Xynole polyester cloth

[red baron]

Hello, everyone!

I'm new to the forum and need some info re using Xynole polyester cloth combined with epoxy resin to cover the hull & possibly the deck of the 20' Maryland Crabbing Skiff that I'm going to begin building within the next two weeks. The designer, Reuel Parker, recommends Xynole as being more abrasion-resistant than 'glass, and easier to work with.

I've had some very good comments on the stuff but you can never get enough information, so here goes:

- Will Xynole wet out to transparency like fiberglass cloth?

- Does it use significantly more epoxy to saturate than an equivalent weight fiberglass cloth?

- Is a given weight of Xynole cloth the equivalent of the same weight of fiberglass cloth?

Thanks.

[George Roberts]

- Will Xynole wet out to transparency like fiberglass cloth?

no

- Does it use significantly more epoxy to saturate than an equivalent weight fiberglass cloth?

yes

- Is a given weight of Xynole cloth the equivalent of the same weight of fiberglass cloth?

If I read my table right, 4oz Xynole will lay up to the same weight and thickness as 15oz (4 layers of 3.75oz) glass.

[RodB]

Do a search on this forum and you will get lots of information. Xynole is great for adding a nice thick, strong barrier on the bottom of your boat's hull which is more abrasion resistant than fiberglass cloth plus offers exceptional impact resistance. ...all better than fiberglass.

If you search "Xynole" or "Dynel" or "Hull sheathing"...or Fiberglass...you will get all the info you could possibly want. Especially go to:

Xynole usage etc

Yes it does require more epoxy to saturate the cloth etc which is one of the reasons it provides more protection...I would say at least one and one half times as much as fiberglass cloth if not more. It is easier to use because it causes no itching and drapes well over any surface "stretching to fit" easily.

Once the fabric is wetted out with the first coat of epoxy, you will notice "nubs" that are formed by the tiny fibers that stick out. You can use a sharp scraper to cut these off before continuing to fill the weave or not... cutting these off just makes using less epoxy.

Overall Xynole is a better choice for sheathing the hull except for when fiberglass is an integral part of a hulls structure and strength such as in strip-planking hull construction per "Macnaughton's Scantling Rules for Sheathed-Strip Constructon".

There is a techinical article on sheathing fabrics from Gougeon Brothers where the impact resistance is illustrated for varying laters of fabrics from plain 6 oz fiberglass to multiple layers of Xynole, Dynel, Polypropylene, and combinations thereof. For example If one were to intend on heavy hard use you could use two layers of Xynole, very heavy use, use Kevlar below the water line, but all in all I decided to go with one layer of Xynole on my 18 foot shallow water skiff because it showed very good protection compared to all the other choices for only one layer of fabric. I decided you would have to expect quite hard use to justify two layers of fabric period while one layer of Xynole offered plenty of protection.

RB

[ 03-27-2005, 12:58 PM: Message edited by: RodB ]

[Dave Hadfield]

I used it to cover a cabin roof last year. Ditto all the above.

It does not go transparent. You have to paint afterwards.

It takes a lot more epoxy to fill the weave. Expensive combination.

It's a fabric that handles like something you could make clothing out of. Nothing like fiberglass cloth. Stretchy. You have to stretch it into place and tape it down past the corners.

I like it, for when those are the qualities desired.

[Mark Van]

I sheathed my boat with xynole cloth. After 4 years, it holds up well. My last two boats were sheathed with fiberglass, and after a year or so, it started cracking on the corners letting moisture in. The xynole shows no signs of cracking. I think it is because xynole stretches, and fiberglass doesn't.

[paladin]

Xynole in conjunction with a good epoxy like MAS will work with the wood....I have two layers of xynole all over a 44 footer and a third layer to just above the water line. If you are intending on using kevlar put it on the INSIDE of the hull, xynole outside.The xynole is for impact resistance, the kevlar will resist inward puncture....

[Seagull]

I built Parker's 18' sharpie using xynole on bottom, sides, and decks with Mas slow epoxy. Love it. Its a lot easer for me to deal with stretchy xynole than fiberglass cloth 6oz or 10oz weight. Fiberglass cloth does not stretch, it distrots and can be a real nuisance aligning and keeping it in place when applying resin. That you can stretch xynole helps assure a good fit minimizing bubbles when applying the resin. Xynole does not sand well at all. It will fuzz if you sand past the resin coating. Easiest way, I have found to get rid of the fuzz to to cautiousely flame it. The heat knocks it right down. I like working with xynole. Its so much more user friendly than fiberglass. The extra resin and labor xynole requires , to is well worth it. Reuel Parker is a good source for much info on this polyester fabric and is where I first learned about this product. It was a wake up call after using fiberglass products for some 45 years.

[Tom Lathrop]

Good on you Seagull. I have been preaching the values of Xynole for a long time. It has all the good properties you have seen. Many will use Dynel but I don't find it nearly as good. Vectra polypropylene is good also but does not have the peel strength of Xynole since epoxy does not stick to it very well. Epoxy does not stick to fiberglass cloth very well either. Epoxy penetrates and soaks Xynole and the two cannot be separated.

[Todd Bradshaw]

"It was a wake up call after using fiberglass products for some 45 years."

