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Thread: New C5000 build from scratch

  1. #31
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    Building a temporary flange

    So, because this fiberglas mold will be 2 part (one for the bottom half of the hulln the other for the top half of the hull) I needed the create a temporary barrier (flange) which would be the separation line between the 2 mold halves.

    First step was to roughly saw the shape of the hull out of some MDF board, and attaching it to the building board at the exact height (the flange must be set on the widest part of the hull, so that the mold has no negative angles - a part can't be releases from a mold if it has a negative angle)

    Then I placed a large piece of thin cardboard on top of that, and used masking tape the eliminate the gap between the hull and flange.

    mal01.jpg mal02.jpg mal03.jpg mal04.jpg mal05.jpg

  2. #32
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    This piece of cardboard and masking tape was then put on top a a polystyrene panel, it's outlines drawn and sawn and placed over the hull/MDF panel.

    This already gave an incredible tight fit, however since your don't want any resin to leak through, I used model clay to fill any remaining space between the hull and flange, making it completely tight!

    mal06.jpg mal08.jpg mal09.jpg

  3. #33
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    Building the first mold halve

    So, what follows is one of the most important steps in the entire process. It's also the least visible thing: making sure the mold will not stick the the part !!

    So, one must apply sufficient release agent. This is done be applying several layers of release wax on your working piece. Theoretically 1 good layer of release wax would be sufficient, but because this wax is nearly invisible it's very very easy to forget a small area. That why everybody will tell you to apply at least 5 to 7 coats of wax. It's not because you really need 7 layers, it's to minimize the risk of any spot being left over, as that would mean the mold is glued to the part!

    I also applied an additional 2 layers of PVA parting agent (poly vinyl alcohol). This creates a real barrier between your mold and piece, and because I did not use DD lack (2 compontent paint) on my hull, I really need a good barrier, otherwise the styrene damps in the polyester resin would eat right through the wax and attack the paint (and then your mold will look like your finger when you have been in the water to long!!)

    But then finally I could start with the gelcoat layer. I applied 2 layers of gelcoat.

    mal10.jpg mal11.jpg mal12.jpg

  4. #34
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    After the gelcoat has set (minimum 3 hours, maximum 24 hours in my case - it really depends on the brand you are using) I started laminating a first layer with fiberglass of 6oz in combination with a vinylester resin.

    After that first layer with 6oz fiberglass (with is more flexibel and will follow the corners better) I then continued to apply 4 layers of 13oz. fiberglass in combination with a special polyester resin (specific resin for molds, which has less shrink than regular polyester resin, and also allows for more layers in one session due to lower heat dissipation)

    Finally I also added a wooden frame to the mold the reinforce it and make is generally more rigid.

    mal13.jpg mal14.jpg mal15.jpg mal16.jpg mal17.jpg

  5. #35
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    Then it was time to flip the entire structure upside down, allowing me to remove the original building board as well as the temporary flange that I had installed.

    mal18.jpg mal19.jpg mal20.jpg

  6. #36
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    Building the second mold halve

    So, with the building board and temporary flange removed, it was time to build the second halve of this mold. Because the first halve of the mold now already has a proper flange to itself, you can build the second mold directly against this one.

    Off course ..... very important .... apply release wax and PVA agent before continuing, or the 2 mold halves will be glued together and to the top of the hull indefinitely!!

    Again I first applied 2 layers of gelcoat, after that 1 layer of 6oz fiberglass with vinylester resin and 4 layers of 13 oz fiberglass with special mold polyester resin.

    mal21.jpg mal22.jpg mal23.jpg mal24.jpg

  7. #37
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  8. #38
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    Separating the molds

    I also made a wooden reinforcement frame on this side of the mold. Then came the time to separate to the mold halves from each other and from the hull.

    I started by putting wooden spatulas in between the 2 halves to force a bit of an entry. You must be careful not to damage the gelcoat of the mold by using "hard" tools such as screwdrivers and/or chisels.

    After some prying the top halve finally came loose very clean. Unfortunately the same thing can not be said for the bottom halve. I could not get the hull out of the bottom mold without completely destroying the hull.
    The problem was actually two-fold: while enough release wax and PVA was used not to make the mold and the hull stick together, the mold was actually so tight around the hull that I as not able the get any spatula between the mold and hull the create any form of leverage.... on top of top, the bottom part of the hull has many many corners, the steps, the transom, the lifting strakes... this just makes for a difficult shape and with a mold so tight around it there was no way to get it out undamaged.

    mal28.jpg mal29.jpg mal30.jpg mal31.jpg mal32.jpg

    P.S. The "hull" or better, plug is a lost object anyway. Being the emotionally attached guy I probably would have kept this plug sitting on my shelves for eternity and beyond if it had come out undamaged, while at the same time I would have has some self complain for being in my way all the time

  9. #39
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    The finished mold parts

    So... there you finally have it! 2 finished mold halves, sitting ready to create some nice fiberglass hulls.

    mal33.jpg mal34.jpg mal35.jpg

    Guess I will take a break now to think about my next steps, on how I shall proceed with the build of the fiberglass hulls. I'm haven't made up my mind on how tick the laminate would have to be, which fiber cloth thickness I will use (and how many layers) and if I would stick to a fiberglass/epoxy resin combination or go for carbonfiber/epoxy or a mix in between....

