Fiber Cloth on new Wooden Hull

Discussion in 'Wooden Boat Building and Restoration' started by teoman, Mar 9, 2010.

  1. teoman
    Joined: Mar 2010
    Posts: 24
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Turkey

    teoman Junior Member

    wooww thanks guys. That is a lot of good informatşon for me. Thanks a lot.

    Actually yes it is allready planked. So no way out on that :)

    but thanks for the valuable information. I will go that way. I have to reasearch those products and cost. Hope it will not be too expensive...

    Can wait to have it finished and enjoy a good wine here in Istanbul.

    Just one last thought: isn't it good just to leave the wood without glassing on the outside and inside ?? So it can bread, have contact with air on the inside and just normal coating for paint preparation on the outside ??

    Just wondering.... thanks a lot...
     
  2. alan white
    Joined: Mar 2007
    Posts: 3,731
    Likes: 122, Points: 0, Legacy Rep: 1404
    Location: maine

    alan white Senior Member

    I assumed the picture of the planking was another boat, an example. In any case, I agree that glass on the bias is the way to go where flex is expected. And if chestnut is the only wood available, I understand. I'd like to hear from others about using oak-like woods under glass/epoxy, maybe some experience with older boats originally done that way.
     
  3. apex1

    apex1 Guest

    The species used in Turkey is "Castanea Sativa" , not as hard as Oak, but a hardwood. The reason that it is so common especially for building Gulet´s, is the fact that there are hughe chestnut forests in Turkey.
    The timber is by no means the best choice for boatbuilding (the average Gulet does not get old, to prove that).
    It is acidic, which corrodes fasteners, it is susceptible for warping and difficult to dry.
    Though it is fairly rot resistant.

    Due to the choosen building method, you have no other choice than sheathing the entire outside, and to saturate / encapsulate the inside with at least three layers of resin. The rest was already said by Alan and Ilan.

    Go to Tersaneler Caddesi in Tuzla, about 300 meters behind RMK Tersane is a small road with some 40 yards and boatshops, almost all building in wood epoxy (most to a very crappy quality), ask them about their experience, which resin on chestnut did / do they use! You will find, that most of them are using Mahogany, but there are some still working with Kestane.

    If in doubt: "West systems" should do the trick.


    Regards
    Richard
     
  4. Ilan Voyager
    Joined: May 2004
    Posts: 1,272
    Likes: 196, Points: 63, Legacy Rep: 758
    Location: Cancun Mexico

    Ilan Voyager Senior Member

    Apex thanks for your precision: I know this wood, very used in old roof carpentry and some fishing boats. Very acid, like the european oak it "eats" the screws. Tendency to warp and split if old tree wood is used.
    The West System price will be prohibitive, West makes you pay the name, and, very personal opinion, it's not worth the price.
    You have Sicomin ( http://sicomin.com/prod.asp?scat_num=12#product25 ) in France with the very good SR 5550 which will be probably cheaper.
    There are surely some epoxy formulators in Turkey. I used myself a formulator who provided me excellent resins at fair prices during years in France. An acquaintance of mine solved his epoxy problem in Colombia using a local formulator of epoxy resins for tanks and pools in concrete and steel. The requisites are very close to those of naval boat building.
    In fact a good epoxy resin for permanent immersion and good chemical resistance would do the job if it's fluid, flexible and softens above at least 70 degrees Celsius. An easy task for a formulator starting from a Derakane 33 for example.
    All the naval epoxy brands are simply formulators, having their personal recipes.

    Teoman; You're welcome. The tests of adherence are mandatory on an acidic wood.
    1- Peeling fiberglass;
    Cut 4 strips 25 cm long, 5 cm wide in a 10 onz (300 gr m2) cloth fiberglass. Put tape on the last 2 cm of the glass, so it won't glue and you can grip this loose end with pliers.
    Prepare 4 samples of your planks.

    a- 1 plank sanded with 120 grit. 1 coat saturation. Resin the glass strip, just to cover the weave. Let it harden 3 days.
    b- 1 plank sanded with 80 grit. 1 coat saturation. Resin the glass strip, just to cover the weave. Let it harden 3 days.
    c- 1 plank sanded with 80 grit. Clean it with Xylene and let it dry. 1 coat saturation. Resin the glass strip, just to cover the weave. Let it harden 3 days.
    d- 1 plank sanded with 80 grit. Clean it with monoethylene glycol diluted a 50% with very soft or distilled water and let it dry. 1 coat saturation. Resin the glass strip, just to cover the weave. Let it harden 3 days.

