Gluing aluminium to foam

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?

 

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.

 

What is the type of foam you are intending to use ?

 

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.

 

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.

 

Is this going into salt water ?

 

hmm... not often, but possible

 

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.

 

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

 

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?

 

You might consider placing the outer layers of aramid or teflon.

 

Rivergybsy, if you are a "metal man", make the thing out of alloy, not the triple treatment.

 

These alloy/polyethylene sandwich panels have the same expansion coefficients.

Maybe mechanically attach/glue polyethylene sheets to hull, then bond on the alloy.

http://www.aalco.co.uk/datasheets/Aluminium-Alloy-Aalcopanel-Composite-Panels_258.ashx

 

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

 

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'.