    Any suggestions about layer thickness and fiber cloth weight is appreciated, as I don't really have a clue at this point how many layers or thickness would be good (you don't want the hull to be to thick and heavy, but you do want it to be strong and stiff enough to withstand the forces on the water...)

  10. #40
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    Excellent work on the molds! I am looking forward to the further steps.
    Shawn

  11. #41
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    How much work I have done! I am impressed and grateful for the images.
    Following your construction.
    Regards!
    Hernán

  12. #42
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    Very nice work!
    We found out that it is better to reinforce the mold with wooden rails after you get the plug out... this way it has some give and you can fit some tools in the space. Compressed air around 4-5bar works quite well (I heard) but a very good trick is to use some thin plastic stock (0.4mm) and push it as much as it will go under the plug. Some of the best tools for this are also thin plastic aircraft propellers.
    As for layers, a light racing hull in this size will probably go for 100g glass + 100g lass +160g carbon + 100g glass, with carbon tow and epoxy thickened with fumed silica applied in the corners before that to avoid bubbles and get sharp corners.
    It is usually better to make it lighter and reinforce where needed, at least on the first pull from the mold (which is also the worst looking one, the second will be ok).
    Cornel

  13. #43
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    Thanks CornelP.... guess it's too late now to reinforce the mold after getting the plug out

    I'll try your suggestion for the layup. I have no idea how stiff/strong that will turn out, but calculating the weight of the suggested fiber cloth + required epoxy resin for those cloths, I'm coming up at around 1000-1100 g. which is about the weight I have seen for these size of hull from MHZ and/or HPR boats.

  14. #44
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    Wow!
    Vac-U-Tug Jr (13mph)

  15. #45
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    That looks a great project. I wish you all the best in creating your boats

  16. #46
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    Hello Everybody.

    After a long absence I have finally found some time and courage to create a hull from the molds I build last year.

    First step was off course making sure that the hull would not stick to my molds, so it's Wax on... Wax off... I've added a total of 5 wax layers.
    The white wash visible is the unpolished wax.

    After the wax was applied on all molds, I started with a layer of white epoxy gelcoat.

    gelcoat01.jpgwax01.jpgwax02.jpggelcoat02.jpggelcoat03.jpg

  17. #47
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    Here's the canopy with it's first layer of fiberglass applied:

    rompje01.jpg

    I don't have a vacuum pump at my disposal, but I figured adding some weight on top of the fiberglass would help in keeping the fibers pressed together and to to mold, so I poured some sand into the molds (I first added a layer of peel ply, so the sand would not stick to my fiberglass piece!)

    rompje02.jpgrompje02b.jpg

    Here the canopy and upper hull part freshly pulled from the molds:
    rompje03.jpgrompje04.jpg

  18. #48
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    Here's the upper hull half, first pictures the edge needs trimming, and the second picture the trimming has been done:
    rompje05.jpgrompje06.jpg

    First fitting of the canopy on the upper hull part:
    rompje07.jpg

    And the lower hull part, first pictures still inside the mold (after removal of the sand and peel ply) and second picture removed from the mold
    rompje08.jpgrompje09.jpg

    Creating this lower half was a real pain in the *ss, as it had lots of straight corners. The first layer of fiber would go on fine (it's only 160 gr/m² or 4.7 oz/square yard) but my additional layers which I use to build thickness are 300 gr/m² (8.8 oz/sq yard) and those already proved a bit to stiff to nicely follow every corner.... I should go for more layers with thinner fiberglass, or invest in vacuum infusion technology here

    Ooh, and getting that bottom part out of the mold also proved very very very daunting, again all those corners makes this part very challenging!!