    Now you take the glass strip with the pliers and peel it out. Look at the resin remaining on the wood.
    If the resin is gone with the cloth, totally or partly leaving the bare wood, it's no good at all. Failed. No adhesion.
    If the resin stays on the wood, having the print of the cloth weave, that means that the bond between the resin and the wood is stronger that the bond of the resin and the cloth -I simplify, I won't enter in the details of fracture mode of the resin-. Good.

    2- Prepare another 4 samples of wood, sanded and cleaned as for the first test.
    Put three coats of resin; first saturation, light sanding, two normal coats. Let it harden 3 days.
    Take a good cutter and with a ruler, make a square grid of cuts every 1.5 mm through the resin.
    If the resin falls from the wood at this state it's not good at all. But that's not all.
    Take a good tape, very adhesive like duct tape, brown tape something that glues ferociously. Put it on the resin grid, squeeze well to get a total adhesion of the tape and peel it out.
    More than 20% of the 1.5*1.5 mm squares stay glued on the tape and left the wood; failed. Between 10 and 20 % not too bad but can be better. Less than 10%, more than 5 % very good: acceptable. Less than 5% excellent.

    This test can be used also with paints to test the adhesion on the substrate.
    Be not afraid, epoxy resins glue very well on Western Red Cedar which is also a very acidic wood. It's just a good and necessary precaution.

    With a wood like this chestnut YOU MUST USE glass fiber cloth outside. At 45° it would be better. With the tendency of the chestnut for checking, 2 coats of fiber would be a plus. Douglas fir has the same defect and it's used with epoxy resin and glass fiber with reasonable succes.

    White or very light color final paint mandatory. Dark paints and epoxy resin under the hot Turkish sun won't last.
     
  5. troy2000
    Joined: Nov 2009
    Posts: 1,743
    Likes: 170, Points: 63, Legacy Rep: 2078
    Location: California

    troy2000 Senior Member

    ????? The old lumber schooners that plied the West Coast of the US were made of the same Douglas Fir that they carried for a cargo. According to what I've read, they used it for framing, planking, decking and spars. And there were certainly no epoxy resins or glass fiber available at the time.

    The C.A. Thayer, a three-masted schooner built of Douglas Fir in 1895, carried lumber until 1912. She then became a salmon packet, and later a Bering Sea cod fishing vessel. Her last voyage was in 1950, according to a web page devoted to her. But it refers to a picture of codfish being salted down in her hold in 1953, so apparently she was still earning her keep even after that.

    http://www.techprose.com/Samples/SFMaritime/thayermoreinfo.htm

    Maybe they just didn't worry as much about checking in those days, on a working vessel?

    By the way, the C.A. Thayer was bought by the State of California in 1957, and restored as a museum ship. She's still around, berthed in San Francisco.
     
  6. apex1

    apex1 Guest

    Thanks Ilan,

    yes there are formulators in Turkey, but not worth talking. I import all my stuff from Germany and at several hundred TONNES per annum that is still worth the extra cost!
    The Turkish sun is not soo dramatic for a appropriate resin (dark colour), Florida is much hotter. But I sell my boats even with dark blue hulls in Florida. Although we are using the right resin (high Tg) and postcure the entire boat at 80°C.

    "West" is just very common in the small boatshops in Turkey, of course you pay mainly the name, rather than the stuff.

    Troy

    if this boat would have been built as a classic wooden boat in carvel planked manner and caulked, it could do without epoxy treatment, sure. But it is already a "wood / epoxy" build (done improper to save some pennies), now he has NO CHANCE, he MUST encapsulate the entire wooden structure in epoxy and he MUST apply at least two layers of glass at the hull (outside).

    Regards
    Richard
     
  7. teoman
    Joined: Mar 2010
    Posts: 24
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Turkey

    teoman Junior Member

    Hey,
    Actuallly the goal is not to save money, I wasn t told of any implication created by having the two layeer epoxied together. I appreciate and thank you for giving me a way out of that. I think we all agree that I should glass inner and outer.

    Richard if I understood correctly, you do import all the product needed for glassing from Germany. I am also looking for the same things. do you sell it as well ?? please let me know.

    I am wondering something. They do a lot of laminated yachts around here 3-4 or even 5 layer. If I am coorect all those layers are epoxied together. So all those yachts would need to have the inner and outer glassed as well ??
     
  8. apex1

    apex1 Guest

    NOT THE INNER SURFACE !!!

    Glassing the outer surface is mandatory, but inside you are fine with three layers of pure resin (apply them wet in wet).

