Gluing aluminium to foam

Discussion in 'Materials' started by rivergybsy, Mar 16, 2015.

  1. rivergybsy
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    rivergybsy Junior Member

    I plan to build a houseboat/riverboat. About 8m long and 2.4m wide. I intend to build it very light with foam and glass, however, I would like to cover the hull with 1mm aluminium for extra impact protection. So the sandwich will be alu/foam/glass
    I was thinking of using the same Epoxy as I will use for the glass, but …. any better ideas?
     
  2. TANSL
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    TANSL Senior Member

    There are many problems to make this union work properly. One is the very different expansion capacity of each material. This can make the glue is not capable of withstanding the shear stresses will occur. Not a good idea (or very bad idea) use such different materials.
     
  3. Mr Efficiency
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    Mr Efficiency Senior Member

    What is the type of foam you are intending to use ?
     
  4. Mr Efficiency
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    Mr Efficiency Senior Member

    The bill for epoxy will be frightening if you intend to laminate an 8 metre hull out of it, it really is not a sound choice except for specialized applications.
     
  5. rivergybsy
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    rivergybsy Junior Member

    Thanks for the quick response

    I am at a very early stage of planning and work on the concept. Tansl makes a very important point of thermal expansion.
    I planed to use high density urethane foam, but am open to any suggestion.
    My background is automotive, coach and caravan building. I have a few thousand hours sea time, fixed a lot of boats, but never built one.
     
  6. Mr Efficiency
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    Mr Efficiency Senior Member

    Is this going into salt water ?
     
  7. rivergybsy
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    rivergybsy Junior Member

    hmm... not often, but possible
     
  8. Mr Efficiency
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    Mr Efficiency Senior Member

    Mixing aluminium and GRP in the hull of a boat is unusual (though you might see glass hulls with alloy upperworks, or vice versa). To further complicate by having PU foam as part of the structure as well, seems to be taking novelty too far.
     
  9. Mr Efficiency
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    Mr Efficiency Senior Member

    Google "poultice corrosion" and you will see that glueing alloy to foam could have a downside.
     
  10. rivergybsy
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    rivergybsy Junior Member

    Thanks Mr Efficiency

    I am aware of the corrosion issues, but I like the impact resistance of aluminium, probably because I am a metal man. I realise that it would be far more simple and less costly if I would build the hull with foam and glass. The temptation is to ad a few more layers of glass to protect the hull, but I don't think that this would make it much stronger, just heavier. I intend to use this boat in shallow rivers and beach it once in a while.
    Can anyone advise me on the issue alu vs foam and glass in regards to impact and abrasive strength?
     
  11. TANSL
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    TANSL Senior Member

    You might consider placing the outer layers of aramid or teflon.
     
  12. Mr Efficiency
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    Mr Efficiency Senior Member

    Rivergybsy, if you are a "metal man", make the thing out of alloy, not the triple treatment.
     
  13. rustybarge
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    rustybarge Cheetah 25' Powercat.

  14. Mr Efficiency
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    Mr Efficiency Senior Member

    So glass+foam+alloy+polyethylene ? It is getting worse !
     

  15. JSL
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    JSL Senior Member

    All of the previous comments against this idea are valid. Plus, 1 mm of aluminum probably would not give you much impact protection from another boat or 'dock strike'.
     
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