Removing Seized Fitting in Boom

[Birdseye]

. Many people recommend heat cycles but I doubt this would have been effective. The fitting was not 'bonded in' by the corrosion - the aluminium oxide has minimal strength. Rather it is, in my opinion, just that the volume of aluminium oxide produces pressure and high interference i.e. high friction and heat cycles would have no effect on this.

Right and wrong! Yes it is the volume of the corrosion product that makes it tight but heat definitely does work because the ally has a higher coefficient of expansion than the stainless.

If you are replacing the stainless bits use some duralac to prevent such corrosion repeating.