anyone with any experience using c-flex?

Discussion in 'Fiberglass and Composite Boat Building' started by tugboat, Aug 28, 2013.

  1. Herman
    Joined: Oct 2004
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    Herman Senior Member

    I have never found them to be difficult... They actually have been taken over by Scott Bader, so the right resin must be obtainable. If they do not sell direct, they sure know to direct you to someone who does.
     
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  2. tugboat

    tugboat Previous Member

    That is absolutely incorrect - please read the literature on it which specifies a structural advantage in the longitudinal direction, while reducing weight...

    if you don't believe me - you are welcome to go call up Ken Hankinson and/or Seemann composites - and have it out with them...


    I've made my choice. so I am not going back...its been too many years of listening to too many people on boat forums telling what they THINK I should be doing...

    - so at some point I've got to stop looping and get on with my build...

    and I agree wholeheartedly with Samsam--its a tugboat not an America's cup contender...
    I had hoped to get some positive cases of those who have used the stuff. but boats are still being built out of it so hopefully someone can come along and offer support for it rather than flaming me in a post.

    as far as the epoxy goes- I agree with you and Ill use what Dave Sintes uses- iso resin. But It sure would be nice to use epoxy throughout the build...
     
  3. tugboat

    tugboat Previous Member

    just to put the matter to rest about costs

    c-flex- 1520.00 u.s.
    stations frames- 200.00
    cnc cutting- 350.00 cdn
    strongback- 150.00 more or less...
    time to apply c-flex- about 4-6 hours max!
    I will use 6 layers of triax using different orientations.
    triax- 431.00 per roll x 4 rolls
    resin using iso- aprox 220- 250 kg's x 5.50 per kg.= 1375.00
    resin for c-flex -aprox- 15 gals- 600.00

    rough costs (omitting some items etc.,)

    about 7200.00 U.S. aprox.(not including the bog)

    we pay more here too for resins and cloth...
     
  4. waikikin
    Joined: Jan 2006
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    waikikin Senior Member

    Tugboat, if using iso/poly you really should consider using at least a 3/4 oz chopstrand mat in between layers of the triax, you might then be able to drop a layer or two of triax & meet standard building practice with this resin, with epoxy cloth/stitched on cloth/stitched fabric is ok but poly not unless using very light fabrics.
    Jeff
     
  5. groper
    Joined: Jun 2011
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    groper Senior Member

    What about the combi mats jeff, like 1708 for example as they call it over there? has choppy on one side then directional fabric on the other... Have you priced these out tug?

    Poly resins typically use a csm layer between cured laminates tb, helps with adhesion and accounts for the resins reduced mechanical properties.
     
  6. waikikin
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    waikikin Senior Member

    Hi Groper, maybe because I learnt in the eighties, what was considered a "quality" laminate back then was neat in appearance, I like to throw a little chop like 225 over cut fabric edges/overlaps, usually no extra resin required, just sucks some excess from the substrate(lightest... no, but nice), it's easy to tear some strips to bury tabbing, helps in fairing out & protects the long fibers of the stitched fabric, peelply does similar so it's good too. The combo fabrics I've used very occasionally, seem ok & to be ideal for prewetting tabbing bandages for bulkheads & hull deck joins, maybe not quite as versatile or conformable overall especially given that all edges get cut rather than torn in, qualified by my relative inexperience with the combos.
    Jeff.
     
  7. SamSam
    Joined: Feb 2005
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    Location: Coastal Georgia

    SamSam Senior Member

    Yes, you need mats between the woven materials. The resin is the weak point of the laminate and mat helps fill in the resin rich area between laminates. It helps tie the wovens together. It also helps prevent possible wicking of water through the layers. It helps control print through. Plus it bulks the laminate up quickly for thickness and at the same time, with a little skillful rolling with a bubble buster on the mat or the wovens, or a squeegee on the wovens, you can accomplish a lot of the fairing as you laminate, so final fairing is easier.

    Use the iso resin, it is worth the little extra it costs.

    The 10 C or 50 F temperatures while laminating that you mentioned might be a concern.

