Epoxy Resin for Hull Repair

Discussion in 'Fiberglass and Composite Boat Building' started by shamsul hasan, Mar 10, 2013.

  1. shamsul hasan
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    shamsul hasan Junior Member

    Can Industrial Resin made by Nan Ya (Taiwan) NPEL 128 with cps of 12000 at 25 degrees C, be used for fiberglass work. This resin is used for following application:
    Laminates,Filament winding, encapsulation, civil engineering,tooling, coating and adhesives.
    I cannot find West System or any other Marine Grade Epoxy Resin in my country.
    Any Help would be greatly appreciated.
    Thanks & Regards
    Shams
    PS: Properties of NPEL 128 are,Diglcidyle ether of Bisphenol-A
     
  2. Herman
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    Herman Senior Member

    This is an unmodified resin, which is too thick to handle. Try to look for a thinner resin, some 700-1500 cps. Or ask the supplier if they have a reactive diluent available.
     
  3. shamsul hasan
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    shamsul hasan Junior Member

    Thanks!!
    Yes, they have a diluent resin available NPEK 048. The specs are: Low viscosity group ( reactive diluent) made from epoxilation of C12-C14 alcohol.The addition of NPEK 048 in the BPA or BPF epoxy resin system will achieve viscosity reduction with minimum reduction in physical strength. Chemical composition of NPEK 048 is C12-C14 Alkyl glycidyle ether. Viscosity at 25 degrees centigrade 5-20.
    The current temp in my Country is 36 degrees C it will go upto 40 in the next few months. Npel 128 viscosity graph shows cps 4000-5000 at 35 degree C.
     
  4. PAR
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    PAR Yacht Designer/Builder

    I would think a non-reactive diluent would be a better choice.
     
  5. Herman
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    Herman Senior Member

    Tell me why?

    About all laminating epoxies are a base epoxy, and either a monofunctional or difunctional reactive diluent.

    Non reactive diluents have a huge impact on performance.

    Ask your supplier on the amount of C12-C14 that is needed to dilute to 2000 cps at 25 degrees or so. They probably have a chart or at least an idea.

    I would prefer BDGE, but C12-C14 is not bad either, for your application.

    What about curing agents?
     
  6. shamsul hasan
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    shamsul hasan Junior Member

    I have not been able to get complete specs for the curing agent. Most of the curing agents are for civil engineering purposes.905-3 from Yun Teh, Taiwan is one. Will have complete specs of all that is available tomorrow.However,I am sure,nothing will be available for marine. Tell me something? My project entails a lot of fiberglass work. The core repair is not that much,but I am making some modifications in the stern gear. The boat was grounded and its V brackets got damaged beyond repair. Trojan 12 meter is out of production so can't get original parts. I am going for Glass-In brackets made by Teignbridge UK. I have involved a naval architect to help me out. This would require major fiberglass reinforcement for the brackets. I was wondering ?? Its such a critical task that I should not mess around with it,therefore, resin, curing agent and fiberglass cloth should be nothing less then the job entails. I can import from UK. Checked up with FEDEX Resin is not hazadarous from transportation point of view and the curing agent is Hazardrous category 8,which can be transported by air.Your suggestions would be of great value to me. Thanks!!!
    Kind Regards
    Shams
     
  7. Herman
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    Herman Senior Member

    Let me know what you can get, and specifications. You will be hand laminating, I presume?

    Do you have things like bubble busters (serrated rollers) and peelply?
     
  8. shamsul hasan
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    shamsul hasan Junior Member

    Yes, will be hand laminating. I have bubble busters but not peelply.
     
  9. Herman
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    Herman Senior Member

    OK, no problem. It makes life easier, but you can live without.
     
  10. shamsul hasan
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    shamsul hasan Junior Member

    Good Morning!! Here is what I found today.
    1.Standard Liquid Epoxy Resin(Bisphenol-A) YD 128 Manufactured by Kukdo Korea. It has excellent adhesion,chemical,heat resistance etc. It is cured with various hardeners (Polyamide Resin, Aromatic Polyamine, Aliphatic Polyamine and anhydride compound).General usage; paints,electrical,civil construction,adhesives,filament winding,fiberglass reinforcement resin and stabilizer for polyvinyl chloride. It has a viscosity of 11500-13500 at 25 C. All tech data is available on their web site.

    2.LGE by Kukdo its a diluent which is Glycidyl Ether of a mixture of C12-C14 aliphatic alcohol.LGE is a mono functional reactive diluent which has low toxicity,low vapor pressure and low volatile content. LGE provides good flexibility and adhesion on nonpolor surfaces. LGE can be used in various paints,floor coating etc. It has a viscosity of 5-20 at 25 C. The diluting ratio of YD 128 at 25 degrees C is as follows:
    5%-4000 CPS, 10%-1900, 15%-800 and 20%-300.

    3.Curing Agent;Aradur 43 manufactured by Huntsman. Its low viscosity,modified,cycloaliphatic polyamine hardener.Its features are; low viscosity,good curing properties with relatively long working time.Good mechanical properties,good chemical resistance,good anti-corrosion protection.
    Specified Key Data:Aspect (visual)-Clear Liquid, Colour (Gardner,iSO 4630)-<4, Amine number(ISO 9702)-260/280 (mgKOH/g), Viscosity at 25 C 290-450 (mPa s)
    Typical Data: H+ active equivalent 115 g/eg,Density at 20 C 1.02 g/cm3, flash point 131C, gel time with GY250/Aradur 43 100:60 p.b.w 45 min and with GY 783/Aradur 43 100:60 is 60 min.

    This is all available from one supplier. The Nan Ya supplier could not give me specs for curing agent. The supplier can provide me accelerators also.
    Hope this info is useful.
    Kind Regards
    Shams
     
  11. Herman
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    Herman Senior Member

    OK. Aradur 43 is a good hardener, easy to work with, relatively long open time. (own experience). Only thing is the heat resistance, which is 43 degrees C, so not very high. Nothing too problematic for boat construction, but getting a 100% perfect optical part is impossible.
    This stuff is cold-curing, which is good.

    IF they have anything to mix in, like IPD, then you can raise the heat resistance.

    Fro the resin: These 2 ingredients can work. I would start mixing in 10% max diluent, which will give you a resin which is very similar to Araldite GY253
     
  12. shamsul hasan
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    shamsul hasan Junior Member

    Thanks again for your help.Temp during the day can go upto 45C, I don't know how will that effect low heat resistance? Another question? Workers here are experienced in hand laminating hull with vinyl resin, mat and 600-800 gms woven roving (plain square weave). They have never used Epoxy.I understand that mat does not go well with Epoxy? Should I just go with roving? and no mat layers.
     
  13. Herman
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    Herman Senior Member

    Indeed. No mat, just roving with epoxy. Other options are multiaxials and woven fabrics.
    They will notice that epoxy impregnates slower. Have them do a test piece to get used to the material.

    Any other hardener? Perhaps they have Aradur 26?
     
  14. shamsul hasan
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    shamsul hasan Junior Member

    They only have Aradur 43 and they use it here. If the heat resistance issue is only when its not mixed? That can be managed.Even once its mixed that also can be managed,but during the curing process managing temp below 43C can become difficult.
    I will have them do a sample first before starting the process. Some pictures of the project are attached.
     

    Attached Files:


  15. shamsul hasan
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    shamsul hasan Junior Member

    Few more pictures of work in progress.
     

    Attached Files:

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