Xynole, Dynel and similar fabrics have very different flex, rigidity and elongation characteristics from fabrics like fiberglass, Kevlar and carbon fiber. There are specific jobs that one category can do much better than another and all can be useful, but jumping to conclusions that one is "better" than another isn't very accurate or smart. There are certainly applications where Xynole may be a better choice, but there are others where it could cause your boat to fall apart. If you want to be good at composite boatbuilding, you need to learn when and why to use one fabric over another.

[Tom Lathrop]

"It was a wake up call after using fiberglass products for some 45 years."

Xynole, Dynel and similar fabrics have very different flex, rigidity and elongation characteristics from fabrics like fiberglass, Kevlar and carbon fiber. There are specific jobs that one category can do much better than another and all can be useful, but jumping to conclusions that one is "better" than another isn't very accurate or smart. There are certainly applications where Xynole may be a better choice, but there are others where it could cause your boat to fall apart. If you want to be good at composite boatbuilding, you need to learn when and why to use one fabric over another.

Well Todd, I thought it was pretty clear where Xynole was considered "better" than fiberglass. Sure, Xynole is not "better" in all cases but in sheathing a wooden hull for abrasion resistance, puncture resistance and peel strength, it is far superior.

Having made a number of objective tests of these properties, I am confident in recommending it for these uses over equal weights of fiberglass.

[JimConlin]

<SNIP>
There is a techinical article on sheathing fabrics from Gougeon Brothers
<SNIP>

Where can I find this article?

[Todd Bradshaw]

"Epoxy does not stick to fiberglass cloth very well either. Epoxy penetrates and soaks Xynole and the two cannot be separated."

Sorry Tom, but this statement just isn't true and doesn't make any sense. Epoxy sticks just fine to fiberglass (try to remove the epoxy resin from a hunk of saturated fiberglass cloth and you'll see what I mean).

I have nothing against Xynole or Dynel. My point above was just to echo the point that Rod made. As a structural material that may be needed to provide stiffness as a component of strength and durability, these non-glass fabrics tend to perform poorly, as they also do when you start comparing strength to weight ratios on boats which need to be light. Since this thread was started as a series of questions from someone wanting specific information on Xynole and having trouble finding information on it, I think these other characteristics deserve to be mentioned as well as instances where other materials may be a better choice.

[pipefitter]

The only FG that epoxy doesn't wet out is those with polyester soluble binders such as standard CSM. There is satin weaves that will conform better that square weaves. Also,on the dry fits of the cloths,the torture areas are obvious and should be relieved by darting or notching much like when doing upholstery work and is part of the art of a tidy and tight glass job. There are cloths that are designed to be used with epoxy that are sewn instead of bonded etc.

[Tom Lathrop]

"Epoxy does not stick to fiberglass cloth very well either. Epoxy penetrates and soaks Xynole and the two cannot be separated."

Sorry Tom, but this statement just isn't true and doesn't make any sense. Epoxy sticks just fine to fiberglass (try to remove the epoxy resin from a hunk of saturated fiberglass cloth and you'll see what I mean).

I have nothing against Xynole or Dynel. My point above was just to echo the point that Rod made. As a structural material that may be needed to provide stiffness as a component of strength and durability, these non-glass fabrics tend to perform poorly, as they also do when you start comparing strength to weight ratios on boats which need to be light. Since this thread was started as a series of questions from someone wanting specific information on Xynole and having trouble finding information on it, I think these other characteristics deserve to be mentioned as well as instances where other materials may be a better choice.

Todd, I don't have any problem understanding your points but you seem to be missing what I am saying and what this thread is about. I only said Xynole is best for a protective sheathing and that is the only application for which I would recommend it.

I have made peel tests of a number of fabrics and know that fiberglass tape will often peel off the wood substrate, leaving a surface of epoxy on the wood and very little on the fiberglass cloth. This cloth, on its underside, often looked much like it did before epoxy was applied. This indicates to me that there is poor adhesion of epoxy to glass and this tape was intended for use with epoxy. The force required to separate FG from the substrate is far less than that required to peel Xynole from the substrate. In addition the wood surface peeled with the Xynole and never separated epoxy from fabric.

The reason is pretty clear if you just look at the two fabrics. Xynole is a loosely woven material with very open fuzzy fibers that the epoxy totally penetrates. Sure, epoxy penetrates through FG but the fibers are very smooth and epoxy will separate from fiberglass under strain. I made several experimental tests to look into the characteristics of fabrics, including Vectra, fiberglass cloth tape, Dynel, Xynole and unwoven biaxial FG material.

You can say that this doesn't make sense if you like but I will stick by the conclusions drawn from my own objective tests of abrasion and peeling rather than mental suppositions. These tests were made for my own education to determine the best sheathing fabric for my own boats but were also reported in an article in Boatbuilder magazine some years ago.

[Todd Bradshaw]

I have no problem with a statement like "Xynole/epoxy is less prone to delamination from a wooden surface than a similar fiberglass/epoxy application" - but that's not what you said. You said that "epoxy doesn't stick to fiberglass cloth very well" and explained that the epoxy couldn't be seperated from Xynole - as if epoxy could be seperated from fiberglass. These statements are false and there are thousands of examples out there that prove they're false. I have no problem with your tests or their findings. I have no problem with the most recent, more detailed explanation of your tests and their findings, but the original statement was vague and simply not true.

