Abrasion in back of Pilot

[bchaplin]

Does anyone else have this kind of thing going on in the inside of the back compartment of their Pilot? I can't think what is causing it. I haven't noticed it before, but it could have been there for a while.






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[tpnl]

It looks like the interior waterproof urethane coating is coming off - perhaps by rubbing against something rough? I have something like this on my 2004 Brain Bag - but it was my fault for washing it in the washing machine a few times. Also, could that section have come into contact (for a while) with something like rubbing alcohol or nail polish remover/acetone (basically something that can be destructive to fabrics)? Other than that, it could be an rare unfortunate defect.

[bchaplin]

If it is just the coating and not the fabric I don't mind. I can respray it, since I have Nikwax. It is unlikely to have come into contact with the chemicals you mention, but who knows?

[GoStanford]

If it is just the coating and not the fabric I don't mind. I can respray it, since I have Nikwax. It is unlikely to have come into contact with the chemicals you mention, but who knows?

Can you post a Nikwax tutorial for those of us who have never used it? I have never gotten a bottle but I can see needing it down the road for maintenance.

[bchaplin]

If it works, I will.


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[tpnl]

Just to clarify - the issue in your pictures is is not the Nikwax waterproofer IMHO. In each TB bag (that I know of), there are 2 things done for waterproofing.
On the exterior, the Nikwax is sprayed on so the fabric does not get wet and needs to be recoated every so often. The urethane is something different. It is permanent and acts as a second waterproof barrier between the fabric and the inner contents (as opposed to a barrier between the rain and the fabric which is the job of the Nikwax).

See this part of the TB Faq on waterproofing: TOM BIHN: FAQs

Essentially, there is no good (read permanent) way to recoat the urethane - you can buy some urethane spray I think and recoat it but it tends to flake off after a while (this is what I have been told).

Hope this explains things a bit better.

Cheers!

[bchaplin]

Oh, I see. Thanks. I misunderstood.
Maybe I could get an iron-on patch (like the kind you use for jeans; I don't even know if they are sold anymore), to prevent further fraying.

Just to clarify - the issue in your pictures is is not the Nikwax waterproofer IMHO. In each TB bag (that I know of), there are 2 things done for waterproofing.
On the exterior, the Nikwax is sprayed on so the fabric does not get wet and needs to be recoated every so often. The urethane is something different. It is permanent and acts as a second waterproof barrier between the fabric and the inner contents (as opposed to a barrier between the rain and the fabric which is the job of the Nikwax).

See this part of the TB Faq on waterproofing: TOM BIHN: FAQs

Essentially, there is no good (read permanent) way to recoat the urethane - you can buy some urethane spray I think and recoat it but it tends to flake off after a while (this is what I have been told).

Hope this explains things a bit better.

Cheers!

[adalangdon]

Oh, I see. Thanks. I misunderstood.
Maybe I could get an iron-on patch (like the kind you use for jeans; I don't even know if they are sold anymore), to prevent further fraying.

I would be extremely careful with iron-on patches! Maybe the ones I've worked with sucked, but you need to whack those things with an iron at the max (i.e. cotton, linen) setting to get them to stick. That would only be really okay if you were ironing onto cotton fabrics. I think. Someone with more experience will know better.

[icebeng]

Is there such a thing as safe fabric glue? That might work better.

[adalangdon]

Is there such a thing as safe fabric glue? That might work better.

There's Liquid Stitch, which came to me highly recommended but doesn't help iron-on patches stick better, or so I found. The problem lies with the iron-on backing-- it's smooth and will not let something as wimpy as fabric glue bond to it. That's why when I try to stick decorative patches onto cordura, I first attempt to strip off the backing (sometimes you just can't), then glue + sew.

I'd be very interested to know if there are stronger fabric glues out there!

[tpnl]

Don't laugh ... what about duct tape? There are ones that are black in color and it will keep water out pretty well. Cutting a small round patch would work.
Also, getting a tent patch kit should work...after-all, the Nikwax is for tents and gear.

Hope this helps!

Cheers!

[icebeng]

Quick question: how much of the waterproofing is provided by the urethane layer?
Would a bag without the urethane layer be totally susceptible to rain?

[tpnl]

Based on what I understand:

Essentially, to make a bag waterproof, there is usually a multi-layer protection approach used. You need to protect the bag fabric from getting wet (and shrinking), protect the inside contents and make sure water does not get throught seams and zippers.

The urethane is only one part. It is a permanent part that is used to protect the inside of the bag. However, it cannot cover seams, zippers or the outside fabric itself
So, to answer your question, the urethane provides most of the waterproofing between the outside fabric and the inside of the bag but misses the seams and zippers.

The nikwax waterproofing spray is another part and is the first barrier that keeps water from soaking the fabric and getting though the seams. However, it is temporary as it wears off and needs to be replenished.
So, to answer your question, a bag without the urethane layer can still be waterproofed via the waterproofing spray. However, this is temporary and needs to be reapplied as you brush the waterproofing off the bag in normal use.

The YKK zippers esnsure the zipper part does not allow water in.

Bag design is important for waterproofing - ie - physically designing no places where water can pool (e.g. the fabric zipper covers on the Brain Bag, how the connection points between zippers and bag fabric are sewn, no open top pocket sections of the bag, streamlining bag so water flows off when sitting normally). This is where the years of experience that Tom Bihn and his crew have really shines.

Finally, material choice is important too. Ballistic Nylon / Cordura are a good balance of strengh and quick drying. For example, Polyester is better for drying faster when wet but is not nearly as durable or strong - Cotton - takes a long time to dry. Dyneema is fairly well waterproof because of the way it is designed.

I may have missed other factors so others, please add in.

Hope this helps
Cheers!

[saikyo]

I have the same problem and posted about it in another thread.

[DeBru]

Is it possible that it is heat damage to the coating, perhaps from a hot battery on a laptop or tablet? FWIW, I definitely would not use an iron on patch, the temp needed to fuse the glue would very likely melt the nylon. Maybe try using a small craft paint brush and apply a clear, strong glue? something like Liquid Stitch that adalangdon mentioned.