  19. #49
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    Some close-up shots of the bottom part:
    rompje11.jpgrompje10.jpg

    First trail fitting of the upper and lower halves. There do align quiet nicely.
    rompje12.jpg

    Again, both halves are not joined together, but I added the canopy on top. This almost looks like a boat, doesn't it?
    rompje13.jpg

    And finally a view from the front.
    rompje14.jpg

    So, this is my first pull from my molds. Especially the bottom halve proved very tricky, a real big challenge! Now I'm thinking about the next steps of the build. Off course I should join both halves, and normally this would be best done while they are in the molds. However, both molds are closed, and I do not want to cut the canopy part of the upper mold out, since I'm seriously thinking about experimenting with vacuum in the future (and a hole in the mold would make the vacuum difficult/impossible)

    I'm also thinking of adding a layer of carbon fiber for added stiffness. I was first thinking about going full fiberglass on my first hull, but since it turned out quiet nice, perhaps reinforcing it with carbon isn't such a bad idea. It will add lots of stiffness and strength as this hull could really be used for driving, it's not a "first pull gone totally wrong" piece of scrap...

  20. #50
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    Congratulations! It is looking great. How big is this one?

    Shawn

  21. #51
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    Impressive project, and great work!
    I'm no expert in the subject but have gained a few experiences from moulding epoxy/glass. A bit late but I noticed you used model clay/putty to seal the parting board to the plug. In my experience this can cause some issues with your surface finish and make parting the mould from the plug problematic. I've had several types of model putty attack the paint on my plug, and cause much agony of moulds "glued" to plugs around the parting flange edge.
    In regards to laying your glass in the mould - I'ts hard to see in the pictures and maybe you already know, but the cloth weave should always (if possible) be 45° against the edge to better "stick". Often I'ts better to lay down several smaller pieces to be able to lay the weave in an angle against corners and edges.
    I'm rambling, and you probably already know all this :D

  22. #52
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    Quote Originally Posted by srislash View Post
    Congratulations! It is looking great. How big is this one?
    Shawn
    Mmm good point, looks like I did not yet mention that in this build thread.... the overall length of the hull is 110 cm (43,33 inches)

    Quote Originally Posted by SpeedDevice View Post
    Impressive project, and great work!
    I'm no expert in the subject but have gained a few experiences from moulding epoxy/glass. A bit late but I noticed you used model clay/putty to seal the parting board to the plug. In my experience this can cause some issues with your surface finish and make parting the mould from the plug problematic. I've had several types of model putty attack the paint on my plug, and cause much agony of moulds "glued" to plugs around the parting flange edge.
    In regards to laying your glass in the mould - I'ts hard to see in the pictures and maybe you already know, but the cloth weave should always (if possible) be 45° against the edge to better "stick". Often I'ts better to lay down several smaller pieces to be able to lay the weave in an angle against corners and edges.
    I'm rambling, and you probably already know all this :D
    About the putty/clay: I didn't experience any problems with that at the time, however I must say I purchased mine at the same store where I bought all other materials (fiberglass/polyester resin/gelcoat etc) so they probably now which one works best

    Good advice on that 45° angle, I wasn't really aware of that and was not paying special attention to that, but I do use twill weave cloth (instead of the regular square ones) and due to the twill weave, you kind of have a 45° rotated pattern anyway. Looking at my pictures it does look like most fibers are more on a 45° angle instead of a 90°...

  23. #53
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    Quote Originally Posted by dazzler View Post
    Mmm good point, looks like I did not yet mention that in this build thread.... the overall length of the hull is 110 cm (43,33 inches)


    About the putty/clay: I didn't experience any problems with that at the time, however I must say I purchased mine at the same store where I bought all other materials (fiberglass/polyester resin/gelcoat etc) so they probably now which one works best Then you probably got the right product I finally got some mould wax that worked very well

    Good advice on that 45° angle, I wasn't really aware of that and was not paying special attention to that, but I do use twill weave cloth (instead of the regular square ones) and due to the twill weave, you kind of have a 45° rotated pattern anyway. Looking at my pictures it does look like most fibers are more on a 45° angle instead of a 90°...
    I only got experience with twill cloth, but I wrongfully call it glass all the time. Another thing I experienced is that for our "small" layups I would never use anything heavier than 200g/m², and even those can be pesky to lay up if not in 45 degrees without vacuum

  24. #54
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    Quote Originally Posted by SpeedDevice View Post
    I only got experience with twill cloth, but I wrongfully call it glass all the time. Another thing I experienced is that for our "small" layups I would never use anything heavier than 200g/m², and even those can be pesky to lay up if not in 45 degrees without vacuum
    Well, I notice that some terms get mixed often actually twill cloth is glass cloth. There's 2 aspects: first is the basic material, which is usually glass, carbon and kevlar (aramid). Then there is the way they are woven: most common are either 'plain' or 'twill' but it can also be unidirectional or multiaxial. And even there you have variations. Most common twill is 2/2 (meaning two strands go under, 2 strands go over each other) but there are a lot of more exotic variations available!

