please advise on making a male mold?

Discussion in 'Fiberglass and Composite Boat Building' started by tugboat, Aug 10, 2013.

  1. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    I'm not going to get into a discussion with someone who clearly doesn't have a clue what vinylester is, nor the marketing value of the word epoxy, used in the name of a product. Most thermoset polymers have a portion of the epoxy molecule in them, but then again, you'd actually have to know what's in the goo's you work with.

    Tug, pull the samples for yourself and see which ones smell like it's brain cancer in a can and which don't. Epoxy has a very mild ammonia like vapor, which lasts a few seconds after the can is opened. It disappears quickly because of it's high molecule pressure, unless confined within an enclosed space, like a locker or cabinet. This isn't the case with styrene kicked resin systems and no arguing with someone as clearly biased as Tunnels, will solve this.

    All resin systems have a learning curve, but once procedures and down, epoxy is much easier to live with and work with, not to mention, you don't have to live in an industrial area, just to open a can. A lot of places will force you to stop using the styrene resins, just because of the smell, unless of course you live in a third world country that doesn't care what you do.
     
  2. tunnels

    tunnels Previous Member

  3. tugboat

    tugboat Previous Member

    Good morning Par...
    According to Hankinson's book(which is about all I have to go on) he states that v-ester is a poly resin. as is iso and ortho.
    I get what your saying WRT the epoxy- and believe me if I could afford the 3.5 times more costs for the epoxy I would but it is going to come down to finances. a 6500.00 shell (deck not included) or a 10 000 dollar shell . the smell difference and the properties and workability doesn't justify the 3.5 times extra costs. I did price out a drum at Noah's. of course its inflated in price because they are middle men...but it was 2500.00 for the drum and then 1000 or so for the hardener...a five gallon kit here is about 500.00
    there us a place called Clark craft though that sells epoxy. called system 2 I believe. I have used it and it is amazing stuff. 1:1 ratio! I think 10 gallons is about 500.00-600.00 not too bad. ill need about 110 gallons for this hull....that adds up fast - poly is sufficient though at much less the costs..i will put an epoxy barrier coat on the hull after. hopefully this is common practice?

    cheers Par!
     
  4. tugboat

    tugboat Previous Member

    Par quick question- what materials would you use for the furring strips - and would you use ordinary Styrofoam?
     
  5. michael pierzga
    Joined: Dec 2008
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    Location: spain

    michael pierzga Senior Member

    For a guy like me, with my bad back, laminating the inside skin of the hull is painfull. Very poor work posture...lots of climbing in and out

    The beauty of that dingy construction is the half boat mold. Easy to laminate the interior, easy to join the two halves and easy to laminate the exterior.


    For Tug it might be worth looking at
     
  6. tugboat

    tugboat Previous Member

    Michael- so maybe using two half molds? each one a mirror of the other?

    seems like a good way for guys with bad backs?- I'm assuming you would epoxy the hulls together?
     
  7. michael pierzga
    Joined: Dec 2008
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    Location: spain

    michael pierzga Senior Member

    Ive never done it.

    Ive only worked on conventional foam core hulls, built over a male one piece mold.

    Certainly you need to join the two halves.

    You might ask a pro laminator about the technique for a boat your size and whether it is worth the hassle.

    The very best way to do it would be to contract a naval architect to design the boat and propose a built method that suite your needs.

    Naval architects are pretty smart and know many tricks that save time and money.
     
  8. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Any junk wood can be used for the furring strips. The best way is to buy 2x12's and rip the edge off at 3/4", which will give you a furring strip, often with quarter sawn orientation.

    If you're buying supplies from Noah, you're paying full retail which means a $40 a gallon epoxy will cost $120. Buy epoxy on line and have it shipped. Progressive Epoxy Products and Bateau.com will give you the best prices.

    If using polyester or vinylester, regular Styrofoam will melt. You can cover the foam with something, though I've never used this method.

    I agree with Micheal, you probably need a custom design and/or build method. It may be possible to modify a stock design, saving some money, as well has having a previous design's build method upgraded to a new method. This is a fairly common request for designers and NA's.
     
  9. groper
    Joined: Jun 2011
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    Location: australia

    groper Senior Member

    Tug,

    After you stand your section frames on the strongback, batten them out with a 3/4"x1 3/4" timber. After that, transverse strip plank it with 3mm plywood, whatever cheap stuff you can find, cut into 12" wide strips, tho it depends on how much compound there is.

