How many from mold?

Discussion in 'Fiberglass and Composite Boat Building' started by Love2boat, Dec 8, 2011.

  1. Love2boat
    Joined: Dec 2011
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    Location: Tampa

    Love2boat Junior Member

    Hello,

    How many hulls can one expect to get from a quality made mold? What does one usually do when this number is reached? Use the prior hull as a plug to make a new mold?

    Thanks,
    Jason
     
  2. tunnels

    tunnels Previous Member

    One company i worked for we were making a 28 foot yachts a week hand laid and whn i left wer in the 300 th boat . so its only limited to how well you take care of your moulds
    A shower company we pulled 2 a day for the 3 years i worked there .
    A 36 foot power boat was in the 200 plus whn i left , Got checked and waxed evey boat !
    these were old moulds , newer with better resin will last even longer . Abuse will limit there life ! dont look after dont exspect to last real simple . :D:p:p
     
  3. iceboater
    Joined: Jan 2011
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    Location: Iceland

    iceboater Junior Member

    It is generally advised to keep the 2nd pull from the mold to use for a plug later on.
     
    1 person likes this.
  4. Eric Sponberg
    Joined: Dec 2001
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    Location: On board Corroboree

    Eric Sponberg Senior Member

    What we used to do at TPI is build the first plug boat, take a mold from it, and then take special plugs from the mold in order to make replacement molds. Our molds, for the likes of the J-24 and the Freedom 40, were ventral seamed, so they were two-part molds with the mating flanges down the centerline and then up one side of the transom. The J-24 was available with lots of different stripe graphics, so we striped the inside of the molds, and then the replacement plugs, with alternating colors of orange and black gelcoat in the various striping patterns. Tape off the appropriate color stripe pattern, gelcoat according to the color scheme for the stripes, and then overcoat that with the basic hull color, usually white. Some stripes came with a rainbow of colors, so an owner could really customize the hull.

    The molds had their flanges and lock keys built into them, so when we did a replacement plug, this was made up of two halves, male shapes of each half mold, with the flanges and lock keys incorporated into them. So the mold was made, and then the plugs were made from the molds and stored for later use to make more molds when the originals wore out. We would generally plan on 300-500 parts coming from each mold. We also were the authorized supplier of J-24 molds to all other authorized builders around the world, so we used the master plugs to make all the other authorized molds. The last I heard, which was back in the 90s, that world wide the J-24 was well over 5,000 units. I don't know what the final count is now.

    Eric
     
  5. m3mm0s rib
    Joined: Aug 2011
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    Location: GREECE

    m3mm0s rib Senior Member

    Usually about 40-50 hull. If the mold is maintained and properly fastened perhaps 70. AFTER NEED RENEWAL
     
  6. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    It depends on a few different things, size, shape, material it's made from, temperature reached during exotherm, care used in de-molding, storage conditions, mold release, gel coat type (both the mold and hull), plus others.

    I have customers that go 50 parts before needing to apply more mold release, others do it every time.

    Typically, the limiting factors in a molds life are how well it was built and how well it has been taken care of.
     
  7. tunnels

    tunnels Previous Member

    Sorry if looked after mould coul last for many years and in to the hundreds of boats . Wax every time and dont over heat with thick laminates . have a good supporting frame, treat the mould with respect If the surface gets deteriorated it can be painted with a good quality hi gloss 2 pot polyuretane . hulls are easy to demold decks have more shapes and places where they change shape over time and heat . Decks date and go out of style and fashion Hulls dont A HULL IS A HULL AND DONT CHANGE THAT MUCH !! :):D:pSPECIALLY THE BOTTOM FROMTHE CHINE DOWN
     
  8. latman
    Joined: Mar 2010
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    Location: Australia

    latman Junior Member

    What i find is that chipped corners , and "wax buildup" are the two factors that "age "my moulds (australian spelling) Also any backside whacking to release (with a rubber mallett) will make ugly star cracks and care must also be taken that any external metal or timber reinforcements do not "print" onto your moulds, If you expect a design change will be needed after a number of parts are sold then there is no point to saving a part as a plug for a new mould.
     

  9. tunnels

    tunnels Previous Member

    WHAT YOU HAVE JUST DISCRIBED A PERSON WOULD BE FIRED FOR ON THE SPOT IF YOU EVER HIT ANY MOULD . tHERE IS NO NEED EVER TO HIT A MOULD IF ITS BEEN WAXED PROPERLY AND IF ITS BIG LIKE A HULL SIMPLY FLOAT IT OUT 10 TO 20 LITRES OF WATER OR LESS IS ALL THATS REQUIRED TO FLOAT A 36FOOT HULL OUT OF A MOULD . iF YOU GET WAX BUILD UP SOMEONE IS NOT POLISHING PROPERLY SHOULD TRY USING PVA INSTEAD OF WAX !! tHE PRODUCT ALMOST FALLS OUT THERE NEVER A BUILD UP OF ANY SORT AND YOU CAN LEAVE YOUR TIN OF WAX ON THE SHELF FOR EVER i HAVE IN THE PLACE WHERE I AM WORKING A HEAP OF ABUSED MOULDS THAT HAVE HAD A HARD LIFE !! THEY CAME FROM AUSTRALIA !!:p
     
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