Surface treatment for Aluminium sail drive leg

[morgandlm]

Can anyone please advise on the appropriate treatment for a corroded aluminium sail drive leg. Advice and previous treatment so far has included:
(a) Don't use primer but slap on several coats of epoxy to bare, clean metal.
(b) Use Primacon onto the clean metal then epoxy
(c) Use an aluminium primer (Hammerite?) then anti foul

The corrosion is possibly the result of a previously poorly fitted anode. Over several years the sail drive has been patch repaired using the above "remedies". None seem fully effective.

Grateful for any experienced based advice
Morgan

 

[colhel]

I just use Primacon and boot top.
Don't use "normal" antifoul as this causes the alluminium to corrode.

 

[VicS]

Clean down to bare metal..... grit blasting with a soft grit to remove all the oxide from pits.

Sand if necessary with a coarse-ish paper to provide a good key

5 coats of Interprotect epoxy.
then
5 coats of Primocon followed by a suitable antifouling. Eg Trilux 33

Note epoxy then Primocon not the other way round!


If you don't get rid of all the oxide first you will be wasting time, effort and money. You might just as well use the garden gate stuff ... "Hammer It" or what ever it's called

 

[BACUS]

sail drive leg

do as VicS advises but would recomend that after you have applied your first coat of epoxy paint abraid the surface with paint still wet so that any oxidation that is just trying to form is removed and covered with paint instantly then put some more paint on
Regards
Bacus

 

[wot]

If yu really want to do it properly then:

1. Mechanically remove corrosion as stated by VicS
2. Chemically treat remaining corrosion (yes, there will be some) using Deoxidine 624
3. Apply a Chromate conversion treatment (Alocrom 1200 or Alodine 600)
4. Apply protective paint finish as recommended by VicS

 

[Madhatter]

Ask this chap

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