aluminium needing to be drilled

[tomframe]

I have a brilliant toe rail fitted to my boat, basically to keep my children out the water, but I need to drill some holes in it to fit various bits of gear, what is the best way to ensure that once its drilled it does not corrode due to the fact that the drilling will compromise the anodized finish.

there must be some magic paint around that will do the job? (and last)

 

[Birdseye]

No there isnt, whatever anyone tells you. Ally is an absolute pig to paint.

 

[Guest]

If it is for a bolt then Duralac it.

 

[sandeel]

aircraft use something called Alodine, chromic acid I think which passifies the surface and gives a gold colour however this product below seems to give a clear finish

look here
I have not used it personally, maybe someone else on here has
regards
john

 

[VicS]

If it not a hole that a bolt will be fitted though permanently and you dont want to paint it yellow with Duralac there is/was a "paint" called aluchrom, alichrome or some such similar name. No idea where you will get it though. It was/is used in the aircraft industry.

You could try priming with the Hammerite primer for aluminium and then painting with "silver" Hammerite, or with a zinc chromate based primer followed by ordinary aluminium paint. Is there any thing for "doing up" alloy wheels that would be suitable?

The trouble with any coating will be the ease with which it is chipped etc by the fittings you fit.

 

[Oldhand]

Alochrome is what I think you mean, it comes in 2 parts and has to mixed. It passivates a clean aluminium surface and is a substitute for anodising where this is not possible. I believe Alochrome contains arsenic so proper precautions are required. As has been stated in another response, Duralac minimises aluminium corrosion where fasteners (botls, rivets etc) of a dissimilar metal are used through aluminium

 

[ThreeSummers]

Am I wrong in thinking that aluminium does not corrode - it oxidises, and that layer of oxididised ali then protects the ali underneath?

 

[Guest]

The key is movement. A nice piece of aluminium (correct grade) will be fine as long as you do not rub the oxides off. Any movement and they will disappear. If you put a bolt through then you get corrosion from metal contact and trapped moisture. Normally you bolt hard a piece of stainless and let the movement occur between stainless and stainless.

 

[nedmin]

I,m a firm believer in silicon grease,slop plenty on tighten bolt and wipe off excess.On my steel boats if drilling a hole,I have always used without any probs.

 

[William_H]

If you consider the usual toe rail with lots of holes and that these are intended to have shackles and blocks fitted and you consider that people use these holes for many years with blocks attached then the anodising or other finished must wear off almost immediately.

The holes do not seem to corrode or wear larger so why worry. ie just drill the holes. olewill

 

[graham]

Could you drill oversize then epoxy in a piece of plastic tube?