3M Kapton tape vs. the stuff from Ebay...

Does anyone know what is so special about the real 3M kapton tape as compared to the ubiquitous Chinese variety? A 100mm x 100' roll of Chinese stuff sells for under $20.00 on ebay, but the real 3M stuff goes for $348/roll on Mouser.com and $567/roll on Grainger. What am I missing here?? I thought I might have been looking at case quantities, but I don't think so... 5yd rolls of 3M stuff seem to sell for around $100.

Ebay:
[www.ebay.com]

Mouser:
[www.mouser.com]

Grainger:
[www.grainger.com]

Well, with the Kapton tape they usaually spell it different, like Koptan vs. Kapton. This loser on Ebay is openig himself up to trademark and copyright lawsuits if he's passing chinese slave labor off as Kapton tape. But, to the root of the question, there's not much difference between knockoff chinese products and the real deal. That's because they don't give a crap about patents or intellectual property. They just steal it.

Why do you need 2.7 mil? I can buy 1mil 4" (100mm) by 36 yards from amazon.com for under $40 - polyimide tape - and since it's prime I don't even have to pay for shipping.

I would think amazon would honor any IP licenses.

i got 8.5x11" samples from dupont for free in 3 and 5 mil, they still rip so its not really a big difference for the extra thickness.

Hi,
Kapton is the brand name for DuPont, the inventor and patent holder. . 3M sells Polyimide tape under the 3M brand along with Scotch brand tape.

I got a roll of this "200mm X100ft Kapton Tape" for about $25 on eBay and before that payed like $10 for 50mm x 100ft Polyimide tape (search eBay)
I paid almost twice that for a roll of 1/2" by 33yrd double sided real DuPont Kapton tape.

One thing is that all the eBay stuff is 1 mil, whereas you can get up to 5 mil from DuPont or 3M. The eBay stuff works just fine on my Mendel Prusa i2 over borosilicate glass. The real stuff I have is 3 mil so it's much tougher and hard to compare.

Bottom line, for printing ABS purposes, I've found the eBay stuff to be more than adequate,. Also, for the price you can use several layers of tape, which probably offers more strength than thicker tape.

The reason DuPont charges so much over price of materials and labor is that most of their sales are to the US military and aerospace industry. In order to justify the high prices they charge the government on the GSA Schedule, they have to show that what they charge retail is some percent over what they charge the government, (when you work in DC (USA) you find these things out. I really don't know much about 3M except that is listed on the Dow Jones Industrial index. I guess when you make $30 Billion a year, you don't have to cater to the little guy

Edited 3 time(s). Last edit at 11/16/2013 01:15AM by 3DMD.

Since kapton was used back on the Apollo missions ( [www.thespacestore.com] ) and patent is normally 17 or 20 years in the USA, I'm guessing they don't need to worry about that and are just skating around trademark issues. I've been using some knock-off stuff called kaptan tape also from Ebay and it's been working just fine. It's completely unaffected up to 300C, doesn't ignite at 400C and has adequate adhesion to both PLA and ABS when heated.

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If it is wiped with acetone, and occasionally with ABS juice, there seems to be no difference between cheap Kapton and 3M Kapton (by whatever name). If it is fresh and washed only with the soapy water used to put the film on the glass, the cheap Kapton seems to need 5 to 10 degrees more temperature.

The same can't be said for blue builders tape where 3M builders tape is vastly superior to the identical looking stuff from the pound shop.

Mike

For anyone in the UK, this is where I have twice bought Kapton/Polymide tape: http://themaskingshop.co.uk/detail.asp?catID=12a. Quick shipping and reliable.

I use the 20mm kind on my print bed. I change it only when it gets ripped by accident. I think the reel will last me at least a year if not longer.

Andy

Edited 3 time(s). Last edit at 11/16/2013 04:45AM by ajayre.

Thanks to all who have replied! I have actually been using some "kapton" tape that I purchased from Robotdigg.com and I have been perfectly happy with the results. I'm running a bit low, and I was hoping to find a good U.S. supplier - that's how I happened upon the 3M offerings which had me so confused. Thank you 3DMD for pointing out that my tax dollars are going to support the $30B companies who really need it most. I'm not sure whether to start the revolution or just buy shares of 3M and DuPont.

If anyone is curious about the Robotdigg kapton tape, I have nothing but great things to say about it. I was just hoping to find something stateside with a shorter lead-time. If anyone has experience with other vendors or tapes, share them here!

Quote
Azrael_UK
Since kapton was used back on the Apollo missions ( [www.thespacestore.com] ) and patent is normally 17 or 20 years in the USA, I'm guessing they don't need to worry about that and are just skating around trademark issues. I've been using some knock-off stuff called kaptan tape also from Ebay and it's been working just fine. It's completely unaffected up to 300C, doesn't ignite at 400C and has adequate adhesion to both PLA and ABS when heated.

The polyimide tape patent has expired. It is a trademark issue and 3m uses their traditional numbering scheme for that line of tape. Differences between the name brand and the off brands are the specs and quality of product for a suited purpose. You don't see this with a Reprap because it's a low demand app but in other industrial uses the name brand tapes are superior and in many, if not most cases outperform the off brand tapes. The high end tapes are suitable for apps like wave solder masking and apps that require conductive tape that performs to a high tolerance spec.

The 5mil squares I got from Printrbot seem to be, more or less, permanent. The stuff I got off of ebay ripped almost every time I pulled a part off. The Printrbot sheet is very sturdy and I don't use any of the ebay tape anymore. The sheets seemed pricey at the time but they really are a bargain. I've been using the same two sheets (on 3mm mirror tiles) for the last six months with no issues.