New shower enclosure corroding already due to reaction between aluminium surround and steel fixing screws. Inevitable? Drainage and wastage systems and plumbing help, advice and answers

[benawhile]

Hi
We had this "Lakes" brand shower enclosure fitted 3 years ago and already corroding as shown. Even worse, one of the fixing screws is corroded in place and sheered off.
THe model is "Coastline Corner Entry"
I need to replace the steel self tappers with aluminium ones but can't get anything smaller than 4mm, I need 3.5mm.
Then I need to remove corrosion as best I can and corrosion proof the area.
Does anyone have suggestions or experience?
But why does a firm like Lakes supply two different metals that are obviously going to corrode when they get damp. Are all shower enclosures made like this?

[stoneyboy]

Hi benawhile ,
The problem is not the screws - they are stainless, the issue is the cuts to the ends of the frame sections which expose virgin aluminium, the corrosion starts here and creeps along the adjacent anodised surface.
You could rub down the corroded sections and then spray with automotive lacquer or aluminium paint, trial and error will be needed to see which works best.
The issue with the stainless screws is that they are machined evenly right up to the head, this creates a weak spot and most breaks occur with the head coming off.
Regards SB

[benawhile]

Thank you, that's very helpful and makes sense. I am not good at getting things to look brand new and ale to put up with the small amount of surface corrosion but can you recommend the best treatment for the virgin aluminium surfaces once I've scrubbed all the white powder to prevent reoccurence and spread, same for the exposed anodised surfaces? The shower gets very little use and I'm assuming the dampness is in the atmosphere and splashes from the adjacent w/c. Corrosion at ground level is much worse than up top, where there is none.
After research I have bought two products:
ASC-1 Anti seize
RAIN-X, a glass cleaner with rain repellant
I propose the ASC-1 to squirt around inside and the RAIN-X as an exterior surface repellant

[stoneyboy]

Hi benawhile,
Suggest you paint the cut aluminium adhesive with a silver car paint before you refit the corner(s). A touch up pen is a deal for this. Once assembled use the two products you propose.
The problem is bound to re-appear it a matter of regular maintenance to keep it at bay.
Regards S