[Tom Lathrop]

Todd,

It doesn't pay to be so certain about anything without leaving some room for different experiences.

I am sending you some photos by email that show significant separation of epoxy from fiberglass ( 2 samples in photo 1) in some peel test samples. I would post them but don't know how. There is also a photo that shows complete separation of Vectra (photo 2) from the epoxy on the substrake and another (photo3) that shows complete separation of both epoxy and Xynole from the wood substrake. These tests were run in an objective engineering fashion and I have no ax to grind in the outcome of these experiments.

Well, maybe a small ax when someone accuses me of being either dumb or stupid. I'm sure you are a smart fellow based on your many posts of sail making and handling. Well, I am pretty smart too and don't wish to be confrontational but you keep pulling my chain.
---------------
Added to say that I wanted to send you an email but your don't allow them in your profile. If you wish to see the photos, send me an email and I will send them in reply. Otherwise please refrain from claims that my statements on this subject are false. If someone else will post the photos let me know.

Peace.

[RodB]

Jim,

The article I speak of is about a study by West Systems on the decks of the Ticongeroga...and its pretty exhaustive on the many synthetic fabrics...in use by themselves and intermixed with each other plus fiberglass cloth. I will have to copy it (scan it) and then post it here. I think that will be simpler.

RodB

[Todd Bradshaw]

Tom, for the last time, the only thing that I think is "dumb or stupid" is trying to have an intelligent discussion about the various characteristics of a certain material or group of materials and not looking carefully at all sides of the issue. All I have tried to do throughout this discussion is to show that there are things that Xynole may do better and other things that fiberglass will do better and anyone working with these materials would be wise to learn the differences.

Since I have said nothing to discredit your peeling experiments, I don't know why you feel like you need to send me photographs of them. If you will carefully read my references to them in my last post, it will save me the trouble of typing them again. Like it or not, the statement that epoxy does not stick well to fiberglass is false and always will be false. Otherwise, I'd have a whole pile of old fiberglass stuff, from skis to boats to kayak paddles that would be falling apart. I'm not saying that Xynole couldn't be less prone to delaminating in some of those instances, but obviously there was something that fiberglass could contribute to those applications that fabrics like Dynel, nylon or Xynole could not - and that was more important than peel strength in those applications.

Nobody is pulling your chain except you, but I am starting to wonder what it's attached to? My e-mail address is listed right at the bottom of my profile, just as it always has been. I turned off the personal messaging stuff ages ago because I was always forgetting to check for them.

[Tom Lathrop]

What the chain is attached to is your demand that everyone believe that fiberglass cannot be peeled away from epoxy. That is the direct challenge to the results of my experimental tests to which I am responding. That and the fact that you insist on driving the thread from its original question. Since you refuse to look at the photos that show that fiberglass and epoxy can readily separate, I have no further reason to discuss this with you.

As far as the two of us is concerned and in the interest of forum harmony, I am willing to yield to your position. For the rest of those on this thread, I leave them to make their own conclusions as I have made mine.

It's not so much what you don't know that prevents learning. It's what you know that ain't so.

[Todd Bradshaw]

Tom, If I need you to tell me what I said or what I mean, I'll let you know. You're free to pull your own chain all you want (in the privacy of your own room ) - but don't blame it on me.

I didn't once demand, say, or even hint that "fiberglass can not be peeled away from epoxy". I said quote:"I'm not saying that Xynole couldn't be less prone to delaminating in some of those instances, but obviously there was something that fiberglass could contribute to those applications that fabrics like Dynel, nylon or Xynole could not - and that was more important than peel strength in those applications."

The only way that this can be twisted into "fiberglass can not be peeled away from epoxy" is if you either don't understand it or you simply chose to ignore it, modify it to suit your argument and then falsely attribute it to me.

As for "refusing to look at your sample photos", I haven't refused your offer, I simply said that I'm not sure why you feel the need to send them to me, since I haven't tried to refute the experiments or the results. Whether you like it or not though, there are applications (including certain sheathing projects) where fiberglass is well proven to be superior because of other characteristics that it adds to the mix which make it more desirable, despite having less peel strength. - The world is chocked full of examples of them and choosing to ignore them to make a point would truly be stupid. Do you want me to send you pictures of the half-dozen pairs of 30-year-old, wood-cored, hand-wrapped with epoxy/fiberglass skis that I own to prove that it can work? Of course not, as it would be a waste of both your time and mine....unless for some reason you don't believe that they exist, in which case I can certainly provide them.

As for being off topic, the original poster wanted information comparing Xynole to fiberglass cloth and his last question was "Is a given weight of Xynole cloth the equivalent of the same weight of fiberglass cloth?" There is no one correct answer to this question and each fabric has it's good points and it's bad. There are instances where each one may be far superior to the other and in reality, I suspect very few where they are equivalents and it doesn't matter which one you use. To ignore this fact would not be very wise.

For the boat in question, as long as the designer's scantlings are adequate for providing the required structure, which they obviously are because that's the sheathing requested in the plan, Xynole should work great. I certainly have no problems with that. But if the red barron really wants to learn to work with Xynole, he also needs to learn when it may or may not be the appropriate material to use. Since when is learning when to use a certain product and when not to use it off topic on this forum? The latter many times may prove to be more important than the former.

