To Speheretex Or Not Speheretex That Is The Question

Discussion in 'Fiberglass and Composite Boat Building' started by jiggerpro, Feb 11, 2011.

  1. jiggerpro
    Joined: Sep 2007
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    jiggerpro Senior Member

    Reading our forums, I came across this product called spherecore made by the speheretex brand, I have read thoroughly their website and found their product called spherecore SBC to at least in theory "sounded" very interesting ( I already asked for some test samples ), the product and how is made seems like many good ideas, simple and robust and I have to say that quite reluctantly I have accepted my Sp systems engineer advise of using sandwhich construction also below the waterline, he saying that epoxy is a completely impermeable substance and saying the same for the proposed core which was corecell M.

    As I see it, the surest way to avoid water entering anything is not giving the water the volume to occupy.

    And I am now thinking that I should make my boats with spherecore in the bottom and transom ( with its many neccessary holes ) because with its density and all plastic construction not only would this provide for an insurance against water permeation into the core ( because there would be no core but spherecore instead and it has no voids for the water to occupy ), it should also provide for a better compression strenght wich should be good to avoid compression of the core under the outboard installation bolts localized pressure areas.

    As transoms of the projected boat ( a 33 feet sportfisher outboard powered) should have so many holes necessary for the attachment of the engines, trim tabs, and underwater led lighting, with many of them under the waterline, I do not completely believe in the told by Sp Systems story about the complete water resistance of both the epoxy resin and the corecell so this new to me product the Spherecore looks like an insurance against many things, among them even a less prone to printhorough laminate and the aforementioned improvements in regards to better compression strength in the transom and better anti water intrusion properties.

    So what has been the experiences, something to worry about ??

    So hence the tiltle of this thread "To spheretex or not spheretex ........
     
  2. fg1inc

    fg1inc Guest

    Water enters a cored bottom at the site of any penetration, thru-hulls, scoops, struts, etc. Therefore it is imperative that every penetration site has the core replaced with solid laminate. It really doesn't matter what core you use, if you do it correctly your water intrusion problems will be minimized or eliminated.
     
  3. waikikin
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    waikikin Senior Member

    Looks like a similar material to Coremat or Upica mat, great products- kinda resin hungry though so heavyish. I had a boat from "Beach Marine" that used coremat every where except decks, was a good boat. Regards from Jeff.
     
  4. tunnels

    tunnels Previous Member

    Everyone i have ever know has completely the wrong idea about how to use and where to use core matt !!! Of any brand .
    There are places you should never use it as well .
    Time to start a new tread on Corematts !!:?:
    The shperetex core you need to watch the videos that are on there site and re watch a few times till all the information really sinks in . Its a good product but in Boats , careful where you use it and what you use in for !!
    Like all new products theres a learning curve in this case its more like a straight line going straight up and no curve .
    Very interesting but !!
     
  5. jiggerpro
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    jiggerpro Senior Member

    I believe that their product Spehretex Sphere core SBC is quite different from coremat in that it coremat is not much more than a resin hungry sponge .......... on the other side spheretex introduces some hollow micro spheres of plastic into the resin matrix and in theory this should reduce its weight ............ it sounds like a very good idea at least in theory
     
  6. tunnels

    tunnels Previous Member

    Have you seen their site and watched their videos ?? :confused:

    Its the same principle as core mate just a modern version with additions
    Need to disect corematt and see what its made of and how its made !!:)
     
  7. waikikin
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    waikikin Senior Member

    I think they're pretty similar- from --"Lantor Coremat®

    The Nonwoven core and liner for hand lay-up and spray-up processes

    Coremat is a polyester nonwoven that contains microspheres and is used as a thin core (bulker mat) or print blocker (liner) in fibre reinforced laminates, manufactured in Hand Lay-Up or Spray-Up processes. Coremat should always be fully impregnated with resin the microspheres in Coremat prevent excessive resin up-take. The most important reasons to use Coremat are:

    * Weight saving
    * Resin and glass saving
    * Stiffness increase
    * Fast thickness build-up
    * Excellent surface finish

    Coremat® Xi

    Xi

    Coremat Xi is the world's standard for bulker mats. The Coremat resin consumption is about 600 grams per mm thickness. It contains a resin indicator which changes colour to show that resin has been applied to the Coremat.
    Coremat Xi is very soft and pliable when it is wet and therefore very suitable for complex shapes.


    Coremat® XM

    Coremat XM has a low resin take up: 500 gram of resin per mm thickness. It is therefore suitable for weight critical applications. The hexagonal cell pattern results in a very consistent thickness in the product. Coremat XM has a very high wet tensile strength; it is therefore often used in applications where mats are pre-wetted outside the mould"

    The Upicamat uses similar amounts of resin, Speretex quotes from 400-650grammes perM2 permm of thickness depending on product.

    resin take up rates seem pretty similar per mm of thickness quoted from both sites...... I'd say all brands are terrific materials in the correct applications. If the price, service & certification suit, thats how I'd choose. All the best from Jeff.
     
