Mast Painting/Stripping

[philmarks]

I have 2 x 15m masts which are painted black (rather poorly and not by me!!). This winter I'm biting the bullet and unstepping them. I don't really want to have to maintain a paint job on these long-term, so I'm thinking of stripping them of the paint. Because I have corrugated alu strip steps on each of them, it will be a really fiddly and time consuming job.

Anyone know if it's safe to use a proprietary paint stripper on them or will it damage the anodising?

Any other relevant tips? Eg if I did re-paint them, what's the best paint to use? Have heard of Awlgrip being used but I understand that would need an etching primer on alu, and I don't really want to do that.

Thanks in advance for any guidance
rgds
Phil

 

[ccscott49]

Why were they painted in the first place? Probably because the anodising was damaged?? Anyway the aluminium will be OK even if it isn't anodised, as it will naturally get a coating of oxide on it which will protect it. Normal nitromors might attack the anodising, as its caustic, but maybe the fibreglass paint remover may be better. I would contact one of the paint manufacturers or mast builders.

 

[AndrewB]

I repainted an ali binnacle with failing paint a little while back. Prepped by wire-brushing off the remaining paint and the powdery oxide, then sanded smooth. Saw no need to etch onto what was not a shiny smooth surface, so applied a few coats of epoxy primer followed by two-pack polyurethane topcoat. Looks fine after four years.

At one time, black anodizing was used on masts. Are yours definitely painted?

The big problem with aluminium is where stainless steel fittings are attached. This sets up electrolysis that once started, will undermine any paint. This is a common reason why masts get painted - and why the paint fails so soon thereafter. The only way to stop it (for a while at least) is to remove the fittings (probably by drilling out) and refit, using zinc chromate paste, rubber washers etc. Otherwise you can't expect a repaint job to be successful.

 

[vyv_cox]

I would be very careful. Caustic substances, such as are used in some paint strippers, will readily attack aluminium, whether it is anodised or not. This is not to say that the aluminium will disappear in a trice, but any left after use will staedily work its way through the metal. However, the etching that will occur will make a very good surface for new painting. I would try a small area first and wash copiously with a hosepipe when finished. Be extra cautious around fittings, particularly pop-rivetted ones.

 

[Joe_Cole]

Only two comments.

1. I would check the paint stripper with the manufacturer. There's many paint strippers on the market and I think that most will be OK. If the manufacturer can't help then look elsewhere.

2. I'm not sure why you don't want to use etch primer on aluminium. These primers have been around for years any they make an incredible difference to paint adhesion on alli. Personally I'ld be happy to use it, safe in the knowledge that, once done, I wouldn't need to do the job again for years!

3. (I know I said two comments!) Why not take the steps off and refix them once the job has been done?

Regards

Joe

 

[philmarks]

There are about 40 steps. I don't want to lose a season's sailing!! The problems are not around the steps, but general flaking and chipping due to poor adhesion/low quality paint.

 

[AndyL]

Taking the steps off will still be the best option

It's only 160 rivets. Half a day to remove them: using the correct size bit drill the heads off - keep a pair of pliers handy to stip the heads off the drill bit. Pull the steps off the rivet stubs and punch the rivets in.

Now you have a clear surface for the paint job.

When you rivet the steps back on (borrow one of the concertina type riveters) don't forget to dip the new rivets in that anti-corrosion stuff - name escapes me right now, but I can check.

 

[AndyL]

I mean Duralac

Use it everywhere when re-attaching stuff to your mast.