Do all Kapton tapes have the same performance ? - Page 1
Forum section: electronics / beginners

author: l3gi0n
author_rank: Regular Contributor
timestamp: October 20, 2021, 05:41:17 pm
content: I bought 2 rolls of Kapton tapes a while back. The seller claims Short period Heat Resistance is260℃and Long period Heat Resistance is220℃.I am looking at another model that claims Short period Heat Resistance is300℃and Long period Heat Resistance is260℃.Should I purchase the second one because it performs better ?I want to place several SMDs on a rail with solder on it, then use Kapton tape to keep them in place and prevent movement and then use hot air to make the connections...

author: wraper
author_rank: Unknown
timestamp: October 20, 2021, 05:49:59 pm
content: Beside that they have a different thickness, the major difference is adhesive. And it's performance is vastly different among tapes of different price range.

author: l3gi0n
author_rank: Regular Contributor
timestamp: October 20, 2021, 05:56:12 pm
content: Are the rolls that I have adequate ?I have these :https://www.amazon.ca/gp/product/B00XH9Y7FU/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1Can you recommend something better ? for the task I need them for ?

author: wraper
author_rank: Unknown
timestamp: October 20, 2021, 06:06:42 pm
content: It's a cheap stuff. If you want the adhesive to hold at high temperature, probably get something else several times more expensive and with a reputable brand name. Otherwise it should be OK. Likely there is something like Koptan written on the piece of paper at start of the roll, since Kapton is a trademark of DuPont. A really good stuff like 3M costs a lothttps://www.digikey.com/en/products/detail/3m/5413-AMBER-1-2IN-X-36YD/59546?shttps://www.digikey.com/en/products/detail/3m/92-AMBER-1-2-X36YD/1630230

author: wraper
author_rank: Unknown
timestamp: October 20, 2021, 06:14:21 pm
content: BTW if you want it to cover something while you are soldering those capacitors from the other thread, you don't need it really unless there are some heat sensitive plastic parts nearby.

author: l3gi0n
author_rank: Regular Contributor
timestamp: October 20, 2021, 06:20:31 pm
content: I want to tape the caps and then heat them...without the tape the caps move around too much..

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 20, 2021, 06:37:02 pm
content: If it's proper polyimide film, and not like, Idunno, does anyone dye polyester to fake it? I wouldn't put it past them... Needless to say if you're buying no-names from, whatever, Amazon, Ali, eBay... you're gonna get whatever. Maybe it's the real deal, maybe it's an empty box.Anyway, there's the two parts, as you can see. Polyimide film by itself is incredibly robust, it can survive nearly red hot (for brief periods) before turning to crud. So it's obviously fantastic for soldering.The trouble is sticking it in place. There's three common adhesives, more or less: rubber, acrylic and silicone, in increasing order of melting point. The first one just bubbles and burns at soldering temp, I think? The second can be used but gets very soft, or bubbly. The last basically shrugs it off, good as at room temp.The one thing I think silicone adhesive does poorly, is oils. Fingerprints don't go well together, clean everything that's touching it (so, wash your hands or clean with solvent, clean the work etc.).3M #92 is pretty good, or I think that's what I have, the number wore off it long ago...Tim

author: l3gi0n
author_rank: Regular Contributor
timestamp: October 20, 2021, 07:39:45 pm
content: I guess the rolls that I have are good enough since they use silicon ? I used some of the tape on my glass table and the stickiness is reasonable...Besides keeping SMDs in place, I want to tape an IHS to the CPU so that when I flip the board the IHS wouldn't fall off..Would they lose their stickiness at 100C ?Can they withstand the hot air for soldering SMDs ?Should I purchase a roll that can withstand higher temperatures ? Mine can withstand 260C ...

author: wizard69
author_rank: Super Contributor
timestamp: October 25, 2021, 08:58:48 pm
content: Really you need to download the manufactures datasheet. We don't know who the manufacture is and thus have no idea how the tape will perform.Given that I have to wonder why you need to tape everything down as it is. Parts move under reflow it is sort of part of the process. If you don't want them to move maybe a glue would make more sense. The problem as I see it if you remove the tape after soldering you will stress the parts - how much I have no idea.I don't know the specifics here but generally I don't like taping things in place as part of an assembly process.Quote from: l3gi0n on October 20, 2021, 07:39:45 pm

author: BrokenYugo
author_rank: Super Contributor
timestamp: October 26, 2021, 12:29:39 am
content: There's a reason the cheap stuff is cheap, they pass the job of characterizing it on to you.If you need something you can trust performs to spec you can't go wrong with 3M.

author: Siwastaja
author_rank: Super Contributor
timestamp: October 26, 2021, 11:43:37 am
content: With anything from Ebay/Amazon, all bets are totally off.Personal experience: Kapton tape isn't even Kapton. I don't mean as brand name; I have got "Kapton" tape which isn't polyimide tape at all, but some polyester or similar plastic. How do I know? It melts already at some 150 degC. Complete scam.Sometimes you do get polyimide and it really seems quite equivalent to actual Kapton, but then again, the adhesive may be total joke.Just don't buy Kapton from Ebay, my success rate is close to 0%.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 26, 2021, 01:05:06 pm
content: Quote from: Siwastaja on October 26, 2021, 11:43:37 amAh, so you HAVE seen dyed stuff? That confirms it.Tim

author: Siwastaja
author_rank: Super Contributor
timestamp: October 26, 2021, 01:07:43 pm
content: Yes indeed. The "feeling" was quite right, including the color, and surprisingly that particular tape had fairly good adhesive so ended up using it for anything requiring "general purpose" tape with no temperature resistance.

author: wraper
author_rank: Unknown
timestamp: October 26, 2021, 01:16:22 pm
content: I've bought several cheap tapes from ebay and all of them were the real stuff.

author: Siwastaja
author_rank: Super Contributor
timestamp: October 26, 2021, 04:45:39 pm
content: Let me clarify the "not even polyimide" case was just once.I have bought more after that and the only problem has been totally substandard adhesive to the point of the product being useless.The "total fake" was more useful to me, actually.