Composite (glass/foam/glass) For Beginners?

Discussion in 'Fiberglass and Composite Boat Building' started by CatBuilder, Oct 15, 2010.

  1. CatBuilder

    CatBuilder Previous Member

    War Whoop: Do you have to use bonding paste? I can use epoxy straight to the foam, right?
     
  2. Herman
    Joined: Oct 2004
    Posts: 1,618
    Likes: 94, Points: 48, Legacy Rep: 1240
    Location: The Netherlands

    Herman Senior Member

    Can you specify the laminates? Multiaxial naming convention seems to be different for every manufacturer.

    Indeed, thicker laminates benefit more from infusion. Thickest I have done so far was some 75 mm (3")

    Hand layup: Luckily the fiber/volume ratio of hand laid multiaxials is closer to infused multiaxials than for instance with mat or roving. So the difference will be not that much.

    Postcure: A postcure before final sanding and finishing is very beneficial. Get is at hot as you can, within limits. 48C is already great. Where I live this is almost impossible without a heating source.
     
  3. Herman
    Joined: Oct 2004
    Posts: 1,618
    Likes: 94, Points: 48, Legacy Rep: 1240
    Location: The Netherlands

    Herman Senior Member

    Oh, yes, you can use epoxy straight on the foam. Some people first spread some slightly thickened epoxy on the foam with a throwel. Never tested that, though.
     
  4. War Whoop
    Joined: Jun 2003
    Posts: 661
    Likes: 16, Points: 0, Legacy Rep: 84
    Location: Sunny Ft Lauderdale Fla

    War Whoop Senior Member

    Bonding the foam to a cured laminate? I would use something like spabond from SP.
     
  5. CatBuilder

    CatBuilder Previous Member

    No, the foam is down first in my case, so epoxy would be wet bonding to virgin foam.
     
  6. War Whoop
    Joined: Jun 2003
    Posts: 661
    Likes: 16, Points: 0, Legacy Rep: 84
    Location: Sunny Ft Lauderdale Fla

    War Whoop Senior Member

    That is ideal, I would watch the weight and use damage tolerant core material.
     
  7. CatBuilder

    CatBuilder Previous Member

    Laminate specification:

    CDB200: 20oz Triaxial, 10oz at 0deg, 5oz at +45deg, 5oz at -45deg NO MAT
    CDB340: 34oz Triaxial, 15oz at 0deg, 9oz at +45deg, 9oz at -45deg NO MAT
    DBM1708:17oz Triaxial Tape at +/-45, 90 Deg, 8oz mat

    This link will help with the naming convention we use in the
    States:

    http://www.owenscorningchina.com/upload/File/466671169.pdf



    LAM-A 3 layers CDB200 triaxial
    LAM-B 2 layers CDB340 triaxial
    LAM-C 2 layers CDB200 triaxial
    LAM-D CDB340 triaxial
    LAM-E CDB200 triaxial
    CORE-A 6#PVC
    CORE-B 5#PVC
    TAPE 6" triaxial tape for hull frame/hull joint DBM1708

    The layups will go LAM-A/6#Foam/LAM-B for hulls. Are the methods we are talking about still good for these very thick laminates?
     
  8. apex1

    apex1 Guest

    Yes, to make it short.

    And you don´t need anything but the neat resin on the foam.
     
  9. War Whoop
    Joined: Jun 2003
    Posts: 661
    Likes: 16, Points: 0, Legacy Rep: 84
    Location: Sunny Ft Lauderdale Fla

    War Whoop Senior Member

    What is the core size? and have you checked the material @ http://www.vectorply.com/
     
  10. CatBuilder

    CatBuilder Previous Member

    Hmm... the materials list doesn't specify the thickness, just the density.

    I guess I'll have to ask or wait until I see the new plans for foam/glass.

    Thanks for the link to vectoryply. They have all the triaxial! Nice!
     
  11. War Whoop
    Joined: Jun 2003
    Posts: 661
    Likes: 16, Points: 0, Legacy Rep: 84
    Location: Sunny Ft Lauderdale Fla

    War Whoop Senior Member

    They have a good program as well ,The core thickness should have been listed.
     
  12. Herman
    Joined: Oct 2004
    Posts: 1,618
    Likes: 94, Points: 48, Legacy Rep: 1240
    Location: The Netherlands

    Herman Senior Member

    These are quite heavy multiaxials to laminate with epoxy resin by hand.

    I would definately define a laminate plan that uses less heavy fabrics. Downside is that you need to use more layers, and that per kg (lbs) the material is slightly more expensive, but it also means the laminating job is more controllable, giving better (less voids) results.
    Also, with more layers you can take the opportunity to butt-join the fabrics, so no lumps are generated. (I usually only recommend that at 3 layers or more, or 4 layers or more to be conservative)

    I will take an example laminate: (lam B)

    34 oz / sq yd * 2

    Breakdown of the laminate:

    30 oz @ 0
    18 oz @ +45
    18 oz @ -45

    Depending on what is available, I would probably try to do 2 layers of Biax 18 oz, and 2 layers of uni 15 oz:

    This gives the same results, but is much easier to laminate.

