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Comment by Rebelgecko | Hacker News Reader

Kapton tape is also a great example of how Amazon algorithmically enables knockoff and counterfeit goods.

I recently bought the #1 result on Amazon for "kapton tape". A banner on the item's description proclaimed that the listing was "Amazon's Choice for Kapton tape". So I ordered it without doing any more due diligence. When the item arrives, it turns out that it isn't Kapton. It's a knockoff called "Koptan". In their defense, the actual vendor's description doesn't call it Kapton, just the "Amazon's Choice" banner. Kinda sneaky

The tape I got looks a lot like Kapton. But is actually the same thing? Who the fuck knows. At the very least, my house hasn't burned down yet

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I bought a roll direct from 3M a few weeks back. Was well over $40. It would also appear they don't call it kapton, but instead thermosetting adhesive.

Checkout 3M 5413 AMBER. Larger rolls can cost upwards of $300, not cheap stuff.

I should also warn, if you decide to take the risk buying this fake krapton garbage, you do risk an electrical fire. Unless you yourself have tested the resistance this tape provides versus the real deal, DO NOT assume it is an insulator!

Digikey is one of the primary vendors of 3M, and well known for reliability as a counterfeit-free distributor.

https://www.digikey.com/short/zrz730

Also, even if you've not used them before or have no need of kapton tape, take a look because their parametric search is one of the greatest I've seen, and makes Amazon's Choice system seem awful in comparison.

Yes, I regularly order from them, but shipping via DigiKey hasn't been great lately where I live so I went with 3M. I also highly recommend digi-key for anyone's kapton needs. Edit: spelling

> shipping via DigiKey hasn't been great lately where I live

I'm super curious where you live, approximately! I'm in Saskatchewan, and Digi-Key reliably gets me parts next-day, even when shipped DDP (they take care of all of the duty for me). For crossing a border, that's pretty incredible!

I've been tending toward using Mouser lately. DigiKey seems to be playing games with low-volume prices on me lately as well as screwing up shipping.

The only trouble we've had with Digi-Key over the last six months, with dozens of orders, has been coming too close to their end-of-day shipment cutoff. (It seems to be closer in practice to 7:30pm than their advertised 8 CT, but I'm not begrudging them that during this pandemic! This is avoiding restricted materials such as lithium batteries, flux, etc., as well as avoiding value-added items. Order those earlier in the day if you want them fast!) Most of our orders are overnighted, for what that's worth; I know the big distributors do treat overnights differently.

We have never seen a single issue with pricing not as advertised at small quantities, or a shipping mistake not directly attributable to the carrier.

Mouser has performed similarly well but is (and has always been) significantly worse with their cutoff. Again, they're nominally 8pm CT but 6 or 6:30 is more realistic if you're counting on it being here the very next day.

Both are amazing if you're used to crappier distributors, but you do pay for it....

> We have never seen a single issue with pricing not as advertised at small quantities

Ah. No, we haven't either.

The issue is that we have caught DigiKey charging different prices based upon login status and cookie status on low volume order items.

This would be fine if they were charging the returning customer less, but we caught them charging more. That made us very unhappy.

Maybe it was a bug. Maybe it was an A/B test. However, if I have to scrutinize my order cart, we're done.

We still use DigiKey. But we have significantly reduced our volume through them and we watch them like a hawk.

OK, now that I wouldn't have expected! Thanks for the heads up! (Not that I'd likely be able to observe it with our weird procurement flow....)

Yeah over the past 3 years about 1/50 parts i order on digikey results in "surprise! that part you already paid for a few days ago was actually backordered because we didnt update the listing so plz wait 2-3 months thanks." quite irritating when working on a schedule of a few weeks. The wasted time reordering only compounds with all the associated procurement beurocracy on my end. I can't imagine they jerk around their high volume customers like this.

I’ve had to dump DigiKey since they use UPS exclusively, since I’m in Australia, UPS has one facility in my city. It’s a real pain to haul my ass out there because UPS have zero alternative arrangements over here. It’s delivery to the person/address or hold at the facility out in the middle of no where.

So, uh, why not just get it delivered to your address? What am I missing? That's how UPS works.

USA != world

1. UPS do not leave packages at door in all countries

2. Some people live in apartments with nowhere safe for packages to be left

3. In some cities/countries in-person delivery does not exist at all. Only "collect at post office"

I like DigiKey, but sometime they're neither convenient nor competitive.

Food for consideration: since 3M is a ECIA member manufacturer[1], if the source isn't direct from the cow's mouth or one of their authorized distributors, it's prima facie suspect in my eyes and cannot be trusted on anything with skin in the game.

[1] https://www.trustedparts.com/en/manufacturers/3m

If it's not made my Dupont, it's not Kapton... it's polyimide (amber) tape.

And the problem is kapton is just one of many polyimides, (pmda-oda) there are other others like P84 (btda-tdi/mdi).

But nobody knows the generic name (the acronym isn't even in the wikipedia article) so fly by night vendors use 'kapton' wherever they can get away with it.

(and as with teflon, iirc they sell other polymers under the name of kapton too)

If it’s cheap, it’s not polyimide chemistry...

The comments beneath the article have some discussion about Koptan / Krapton.

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