    After youve done that, bog it out using cheap sheetrockfilling compound bought from the hardware wholesaler by the 5 gallon drums. After youve bogged it out and faired it using this cheap stuff, give it 2 coats of resin which will harden up the surface and seal it. After youve done that, you can either continue to build a fine surface mold or just paint it with a tooling flowcoat as your going to do alot more work inside the hull anyway and you may not need a high quality finish inside much of the bilge anyway - so why bother making a mickey mouse male mold, just get on with the laminating of the hull and fair the places you need later.

    Once you have a reasonable, sealed, and hard surface for the male mold, you can go on and apply the mold release and continue with the layup - although its best to wait 2 weeks to let the reactivity of the tooling flow coatsettle down and reduce chances of a bad stick up.

    Once youve laminated the hull, flip it over with a crane and pop it off using compressed air fittings you put in prior, if it sticks up bad then disassemble the mold from the inside. Once its all out, continue with your foam stringers laminated over and then frame grid over that - could use your PP honeycomb panels for this including watertight bulkheads etc.

    Once all thats in, you can start the deck over it all - again the PP honeycomb panels will make good for this. Finish that and start the wheelhouse on top, again the PP honeycomb flat panels could work well for this also.

    Clear as mud?
     
  10. tunnels

    tunnels Previous Member

    Still not found the magic formular yet ??

    Why would anyone pick on styro- foam or even think about using it ?? :mad:
    its used for mc Donald's packaging for ham burgers and coffee cups ! is that what you going to make your dream boat out of ??
    You been all down this track for months and months and really nothing has changed !! just keeps going round and round and getting no where !!:?:
    You wanted solid glass laminate before now its hamburger packaging !! :eek::confused:
    And as for using junky wood to make a mould or former out of you must be kidding !! ,you get what you get !! wood moves and moves a lot !!The more junky rubbish wood you use the more fairing will be involved for sure .
    What you save with one hand you could spend a lot more just trying to get the right shape and Fairing etc . :idea:
     
  11. tugboat

    tugboat Previous Member

    ughhh!!!:mad: why does it have to be so complicated?...im thinking of throwing in the towel for a simple stock design...

    oh btw thanks again Par. yes I was thinking of covering the ST. Foam with a paint like enamel or some barrier of epoxy even?
     
  12. tugboat

    tugboat Previous Member

    tunnels- no no... I was saying that I would cover the mold with Styrofoam..not make my hull from it..;)
     
  13. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 471, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    More usefulness from Tunnels. Styrofoam can and does work, though it will need sheeting to keep the styrene from eating it. Wooden furring strips are a time honored method, done thousands of times and the movement is all but irrelevant, for the same reasons a foam substrate over station molds works. The fabrics never actually touch the foam or the furring strips, so they can move around all they want. Lastly, any male molded piece will require a lot of fairing, regardless of the technique used to get the shape. It's the nature of the beast when laminating from inside to outside. This is why manufactures use female molds.

    In fact you needn't go to a lot of trouble fairing the foam or furring strips, because this is the inside of the hull, on a male mold and most really don't go to a lot of trouble, fairing things that will be covered by a liner, furniture, ceilings, etc. If you're accurate with your station molds and apply whatever over it with similar diligence (foam, cheap plywood, furring strips, whatever), the fairing process will be what it is, on the outside. Instead of materials and methods condemnation, maybe Tunnels can enlighten us on a better one off, single skin process, that doesn't use cardboard, plywood, cheap foam or furring strips. Is it all you can do to *****, moan and find fault with every post? How about something constructive and innovative from your decades of laminating experience instead.
     
  14. tunnels

    tunnels Previous Member

    Something else to look at !!

    http://www.trawlerforum.com/forums/...m-40-trawler-canal-boat-11212.html#post172659

    This is off the first post of today and has a steel hull being built inside a steel frame . There's no reason at all why this same method couldn't be used to build a glass boat !! make patterns of the glass panels and fit inside the frames and glass over the joins inside and out same principle as a stitch and tape but because of the size its could be built inside a frame not outside Has been done lots times wilth dinghy's and small boats and would be only limited to ones imagination to build a bigger boats the same method . The glass joins inside and out could be peel plyed in to the panelled edges and up to 300 mm wide on each panels so have the join600mm wide and thick enough for 3 layers of triaxle glass both sides . if the panels made dead fair would save hours and hours of prep ready for painting . rip off the peel ply and prime and hi build undercoat and just the joins to fair . Inside would have all glass framing . and steel bed for the steam engine etc etc !!!

    I have the feeling its been done in Australia only with glass balsa glass panels and on quite big boats ages ago !!. there also another place that's making per-made panels with a z join a couple of three months back !! could all be done rather that all the bumming around with frames and Styrofoam etc etc
     

  15. tugboat

    tugboat Previous Member

    that hull looks like mine or very similar...
     
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