Roger,

I am just throwing out these thoughts, as it is hard to consider/measure all the factors relating to rain versus static pressure. Plus, I have the flu and it is hard to sit still :)

"Just a thought, Here are some of the makers specs:"

James,

The links don't say much about water resistance.
In the last one, CT says:

"B. Surface Coatings
Film coatings, such as Mylar (a biaxially oriented PET), are used for their high tensile strength, toughness, chemical and dimensional stability, gas barrier properties, high temperature resistance and low coefficient of friction."

No mention of water resistance.

This darn thread was the final factor in my decision to put 1 oz rather than .5 oz cuben on the underside of my splash bivy. I'm sure the .5 would have been fine, but after reading this thread that little voice of doubt really worked away at me.

> No mention of water resistance.

How ... interesting!

Cheers

No, that's right. They do, however, mention it in the front adds. The one about the inflatable rafts.

From the Protocol B thread in the MYOG section, Ben Smith's samples of 0.51oz (CT1K.08) and 0.69oz (CT1K.18) both were waterproof beyond the testing limit of Richards's machine (3500mm). That's a huge difference between the 420mm observed here and elsewhere.

I forgot that the testing results would be posted in another thread in a different forum. Too bad they aren't here. Richard, thanks for conducting and posting results.

Based on the photos of the cuben fabric in the MYOG thread, there appear to be different weaves for the same weight of fabric or the photos are not all of the same magnification. The one submitted by Ken Larson has a wider weave and the picture appears to indicate black areas, possibly breaches/holes etc. in the material. Whereas the samples submitted by Ben Smith seem to have a tighter weave and less or none of the black areas noted in the Ken Larson sample.

Konrad posited that the Ken Larson sample must be used and therefore the use has caused the degredation. A good idea. Can this "stuffing" really be the cause to degrade the fabric that much? Or is it that the samples of .51 oz cuben from Ben/Ken are different grades or types of material? It is noted that Ben's samples have exact nomenclature numbers and Ben's do not. Maybe Ken's is significanlty older than Ben's? Not the newest iterations of the material? -This is all very interesting. I just hope that stuffing/general use of the fabric cannot/does not degrade the material in such a way.

Richard, did the samples from Ken and Ben(.51 oz) look all that different to the naked eye? What was the porosity of these individual samples?

Warren,

Air permeability testing is MUCH more time consuming that HH testing. Ben Smith wanted to test some non-coated fabrics and I agreed to do it for him as a one-time favor. The objective of protocol B is HH testing of coated fabrics only.

All micrographs were taken with the exact same magnification (200x) and the exact same bottom lighting level. Unfortunately heavy polyurethane coatings are opaque and so little light reaches the fabric to illuminate it. Fortunately UL fabrics are either silnylon or Cuben and the light more clearly shows the weave structure.

I do not know why the first three samples tested with low HH. Two different samples were tested by me and one by Ziff. It is OK for the readers to guess now. I prefer to conduct the aging tests and study their results before I make a guess.

Edited by richard295 on 03/31/2011 13:37:38 MDT.

WoW! What an evening's entertainment. Big diff between 3515 ( maybe higher? who knows? since that's where the machine stops right ?) and 422

Cola,

Per the International Standards Organization 811, a shelter fly needs to have a minimum HH 1,5000 mm H2O to be "rain proof". You are correct, that there is a BIG difference between the first two Cuben samples I tested plus the one Ziff tested at approximately 422 mm H2O versus the last two I tested at >3,515 mm H2O.

Submissions from two other people just arrived in the mail a few minutes ago. So, stay tuned later this evening for updates on the Protocol B thread to what you called, "WOW, What an evening's entertainment".

Richard,

Thanks for the education on permeability. Didn't realize it was time consuming.

I thought that all the graphs indicated a magnification of 200x.

I figured you'd want to wait for ALL the data to come in. And thats statistically smart. Thanks again for all your work. This is some interesting stuff.

BTW, It would be great if the fabrics undergo a 200x magnification before and after testing, both being completed before the aging.

