line it is "on" ends up with stupid vertical spacing that makes reading the text a pain.

author: Someone
author_rank: Super Contributor
timestamp: July 02, 2025, 11:32:43 pm
content: Quote from: KE5FX on July 02, 2025, 11:19:11 pmSome people are the reverse. Particularly when a thread is returned to and you don't need to see the extra detail each time (multiplied when inline images are quoted).There is a time/place for inline images where the text requires reference to an image to make sense. But illustrative examples that add nothing beyond the text like this thread are probably best as clickable thumbnails (inline or end of post).

author: KE5FX
author_rank: Super Contributor
timestamp: July 02, 2025, 11:41:20 pm
content: Quote from: Someone on July 02, 2025, 11:28:15 pmHmm, it doesn't look too bad here:I do prefer it when posters use smaller inline images, though.

author: thm_w
author_rank: Super Contributor
timestamp: July 03, 2025, 12:11:57 am
content: Quote from: Someone on July 02, 2025, 11:28:15 pmohh yeah didn't notice that as I had a narrow window like KE5FX, it should probably auto add a newline when you insert the image.

author: floobydust
author_rank: Super Contributor
timestamp: July 03, 2025, 01:39:08 am
content: Just looking at commodity price alone, copper is 5x the price compared to aluminum.But you get galvanic corrosion at any interface of two dissimilar metals. This is long known from aluminum wiring.So the crimp's swage would have to be special, or this is a commie plot for secret short lifetime on these, complete with plastic propaganda cover

author: amyk
author_rank: Super Contributor
timestamp: July 03, 2025, 02:42:32 am
content: Brazed copper-aluminium joints are common in the HVAC industry.

author: coppercone2
author_rank: Super Contributor
timestamp: July 03, 2025, 03:02:49 am
content: I want to start a fraternal religious organization that is dedicated to installing pure silver pipes disguised as copper and aluminum. This is how my friends we get aliens to notice our planet.

author: johansen
author_rank: Super Contributor
timestamp: July 03, 2025, 03:28:41 am
content: Epoxy joined and crimped copper to aluminum tube transitions have held up without leaking for 50 years. Ive found them in a 1976 trane, as well as a 1980's era window ac unit still full of r22.If you get 10 years out of your slightly cheaper aluminum minisplit lineset, thank the gods who will institute another refridgerant transition by 2036 for sure.Also please note that aluminum will not suffer from formicary corrosion brought on by the lineset insulation off gassing acid..

author: floobydust
author_rank: Super Contributor
timestamp: July 03, 2025, 04:12:33 am
content: Quote from: amyk on July 03, 2025, 02:42:32 amAin't nobody got time for brazing. This is mass produced slop, probably slave or child labour.There are refrigerators where these connections corrode and then it leaks and you should buy a new fridge, after all the hassle with leaks and spoiled food.I like the attention to detail, the plastic coating is really nice looking. It should be commie red maybe, put the nation's flag on it claim victory over the West.Quote from: coppercone2 on July 03, 2025, 03:02:49 amFake silver, fake gold - it's already out there for the audiofools. My gold banana jacks sticking to a magnet and adding measurable THD as Douglas Self found. lol.You've got it backwards using expensive real silver disguised as a cheaper metal. Scamming the aliens not a good idea. It's gonna hurt.Quote from: johansen on July 03, 2025, 03:28:41 amI have trouble believing the temperature swings and pressure is OK with epoxyAll I see is soldered tubing connections in the A/C I've owned.

author: elektryk
author_rank: Regular Contributor
timestamp: July 03, 2025, 06:06:09 am
content: Quote from: floobydust on July 03, 2025, 04:12:33 amThere is also other soultion called Lokring.

author: 5U4GB
author_rank: Super Contributor
timestamp: July 03, 2025, 12:22:39 pm
content: Quote from: NE666 on July 02, 2025, 02:42:59 pmAlso, is it actually pretending to be copper or just alu with a plastic sheath to protect it from scratches/galvanic corrosion/whatever?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: July 03, 2025, 02:30:45 pm
content: Quote from: 5U4GB on July 03, 2025, 12:22:39 pmThere is only one reason the plastic sheath is used to make it look exactly like copper - even has a metallic finish. Actually quite impressive!

author: johansen
author_rank: Super Contributor
timestamp: July 03, 2025, 05:52:58 pm
content: Quote from: floobydust on July 03, 2025, 04:12:33 amits a mechanical crimp but the epoxy, which looks like jb weld, is what seals it.I asked about it on reddit and someone said they were common on 1970's motorhome ac systems. Brazing alloys for aluminum-copper replaced those joints.Quote from: floobydust on July 03, 2025, 04:12:33 amnot true at all. many companies cut off the flares on minisplit heads and braze the joints to increase reliability.

author: floobydust
author_rank: Super Contributor
timestamp: July 03, 2025, 08:12:20 pm
content: I meant the labour costs are higher for brazing, as it takes more time.Wondering, looking at the BoM costs. Roughly, copper tubing is say $2 a foot, so $0.40 for aluminum/ft.With this scam, you're saving $1.60/ft plus time to do the connection.I have seen PE plastic sleeve used to corrosion-protect copper tubing in HVAC. No idea how aluminum does in comparison.

author: nctnico
author_rank: Super Contributor
timestamp: July 03, 2025, 09:22:01 pm
content: Quote from: johansen on July 03, 2025, 05:52:58 pmProbably a numbers game. The chance a flare connection leaks and needing to spend time on it versus getting the torch out and be done with it.When I researched my airco install I learned the flare nuts need to be fastened using a torque wrench. If not tightened with the right torque, they may start to leak or crack. Still, I went for the torque wrench route but as an extra safeguard, I used a sealant (specifically for refrigeration piping) on the flare connections to have a higher chance they are gas tight. But I can totally understand why a professional airco installer would cut the flares off and put a brazed joint in.

author: tooki
author_rank: Super Contributor
timestamp: July 04, 2025, 08:42:55 am
content: Quote from: thm_w on July 02, 2025, 10:58:07 pmEspecially on mobile, where viewport sizes can be unusually small, they often cause unfortunate behavior, in particular, horizontal scrolling that takes priority over vertical scrolling, making it difficult to scroll the page.

author: KE5FX
author_rank: Super Contributor
timestamp: July 04, 2025, 05:15:09 pm
content: Bummer