    With infusion, weight of the fabric is not a concern.

    ----
    Overlaps, revisited: I see some laminates are specified as 1 layer. Are these for small parts, so you do not need overlaps? Keep in mind that 1 heavy layer, with an overlap, creates a nasty bump which needs a lot of fairing. Better then are 2 layers with staggered overlaps.
     
  13. War Whoop
    Joined: Jun 2003
    Posts: 661
    Likes: 16, Points: 0, Legacy Rep: 84
    Location: Sunny Ft Lauderdale Fla

    War Whoop Senior Member

    Wet bagging is an option, in the 17 -18 Oz range 5 layers could be done per session easy,there is no way I would go with a straight hand layup as my end laminate. butt joining ,from the work I have done we saw @15% drop in physical (6 laminates went down) not worth really mentioning, also on the light fabrics the lap is nothing if you bag,on my boats the laps were planned for and the core was sanded back slightly at those locations ,especially the transom/hullshell. fortunately you are going plastic foam and the infusing is open for consideration,I would not infuse Balsa as that is exactly what you are doing.
     
  14. AndrewK
    Joined: Mar 2007
    Posts: 490
    Likes: 51, Points: 28, Legacy Rep: 344
    Location: Australia

    AndrewK Senior Member

    Thanks Richard, I just tried this but all I seem to get is Catbuilders comments outside the QUOTE area of post#78. I also tried clicking on the multi quote tab first with no success. For the moment I will trie copy and paste.
     

  15. AndrewK
    Joined: Mar 2007
    Posts: 490
    Likes: 51, Points: 28, Legacy Rep: 344
    Location: Australia

    AndrewK Senior Member

    Originally Posted by AndrewK View Post
    Catbuilder, I also think that you should build a boat only if you enjoy the building process and not in order to save money.
    I do understand your dilemma that the second hand production boats are not good sailing boats.

    Well, here's why I'm building: I need a charter cat (overnight term charters) and I need one that sails well. I also need one that is within my budget. This catamaran does not exist on the used market and my budget is <$300K. This means I have absolutely no choice but to build one, or to find another career (I do this professionally, not mom and pop style). This is my full time career. So, you can see that I do need to build. That said, I do not enjoy it. It is not my favorite thing to do. I have fully restored 2 prior boats. While the feeling of accomplishment is great, the work is less than desirable. Hope this makes sense. I am doing this because I have to, not because I want to. There are literally no other ways to get a good sailing charterable cat for under $300K.

    OK it is possible to build a cat in the 12 - 14m range in that time because it has been done. But these are very basic finishes on the inside and just acceptable standard on the outside. For a home builder three years is an exception rather than the norm, most would take 5 -6 years and some 10+ years.
    I can't see 10 years. Are you counting full time work, or someone fiddling around for 10 years? I know a guy who build an Oram 44C in (if I recall) 3 or 4 years. He did this while working a full time job and had a family with young children as well. I think it is how committed you are to the project. My plan is for 7000 man-hours. Isn't that enough? I'm thinking it is more than enough... nearly 1/3 more. I think the project is best measured in man-hours, not years, right?
    Yes measuring in hours is the correct way, I used years to drive the point. If you take the Oram 44 as an example its around 4,500 hrs and this is for a kit boat that has been computer cut out of duflex panels. This is a big time saving as it takes a week to z press all the sheets together and then you glue and tape things together. There is a huge difference in hours it takes to laminate both sides of the 300+sqm of surface area in a boat as yours compared to just taping. All being precut also means a huge reduction in thinking and planning as well as not being tempted to change things as this can be a very big time waster.

    A friend has just launched a 12m foam striped catamaran and it cost him AUD $530K and six years of hard labor, 12 moths alone for fairing and painting but the standard is very good and lots of equipment. He could have built the Bob Oram 44 which is a better sailing boat for half the money and half the time.

    If you must build and you are time and money constrained then do not go down the vacuum consolidation path.

    This worries me a lot. Did your friend spend 6 years, 40+ hours a week, working every week?
    He treated it as a job, worked 40 - 50hrs a week and had 4 weeks vacation each year. He also had help for the fairing and painting, I think his design (Grainger) was also meant to be 7,000hrs

    So what about DuFlex? If I'm strip planking all that foam anyway, why not get DuFlex strip planks and just tape them together, like on the Oram builds? I know they have eglass/corecell/eglass panels over at DuFLex. What do you (or does anyone) think of that? Seems if I'm going to go through the PITA of strip planking all that foam, I might as well strip plank something that is already laminated and already contains the lowest resin content. I would imagine the DuFlex panels are as light and strong as possible and compared to what an amateur could do with bagging or infusion, I am thinking I'd end up with a lighter boat overall. What does anyone think of this?
    This is one option that many builders use when doing longitudinal strips, but the panels are only preglassed with UD. The UD runs along the strips so when you rip the sheets up you cut parallel to the fiber. The advantage of this approach is that strips have some stiffness and will take up a fair shape and are much easier to handle. As well as then only having to hand laminate one layer of triaxial transversely so the final laminate ends up being a quad.

    Both timber and foam planking will take about the same time, so the decision is based on cost and personal preference and to some extent resale value.

