Some advice on costing

Discussion in 'Fiberglass and Composite Boat Building' started by pleasedontsink, Mar 24, 2016.

  1. pleasedontsink
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    pleasedontsink Junior Member

    Hello all,

    I am looking at making moulds that would be used many times hopefully. I have no experience in plug and mould making and from what I have read I will need to do a lot of research and practice before proceeding.
    I have been quoted around 50 thousand from a fibreglass company.
    I am willing to do the work and research if it would save me a lot of money so my question is..... Will it save a lot of money to do it myself or should I just spend the money to have it done professionally?
    I thought it might save heaps to do it myself as it is so labour intensive.
    Any advice would be appreciated.

    Cheers.
     
  2. Jamie Kennedy
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    Jamie Kennedy Senior Member

    Molds can be very expensive, especially if you want to be able to use them more than once. They tend to be heavier than the boat, so there is more materials and labour there. Also, the finish work has to be just as good on the finished surfaces, of which there are just as many. Finally, you usually don't have a mold to build a mold with. You have to build a plug first. Where you planning on at least building the plug for them, or are they doing that also? It is important not to build a plug that is difficult to build a mold for. This increases mold costs and manufacturing costs of your product.

    It would be best to gain some experience by building your own plug, and mold, and a few finished products. Start with something small that you can do all on your own. Something very small, like flower planters, or model boats. Even a small dinghy or canoe could get expensive as you will likely have to throw it all away and recover no costs. Not so small that it's not realistic, but not so big that it is too expensive.

    Even the molds for an Optimist Dinghy can be very expensive. But even if you eventually have another company make molds, or do production runs, it would be worthwhile getting some experience yourself so that you understand some of the things that they have to deal with. Cheers.
     
  3. pleasedontsink
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    pleasedontsink Junior Member

    Thank for your reply.
    The price I was quoted was to build the plug, mould and finished product.
    The guy said once the mould has been built it would not cost much for a fiberglass part to be made. This is what led me into looking at doing it myself.
    Are the materials and resins, gels, very expensive or is it the labour costs that make it expensive? I would certainly look at building the plug myself and getting him to do the rest of the job if it was the work in the plug that was the expensive part.
     
  4. Jamie Kennedy
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    Jamie Kennedy Senior Member

    Polyester resin and fibreglass cloth and matt are reasonably cheap materials. Resins like epoxy and fibres like carbon fibre cost considerably more in term of weight, and usually have higher labour costs as well. I don't do a lot of manufacturing. Some items, like circular tanks, can have labour reduced by building special equipment that rotates the product as you are blowing fibre strands and resins in a pattern. Usually this is enough, but in theory you could take it a step further and automate it. Depends on what you are building, and how many you are building. As for most things $1 a pound is a pretty rough starting point for simple polyester and glass products, with labour being half of that, but not including overhead. Material costs can go up to $10 a pound, or higher, if you are using exotic materials, but you are reducing weight also. Labour costs can always be increased to meet what ever budget is available. Not so easy to reduce though. ;-)

    Good engineering is key. It can save money and produce a superior product.
    Unfortunately, as with most things in life, too much of the game is marketing.

    "If people don't want to come out to the ball park, you can't stop them." - Yogi Berra
     
  5. pleasedontsink
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    pleasedontsink Junior Member

    What I am actually trying to build is a floatation room. It is a rectangle box that will fit a person. It has very high salinity salt water in it so the glass will need to be resistant to this environment. The reason I am on a boat building forum is that the glassing is the same. You are trying to keep the water out, I am trying to keep it in. Also the fact that this looked by far to be the best forum. Now that I have started looking the wife already wants a kayak haha.
    for my project there will be a tub for the bottom, walls and a tub for the roof.
    there will be no split moulds needed to be made so its relatively straight forward.
    I really appreciate your comments.

    cheers.
     
  6. gonzo
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    gonzo Senior Member

    You need a male mold, which is easier to make. The flotation chambers I've seen are simply a tube with a door at one end. Is this a commercial venture or a one-off? If you are planning to produce them, your best bet would be to hire an employee familiar with molds and production. For a one-off, this will be really expensive. Have you considered buying a tank from the many suppliers in Australia? They make them in different materials, including fiberglass, and you would only have to do some modifications.
     
  7. pleasedontsink
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    pleasedontsink Junior Member

    I am looking to make them to sell eventually. I am also looking to do a float room which is a lot bigger than a chamber. it will be in several pieces that bolt together so it can fit through a standard door. I also have some other ideas that will be custom features so I need my own design. If it was just for me I would use a standard tank but I do want to manufacture eventually. My background is control systems so the fiberglassing is the part that is out of my realm. the rest I have covered.

