Quote:
Originally Posted by Leither
One of the problems about this oxide layer is that it is relatively soft and easily damaged, so where the metal is exposed to regular abrasion then there could be an erosion problem.
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Thanks for the chemistry lesson. I agree with everything, but I would point out that That an aluminium boat is less prone to abrasion problems than a fiberglass one. Many owners have commented how they have rubbed against a pier etc in a storm and done no damage in conditions that would have damaged a fiberglass boat. I guess the abrasion resistance of aluminium oxide might be low compared to other metals, but not gelcoat.
The oxide also reforms almost instantly. One trick when tring to glue aluminim is to sand off the oxide under a layer of glue to stop air reaching the aluminium and reforming the oxide layer. If you sand then apply the glue the oxide will have reformed.
I also have never heard of a practical problem with aluminium corroding in areas of high abrasion. There can be significant problems with both aluminium and ss coroding if air does not reach the surface. This "crevice corrosion" has caused many a problem with aluminium and ss water tanks, but that is a seperate issue. If boatbuilder would stop using aluminium for unsuitable applictions such as water and fuel tanks aluminium boats would have a much better reputation.