[allananicol]

Hi all,
Be interested if this material is available in Aus for trial. Quick net search shown no results.....but that may be just my weak search on the name.

[George Ray]

I have heard that Xynole polyester does not cause skin irritation from handling or sanding. Hooray!
While I have never used Xynole, I have been aware of it for many years.

[kengrome]

I have been preaching the values of Xynole for a long time. It has all the good properties you have seen. Many will use Dynel but I don't find it nearly as good.

Tom, I'm wondering if you might tell us (or at least tell me) why Xynole is better than Dynel?

Defender Industries appears to be one of the few sources (if not the only source) of Xynole in the USA and perhaps the world. Yet they seem to promote Dynel more heavily than Xynole, and they charge more for Dynel as well. I think the higher price may convince some people that Dynel is better. After all, if it costs more it must be better, right? At least this is the typical line of thinking for some people ... yet you say just the opposite in this case.

Please note that I am NOT challenging your assertion that Xynole is better! I am simply looking for any practical reasons you may have -- based on your own personal experience with both of these fabrics -- that might steer me to focus on the best one for a project I'm considering. If you say Xynole is better I believe you without hesitation, I just want to know why you say this so I can consider your reasons before I proceed, that's all.

Thanks!

[Bill Perkins]

I bought the Xynole for my boats bottom and decks from Raka , so there are at least 2 sources . Ruel Parker recommended it ,and Tom shared some interesting abrasion tests with me that he'd done .If I'm remembering correctly ,it's there that Xynol out performed Dynel . If the crab skiffs decks are not to be walked on ,I wouldn't use it there .

[kengrome]

I bought the Xynole for my boats bottom and decks from Raka , so there are at least 2 sources.

I just learned about Raka myself, thanks Bill. Their prices are even better than Defender and their Xynole is 9 inches wider than Defender's -- which makes them an even better source of this fabric, at least in financial terms.

I also learned that Xynole is 100% polyester and Dynel is modacrylic composed of 85 percent acrylonitrile and 15% PVC. Since polyester and modacrylic are two very different materials it's no wonder they perform differently.

[mcdenny]

I got Xynole from Raka too. Larry recommended it over Dynel for canvas-look decks.

BTW, it came wrinkled and had to be ironed back flat.

Much nicer to work with than fiberglass and gave just the texture I wanted with one coat of epoxy (sucks it up like a sponge) and 2 or 3 coats Brightsides.

[Tom Lathrop]

Ken,

In the abrasion tests, Dynel and Xynole were very close. Both took about 6 times more sanding cycles and time to break through compared to a layer of 10oz fiberglass. When normalized for thickness, the advantage was about 2 1/2 times as abrasion resistant. That is because both Dynel and Xynole make a much thicker sheath that does 10oz fiberglass woven cloth. One layer of 10oz fiberglass was about twice as abrasion resistant as an equal thickness of epoxy alone.

I would not use any of the synthetic cloths I tested on a boat where light weight is critical because the finished sheath is much heavier than a sheath of fiberglass. On other jobs, I consider the extra thickness of epoxy a plus in waterproofing plus the other advantages.

I set up a jig where samples of each material was run against a spinning 8" Makita sander in cycles operated by a 30 rpm motor driven cam. I laid a fine wire between the test sample and the wood substrate which was connected to a quartz clock. The clock was started when the test unit was turned and stopped automatically when the wire was cut by the sander. Several samples of each material was used in the tests.

It was in the peel tests that Xynole greatly outperformed Dynel. I was never able to peel actually Dynel off the wood substrate because it always broke off before very much load was applied. I cannot say what the reason for this is but since the performance both fabrics appear to be almost identical in other respects, I see no reason to ever choose Dynel over Xynole. My samples of Dynel had been stored in my shop for some years before the tests and that may have had some bearing on the results but if shelf life is a problem with it, that is not good either.

I buy many things from RAKA and find Larry to be very helpful. I do recommend that you insist that Xynole be sent on a roll tube rather than folded. It is not easy, even with ironing, to get wrinkles out. It may cost more but is worth it.

By the way, I have no problem whatever with any challenge of anything I might say. I just kind of lost my cool (which I regret) when I was told sternly and repeatedly that what I observed in my own experience could not possibly ever happen.

[GregW]

Does anybody know if xynole goes by any other name? I know it's a polyester cloth, however it appears to have a rather limited availability, Defender and Raka being the only two known distributors. I was thinking that if one actually knew what it was one could contact industrial fabric manufactures to see if they make it, or at least have something similar, This may make it both cheaper and easier to source.

[Bill Perkins]

Thanks for the correction Tom . I couldn't lay hands on the test results you sent me a few years ago . I haven't rubbed my boat's bottom hard enough to even go through the epoxy primer yet ,but I'm bound to hit something eventually . I swore my new outboard would never touch bottom ,but I see it's foot's been polished by the sandy mud we have down here .