    Well, to be frank, I've never been a "wood guy." All of my wood projects have had problems, including my Kurt Hughes cylinder mold, which developed splits. Honestly, I hate wood. I don't like working with it. Give me plastic and I can put together anything well. It's been this way since I was a kid. I'm in my 30's, so plastic is more familiar to me as a material. Personal preference is that I like working with plastics. Resale value is a huge concern to me because not only my life's savings, but a couple years of my wife's currently unearned income will be in this boat. So, we need good resale value.
    You do not need to have any traditional timber skills to build a strip plank timber core boat, its actually easier than longitudinal strip planking in foam unless the foam is preglassed as mentioned above. It is also cheaper.

    Hand laminating timber core, hand laminating foam core and vacuum consolidated foam core will all produce an exceptional boat.
    Which is better depends on your priorities, timber core will be a more serviceable boat as it will not bruise as easily if knocked hard. Hand laminated foam will be lighter than the timber core but not significantly but will be more easily bruised. Vacuum consolidated foam cored will be the lightest and most fragile. The weight difference will be in the order of 200 - 500kg between each case, get actual differences from Kurt.

    The one part of this that's not work related is my dream to have a catamaran that sails well. This means less weight. I want to go to windward well (boards and a light boat). I'm OK with a boat that is fragile in impact. I have 20 years on the water and at least 10 of them full time chartering and living aboard boats full time. I have so many hours at sea it's a bit silly. In all that time from Venezuela to Canada, I only grounded one time in the Intracoastal Waterway, which is like a small canal on the East Coast of the States. It was not as deep as the chart suggested and I touched bottom. Other than that, I've never had any instance where my boat has had a bump at any time. I'm an overly cautious navigator and pilot. So... I'd rather have a light, fast, good sailing machine than have impact resistance. That's what the triple watertight bulkheads in Kurt's design is for. I can lob off a good part of my bow without getting water inside. So... I'm looking for light weight as a priority.
    The difference between foam core and timber core I was referring to is not grounding impact but accidental (no fenders) hard bumps and scrapes at docks, hard tenders etc. Timber core will stand up to it much better than foam unless you compensate by overbuilding the laminate on the foam boat and then you have eroded all of your weight differential.

    Foam, both crosslinked PVC and corecell are fit for your purpose, yes corcell or Airex R63 liner pvc due to their higher elongation are better for hulls or at least below the water line. But not necessary, far more boats are build from crosslinked pvc than the other two and are still fit for purpose. So if you can afford it then do so.

    Both PVC and corecell comes in different grades not just density but service temperature as well so you select the appropriate grade for the service and processing requirements. I have used corecell A in my catamaran hulls, this has one of the lowest softening points (~73'C) so you can still post cure at 60 - 65'C if required.

    Good points. If I use DuFlex, do I need to do any or much post curing? Would I just use a heat gun? If I do full glass/foam/glass manual layups, I wold need to post cure every inch of the boat, right?
    No not heat gun, but this has been dealt with here and your previous threads.

    And how about delamination issues? I've seen so very many foam cats on the used market with huge delamination issues. Is this because they are polyester or vinylester, rather than epoxy? That was my theory as the one and only foam cat I looked at (out of about 10) a few years back that had no delamination issues was a Kelsall. I know he uses foam and epoxy, so I was thinking that is why his might have stayed together. Of course, not delaminating is a HUGE concern.
    Resin is not the issue it is quality of work, there is nothing wrong with a good 50:50wt% hand laminate. Hand laminating is the most full proof way, vacuum consolidation will improve things but at the expense of time and money in which you are short of.

    Regarding your question on reinforcement orientation, Kurt will specify what is required for the timber and foam versions. But it will be multiaxial, what you referred to is a unidirectional (UD) this comes in both forms warp (along the length, o deg) and weft (across, 90 deg).
    Typically for a timber core you only use a DB +/-45 or a triaxial +45/0/-45 with the 0 deg across the hull. This is because the timber grain is along the hull and has enough strength on its own. The laminate for the foam version could be anything from 0/90, +/-45, a triaxial or a quad.


    Gotcha. I probably didn't use the correct terminology. Thanks. I understand what you are saying. I'll see what Kurt has in the plans for the foam version he is sending to me.

    If you go down the foam route I differ from Herman and prefer to hand laminate in a concave half hull on its side so can give you reasons for this if need be.
     
Loading...
Similar Threads
  1. fallguy
    Replies:
    120
    Views:
    8,089
  2. mrdebian
    Replies:
    15
    Views:
    1,379
  3. Chotu
    Replies:
    8
    Views:
    1,211
  4. bajansailor
    Replies:
    13
    Views:
    1,263
  5. cando2
    Replies:
    10
    Views:
    1,395
  6. Robert Biegler
    Replies:
    61
    Views:
    5,509
  7. Markusik
    Replies:
    11
    Views:
    1,338
  8. fallguy
    Replies:
    12
    Views:
    1,609
  9. Mark C. Schreiter
    Replies:
    29
    Views:
    2,803
  10. Scott M..
    Replies:
    61
    Views:
    7,264
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.