S-glass vs E-glass

[Guest]

Inside will be Kevlar. Outside will be E-glass and S-glass.

I am no materials master, and use mostly 4 and 6 oz S-glass, E-glass selvage edge tapes and Dynel (no carbon or kevlar). I do have a my-precious roll of 1 inch fine weave S-glass tape that I like a lot (gift from a guy in the aerospace industry, wish I’d take two rolls when he offered). In the olden days I used a lot of crappy E-glass that would Medusa hair fray at a glance because that was what was available locally.

I am sure I am missing something here, but from (what little) I know about fiberglass cloth S-glass is purported to be superior in flex resistance, tensile strength and flexural strength. In a mixed materials layup what benefit does E-glass provide?

 

[pblanc]

S fiberglass is said to have a higher modulus than E glass so it is stiffer. Normally a good thing although in some cases greater stiffness might not be desired.

S fiberglass is typically more than twice as expensive as E 'glass of similar design and weight but it is not twice as strong. E fiberglass therefore has a better cost to strength ratio.

For some designs I could see using an exterior layer of S fiberglass (for its superior abrasion resistance) over one or more layers of E 'glass in order to keep costs down.

 

[Alan Gage]

For some designs I could see using an exterior layer of S fiberglass (for its superior abrasion resistance) over one or more layers of E 'glass in order to keep costs down.

That's my plan. I'm not worried as much about strength and abrasion resistance above the water line so the hull will get a full blanket of E-glass and then S-glass below the waterline with extra at the stems buried under Dynel skid plates.

Not only is S-glass expensive (in the same ballpark as Kevlar and Carbon) but it's also not an easy fabric to source, especially in wide rolls. So I usually just buy it in 30" widths and use it below the waterline.

While we're on the topic does anyone know for sure what most boat manufacturers are using for fiberglass? Rarely do I hear any of them specify the use of S-glass so I'm assuming E-glass is being used a majority of the time. Despite being weaker and more prone to abrasion it seems to hold up just fine under most situations.

Alan

 

[pblanc]

Sweet Composites sells S fiberglass in both 4 oz/sq yd and 6 oz/sq yd weights in 60" width.

 

[Glenn MacGrady]

While we're on the topic does anyone know for sure what most boat manufacturers are using for fiberglass? Rarely do I hear any of them specify the use of S-glass so I'm assuming E-glass is being used a majority of the time.

I don't assume that, but then I have no idea what most boat manufacturers use today. The big ones have a variety of composite offerings.

What I do know is that I've had two flatwater canoes, one whitewater canoe, one whitewater/flatwater combi canoe, one seakayak, and one outrigger canoe custom made from basically one man shops, and none of them ever suggested E glass for the fiberglass layers. All those canoes have carbon and/or Kevlar combined with S glass. To the best of my recollection, all those builders affirmatively recommended S glass, as against lower cost E glass, for the best composite construction characteristics. Of course, most of these were high end canoes when new.

In particular, the builders I taking about were: John Berry (ME), Mike Galt (BJX, Caper), Kerry King (Surge seakayak), Jude Turczynski (Huki V1-B) and Dave Curtis (SRT - used).

I also have two composite canoes from large boat builders, a Swift Winisk and a Bell Wildfire. I have always been under the impression that the glass layers and reinforcements were S, but I guess I don't know that for sure.

If a canoe were going to be used in whitewater, especially way out in the wilderness, impact and abrasion strength would be HIGH on my list of requirements. If I didn't go with Royalex, I'd want S glass on the outside of the entire hull, not just the bottom, because of the very real possibility of hitting rocks up high particularly if the canoe is upside down. On a canoe strictly for lakes and slow smoothwater, I'd be less concerned about impacts and abrasion.

 

[Alan Gage]

What I do know is that I've had two flatwater canoes, one whitewater canoe, one whitewater/flatwater combi canoe, one seakayak, and one outrigger canoe custom made from basically one man shops, and none of them ever suggested E glass for the fiberglass layers. All those canoes have carbon and/or Kevlar combined with S glass. To the best of my recollection, all those builders affirmatively recommended S glass, as against lower cost E glass, for the best composite construction characteristics. Of course, most of these were high end canoes when new.

That's good to know. I was thinking of what Savage River says about their various layups. The Expedition layup is the only one that specifies S-glass so I assume the other layups that use fiberglass are E-glass. And the carbon/kevlar layup makes no mention of fiberglass at all, which I'd sure want on the outside to protect the carbon, which doesn't seem to hold up well to abrasion.

Layup descriptions at the bottom of the page: http://www.savageriver.com/canoes/recreational/deep-creek-solo

Alan

 

[Glenn MacGrady]

Hard to find fiberglass info on the sites of some of the biggest manufacturers. They don't specify the type of fiberglass.

Dave Curtis at Hemlock uses S in his Premium+ layup and Lite-Tech whitewater layup and E in his lower cost layup.