There was a sailboat at the WB show ( best of show?) that had a cabin top with exposed weave -Dynel I think .It seems to me that the exposed weave Dynel has a more rigid , geometrically perfect pattern as opposed to the Xynole ,which on my deck has a slightly more relaxed weave which fit my work boat look . I've got seams and laps that are less than perfect ,but they blend in well .A side by side visual comparison would be interesting if anyone has that .

I was able to route a pretty tight radius on the deck at the sheer and wrap the cloth down to be capped by the rub rail . It's good at details like that .Mr. Parker told me he has wrapped the cloth over lapstrake planking , but I didn't go that route .Is there a difference in drapability between the two cloths ?

[kengrome]

Tom, thanks for the great report, very informative and helpful! One question, were the Dynel and Xynole fabrics both 4.0 ounce per square yard?

It's funny that you mention how the Xynole has greater peel strength than fiberglass. I've studied Renn Tolman's boat building book carefully, and on page 11 he seems to disagree with you on the peel strength issue:

There are two solutions to the 'glass cracking problem that are sometimes put forward. The first is to use Kevlar, Xynole or some other non-'glass cloth. These so-called synthetics are not only stronger than 'glass but stretch more. Unfortunately, synthetics are much more expensive and harder to work with than 'glass. Add to this that they have inferior "peel strength", and so are subject to being ripped off the bottom of your skiff in a full sheet by water pressure if even a small area is damaged.

Before I read this I had previously seen more than a few reports stating that Dynel and Xynole are easier to work with than fiberglass, yet Renn says just the opposite. This "difference of opinion" made me question the validity of his comments on peel strength too ...

Renn seems to relate peel strength to water pressure. Is he talking about water pressure inside the plywood hull I wonder? I suppose his conclusion might be correct, but your tests seem more credible to me, and now I think Renn was just expressing a personal fear or perhaps a theory when he commented about peel strength.

I didn't use Xynole on my Tolman Seabright hull even though I knew it was more abrasion resistant than fiberglass -- specifically because of Renn's peel strength concerns. Now I'm wondering if a layer of Xynole might have been better after all ... ?

[kengrome]

Does anybody know if xynole goes by any other name?

Greg, I haven't been able to find anything online about Xynole as a trademarked name or patented process or anything similar. This makes me wonder ...

Did someone in the boat building industry experiment with cheap polyester fabrics a long time ago and learn that it works even better than fiberglass in terms of abrasion resistance? And might this person have coined the term "Xynole" for this common everyday fabric -- so he could buy it from the textile companies cheaply only to turn around and resell it as a 'specialty marine fabric' for a much higher price?

I know it's a polyester cloth, however it appears to have a rather limited availability, Defender and Raka being the only two known distributors.

I think Xynole is really nothing more than heavyweight plain weave polyester fabric -- which means it should be cheap -- and can be woven by practically any textile mill in the world.

I was thinking that if one actually knew what it was one could contact industrial fabric manufactures to see if they make it, or at least have something similar. This may make it both cheaper and easier to source.

I have a surprise for you: When I contacted Southern Industrial Fabrics and asked about the Xynole they supply to Defender Industries they told me:

Per you request for the Xynole product we don't call it by that name. I can only assume it would be our modacrylic fabric we sell to Defender. We also supply them a polyester so I don't know which item it is exactly.

So I went back to the Defender web site and got the detailed info for these fabrics and sent it all to Southern Industrial. They confirmed that the modacrylic they sell to Defender is Dynel and the Xynole is polyester. Surprisingly they also told me they will sell me 3000 yards (their minimum order) of the polyester for only $2.15 a yard ...

Yes, this is the very same fabric Defender brands as "Xynole" and resells to boat builders in small quantities for $8.95 a yard!

Knowing all this, it might 'make sense' for one or more of you to buy the minimum order of 3000 yards, hang it in your garage, and resell it to everyone else for twice the price. You'll be able to use as much as you want for all your new boat building projects, and you would be doing a favor to the small boating community in the USA by providing them with an affordable source for Xynole at about half its regular retail price.

[Tom Lathrop]

Tom, thanks for the great report, very informative and helpful! One question, were the Dynel and Xynole fabrics both 4.0 ounce per square yard?

It's funny that you mention how the Xynole has greater peel strength than fiberglass. I've studied Renn Tolman's boat building book carefully, and on page 11 he seems to disagree with you on the peel strength issue:

Renn seems to relate peel strength to water pressure. Is he talking about water pressure inside the plywood hull I wonder? I suppose his conclusion might be correct, but your tests seem more credible to me, and now I think Renn was just expressing a personal fear or perhaps a theory when he commented about peel strength.

I didn't use Xynole on my Tolman Seabright hull even though I knew it was more abrasion resistant than fiberglass -- specifically because of Renn's peel strength concerns. Now I'm wondering if a layer of Xynole might have been better after all ... ?

I too have read Renn's work and admire his efforts. I can not give any explanation for his statement.

My tests show that epoxy bonds to Xynole better than to wood. I do not mean that epoxy sticks to polyester better than wood but that the structure of the Xynole captures the epoxy in its fuzzy open weave and will not let go. What that means is that separation always occurred at the wood/epoxy interface and that wood splinters always came off with the peeling of the test sample. Peeling fiberglass resulted in 50% or more of the wood surface retaining the epoxy and the backside of the fiberglass was fairly clean that part of the contact area.

