Cuben fiber modifications

I use the micro fine needles and gutterman polyester thread on cuben. Always sew first and then tape last if you are using tape to reinforce or seam seal as the glue on the tape will gum up your needle. You can't cut cuben with normal scissors- I use a utility knife with heavy duty hardened blades.

Thanks for the insight jimmy! Ok so I should apply cuben tape/seam seal on the edges so the slit doesn't widen? Also noticed that zpacks has stick on patches with pull loop. Will these stick to outside of pack or only work on interior?

The stick on stuff from Zpacks sticks very well to cuben. If you did not want to sew the velcro on you could just use some seam grip. With cuben the wider (longer) the stitch the better, real tight stitches will weaken the material. Yes I would use a little piece of tape or cuben to reinforce around the hole/slit.

Awesome thanks. What brand of seam grip do you recommend and is this permanent or can it be removed somehow? Also are there any self adhesive velcro patches that will stick to cuben that your aware of?

"Also are there any self adhesive velcro patches that will stick to cuben that your aware of?" Most things stick to cuben. Zpacks used make stick on velcro patches. Maybe they can make some up for you?

Seam Grip is a brand. They make several sizes. You can buy adhesive backed velcro at local fabric store. owfinc.com sells it.

When people say everything sticks to cuben, they're referring to the urethane laminate, not the polyester weave of your hybrid material. Seam Grip brand seam sealer will indeed work because it is a urethane based sealer. You can use that to glue on strips of regular velcro. Self adhesive velcro might work; glue-on will definitely work. Any time you attach anything flexible w/o sewing, it's best to round the corners first. Pointy corners can start to peel. Cuben tape will work on the inside to seal any stitches you might add, and to re-enforce the hole. You may find that a 1" straight slit is too small. I have a pack w/ hydration port that's a bit too tight and it's a nuisance. Taking the time to model your hydration port w/ some scrap fabric or plastic film (a garbage bag will do) will be time well spent.

Thanks Rene, very helpful answer. If I did use seam grip to apply the velcro is there a way to remove it later without compromising the cuben?

The laminate that holds together the spectra fibers in cuben fiber is a urethane. Anything that could dissolve a urethane sealant would likely damage your bag in the process. I'm guessing you want to be able to remove what ever you attach in case you don't like it? You could mock your attachments with tape to try them out. They may not last more than a day or two on the trail and you'd have to be gentle, but it would give you a lot of practical information. If you want something real that you can still remove, you should either sew it on, and accept the needle holes, or come up with a design with everything on the inside of the pack and just cut off what you can if you don't like it – at least the mess will be hidden. Adhesives will work on the laminate side of you pack material, but do your homework before picking one. Some tapes have a bonding strength greater than that of the bond between the laminate layers in cuben, so if you try to peel them off, you'll delaminate the fabric. To rain-proof a hydration port on the inside of the pack, imagine the little hoods you see over dryer vents on the side of a house. Turn that upside down and put it on the inside. A rectangular patch sealed on 3 sides would do the trick. If you use adhesives, you'll need to use extra tape on the inside of the patch to prevent it from peeling off when you insert and remove the hose. Feel free to PM me if you don't know what I'm talking about w/ the extra tape.