    I always used the separate materials instead of combos. For one thing, sometimes a lot of plain mat was needed and I couldn't afford having extra rolls of this and that kind of glass product around. Another was availability. It was also harder to drape wovens around when they were attached to mat.

    We did use FabMat, which was 24 oz WR stuck/glued to 1 1/2 oz mat (not stitched) for tabbing in bulkheads and such. You had to make cuts in the 8" wide strip so it would comform to stringers etc. It was too thick to wetout from one side, so the practice was to lay it on cardboard, wet the mat side and then transfer the whole mess over to the bulkhead before all the binder dissolved and the strip fell apart. I quickly evolved to laying it in place dry, folding up the hull side of the tabbing and wetting out the mat, putting that side back down and then doing the same to the bulkhead side, and finally wetting out the whole thing from the WR outside. It was much easier, cleaner, quicker and looked much better that way.
     
  8. tugboat

    tugboat Previous Member

    Hi Jeff- thanks for the info- I've been getting different opinions on using epoxy... do you think its worth the extra costs?

    last year I did lay up- on one sq ft. 8 layers of tri 22 oz. using poly. it bonded well. did not delaminate but im guessing that a large hull such as a 30 ft'er is going to be different?
    I would prefer the epoxy...what's your take? id rather use the knitted all the way through if possible?
     
  9. tugboat

    tugboat Previous Member

    Groper- you mentiond that epoxy is better ? (I think).

    this was what I wanted to use after I thought about it.
    then I got flamed by Ilan Voyager. he said not to... so there are differing opinions.

    This is a problem since im in between all these opinions with people who know more than I.

    my thought is to go with the iso. but my gut feeling is- how can I go wrong(other than costs) with epoxy- no smell- stronger- better lamination properties...does the extra costs give equal benefits by getting better mechanical advantages? in other words is it worth the extra denarius?.

    I did price out the csm backed tri. its not too bad at about 30 cents extra per 9 sq ft or a yard (close to a meter). so its an option for sure.

    epoxy? vs iso?
     
  10. tugboat

    tugboat Previous Member

    Hi Samsam- thanks- I am worried about draping issue. is it possible to staple the triax to the mold? perhaps using frp staples which are all the new rage apparently...

    I can wait till later in the season or heat a shed to bring the temps up. I was thinking of doing it in April when that's about what the day time temps are. but could wait till may or June when it gets warmer...(but hotter than 70 f.)

    there are two seasons here- winter and construction season.

    how about you Samsam- epoxy? vs iso?


    epoxy.

    advantages
    1. stronger(?)
    2.easier to avoid shrink on c-flex
    3. better abrasion resistance.
    4. less osmosis
    5. no smell!
    6. longer cure rate

    disadvantages
    1. costs
    2. marginally stronger??
    3. higher cps
    4. harder to mix(when I used 5 gallons of it to do my last boat- it was great no issues)
    5. sand between coats or use solvent.
    use of peel ply(might be an advantage too!)
    6. longer cure rate
     
  11. SamSam
    Joined: Feb 2005
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    SamSam Senior Member

    It won't de-laminate in that it would be easy to pull apart by hand, so it is hard to tell in a 1 sq ft piece that thick. In a 1 sq ft test piece, if you have just two thin laminations and try to pull them apart, that will show results. That will concentrate the test on the resin.

    In a boat, if something runs into it, the laminate will be held down on the edges so at the point of impact the laminate will be stretched. Thats when inter-laminate shear and de-lamination comes into play. That's where the mat will add a lot of strength to resist that.

    The kind of lay-up you will be doing, a heavy, thick, non-technical laminate is well suited to polyester and is probably the best type for it.
     
  12. SamSam
    Joined: Feb 2005
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    SamSam Senior Member

    I grew up in Minnesota, did construction and made FB canoes there before I left so I understand the seasons. "I remember one nice day last summer." "Yeah. Me too. That's the day we played baseball."

    I never used epoxy much at all. It was too expensive and was not readily available. What little I did use had a very heavy formaldehyde smell which was creepy.

    The hull is a smaller part of your total boat cost and the resin is only part of that cost, so even if you're doubling the cost of the resin, in the long run it's not that big of an expenditure. And it's advantages could quite possibly be more than worth the extra cost.