This was actually a small issue in my tests and in a real situation, I would expect fiberglass to cling to a boat hull well enough that no separation problem would ever occur. Wet wood on the backside could separate any sheath but I would think that would likely occur with the epoxy/wood surface and not the fabric.

[GregW]

Greg, I haven't been able to find anything online about Xynole as a trademarked name or patented process or anything similar. This makes me wonder ...

Did someone in the boat building industry experiment with cheap polyester fabrics a long time ago and learn that it works even better than fiberglass in terms of abrasion resistance? And might this person have coined the term "Xynole" for this common everyday fabric -- so he could buy it from the textile companies cheaply only to turn around and resell it as a 'specialty marine fabric' for a much higher price?

I think Xynole is really nothing more than heavyweight plain weave polyester fabric -- which means it should be cheap -- and can be woven by practically any textile mill in the world.

I have a surprise for you: When I contacted Southern Industrial Fabrics and asked about the Xynole they supply to Defender Industries they told me:

So I went back to the Defender web site and got the detailed info for these fabrics and sent it all to Southern Industrial. They confirmed that the modacrylic they sell to Defender is Dynel and the Xynole is polyester. Surprisingly they also told me they will sell me 3000 yards (their minimum order) of the polyester for only $2.15 a yard ...

Yes, this is the very same fabric Defender brands as "Xynole" and resells to boat builders in small quantities for $8.95 a yard!

Knowing all this, it might 'make sense' for one or more of you to buy the minimum order of 3000 yards, hang it in your garage, and resell it to everyone else for twice the price. You'll be able to use as much as you want for all your new boat building projects, and you would be doing a favor to the small boating community in the USA by providing them with an affordable source for Xynole at about half its regular retail price.

You have done your homework admirably!

After searching high and low for "xynole" and finding nothing as far trademarks or anything else for that matter, I was getting the feeling that this stuff is simply polyester, pure and simple, you appear to have confirmed my suspicions
I guess one can sell "Xynole" at $8.00/yard a lot easier than selling polyester at $8.00/yard.

I think it's time for some experimentation on my part, i.e. buy some "xynole" and buy some plain polyester fabric and see what's what.

[pquince65]

I've searched for the technical article that RobB mentioned on the West System website with no luck. I'd love to get my hands on it. Does anyone know where it was published?

Thanks.

[GregW]

Well I went out and bought myself some xynole from Defender, to see for myself was this mystery fabric was. I mean really, what is this fabric that is only available from only two sources in world, and that no textile manufacture anywhere makes? The fact that the two sources also sell epoxy, is I'm sure, pure coincidence.

My next step was to bring my sample around to a friend of mine who works in the textile business. Despite being in the business for almost twenty years he had never heard of xynole and was rather curious to see for himself what this mystery fabric was. As soon has he saw it, he knew exactly what it was, and what it's used for. However before we jumped to conclusions, we brought my sample to their lab and the technician performed a few quick test. The technician had never heard of xynole either, but after a few quick test, (one involving lighting a small strip on fire) she was sure we were dealing with polyester, no doubt about it. So it turns out that xynole also goes by the less sexy name of "polyester"

So what do they use this for? It's used as re-enforcing backing on flexible materials, commonly bonded to vinyl to keep it from stretching too much. As noted in one of the post above, it's pretty cheap, a couple of bucks a meter, or if you would rather buy xynole (it sounds so much better saying my boat is "sheathed in xynole" than saying "my boat is covered in polyester" ) from the only two distributors in the world, you can pay ~$8-9 a meter, your choice.

[Todd Bradshaw]

I thought you already knew it was polyester, that part's not a secret (and FYI Dynel is acrylic). I agree that it is most likely made for some general purpose which has been marked up for the boat industry, but the actual cost of it and its other properties are much harder to nail down.

Keep in mind that some peel-ply fabrics are also polyester and used as such because epoxy will not stick to them. There are most likely far more versions of polyester fabrics out there that will make decent substitutes for peel-ply than make good substitutes for Xynole and that's the problem here as their use for boat sheathing would have some rather obvious drawbacks.

Even fiberglass fabrics have to be treated with specific compounds (Volan, Silane, etc.) before resin will bond well to them. Grabbing a hunk of fabric that looks similar to Xynole and sticking it to your boat without doing some pretty serious testing first is probably a big mistake. Whether the same treatments that allow resin to bond well to Xynole happen to be commonly used on other polyester fabrics you might find is hard to say, but assuming that all polyester or any similar-looking polyester will work as a substitute for Xynole is very foolish. It's certainly worth doing some adhesion, compatibility and tear strength testing with some promising-looking potential substitutes and comparing them to actual Xynole in the same tests, but just because it's polyester doesn't mean that it will work. There are hundreds of polyester variations. It's like saying "This sailboat mast is made of wood - You guys can spend your money on Spruce and Doug Fir if you want, but I can make a replacement out of any type of wood I can dig up and it should work just fine." We all know the outcome of that one.

[kengrome]

Well I went out and bought myself some xynole from Defender, to see for myself was this mystery fabric was. I mean really, what is this fabric that is only available from only two sources in world, and that no textile manufacture anywhere makes?

Of course a textile maker manufactures it! It's made right there in the USA as a matter of fact.

