Effect of aluminium hangers on galvanised iron/steel balustrade?

The activity series. The further they are apart, the faster any reaction.

So, if the Al is Aluminium and the Zn is Zinc this means they are quite close and less reactive?

...Al > H( water) > Mn > Zn >...

But not if they are insulated. The simplest solution might be to use something like heat shrink, PVC tube, or even a tight wrapping of PVC tape over the potential contact points.

Inspiring, thanks.

IIRC aluminium and zinc are not too bad, helped by the fact that the oxide on aluminium can be a fairly effective insulator.

Thinking about it, TV aerials often have zinc plated clamps on aluminium tubes. I was going to suggest that soft spacers are good if there is any small amplitude motion (because the rubbing can remove oxides and promote electrical contact) but the evidence of TV aerials, exposed to wind, suggests you might not need to worry.

Why not look in the Builders Metalwork section of Screwfix plenty of galvanised brackets, gallows brackets and restraint straps that might do. They may not be particularly aesthetic but if out of sight will certainly do the job for you.

Richard

Good idea. I'll have a look.

I'd not say so, it really depends on the construction. I have seen this done in outside shop displays with no apparent issues other than the usual oxidisation of each material due to being unprotected. Brian

From school chemistry of sixty years ago: Kate Now Can Make All Zebras File Slowly Past Her Clucking Hens After All

Potassium, Sodium (Na), Calcium, Magnesium, Aluminium, Zinc, Iron (Fe), Tin (Sn), Lead (Pb), Hydrogen, Copper (Cu), Mercury (Hg), Silver (Ag), gold (Au).

The earlier ones in the sequence dissolve before the later ones.

It's extraordinary how these meaningless phrases stick in the mind, even after all this time.

See also

Very good points, though as you suggested earlier pvc or shrink wrap at the contact point would also reduce rubbing damage.

I wonder what his table or shelf is going to be made out of though?

Brian

Education is a wonderful thing.

Another thought, how robust is the balustrade if the force is inwards toward the balcony? Also, plants can be very heavy and lets hope you hang the fixings on the structural part of the balustrade, since I've seen the vertical wrght iron parts of railings come adrift when small children swing on them due, no doubt to poor top fixing strength. Brian

I was thinking wood to match my head, though a chunky plastic plank would be even better, except perhaps for the cost.

Yes oxidisation will be an issue over time. I'd prefer to use stainless steel but it's costlt and harder to work.

It's pretty robust in itself thought the mooring points may benefit from some extra help.

Please Send Charlie McLean A Zebra If The Lean Hen Can't Munch Pure Sweet Grass. (Includes Platinum).

Aluminium is actually quite strange stuff. It would be insanely reactive if it were not protected by a self healing thin aluminium oxide surface layer. It used to be a trick to put a spec of mercury on a sheet of aluminium and watch it crumble to white dust overnight.

Powder coating, shrink wrap or some other plastic inserts to keep the two metals from direct contact would be one way out.

Exactly so.