Swift only mentions glass in its Kevlar Fusion layup and it's S. The other layups seem to use more exotic materials than glass along with carbon and/or Kevlar. (Maybe my Bell Wildfire has no glass at all.)

I'm not sure Esquif's site is up to date, but the one composite boat I could find, the Champlain, is or was made with S glass and Kevlar.

Nighthawk uses S glass when it uses glass.

John Kaz at Millbrook only uses S glass along with Kevlar like his predecessor John Berry.

I can't find my copy of Charlie Waldbridge's classic Boat Builders Manual, but as I recall his tests and experiments drove him to conclude that SSKK was the best whitewater layup.

 

[Guest]

I trust dave Curtis and his judgment.
Turtle

 

[Guest]

S fiberglass is typically more than twice as expensive as E 'glass of similar design and weight but it is not twice as strong. E fiberglass therefore has a better cost to strength ratio.

For some designs I could see using an exterior layer of S fiberglass (for its superior abrasion resistance) over one or more layers of E 'glass in order to keep costs down.

I knew there was a significant cost difference between S-glass and E-glass, but did not realize S-glass was 2X+ more expensive.

And I have no idea what the actual cost difference is when compared to the total expense of crafting a one-off composite canoe, ie using all S-glass vs S-glass and E-glass (kevlar, carbon and etc aside).

Alan and other builder folk, what is the ballparked total materials expense in building a composite canoe, forms, wood, epoxy, staples, sandpaper, brushes, other expendables and glass/kevlar/carbon etc?

 

[Glenn MacGrady]

In my research this morn, I found posts from Charlie Wilson that say Bell used E glass in its white-gold composite, S glass in its early Kev Lite and Kev Deluxe composites, and no glass in its black-gold laminate. So my black-gold Wildfire is carbon on the outside and a Kevlar tweed on the inside.

I think it's Charlie who also told me, to my surprise, that Kevlar is actually lighter than carbon. Carbon is used for rigidity strength instead of glass as an outer layer simply to lower the weight vs. fiberglass when combined with a Kevlar interior. But carbon isn't so good for impacts and abrasion.

If I'm recalling this correctly, then for a remote wilderness tripping canoe that will have to withstand unexpected collisions, drops and maybe even pins while carrying heavy loads, I would choose an SK laminate over a CK laminate for impact and abrasion resistance even though it may be a little heavier than CK. I'd eliminate weight on the SK layup the same way Millbrook has always done -- no exterior gelcoat (or paint). Kaz mixes dye into the resin to get colors without gelcoat weight. For a day paddling or racing canoe I'd definitely go for the lightest weight laminate.

BTW, Dave Curtis's Premium+ layup is S glass on the outside and a bi-weave fabric of carbon and Kevlar on the inside.

 

[Alan Gage]

builder folk, what is the ballparked total materials expense in building a composite canoe, forms, wood, epoxy, staples, sandpaper, brushes, other expendables and glass/kevlar/carbon etc?

It makes a big difference if you're using a core or not. No core=more cloth. I estimate around $1000 just in cloth for the two full composite boats I've built. They have 9 and 10 layers respectively on the bottom center of the hull. Much less in other areas. Probably $1500 for everything. Not quite as much if you do like Jim and use another hull as the mold.

On my current project, in which the wood will stay in place as the core, fabric costs should only be a few hundred dollars. Full layer of E-glass outside with a layer of S-glass below the waterline. One full layer of Kevlar on the inside, another below the water line, and maybe one more full width piece extending gunwale to gunwale in the center 1/3 of the hull. I'm expecting to spend $600-700 total, which includes my normal carbon over cedar gunwales.

All strippers are in essence a composite hull. They just have a stronger and more attractive looking core, as opposed to foam bottom and ribs, that's showcased when clear fiberglass is used. Pretty easy to build a "regular" stripper for $500 or less.

I don't really keep track of my costs when building a boat (don't really want to know) so these estimates could certainly be off a ways.

Alan

 

[Muskrat]

My last canoe was two layers of 6 oz s-glass and one layer of 9 oz kelvar. For a 15 ft canoe it was about $500 plus some Kevlar tape for the ribs. Figure about $300-400 for epoxy. Using e-glass would have saved $110. Total cost for the Canoe was around $1100. 10% cost savings for e-glass. Not bad for a manufacturer, but since building comes well under retail I don't sweat the extra hundred.

Edit: if you can find another canoe to use as the form it's free, I made my own mold so there's two sheets of ply, some 2x6s, pink foam board, and a couple buckets of drywall mud. Maybe $200 there.

 

[pblanc]

There have been a number of whitewater canoes that have utilized carbon fiber in addition to aramid. One was the composite version of the Mad River Outrage canoe that was made by Bell and called the "Outraged". Only about a half-dozen were made and they were intended for whitewater open boat slalom competition. So far as I know, they were pretty much the usual Bell Black Gold layup. I do not believe they had any exterior layer over the carbon other than a clear gel coat.