My next step was to bring my sample around to a friend of mine who works in the textile business. Despite being in the business for almost twenty years he had never heard of xynole ...

No surprise to me. When I contacted the manufacturer they didn't know what the term "Xynole" referred to either. After I told them Defender buys it from them, they said Defender buys only two fabrics from them, and from my description they figured out which one it was -- the polyester fabric, not the other one (Dynel) which is a combination of two different types of plastic threads.

They gave me their product number for what the boating industry calls Xynole so I wouldn't cause any more confusion by calling it Xynole when talking to them about it. They will make it and sell it to anyone of course, you just have to buy a HUGE roll (or multiple rolls) of the stuff.

So it turns out that xynole also goes by the less sexy name of "polyester".

Exactly. Polyester comes in a wide variety of weaves too, so it would make sense to know the correct Xynole weave, thread count, etc. before using just any old generic polyester fabric. Open weave is critical for any Xynole substitute though ...

... and FYI Dynel is acrylic ...

Dynel is actually a combination fabric made with polyester and acrylic, or acrylic and olefin, or two other plastic fibers -- I just don't recall which ones at the moment. That's what I get for growing old, I can't recall all my facts as quickly as I used to ...

I agree that it is most likely made for some general purpose which has been marked up for the boat industry, but the actual cost of it and its other properties are much harder to nail down.

In Asia the cost of bulk commodity fabrics like fiberglass and polyester are based on material weight, with adjustments made for the extra cost of certain types of weaves. You can pretty much count on the fact that a plain weave will cost roughly $X.XX per kilogram from nearly all suppliers, and satin weave $Y.YY, and herringbone weave $Z.ZZ for example.

Keep in mind that some peel-ply fabrics are also polyester and used as such because epoxy will not stick to them.

Let's not forget that one of the other critically important features of peel-ply which makes it work the way it does (in addition to the fact that it is polyester) is the fact that it is a very tight weave material which is very effective at preventing epoxy from getting in between the woven threads. My personal belief is that it's the tight weave that results in so little epoxy gets in between these threads, and this means the fabric is stronger than the epoxy in this area -- and that's why the epoxy rips apart rather than the peel-ply when you try to remove the peel-ply.

On the other hand, Xynole is such an open weave that plenty of epoxy gets in between the threads. Wth so much more epoxy bonding in between the threads, the epoxy ends up being stronger than the Xynole when you try to peel it off. I believe that any time the epoxy is stronger than the fabric, it's the fabric that will fail when you try to peel it off, not the epoxy. Open weave won't peel off, but closed weave will. That's about the size of it.

It's certainly worth doing some adhesion, compatibility and tear strength testing with some promising-looking potential substitutes and comparing them to actual Xynole in the same tests, but just because it's polyester doesn't mean that it will work.

The cheap closed weave polyester I bought in the local fabric store for 20 cents a square meter certainly works great as peel ply!

I bought some open weave polyester to try as a Xynole substitute too but I haven't used it yet, so my personal tests have yet to be commenced. Unfortunately I couldn't compare generic open weave polyester to Xynole anyways since I have no "Xynole" ... but I don't think a direct comparison is necessary anyways. If I cannot peel off the generic stuff then it will work fine as a Xynole substitute in terms of waterproofing and abrasion resistance -- and that's all Xynole is normally used for anyways.

[Todd Bradshaw]

"Dynel is a trade name for a type synthetic fiber used in fibre reinforced plastic composite materials, especially for marine applications. A copolymer of acrylonitrile and vinyl chloride, it shares many properties with both polyacrylonitrile (high abrasion resistance, good tensile strength) and PVC (flame resistance). It is an acrylic resin.

Dynel was originally produced by Union Carbide corporation.

Retrieved from "http://en.wikipedia.org/wiki/Dynel"

"modacrylics ( in modacrylic )
...percent by weight of the chemical compound acrylonitrile. It is a modified form of the acrylic group, fibres composed of a minimum of 85 percent acrylonitrile. Modacrylic fibres include trademarked Dynel (acrylonitrile and polyvinyl chloride) and Verel (acrylonitrile and vinylidene chloride)." (Britanica online)

Dacron (polyester) peel ply.
:A layer of 2.7 oz. Dacron fabric strips or tape laminated into a layup as if it were an extra ply of glass. The peel coat wets out with epoxy like glass cloth and cures along with the rest of the layup. However, the Dacron does not adhere structurally to the glass and when peeled away it leaves a surface ready for glass-to-glass bonding without sanding." (Aircraft Spruce)

Gougeon's is supposedly nylon and like some brands, it is treated with a release agent. In any case, you can generally squeegee resin right through the weave of most peelply (or force it through with a vacuum bagging setup) and remove excess resin. It goes right through the small spaces between the yarns and the fabric gets saturated in the process, so I don't believe your fine weave/coarse weave argument holds water. Very few polyesters are sold without going through some sort of finishing process first, either by the manufacturer of by a special finisher like Kenyon. It's quite difficult to know what may or may not have been applied to a hunk of generic polyester.