Although it's still early in the testing, it is clear that the HH results are varying widely for supposedly the same fabric (CT1K.08).

The main question left seems to be 'why are the results varying widely?'. It seems to me that it has to be either:

A) Some Cuben is created far more waterproof than other Cuben (manufacturing issues)
B) Cuben deteriorates in waterproofness (abrasion? time? creasing? stretching?)

At this point, I don't see any strong evidence indicating whether it's A or B, but testing on B should indicate whether B is true.

Edited by dandydan on 04/01/2011 16:54:10 MDT.

Warren,

Only if there is a dramatic degradation from the Protocol B aging cycles for a Cuben sample, I will take another micrograph of that sample at the end of the aging to help in problem resolution.

Keep in mind that each aging cycle is more than 8x the work of the initial test. There are some people understandably impatient for a quick anomaly resolution.

Check the calibration of you equipment?

Warren Greer, I have been studying some 4 year old Cuben and it has the same black specks that are in the Ken Larson sample. I have been putting it through stress tests. Under my microscope at the same magnification the specs do not appear like breaches in the Mylar but simply are microscopic grist in the adhesive. They do not appear structural or to be breaching structure at all. It's too bad the photos supplied here cannot be of higher quality.

Edited by wildlife on 04/01/2011 11:53:02 MDT.

Nick,

The short answer to your question is, "Yes". The long answer follows:

I test a low HH reading Cuben, followed by a high HH reading Cuben and then repeat the sequence and get the same readings. It seems illogical to me that calibration could possibly explain this phenomenon. If the calibration needed to be adjusted, all the reading would be higher or lower than they should be; different samples wouldn't vary by ~600% HH on a consistently repeatable basis.

MY commercial grade HH tester was manufactured and certified for accuracy May 2009. It was unused and wrapped in plastic until I un-wrapped it about 30 days ago.

Look at the one independent test done by Ziff and the battery of tests done by Lance Marshall. They both used different types of DIY HH test equipment but for each general fabric type tested and the results correlated. Significant calibration error using any of the methods wouldn't have resulted in the results being close.

My significant other is a molecular biology scientist who works in a research lab every day. I have had her independently duplicate my tests using Protocol B and my equipment. The test result differences have been in the noise level. They primarily arise from large sample surfaces where the test head is placed at different random locations by each person.

Mountain Laurel Designs owns a commercial HH tester and Ron has possession of the original sample that precipitated Protocol B. Contact him and ask him if he thinks the anomaly could be explained by equipment calibration.

A shipment of all the virgin samples from the beginning of Protocol B until those received by end of day this Friday are scheduled to be shipped to Roger on Saturday. After the transit time to Australia, contact Roger and ask him if he thinks the anomaly could be explained by equipment calibration.

Edited by richard295 on 04/01/2011 02:02:03 MDT.

I create micro graphs at 1024 x 768 resolutions. When I insert the images in my posts, they are automatically reduced to only 550 x 413 resolutions. Other than posting micrographs to an independent Web site and requiring that forum readers link to another site to see them, is there a way to insert forum images higher than 550 x 413 pixels?

Higher res would be good - whatever it takes to do that. Otherwise I'm not sure what value there is. Lighting could be improved also to provide more contrast.

Edited by wildlife on 04/01/2011 02:05:33 MDT.

Hi everyone!

>At this point, I don't see any strong evidence indicating
>whether it's A or B, but testing on B should indicate
>whether B is true.

Dan, I guess cuben deterioration is rather stochastic process so HH data for different samples should vary. Meantime both "bad" samples has exactly the same (down to milimeters) HH values. Thus it seems variant "A" is more probable IMHO. Bad batch(s) made of substandard mylar film or something alike...

>Keep in mind that each aging cycle is more than 8x the
>work of the initial test. There are some people
>understandably impatient for a quick anomaly resolution.

Richard, I'm the one of whose impatient :-) Was about to push the button and buy this unfortunate CT1K08 just before saw current topic... When are you going to make aging tests? Gonna wait for all samples to arrive to make "virgin" testing before?

Edited by al.vic.pom on 04/01/2011 09:40:53 MDT.