Anyone use Kapton tape for seam sealing silicone coated fabrics?

The adhesive on Kapton tape is DESIGNED to release fairly easily. It is often used for masking purposes when gold-plating PCBs.

If you can find some with a permanent adhesive, do let us know.

Cheers

Hi Roger, thank you for the feedback.  Yeah, i got that sense from reading some of the amazon reviews.  I was hoping that the poor adhesion that some had mentioned, was due specifically to the silicone adhesive used and the fact that they were often taping different plastics and metals which are hard to bond to to begin with, and might not apply as much when bonding it to a silicone coating.

Reasoning being, is that i thought same materials, can bond more molecularly in a direct way?   Like silicone spray DWR sticks (bonds) better to a previously silicone treated fabric, than to non treated fabrics.

Perhaps adding heat and pressure (like using an iron), could help facilitate this?   Either way, it’s inexpensive enough to try without much loss.  Or, are you fairly certain it won’t work well at all?

Hi Justin

The silicone polymer used for the adhesive is designed to have only a small number of available bonds for sticking to another surface. That means it just will not (can not) form a serious bond. They use Kapton as the carrier because the processing temperatures can get very high, while Kapton can handle up to 400 C (not F). So I don’t think either heat or pressure will help. Pity.

Cheers

Good to know Roger.  Are there other tapes out there that use a more bonding silicone based adhesive?

Oh yes, definitely. You want a permanent siloxane adhesive tape. They exist – I use them on my tents, and they do work. A ‘transfer adhesive’ would be best: that is just the adhesive layer and not carrier. You use your own fabric as the carrier, so it match the elasticity of the fabric. Much Googling needed, but you could start at
http://bushwalkingnsw.org.au/clubsites/FAQ/DIY_RNCSeams.htm
https://backpackinglight.com/forums/topic/9431/

Two things to note: Siloxane tapes are more expensive than ordinary tapes, but they work. Also, you will need to leave the tape for 72 hours before you use it. It takes that long for the siloxane to chemically bond with the silicne coating on the fabric. This long time is a major reason why commercial mfrs do not try to tape-seal silnylon seams.

Finding them is difficult, as all the search engines will pick up all the ‘other’ sorts of tapes and so on in an effort to be ‘helpful’. They aren’t; they just confuse the search. Instead, go to the major tape vendors and search for ‘siloxane transfer tape’ there. At least Google etc can help you find them.

Caution: do NOT even try to use a rubber adhesive or an acrylic adhesive. While they are far more common and much cheaper than siloxane, they will not bond. Been there, tried that.

Cheers

Much thanks for the info.  Sounds like it would just be easier, or at least cheaper to use the traditional and more common method of seam sealing silicone coated fabrics.

Have you used the tapes to get a more waterproof seal, to reinforce/strengthen fabric connection, and/or some other reason?

As to whether it would be easier – that would depend on just what you are trying to do. For sure, running a fingertip of silicone sealant along a seam in a tent can be easier and very effective. It can also be effective at coating a line of sewing for mechanical protection, if that sewing is going to rub on the ground.

As to why I use tapes – sometimes it was to get a good waterproof join, sometimes it was to cover over a double line of sewing, and sometimes it was to reinforce a corner or an attachment point. And sometimes a combination of these.

Cheers