Like I said, grabbing a hunk of fabric that looks similar to Xynole and sticking it to your boat without doing some pretty serious testing first is probably a big mistake. You also seem to be overlooking the tear strength issue. Most synthetics sacrifice a hell of a lot of structural rigidity, compared to fiberglass of a similar finished weight. The main justifications for this are increased abrasion resistance and also increased tear strength to help keep a damaged boat in one piece. As long as you're testing, it's worth doing a bit of tear strength testing as well.

[Andrew Craig-Bennett]

Thread retrieved out of interest.

In the UK we used to have a splendid product called Cascover, which was nylon cloth, applied with resorcinol resin, used as a worm shield on conventional wooden hulls as a far simpler alternative to copper sheathing, but the makers lost interest in it a few years back.

So I was wondering if xynole does the same job - it needs to move very slightly with the hull, which Cascover did.

[paladin]

Xynole does move with the wood, which was the primary reason that I used it. But....you also have to be careful of the resin that you use. Some resins are too "stiff" or rigid, and some will flex without crazing. T-88 is minutely elastic, and was the original recommendation, but it is also a bit "thick"....and M.A.S. seems to wet out the fabric much better.

[RodB]

pquince65
Junior Member

Join Date: Nov 2007
Posts: 1
Re: Xynole polyester cloth
I've searched for the technical article that RobB mentioned on the West System website with no luck. I'd love to get my hands on it. Does anyone know where it was published?

Thanks.

Sorry, but I couldn't find that damn article... so I then forgot about it. I recently came across it and can now give you the source.

The Article was called "Testing for the Toughest Deck Coverings for Ticonderoga".... by William D. Bertelsen in West Epoxy's "Epoxyworks", issue #4 spring 1994.

This article is very relevant to this thread in that is shows some interesting characteristics of varying fabrics in conjunction with epoxy.

Here is the article minus a few very small photos...fyi...




continued... the following copy and two charts show the results that helped me decide on using Xynole Polyester to sheath my hull.







The following was an additional test that was attached with the article which is quite pertinent to this thread...



Sorry for the delay.

RodB

[RodB]

bump...

r

[katiedobe]

Ok so has anyone done any testing on the "open weave" over the counter polyester fabric available at any Joanne's Fabric store verses the "authentic Xynole" prescription only marine fabric yet?

If we can start using over the counter polyester fabric what kind of weave count are we looking at. What thread size also?

How about a couple of photos showing Xynole and generic polyester open weave, and generic poly peelable?

Thanks.

[katiedobe]

Insistant bump!

[magwas]

This is new to me, so I have done some research.
Polyesther is still a very broad name covering very different materials.
What I have found:
There are indeed cheap polyester textiles out there, in the textile shop near you. I guess when the point is only to provide a material for epoxy to saturate, they can be adequate for the purpose, but I would not use them for structural components.
Tensile strength of polyester materials are varying in a very broad range. I would say that most of them in the 70-100 MPa range, while there are products which boast ultimate tensile strength in the GPa area (like fiber glass), and there are at least one product which is told to have 3 GPa. It is (if true) better than most kevlar products, and nears carbon fiber (4-6 GPa).
Source of information: http://www.matweb.com/

[BillyBudd]

Now and then during the summer months, a fellow sailor will come up and in hang-dog fashion confess that they sort of rammed my boat on its mooring. While my attitude is that this "goes with the territory," I'm pleased with the way that the xynole topsides nicely survives these not infrequent events. Small indentations are all that I've found--and there are more such dings that confessions. I did the entire 20' boat's exterior, though not of course brightwork, in xynole. Took lots and lots of epoxy!

[Adios]

Yea...but what does it (dynel) look like when finished? The plans for my boat http://www.woodenboat.com/forum/showthread.php?t=97513 calls for dynel/epoxy over 3/8" plywood, I guess to simulate the look of painted canvas. Frankly, I probably don't need the increased impact resistance on the deck. Wouldn't 10 oz. glass give the same look as long as I don't overdo it with the epoxy? It would be cheaper. Does anyone have pictures of dynel finished and painted in this way?

[Adios]

OK...somebody help!

I'm experimenting with some dynel samples before applying this stuff to my deck. The beam of the boat makes in necessary to put a seam down the middle.

This cloth frays very easily. HOW DO YOU MAKE A NEAT, BARELY VISIBLE SEAM? It doesn't handle the same as glass. How about if I commit to having a visible seam and make it neat by sandwiching the cloth ends between to deckboards before wetting out. Need advice!
John McFadden
Charleston

[RodB]

I overlapped Xynole along the keel of my flats skiff and once the Xynole was wetted out and cured for a few hours.. I used one of the Stanley cheese grater type mini planes (Shurform??about 7" long) to cut the "nubs" from the cloth... I now had an epoxy saturated fabric mostly cured...with a clean beveled edge cut by the micro plane blades. It was very simple then to apply some fairing compound along the "drop off" of the overlap ... and then I continued on with applying coats of epoxy. When finished, I had a nice uniform sheathing of Xynole with fair surface.

I think you should use Xynole, not Dynel. . . see above in this thread... and Tom Lathrop will have some input here from his personal tests in the past.

RodB

[Adios]

Rod,

I think that the point with my boat's design is to get it to look like painted canvas. Your method would give a strong seam but might fill in the weave too much.
Is there otherwise a difference in how xynole and dynel handle?
I'm going for looks more than strength with this application.