Choosing fabric for my first MYOG backpack

I made a pack out of a laminate and it delaminated.

Currently I use a 200D Nylon.  Actually, the 210 Robic from rsbtr.  That works pretty good.

I want it to be waterproof, so I like that that 210D Robic is advertised to be waterproof, but it’s still not, so I sprayed it with gear aid tent fabric sealant which made it waterproof.  I expect I’ll have to redo occasionally.  The gap between 200D fibers is too big so it’s hard to get a waterproof coating.

Polyester isn’t as strong as nylon, but not by much.  I would think a 200D polyester would be just as good.

No personal experience, but HyperD 300 might be an alternative. It’s polyester in the same weight class as 210D Robic. The Robic is Nylon 6 (very strong). Both are coated for increased water resistance (PU for HyperD and UTS for Robic — supposedly makes it stronger).

Just going by the specs, the Robic appears stronger while the HyperD is 10% lighter and should absorb less moisture (so will remain lighter when wet).

I’ve built close to 20 packs with a bunch of different fabrics. I still go back and forth on which are my favorites. I find experimenting with different fabrics as fun as playing with different designs :-) Eliminating laminates makes your choice easier.

I have some experience with Challenges RBC fabrics, and I find that they have a very light PU coating and to be less water resistant than other coated fabrics. I’ve not found any specs on the waterproofness of the RBC line either. If you’re not particularly concerned with water resistance, the RBC fabrics are cheap and the polyester will absorb less water. I’d go with at least a 400d fabric (the 450 ripstop is really nice). 200d in polyester is probably a bit weak for a backpack.

I’ve used Ultragrid quite a bit and if you don’t mind the price, it’s the fabric I’d recommend. It’s light, strong, looks good, fairly easy to work with, and has a much better PU coating than the RBC fabrics.

The 200 and 400d Robic fabrics from Ripstop by the Roll are nice and cheap, although probably harder to get in EU.

Good luck with your project!

I’ve made packs with generic 200D nylon and 210D Robic.  I have never seen any failures from fabric ripping or anything.  No need for expensive dyneema.

Just one data point.  I am fairly careful with my gear not to destroy it.

I made a pack with 1.9 osy silnylon and that ripped after a while – that’s too lightweight.

I made my first pack in the last year using the P/U version of RSBTR Hex70 XL fabric.  Really inexpensive at $8.75 per yard.  It has a little thickness to it but weight is low.  Fairly easy to sew as a newbie to sewing. My pack came in at about 15 oz and I started my last trip with 23 lbs and it held fine. The material itself is waterproof but I need to seam seal it.

I’d use this material again as a low cost option

Thanks for the suggestions.

I ended up going with ultragrid.