Hybrid Cuben CDT

Looks nice.

Are the ULA cuben packs waterproof? Not much (or any?) information on their website about their cuben packs.

ZPacks cuben packs aren’t waterproof. Here’s what they say on their FAQ Page:
“Are ZPacks backpacks waterproof?
The Cuben Fiber material is waterproof, and the packs are very water resistant. They should not be considered 100% waterproof due to the sewn through seams, attachment points, and inevitable wear and tear. They will do fine in light rain or a brief shower, but in an all day downpour consider adding a Pack Cover, a Pack Liner, or a poncho.”
ZPacks Backpack FAQ

Negative, they aren't waterproof, although you can get fairly close by taping the seams.

p.s. – You have to email ULA directly about using hybrid cuben. Chris is really easy to work with.

Ryan

Very nice. What do you have planned for the dual side straps?

I've got a hybrid cuben ULA pack on the way as well. It's a Catalyst for longer packrafting trips. Uses green cuben/hybrid fabric (pale ULA green) and a bunch of other mods. Mine's getting seam taped.

Ryan,

What size is the pack?

Thanks

Derrick

Hi Dan,

I fly fish quite a bit so I usually keep my rod tube strapped onto the side. One strap probably would have been OK, but figured a little extra security there couldn't hurt. When not fly fishing, I will just use it for a little more compression. I hope you will post pics of your Catalyst, the pale green sounds interesting. Are you seam taping yourself or ULA?

Derrick – It's Med waist/Long torso. ULA's measurements used to be a little odd for my size, but now they seem spot on.

Ryan

I got a sample of the green cuben hybrid from Chris. It's hard to explain but essentially it's dark "ULA green" cuben on the inside and the outer polyester is still white. The dark cuben inside sorta shows thru though (or maybe the outer polyester is colored a bit) so the result is that the fabric looks green-ish off white. I'd prefer more color, but it's still nice. I'd post a pic of it next to my wife's white HMG Windrider but I seem to have lost the sample now.

For seam taping, I'm going to try making my own tape first. I've got some double sided 1/2" tape on hand that I've used for other cuben projects, so I'm going to make some single sided tape by sticking that to some 1.2oz black cuben scraps, and then cutting out the strips. If that turns into a nightmare or if 1/2" width is too narrow then I'll just buy some cuben seam tape from Zpacks. I want it to be as waterproof as it can be for packrafting, so they've deleted the hydration ports as well.

Great minds think alike – I had the hydration ports removed from my CDT as well(ice axe loops & retainers as well). I will be curious just how water resistant they are with the seam tape applied. 1/2" tape may be just wide enough to cover the seams, but it will be close just going from memory. I ordered some Zpacks tape just out of lazyness. :)

Ryan

I found that on the recent packs I made that tape works fine for long straight seams but it's tougher to get a seal down in the corners or on tricky seams. Seam Grip is a little messier but I think probably more waterproof and adds quite a bit of seam strength. If you want to do it neatly just using some masking tape along the edges.

Do you remove the masking tape when it's all dry? Or right away when you're done applying the sealant? I wonder if the masking tape might get stuck there if there's a lot of seam grip applied and then it's allowed dry.

Any thoughts on 1/2" tape? You think it'll work?

Just thought I'd add a bit of an update that is hot off the ULA presses as of TODAY. My custom hybrid-cuben pack will be the first time they're constructing a pack fully seam-sealed by them. I've ordered the Circuit Pack to be made out of the white hybrid-cuben with black robic fabric layered over black hybrid-cuben on the bottom of the pack and the bottom of the side pockets. Rodney tells me my made-to-order pack will be at my MN doorstep by April 2nd. Can't wait to see and try out this awesome pack!!!

Very cool Elisa! I assume they are taping?

Ryan

Yes, Ryan. They WERE going to be taping my pack, but apparently ULA was sent the double stick tape used to bond cuben fabric together rather than the cuben tape they thought they ordered. Rodney would have been happy to tape my pack as soon as they got the correct product in, but I got anxious for my pack and had them send it right away. The pack should be at my doorstep tomorrow!!! :-)

By the way, from a 9:36 AM call from Rodney to hear from me what customization I wanted on my pack to its completion…by 4:30 PM the SAME business day!!!! They'll send me the cuben tape when they get it and I'll try to do the taping myself. ULA has been GREAT to work with.