Polyimide (kapton) tape - is it that expensive? - Page 1
Forum section: electronics / beginners

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: April 24, 2017, 05:40:37 am
content: Hey guys,I've been wanting to get myself some kapton tape for a while now, and wanted to order some when I order from RS or Farnell next time. However, the ones I find on RS are quite expensive, or at least more than I was expecting. What I'm looking at costs me about 20 euros for a 12.7mm x 33m, 0.076mm thick roll (link at the bottom). Is this a normal price, or should I look at other sources?http://benl.rs-online.com/web/p/electrical-insulation-tapes/8421115/

author: ataradov
author_rank: Super Contributor
timestamp: April 24, 2017, 05:56:40 am
content: Here is the same tape for less than $6 -https://www.amazon.com/BCP-Kapton-Polyimide-Silicone-Adhesive/dp/B00W3FAFP0/Prices in Europe will be different of course, but there is no reason to overpay to "reputable" suppliers. All that stuff works the same.

author: Dago
author_rank: Frequent Contributor
timestamp: April 24, 2017, 06:41:12 am
content: You can get "Koptan" (yes, really!) tape from ebay for < 1$ a roll which seems to work almost as well as the real stuff. Seems to be genuine polyimide (won't be damaged with a soldering iron etc.) and works great. I bought a couple of rolls of each size for like 10-20 $ total...

author: gamalot
author_rank: Super Contributor
timestamp: April 24, 2017, 06:47:46 am
content: I bought a few rolls of Kapton tape on Taobao a few days ago, very cheap.

author: Mechatrommer
author_rank: Super Contributor
timestamp: April 24, 2017, 07:13:01 am
content: $1 but it doesnt stick well or strongly as normal paper tape on some material like paper or plastic, even metal where it suppose to be, i mean it does stick but, easily peelable, not sure the original stuff.http://www.ebay.com.my/itm/10mm-100ft-BGA-High-Temperature-Heat-Resistant-Polyimide-Gold-Kapton-Tape-Roll-/192143849284?hash=item2cbcaa7744:g:FwwAAOSwSlBY3Lq~

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 24, 2017, 08:04:57 am
content: I bought a roll of 3M brand yellow polyester tape and one of 200C Kapton (silicone adhesive), years ago. Hardly made a dent in them. Practically a life supply.There are bigger things to worry about than cheap, shitty tape or paying $40 once in a long while.Tim

author: janoc
author_rank: Super Contributor
timestamp: April 24, 2017, 08:39:36 am
content: Quote from: Mechatrommer on April 24, 2017, 07:13:01 amIt is probably the original stuff. That one doesn't stick so well neither. If you need to use it as a fastener then you shouldn't use Kapton tape. It is mostly to be used as an insulator, either electric or thermal (or both).

author: David Hess
author_rank: Super Contributor
timestamp: April 24, 2017, 03:00:24 pm
content: Kapton tape *is* more expensive but in less demanding applications there are other materials which can be used like Mylar (polyester). Some of the difference may be the adhesive since it takes a high temperature adhesive to take full advantage of the high temperature capability of Kapton.

author: wraper
author_rank: Unknown
timestamp: April 24, 2017, 03:03:02 pm
content: There is a huge difference in adhesive quality if buying ebay tape. Also Chinese tape usually is very thin. The tape itself seem to withstand temperature about the same.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 24, 2017, 03:07:46 pm
content: Note that polyimide is amazing stuff.It can survive up to nearlyred hot temperaturesfor short periods of time.It has very high dielectric strength.It has excellent chemical stability: great resistance to corrosive fumes (other than strong acids or bases), free radicals, high voltage corona, and nuclear radiation.The stuff can survive re-entry from space*.(*Not in and of itself, of course, but metallized polyimide film is used to cover the rear surfaces of re-entry modules. It erodes at a modest rate, doing its job of protecting the module.)There is almost no reason you should ever need to use such a fantastic and amazing material! Perhaps just for the convenience of soldering against it (which it's more than comfortable with!). Fortunately, there's hardly anything that you could substitute for it (everything else is brittle, or melts!), and it's not much more expensive. Wonderful!Tim

author: tszaboo
author_rank: Super Contributor
timestamp: April 24, 2017, 03:08:23 pm
content: Quote from: gamalot on April 24, 2017, 06:47:46 amIs chinese Kapton similar to chinese watts?Everyone knows chinese watts are smaller.

author: rrinker
author_rank: Super Contributor
timestamp: April 24, 2017, 03:27:05 pm
content: Quite often used in model railroading, particularly with DCC decoder installation. In many case, the original system was designed to transfer power from the wheels to the motor as cheaply as possible - this usually involved rubbing metal contact surfaces. For DCC decoders, the motor (brushes) MUST be isolated from the wheels, it's a 4 wire system (2 in, 2 out) and never must the output be allowed to contact the input or the magic smoke is quickly released. Kapton tape is preferred since it is thinner (keeps the motor better aligned with the rest of the mechanicals, and space is often at a premium - a mm here or there can be the difference between the body shell fitting back on or not), stronger (resists wearing through), and also far less messy than black electrical tape, which leaves a gooey mess everywhere. I bought a roll some number of years ago and it's probably more than I'll need in a lifetime, but it's there and available whenever I need it.

author: gamalot
author_rank: Super Contributor
timestamp: April 24, 2017, 03:34:56 pm
content: I just use those tapes to isolate heat while using hot air gun to remove components, so they are not different to me.

author: tszaboo
author_rank: Super Contributor
timestamp: April 24, 2017, 03:37:44 pm
content: Quote from: gamalot on April 24, 2017, 03:34:56 pmYes, and others like me are going to use it to surface mount a little patch PCB inside a test equipment, designed to be working for eternity. Where the glue is supposed to hold, be stable, not conduct.

author: David Hess
author_rank: Super Contributor
timestamp: April 24, 2017, 05:06:45 pm
content: I always like referring to Kapton tape as aerospace tape. We used it to hold assemblies together while they were baked in the oven.

author: james_s
author_rank: Super Contributor
timestamp: April 24, 2017, 05:38:59 pm
content: I got the rolls I have from tapecase.com I think, I don't recall how much it was but it wasn't terribly expensive. It's very useful stuff, I use it to mask solder when I'm soldering something that doesn't have a mask, to tape a thermocouple to something I want to monitor temporarily. Works well for providing thin electrical isolation, it's good stuff.