    I agree that for these kind of hulls 'plain' weave should never be considered as it simply is not flexibel enough to go around the complex curves of these hulls. Twill weave, which has much better drapability, is the way to go. And even then, the heavier ones don't even work out fine. 160 gr/m² was fine for the bottom part, and 300 gr/m² was even fine for the canopy and upper deck, but a 200gr/m² would have been easier probably. On a Dutch forum I was even given the advice to start with a 80 gr/m² on top of the gelcoat.

    anyway, it's a first tryout and lessons learned. If budget allows I'm thinking about purchasing a small vacuum pump and try some resin infusion. I do like the idea that you have unlimited time to properly cut and lay all the fibers into the mold and not getting your hands (gloves) full of resin while pressing everything in the corners and edges while laminating. The idea of a lighter and stronger hull due to a much better fiber/resin ratio is offcourse also very nice :D

  25. #55
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    Nice work. I really prefer infusion. It also allows you to use a foam core material, and make the hull quite strong.
    https://www.easycomposites.co.uk/#!/...foam-core.html
    also, check out MTI Hose. Works beautifully.
    https://german-advanced-composites.c...n-suction-hose
    Cheetah, Super Rio, (Mod) Starship (Mod and sold),

  26. #56
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    There is loads of materials and iterations as you point out. I for one learnt something new just now, about twill and what it means. Thanks 🙂 I concur in regards to starting with a layer of 80g cloth. That's what I've been doing, and either a couple of layers of 200g. Maybe even some CF but never a pure CF layup.

    I've messed about some with vacuum, but not much. Seems to be a lot better when you find the technique. By now I have had a lot of bad luck with plugs and moulds so lost some faith in myself.

    Hope to see more of your build process

  27. #57
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    Quote Originally Posted by larryrose11 View Post
    Nice work. I really prefer infusion. It also allows you to use a foam core material, and make the hull quite strong.
    https://www.easycomposites.co.uk/#!/...foam-core.html
    also, check out MTI Hose. Works beautifully.
    https://german-advanced-composites.c...n-suction-hose
    Hello Larry.
    I've seen both products recently on one of the German online shops I visit in my research... it appears the 3D-Core is well suited for vacuum infusion, and the MTI hose should work nice according to the promo video I watched online.

    There's currently only 3 things stopping me from trying that:
    - Knowledge... It would be some kind of trail and error as I don't know anyone in person that has experience with it and could get me started....
    - Budget... It requires some initial investment in additional materials....
    - Time... Once summer is over, I'll start with renovations on our home and that will require every minute of my free time for the next year or see. It's also the main reason for the lack of budget at this time

  28. #58
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    Hello All.

    Back after a very long absence (due to our home renovation) but now very excited to get building again.

    At the moment I'm puzzling a bit with the placement of the drives and water pickup. At the moment, I have the drives at the lowest possible part of the sponsons, meaning as close as possible to the tunnel walls. If I'm putting them any where 'higher' on the sponson (meaning, more away from the tunnel) the height difference between the sponson and back makes in impossible to align the drives parallel (flush?) with the sponson.

    But - this makes it impossible to mount the water pickup at the lowest part of this sponson - there is simply no room between the wall of the tunnel and the shaft.

    I have found one build thread of a Mystic 138 (https://forums.offshoreelectrics.com...-Boat-assembly) which has the water pickup placed on the other side of the shaft....

    Please have a look at this picture:
    waterpickup.jpg

    So, most build I have seen, place a water pickup at position 1. The build I'm referring to has it in position 2. I have both the single and the dual water pickup in my toolbox, so I can go either way.

    What would be my best option? Put a single or dual pickup at location 2? Or move the shaft to a higher position anyway (meaning they will always point down a bit! - no option to trim them parallel to the hull!) and try to squeeze a single pickup in position 1 anyway?
    I know the water pickup would be more efficient as low as possible - on the other hand moving it to position 2 gives me the benefit of dual inlets. And just for the record, my build would be no means be any 'SAW' material.... I'm more thinking at twin Seaking 180A + Leopard 4082-1600kv on 6s or something in that line...

  29. #59
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    The most important thing is having some stinger adjustability. At almost any reasonable speed, #2 position will get plenty of water. For your use, I vote #2.





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  30. #60
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    I will also show how I positioned the drives, so that there position was exactly as I wanted it to be, and also being symmetrical on both sides.

    For this, I measures the mounting plate and mounting holes of the drive shaft, and used a 3D CAD program to create a mould which I can 3D Print.
    Uitlijn01.jpg

    Below you can see the 3D printed mould part, and how it aligns exactly on the hull. Drilling the mounting holes was easy after this
    Uitlijn02.jpg

    And yes, everything fits well
    Uitlijn03.jpg

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