Which seam tapes bond well to X-pac X-21 RC fabric

[Aaron]

I’m curious if the tape is tacky before it’s heat activated.  I’ve been looking for a non-tacky tape to experiment with – for use in combination with a stitched seam rather than replacing it.  Something that won’t gum up a sewing needle.

[Roger Caffin]

Reply received from Taylor, some follow-ups happening.
Sounds as though a domestic iron should suffice.

As far as I can see, the tape is not tacky before activation. In fact, some care is needed to identify which side goes down, but that is OK.

Testing to follow as soon as I can. May be a couple of days.

Cheers

[A W T]

I’d love to try a sample if there are any still available.  I have several projects in mind.

[Aaron]

So it has a “right” and “wrong” side?  I’ll be interested to see how it works out, and try it if any samples become more widely available.  So far I’ve found Bemis Sewfree tape, but there’s not a lot of info out there about it.  It seems to be a 100% wholesale to manufacturer product designed for special factory equipment, and I’m not sure if any of the varieties are suitable for X-Pac.

[Roger Caffin]

Yes. The convex side goes outwards; the concave side goes to the fabric.

Cheers

[Aaron]

I guess I was imagining a double sided tape bonding on both sides, but now I notice in the previous message Taylor called it seam seal tape.  Still interested to see how it works.

[Roger Caffin]

Ah, no it is not a transfer tape. The closest approximation might be the clear PU-based seam-seal tapes typically used on GTX fabrics across the seams. The easiest-to-find similar product is on Amazon:

Commercially a hot air gun is used plus some rollers to force the adhesive into the fabric. I haven’t found any photos of this process in a short search. A domestic iron should work.

Cheers

[Ryan Smith]

Sweet. Super excited about this. Thanks for the effort, Roger and Taylor.

Ryan

[Aaron]

I think Craig of ProLite Gear is (or was?) a member here and demonstrated some heat bonding experiments in a video some time ago.  He demos some double sided tapes he found at fabric stores, but they have a sticky quality to begin with which I want to avoid.  I’m looking for something that I can basically stitch into a seam, and then melt afterwords for waterproofing.  There seems to be a variety of specialized rubber based film adhesives out there, but I’m not sure if any of them are appropriate, or if they’ll melt at the right temperature.

[Roger Caffin]

Yeah, ‘sticky’ and sewing machine needles don’t play together.
I am not sure that rubber-based adhesives would be suitable under most any circumstances. They do have high tack, but they usually stay sticky. Not good.
I am not sure I would go for the idea of sewing the tape INto the seam myself. Iron on afterwards, sure.

Cheers

[Aaron]

Ironing seam tape to the outside only works if the seam is relatively flat without any other attachments sewn into it. This is fine for a garment or the inside of a bag, assuming all internal seams are smooth without any internal straps or structure protruding from the seams.  But if you want to create an internal frame, pad sleeve, etc, this mostly defeats this method of seam sealing  The theory I’m working from is to attempt sealing between the sewn fabric layers, allowing for sewn in strapping.  Attachment points would have to be sandwiched between two layers of adhesive so water can’t seep in from either side.  Theoretically, it would also greatly strengthen the seam.  I’ve created these sort of seams starting with sticky transfer tape, but only on small tests, as they do gum up the machine.

[Roger Caffin]

Ah, attachment points etc. Always difficult.
I have resorted to using 50 mm wide transfer tape with proofed nylon fabric on the inside of the pack for that sort of thing. On the silnylon tents I just went around with silicone sealant on the outside. Best I can offer.

Cheers

[Doug Coe]

Did this DP seam tape ever come to market? Where could we buy it? Or is there an equivalent tape by another company?

[Roger Caffin]

It is available, but I have stopped trying to use it. All I had was a domestic iron, and I think that fluctuated too much in temperature, so that the bonding was a bit intermittent.

Also, I have some doubts about how well it bonds to the DWR-treated surfaces. I have not actually ‘tested’ this: it is just a suspicion.

I have returned to the old faithfuls: 3M9485 on PU surfaces, and silicone sealant (or siloxane transfer tape) on the silicone surfaces.

Cheers

[Doug Coe]

Roger—Thanks for the update. And for the info on what works for you.

[Roger Caffin]

I have also been trying out the Liteskin fabrics. I made a full-sized version of my frame pack and took it on one hard trip. It went fine.

(The red thing on the face of the pack is my map case.)

The LS07 and LS21 fabrics are light, so one has to exercise some care in bad scrub, but the pack went well.

Cheers

[Doug Coe]

I’m planning on using the DM V15 from ripstopbytheroll. Mid-weight; no “X” threads as wear areas. And cool colors!

[Roger Caffin]

The X-threads were designed for sails, not for packs. This is what can happen in a pack with them:

Not a good idea.

Cheers

[Doug Coe]

Roger—Wow, I had previously read your concerns about the X-threads, but that photo really brings it home.

Btw, that’s a very sleek pack you made with Liteskin! (And, yes, I have spent time reading all of your myog pages on “your” website—very interesting and helpful stuff!)

[Roger Caffin]

Trouble is, the backing fabric is not all that tough, so a bit of rubbing inside the pack and that is what happens.

I don’t like ripstop fabrics either, because the heavy ripstop thread wrecks the hydrostatic head. My testing shows all the leaks are along the ripstop thread; plain fabric has a much higher HH.

Cheers

[Chris L]

I am making a pack from x-pax x21rc and hope to seam seal it with DCF seam tape available from RSBTR, etc. Seems pretty straightforward to flat-fell the seam and tape over it.

My question: if I have a double layer of webbing in the seam (compression strap buckle attachment), will that make the seam too fat to tape? I’m considering making small x-pac tabs that the webbing is sewn into and that are then sewn into the seam – so 4 layers of fabric vs 2 layers of fabric and 2 of webbing. HMG does this on their packs. I’m sure this would lead to a flatter seam for taping but seems fiddly and not sure it’s necessary?

Thanks for any help!

 

[Hoosier T]

I did webbing like you describe on my first pack and man the seam was stiff. I did manage to get it taped but it’s not pretty. I did xpac “flaps” on my second pack and it was much more manageable. If you do the webbing I’d recommend just sewing it into a loop with the loop-making seam outside the pack and see just one layer of webbing into the seam.

[Chris L]

Thanks @jturner140 – that was the answer I needed. Sounds like I better go with fabric tabs.

[Author]

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