    Thanks for your reply.
     
  8. pleasedontsink
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    pleasedontsink Junior Member

    When you say male mould I would need to make a female plug to make the male Mould right? I think I have a good idea about how to make the woodwork for the plug its just the rest I lack the skills on from there.
     
  9. Mr Efficiency
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    Mr Efficiency Senior Member

    Unless you are intimately acquainted with the market for flotation tanks, hasten slowly. There are design considerations that you would need to be fully across, and making plugs and patterns and moulds is skilled work, particularly if you want a professional finish. Making something that only has a smooth gelcoat finish visible, is a big job.
     
  10. pleasedontsink
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    pleasedontsink Junior Member

    Cheers Mr Efficiancy,

    It is not something I am taking lightly and I am doing as much research as I can. If you have any knowledge of the design considerations I would very much like to discuss further. I am doing a ton of research but am keen to hear as many opinions on the matter as I can.

    cheers.
     
  11. pleasedontsink
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    pleasedontsink Junior Member

    I was thinking of making the plugs and sealing them and making them as smooth as I can and then giving the job over to professionals for the making of the mould and parts from there.
     
  12. Jamie Kennedy
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    Jamie Kennedy Senior Member

    Someone should chime in about the effect of high salinity water at high temperatures. It might require a special resin, or gelcoat, but perhaps not.

    As Gonzo said you should not need a plug and female mold. You should only need to make a male mold, perhaps two, but perhaps only one that serves both ends, or top half and bottom half. Perhaps you don't need a mold at all for the top, as it could be a flat sheet. A male mold is essentially the same as a plug, only instead of using it to make a mold, you are using it to make your finished product.

    I think this might lend itself to fast prototyping, and 1/4 or 1/3 scale. If it is built to 1/4 scale, the male mold or molds and the finished production should only be 1/32 or 1/64 the cost of full-sized. 1/32 would be if it is not practical to make it 1/4 as thick, that you can't go less than 1/2 as thick because of the nature of gelcoat and because of the available weights of cloth and matt. Anyhow, you might learn what you need from a 1/3 or 1/4 scale model, and it might also be useful as a demo model, or for giving your pet cat a very, very, relaxing day. :)
     
  13. pleasedontsink
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    pleasedontsink Junior Member

    Hahahaha. I just saw a cat chilling out in my mind then.
    OK great advice. Thanks. I mistook what Gonzo said and thought I still needed a plug as well. This is music to my ears as I was trying to figure out the best way to make the angle where the floor and tub walls meet a rounded transition and this will be much easier on a male mould. I will need four moulds as the roof is different to the top as it has to be on a angle to prevent condensation forming and dripping. The angle will allow it to run off to the walls. one for the walls and 1 for the ends.
    I definitely like the idea of a small scale model to practice on. I was thinking of using bowls, buckets etc. for practice but a scale model would really perfect the design and I could test the gelcoat with the salty warm water as well.
    If anyone has experience with the type of gelcoat required that would help a lot but a boat moored in the tropics would face similar conditions I guess. Not as salty.

    I really appreciate everyone responses. Cheers.
     
  14. pleasedontsink
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    pleasedontsink Junior Member

    Is there a formula for how thick the fiberglass should be per square meter for strength or is that an experience type thing? If someone could help me out with what type of cloth and matt to lay down in what order of laminate that would be fantastic.
    What started out as a thought has already been a massive learning curve and I have not even started physically working yet. I'm very excited for both the upcoming successes and failures. It has turned into more of a challenge now than just wanting a finished product.
     

  15. Jamie Kennedy
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    Jamie Kennedy Senior Member

    There are formulas, and practicalities, and it is also an experience thing. Experience comes from failure.

    Not sure what is required for exposure to hot salt water. Regular gelcoat and polyester and glass might be ok.

    Generally you start with gelcoat, and then matt, and then cloth, and then matt and cloth again. Theoretically that should be strong enough even for a tub 2 or 3 feet deep. That is, until someone gives it a kick, or if someone falls into the tub, or if you drop it down the stairs when you are installing it, or if it crashes through the floor of an upstairs apartment when you fill it with water. This is where the clever design comes in, in terms of overall shape, support in key areas, shapes that serve more than one purpose, and practical considerations. A good design will save weight, and cost.

    A fast prototype will allow you to come up with and test a lot of ideas. You could start with even smaller models that use resin and cotton sheet, or wax and paper towel, or just masking tape. This will give you some ideas of where reinforcement is needed for different shapes.

    The engineering brain is closely connect to eyes and hands.
    Put those opposable thumbs to work and build something. Then break it.

    I am not sure how to determine fantasticity?
     
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