    No, we do not sell our imported products! (that would be very complicated due to the customs regulations)
    But if you follow my advice and go to Tuzla you will find everything you need.

    The boats you are referring to are built "cold moulded", yes every layer of veneer is fully encapsulated in epoxy. In fact every single piece of wood has to be encapsulated. If that is properly executed you have a boat which is as mainenance free (I claim it needs less maintenance) as a GRP boat.

    But too late, your hull is done, so live with it and do the rest proper!

    Regards
    Richard
     
  9. alan white
    Joined: Mar 2007
    Posts: 3,731
    Likes: 122, Points: 0, Legacy Rep: 1404
    Location: maine

    alan white Senior Member

    'Glass is not required, inside or out. The process is called "cold molding". The layers are laminated at angles (the outer sometimes is run fore and aft for appearance).
    Two layers, both going fore and aft, lacks the strength across the grain. The fiberglass is then required inside and out, but glassing between frames inside is a huge amount of work.
    A true cold-molded hull (5 layers, several angles) requires far fewer frames.
    In your case, it appears you are thinking of mixing traditional double-plank with strip-building with a little cold molding thrown in.
    Any one of the methods will work fine (carvel double planking, strip build, or cold-molding), but mixing those methods is tricky and can easily ruin the boat.
    Different woods and different widths of planks, different frame spacing, different requirements for fiberglass, and many other factors come into play as you change from one method to the other. The reason I asked what your maximum plank widths were was because you are using chestnut and the wider you go, the more problematic the result as the boat ages.
     
  10. Ilan Voyager
    Joined: May 2004
    Posts: 1,272
    Likes: 196, Points: 63, Legacy Rep: 758
    Location: Cancun Mexico

    Ilan Voyager Senior Member

    Troy. Apex gave you the answer. Composite wood epoxy has nothing to do with classical boat building, and visibly you have not experience of it. I worked on my first epoxy wood boat on 1971...

    Alan. Words of wisdom...never mix building systems it's a disaster. But it's too late for Teoman, he has to use glass. Improper method, improper wood.

    Apex. Many thanks for your enlightening posts. And your knowledge of the local conditions is invaluable.
    Germany having one of the best chemical industries of the world, no doubt you get excellent products for the boats...and with post cured resin, no problem of heat by the sun! I agree totally with your last post.

    Teoman. The hull is done, not in the proper way, and the simplest way to achieve this boat is to encapsulate it inside with 3 coats of resin (and a fourth coat in the bilges), and outside with 2 layers of glass cloth at 45 degrees (so all the fibers will be used to "support" the glue lines and the wood fiber) with at least 3 to 4 four coats of resin over the cloth. And a good paint. It's the lone system that insures a minimal transfer of water (and water vapor) in the wood.
    I insist heavily that the resin must have an elongation of 5 % for this application. A more rigid resin (like 2 or 3 % elongation) probably will be too brittle for this particular application and will have micro-fissuration or delamination if the boat is a bit flexible.
    A very hard work, but maybe worth to do, it to divide the width of the outer planking so the stresses will be lower. A small fast circular saw, like those used for cutting tiles, with a small wood cutting disk , a good ruler, and lot of "elbow oil" (ie work) are needed. You cut just through the first plank, about 80 % of its thickness, in strips of about 2.5 cm. After the cuts are filled with epoxy and filler. Finishing as said above with glass and epoxy. A big delicate job...
    The chine is a very important place because of the angle change with the induced concentration of stresses. 4 layers of cloth (made by the over lapping) are mandatory. The chine must be rounded so the cloth layers do not "break" over the angle or you'll have surely bubbles and probably a crack line later. The overlap must be at least of 20 cm each side after the glue line of the chine. A lot of fairing is expected...
    Try to contact SICOMIN. They have good products and the prices were good compared to the imported American brands in France. The technical service was excellent. My data is a bit old as I live in Mexico now.
     
  11. apex1

    apex1 Guest

    I beg to differ Alan.
    He is not building with wooden veneers! (cold moulding)

    Glass IS mandatory to strengthen the layers of resin on the outside and apply some abrasion resistance. He otherwise would soon have water intrusion into the wood.

    The building method choosen is (unfortunately) very common in Turkey. The people do not really understand the advantages of the classical building methods and try to "improve" them. Usually the result is sufficient to last for some 10 - 12 years.
    Due to the fact that the planks are already glued together with EP he MUST encapsulate the entire structure in EP too.
    And thats where his original question derives from, it is done so every day in Turkey.
    Of course that is not a proper method. Strip planking would be better, cold moulding like my boats, far better.

