Re Gel Coating a Mould

Discussion in 'Fiberglass and Composite Boat Building' started by EddieV, Jan 5, 2013.

  1. EddieV
    Joined: Jan 2012
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    Location: South Australia

    EddieV Junior Member

    I was wondering if its possible to redo the gel coat on the inside surface of a mould.

    I have got hold of an old mould but the quality of the gel coat in areas is questionable so wondered if its possible to redo the gel coat over the whole mould instead of simply trying to patch up multiple areas.

    In case it matters this is only a small wave ski mould and not a full boat mould so the size is obviously alot smaller.

    The other option would be to try and use the mould as it currently is and if i like it to fix the imperfections in the and make another mould for the future.
     
  2. Landlubber
    Joined: Jun 2007
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    Landlubber Senior Member

    ...sometimes it is easier and cheaper to make a boat from it then redo the whole schmozzle as you say

    As it is so small, I would look at that option. YOu make a mould about 3 to 4 times the thickness of a real boat from it, and reinforce the frame with steel or wood glassed onto it.

    Getting the inside (concave) of a mould really nice is a ******* of a job.
     
  3. Herman
    Joined: Oct 2004
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    Location: The Netherlands

    Herman Senior Member

    It all depends. Re-gelcoating a mould is a pig, but sometimes just neccesary.

    How many parts do you expect to make?

    If just one or 2: Fix the most obvious damages with some gelcoat or epoxy putty, then make a part using a liberal coat of PVA.

    If 3-5: You could regel the mould, or just fix her up with 2K PU paint.

    If more than 5: Make one part, make a new mould and ditch the old one.

    Numbers may vary depending on shape, cost of materials, etc.
     
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  4. ondarvr
    Joined: Dec 2005
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    ondarvr Senior Member

    It also depends on the type of damage currently on the mold. If you just have some chunks missing and bad scratches with a nasty surface, then re-gel coating can work well. If there are a bunch of stress cracks (which is typical) then you need to do a tremendous amount of work before you apply more gel coat, and some stress crack may return anyhow.
     
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  5. tunnels

    tunnels Previous Member

    Look and learn from start to finish !!

    http://www.boatdesign.net/forums/projects-proposals/fairey-hunt-18-a-42011.html

    YOU NEED TO READ AND STUDY THE PICTURES IN THIS POST . The guy bought a old mould and REBUILT the outside frames etc etc resurface coated it and bought it Back up possibly better than new and made a boat . its a credti to him !! I been watching and encouaging him all the way since day one just about :D:p:)
     
  6. EddieV
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    EddieV Junior Member

    wow, that is impressive what he achieved from his starting point.
     
  7. tunnels

    tunnels Previous Member

    Thought you might like that !! The product he used is pretty cool easy to use and is really rought stuff,But shows what can be done !!:D
     
  8. jiggerpro
    Joined: Sep 2007
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    jiggerpro Senior Member

    The guy pointed out by tunnels did a resurfacing but NOT WITH GELCOAT, he did use duratec surfacing products, which are very friendly as opposed to gelcoating a surace wich is not in contact with a mold ...
     
  9. tunnels

    tunnels Previous Member

    So !!
    There are better materials than Gelcoats !! and as you can see dont properly can make a really nice job !! . :p
     
  10. EddieV
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    EddieV Junior Member

    I think at this stage im going to try and produce 1 from the mould as is exists and accept that there will be some touch up work required on the finished product.

    Once assembled and if im happy with it i might then refinish the mould for the second one i intend to produce just because it seems like an interesting project and i would be interested in the results between the first and second unit
     
  11. jiggerpro
    Joined: Sep 2007
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    jiggerpro Senior Member

    Yes Tunnels, the surface obtained with duratec will undoubtly be as shiny as a good gelcoat, but will it be equally durable as a good Tooling Vinylester gelcoat ??? I very much doubt it, but you should know better with your decades of experience ...

    I would be afraid that a mould resurfaced with Duratec might not last enough as to be a really good idea but I might be wrong ...
     
  12. EddieV
    Joined: Jan 2012
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    EddieV Junior Member

    It might be a good idea if the intention of the mould owner was to make a good casting and then make a new mould from that ?
     
  13. tunnels

    tunnels Previous Member

    Tooling gel in most companies i have worked i have seen tooling gel used i have seen it backed with ceramic coatings and all manner if fancy stuff when a few boats have been made and the mould and sits outside in the weather they stiill last as long as each other ,tooling epoxy or what ever . get some unskilled worker aand a rubber hammer and it doesnt matter it stull dammages the same so whats the point
    Unless you have paid orders for a 1000 products you wasting money . wax each time with a thin coat ,dont hit and abuse the moulds and they will last you most of you life time . Tooling gell just shines as good as ordinary gel at less exspence . If you do a good job of the gel coating Ordinary gel last as long as you want it to .
    One of the first jobs i ever did was to make a 38 foot deck mould for a launch , they plucked one product and i had the job of chopping up the mould and binning it .
    A well build mould that has a really a good steel frame is just as good as a thick mould with all the fancy products getting used .. :confused::eek:
     
  14. jiggerpro
    Joined: Sep 2007
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    jiggerpro Senior Member

    Ok Tunnels but what about the durability of the Duratec products to work as a tooling gelcoat which seems to be what the guy doing the Fairey Hunt 18 is intending ??
     

  15. garrybull
    Joined: Nov 2010
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    garrybull Senior Member

    the surface of the mould is still good now as it was when i painted the duratec paints on.

    the mould is sitting outside under a cover.

    it is a little dusty but with a quick wash its as good as it was when first done and will produce another good boat or as many as i want to make from the mould.

    when i restored the mould i did not really have the intentions of selling mouldings.

    i restored it to produce myself a boat and if i were to sell a few i would probably make one more out of the mould and then make a new mould off the newly laid up hull using all the correct gels etc.

    at the moment im now looking in to making a small cat with similar lines to my current boat with nice flared bow sections which i really like.

    it will be around 19ft long x 9ft beam.

    will run 2 pods with a full width platform and have a walk around wheelhouse.
     
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