  8. Herman
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    Herman Senior Member

    All these materials are roughly the same, and made from expancel or similar materials. a polyester veil is soaked or printed with dissolved expancel, then blown up with steam. After that the stuff is dried and rolled up.

    I would not use them for motormounts, I feel more safe with singlee skin. For the rest it is usable material.

    Keep in mind that you need a pressure resistant version (Soric instead of Coremat, or similar from other suppliers) if you are infusing. And you need at least 30-60 minutes before the expancel has reached an equilibrum with the vacuum. Infuse earlier, and you will experience a lot of air in the laminate. (keeping 60 minutes of vacuum is good practive anyway)
     
  9. jiggerpro
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    jiggerpro Senior Member

    Hi Herman;
    Why don´t you think that spheretex being denser than foam is more suitable to standing the localized strains imparted by the motor mounts? Also, being made of truly unconnected cells surrounded completely by resin, the product should be much more resistant to water infiltration than any foam and so It should be a good substitute for the transom core (and its many holes).

    Single skin is very safe, but to attain stiffness any piece needs to be heavier than an equivalent strenght sandwhich one, but any typical foam core in spite of manufacturers claims of them being closed cell and waterproof the truth is they are not .... rot proof maybe they are, but not really waterproof since there are spaces that can be occupied by water and with enough time water finds its way to almost everywhere.

    After reading about the impermeability of epoxy and finding out that it is not totally impermeable I got worried about our planned construction which so far, and as advised by the Gurit´s structural engineer ( who claimed total impermeability of epoxy) has corecell in the hull and yes, below the waterline as well ..... so as boats in Spain and Europe are stored for their whole service life in a mooring and thus susceptible for water damging the core ............ I got worried ...
     
  10. Herman
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    Herman Senior Member

    The spherecore consists of hollow spheres. They can be crushed by high forces. I would not worry for a swim platform, led lights, or whatever, but I would not mess with trim tabs or motor mounts. You only need very local patches of beefed up single skin.

    As for permeability: I would not worry too much. Keep in mind that, although epoxy can be slightly permeable, it is very much less than polyester. Many, many polyester boats are built with cored hulls (also below waterline) and will not give any problem.

    I agree there is also a large amount of boats with cores, and with problems (also without core, but with problems) but in about all of these examples problems can be explained by bad core installation, bad laminations, or just plain misunderstanding or lack of training of the actual workers.
    Take care of ironing out potential problem areas (motor mounts, for example) and build well and careful, and problems will be virtually nil.
     
  11. jiggerpro
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    jiggerpro Senior Member

    Thanks for this more elaborate answer .......... what we were thinking to do in regards to the transom and engines and trim tabs ...... was to make some inserts of solid material in the corecell core where the holes should be placed , we planned on doing that by laying the transom core flat and then pouring some resin mixed with maybe some short glass strands or some mineral powders into the holes ..... the areas more than holes where the corecell will be substituted by this resin rich solid volumes will provide with more than enough crushing resistance in those sensible areas and total impermeability thorough the holes avoiding that the water "see" the foam .......
     
  12. War Whoop
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    War Whoop Senior Member

    Water will not damage corecell,you are confusing this material with something else,Core in general has got a bad rap due to poor shop practices .
     
  13. tunnels

    tunnels Previous Member

    I totally agree !! Workmanship accounts for 90 % of failures , bad habits the other 10% . :confused::p
    I see this just about every day in nearly every place i go to work !!
     
  14. jiggerpro
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    jiggerpro Senior Member

    Hi War Whoop and Tunnels; I was not worried about the water damaging the corecell, what worries me, is to design and build a light, fast and efficient boat, only to discover after some years in the water that the originally light, fast and efficient, now carries 200 or 300 kg of water around wherever you go as an unwanted or uninvited passenger making your light boat a pig, just like it has happened so often with filled with PU foam boats ( regardless of manufacturers claims of the PU foam being closed cell wich certainly it has never been )

    Many design, economic and build efforts are need to be made in order to obtain a light and strong craft and often those efforts are made only to gain relatively small weight reductions so after making those efforts it does not sound reasonable to allow the core to soak in several hundreds of liters of water as indeed has been the case with many "foam present" boats.
     

  15. Herman
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    Herman Senior Member

    Try yourself, with placing a piece of Core-Cell in hot water. If the water is too hot (boiling), it might expand a bit, but water take up is almost nil.

    PU foam is different. In the first place it usually is very light (35 kg/m3) and the pour-in-place foams are many times badly mixed. PU needs to be used very, very carefully and skillfully, to avoid problems, or not used at all. For me the only good use for it is in DIY fridge construction, for its very good insulation properties.

    Do not confuse construction foam (PVC, PET and SAN) with PU foam.
     
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