    The species of chestnut you find in North America are not what is used here I think. "Castanea Sativa"

    Regards
    Richard

    Ilan you type too fast for me mate.................


    teoman

    have a look here how we do it:
    http://www.boatdesign.net/gallery/showphoto.php/photo/14467/ppuser/11121

    and more important, look how they do it in Tuzla!
     
  12. alan white
    Joined: Mar 2007
    Posts: 3,731
    Likes: 122, Points: 0, Legacy Rep: 1404
    Location: maine

    alan white Senior Member

    I didn't say he was building cold-mold. I only commented that the putting together of two layers was a "method" that included an aspect of cold-molding (that being epoxy between layers and between edges) IN COMBINATION with several other methods.
    Question: Did the builder also encapsulate the frames and back-coat the inner planks, ends, floors, etc.? Did he narrow up his planks in anticipation of adding cloth?
    Cold molding or strip alone would be, I think, the better way to go (leaving behind remnants of traditional plank on frame). Cold molding (with thin veneers) is probably best with hard-chine designs as it would self-fair.
    If strip-built in the old way, 1" thick strips could be edge-nailed, and in addition, if carefully stripped, without any adhesive or in fact anything between strips (use fasteners that won't corrode, obviating the worry of acidity causing damage). A lot of ways to go, but now it appears that glassing and heavy encapsulation is the only thing to do at this point.
     
  13. apex1

    apex1 Guest

    Alan,

    my comment was a bit sloppy formulated. I did not understand you said he was cold moulding. I did contradict on the "glass is not required" part!

    Due to the fact that he is not cold moulding he needs to glass the outside. That was what I wanted to say.

    Sorry for confusing.

    Regards
    Richard
     
  14. Ilan Voyager
    Joined: May 2004
    Posts: 1,272
    Likes: 196, Points: 63, Legacy Rep: 758
    Location: Cancun Mexico

    Ilan Voyager Senior Member

    Alan. Look at the pics and you will see immediately that the frame is identical to the chine frames of the post WW2 war chine plywood boats. Massive wood and some plywood pads. No EP coated at the moment of the pic, no laminated beams.

    A such method building uses normally resorcinol glues, that withstand the stresses of a swelling wood. A lot of a long lasting plywood boats (some have 50 years now) have been done like that in the 50's and 60's. But these boats were made with excellent African hard wood plywoods, mahogany structures and silicon bronze screws.

    The double plank variant used oiled calicot, or white lead compound, or lead minium compound between the planks (I imagine the face of a sanitary inspector if you were using now such poisons...) and tons of copper rivets, bronze screws, or double dipped nails. The English luxury yachts used for finishing the Cascover system (a nylon cloth glued with resorcinol).

    As Teoman's boat is already made, all he can do is to coat the inside with three coats of EP, and to keep a close eye on that in the futur.

    A little trick is to make fillets of glass bubbles - only glass bubbles no other filler- everywhere a beam, rib or other cross the planking. Recipe; glass bubbles, a pinch of colloidal silica (cabosil or other brand) and EP with a little too much hardener (for example if the normal ratio is 2 parts of resin/1 of hardener, he uses a ratio 2/1.05 to 1.1) to obtain a consistence of peanut butter or nutella. That gives a slightly soft, rather elastic, and totally compatible EP whitish compound. It will absorb most of the movements between the planking (and deck) and the structure. It's finished with 3 coats of resin. The lines of possible fracture are suppressed - I hope so-.

    All the "outside" corners must be rounded; it's impossible to get a good EP coat on a sharp right angle.

    All this work is labor intensive...and not 100% guaranteed.
     

  15. apex1

    apex1 Guest

    Yeah it is not too easy, but nothing is impossible!

    [​IMG]

    there are two more guys involved to get rid of the entrapped air btw.

    Regards
    Richard
     
Loading...
Similar Threads
  1. urisvan
    Replies:
    7
    Views:
    2,835
  2. bobbrown
    Replies:
    4
    Views:
    688
  3. ned L
    Replies:
    10
    Views:
    2,395
  4. Gabe Neal
    Replies:
    4
    Views:
    3,639
  5. sdowney717
    Replies:
    13
    Views:
    10,231
  6. NorthLakeFisher
    Replies:
    14
    Views:
    635
  7. rangebowdrie
    Replies:
    21
    Views:
    1,913
  8. AAnderson
    Replies:
    5
    Views:
    1,429
  9. Stavbergen
    Replies:
    15
    Views:
    2,589
  10. 300wm
    Replies:
    17
    Views:
    11,347
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.