I have a friend who has one of those boats. It had been used for general whitewater river running and had sustained some cracks.

Andy Phillips of Composite Creations builds his Bulldog using carbon over aramid but covers it with an external layer of S fiberglass. That boat is intended to be a general river runner and play boat. I know a fellow who has one of those as well, and it has held up quite well over a number of years use, but has required some minor patches.

Andy Convery of Echo Paddles builds his composite version of the Ocoee (the Echoee) out of carbon over aramid as well, but covers the exterior with a layer of Innegra H (Innegra/Basalt). A third friend acquired one of those earlier this year. It will be interesting to see how it holds up.

 

[Alan Gage]

Those are interesting examples, Pete. I've got a roll of carbon on hand and I've toyed with the idea of using it instead of E-glass on the outside of this canoe. I don't see myself using it for anything else in the near future so maybe I will. Had also been eyeing Innegra/carbon and Innegra/basalt and was getting a bit overwhelmed in my decision making. Lots of options and precious little real world information on how the different cloths are actually working out.

Alan

 

[pblanc]

Here are some photos of what the Echoee looks like with its outer layer of Innegra/Basalt:

http://www.echopaddles.com/echoee/echoee/

 

[Glenn MacGrady]

Materials, for me, depend on what I am using the canoe for and how long I expect it to last.

I bought all my composite flatwater boats with the expectation they would last my lifetime. The ones I've taken care of have. I also expected my Royalex boats to last, and they have even though stored outside somewhat negligently. I never really expected whitewater canoes, especially composite ones, to last more than a few years, but they sort of have with repairs except for the woodwork. But I don't use them anymore.

I would want a tripping canoe to last my lifetime because I don't really consider consider myself a wilderness tripper. I would never use a foam cored canoe as a tripping canoe, and certainly not for a tripping canoe that will experience real whitewater. I've seen too much damage from relatively minor pins on cored canoes. I'd probably have the same reaction to a canoe cored with thin wood.

All those perspectives would probably change if I were a boat builder, who could create new products for myself in a few months at reasonable cost. Boats would then become more of a disposable item to me. Actually, when I think about it, I'm ENVIOUS.

 

[Alan Gage]

Here are some photos of what the Echoee looks like with its outer layer of Innegra/Basalt:

http://www.echopaddles.com/echoee/echoee/

Interesting that it has a foam core (mentioned in the Rapid review). I might have to rethink that for future builds.

Alan

 

[Glenn MacGrady]

Interesting that it has a foam core (mentioned in the Rapid review). I might have to rethink that for future builds.

Alan

I just sent Andy Convery the following email:

Hi Andy,

Some of us were discussing canoe laminates on canoetripping.net and a question arose as to whether your Echoee had a foam core or not. Your website doesn't say that, but the review in Rapid Magazine does. If you do use a foam core, why? Aren't the carbon layers sufficient for stiffness?

 

[Guest]

I have never really looked at the price delta between S-glass and E-glass. My needs are entirely for patching and repairing, and I have always ordered a few yards of material at a time.

http://sweetcomposites.com/Fiberglass.html

Yoiks.

 

[Alan Gage]

Materials, for me, depend on what I am using the canoe for and how long I expect it to last.

Same here. The only additional thing for me to consider is: Can I do it myself?

I would never use a foam cored canoe as a tripping canoe, and certainly not for a tripping canoe that will experience real whitewater. I've seen too much damage from relatively minor pins on cored canoes. I'd probably have the same reaction to a canoe cored with thin wood.

I'm concerned about foam cores on a serious tripping canoe too but I haven't seen many people complain about failures so maybe it would be ok. Or maybe that's just because most people take something other than a foam cored canoe on serious trips. On lake travel it wouldn't worry me so much. On moving water it does. I'm mostly concerned about the softer core being more prone to puncture and to compress/crease under severe loads, which would greatly reduce the stiffness in that area and perhaps lead to a serious failure. A wood core shouldn't be as prone to a compression failure and would stand up better to punctures. The big question is how much can the wood core flex before the core fractures or separates from the cloth? It will be much stiffer than a solid laminate but that might not be a good thing.

All those perspectives would probably change if I were a boat builder, who could create new products for myself in a few months at reasonable cost. Boats would then become more of a disposable item to me.

Don't think disposable. Think repairable. I really like the ability to design and build a boat for a specific type of trip. If buying a new boat I'd feel forced to buy a more general purpose hull and if buying used, which is what I always used to do, I'm at the mercy of what comes up on the market. Whether or not anything I build will perform better for my purposes than something I could have bought I don't know and in the long run I'll spend more money building than if I'd just went and bought myself a couple of nice, new, canoes. But it makes me happy, teaches me a lot, and gives me something to do in the winter.

Alan