    But as I said, the type of lay-up you're doing is probably the best type for poly, if that's what you use. I used iso, as I could only afford to have one barrel around and it was best for molds and all around better. Low shrink, better heat and chemical resistance properties.

    Maybe they've changed the formulas for epoxy since then, but back then epoxy had a mean reputation for allergic reactions, very akin to poison ivy, and they were accumulative, each reaction added to the last and made you more sensitive. Some to the point of being life changing. Some said that even after the resin was cured, they couldn't use the boat they had made, busting out in rashes and asthma after a little while aboard. But, who knows, it could just be ugly rumors.

    One advantage for epoxy is apparently you can use a different hardener for different temps and low temp cures are apparently possible with it. Poly is more temp sensitive, with only one type hardener. You can vary the hardener amounts somewhat to regulate cure speed but that affects laminate quality or characteristics.

    I don't think you will be able to staple anything through a cured layer of C-Flex.

    Usually in a production build, resin is put on the cured laminate first and that will hold the mat for wet out and then the wet mat will hold the woven material for wet out and then it's rolled with a bubble buster roller. You can use tape, which you have to remove, or some people use a little spray on adhesive to hold materials in place for wet out.

    Try and avoid overhead laminating, that can be troublesome. Part of the problem there is plain weight. Say if you needed 24 oz of woven roving overhead, you would probably have to do two separate sessions using 12 oz cloth, as resin might hold 12 oz at one time but not 24. Or figure out some way (plastic or peel ply) to hold it there until it gels.

    There was an article in Pro Boat Building that tested 2 things in poly layups in thicker (1/4" +) layups of mat ,WR, mat WR etc. They tested surface prep between cured lay-ups and also overlapping vs. butt joints of mats. (I cant remember if the overlap part included the woven cloths too or not, but I think it did) The article writer found that overlaps (all joints staggered x amount, it had a formula) contributed very little to the lay-ups and could easily be dispensed with. On a male build especially, such as this tugboat, you end up grinding off the laps anyways when fairing. As far as the surface prep (using unwaxed laminating resin) I believe they tested (1) between grinding/sanding the surface and then vacuuming, (2) grinding, vacuuming and acetone wipe down, (3) scraping off the few imperfections like bumps or glass splinters that would hold the new laminate off the old and introduce bubbles, bumps etc, followed by vacuuming and an acetone wipe down and (4) scraping and vacuuming. The last one, #4, with the least preparation was found to give the most strength as far as inter-laminar bonding. Also, if I'm not mistaken, this was all done as secondary bonding, i.e. not within a time frame to give chemical bonds.

    It would be handy if someone could find the mid or early 90s article to verify those things. It would probably be tagged with 'secondary bonds' or 'tabbing' or something like that.
     
  13. SamSam
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    SamSam Senior Member

    There is a thing about mat and all other materials that is strange and I don't know why, but csm is sold by oz per sq foot, where cloth and woven roving is sold by the sq yard. So a 1.5 oz mat actually weighs 13.5 oz per sq yard. You have to accommodate that when figuring out for resin needed.

    I don't know about something like 1708. The 08 is the mat, but I don't know if it's 8 oz per sq yd or .8 per sq ft., which would be 7.2 oz per sq yd.
     
  14. SamSam
    Joined: Feb 2005
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    SamSam Senior Member

    One more thing I'm wondering about is the tri ply fabrics and poly resin. I think they are three layers of strand that are not interwoven, but lie on top of each other with stitch or binder to hold it together. I wonder if technically, since there is not any csm between the three layers of strand, if it might not work as well (in poly) compared to woven roving which holds itself together. Inter-laminar shear and all that.
     

  15. brokensheer
    Joined: Jun 2009
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    brokensheer Senior Member

    wish I'd come across this sooner!, I have built boats with c-flex, an will never use it again, it was a great idea 25years ago when nothing else was available, now with core-cell foam its a new game!, first with c-flex whenyou wet it out "hot" as is called for it shrinks and becomes un- fair, even after wetting it out air finds its way into the first laminate and you will end up grinding off your $ spent and you get to do it all over again. none of these issue occour with core-cel, I hope this helps, and I speak from my expieriance
     
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