Just taken all the paint of my aluminum mast and boom now looks super shiny albeit uneven, don't want to repaint just leave it bare, what's the best way to get an even finish and what then, polish?

How uneven? If you have dug into the mast wall excessively with whatever you used to get the paint off this is not ideal. Do you have a photo looking along the mast from heel to top each side? For an even finish would suggest a metre long sanding board - torture board - but don't wear away the mast wall more than (say) 0.2mm.

Good video here with sanding using orbital sander - this is what I have used on 2 mast refurbs.



Have just used one of these on a dinghy refurb - superb sander.

www.makita.com.au/building-construction/category/sanders-polishers/bo5041kx-125mm-5-random-orbital-sander

Suggest don't use polish rather Nyalic - never used it but is apparently the ducks..............an experienced rigger uses it and recommends it..........

www.nyalic.com.au/nyalic.com.au/Home.html

www.nyalic.com.au/nyalic.com.au/MARINE.html#4

See other comments in your prior post

www.seabreeze.com.au/forums/Sailing/General/removing-mast-paint

wet and dry to your desired polish finish, use WD-40 instead of water.
It will weather over time and protect itself,
Then go sailing

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r13 said..
How uneven? If you have dug into the mast wall excessively with whatever you used to get the paint off this is not ideal. Do you have a photo looking along the mast from heel to top each side? For an even finish would suggest a metre long sanding board - torture board - but don't wear away the mast wall more than (say) 0.2mm.

Good video here with sanding using orbital sander - this is what I have used on 2 mast refurbs.

Have just used one of these on a dinghy refurb - superb sander.

www.makita.com.au/building-construction/category/sanders-polishers/bo5041kx-125mm-5-random-orbital-sander

Suggest don't use polish rather Nyalic - never used it but is apparently the ducks..............an experienced rigger uses it and recommends it..........

www.nyalic.com.au/nyalic.com.au/Home.html

www.nyalic.com.au/nyalic.com.au/MARINE.html#4

See other comments in your prior post

www.seabreeze.com.au/forums/Sailing/General/removing-mast-paint

Haven't dug into used a sander to remove paint and a wire brush in the smaller areas it just looks uneven in colour

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Newmo said..
wet and dry to your desired polish finish, use WD-40 instead of water.
It will weather over time and protect itself,
Then go sailing

Wet and dry but with kerosene.

Ok thanks for clarification of "uneven", good that the wall has not been thinned.

As regards Nyalic I just read on another forum that it dissolves when petrol or metho comes into contact with it - just tried to confirm this with TDS's or MSDS's on line - the best I could find was here but they don't mention this.

www.nyalic.co.nz/technical.htm

So my bad in being unaware of this - if you want to go this path suggest check with the Aust site;

www.nyalic.com.au/nyalic.com.au/Home.html

Hard to find where to buy Nyalic off the shelf - the Aust rep at the above link will know - but as per below the 12oz spray can looks like costing an arm and a leg..............

www.nyalic.com/12oz-Aerosol-Can--3PAK_p_111.html

We always sanded the masts if they were painted applied the primer then sprayed the mast, the thickness loss of aluminium on a mast is irrelevant.

I stripped and sanded my boom. It took a long long time. Best thing to use was a random orbital sander with a backing pad. I then finished with wet and dry paper. I then covered in nyalic. I got a couple of small sample bottles off the rep guy for free. Half a bottle was plenty. Its a great product but its single pac, so has all the downfalls of a single pac coating. If I was to do it again i would probably roller on 2 pac paint which I think is possible.

Mate of mine with the alloy Cole 42 refurbished the alloy mast and boom and left the aluminum in a polished state. He then slopped on this stuff with a rag. After a few years it is still annoyingly shiny.

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whiteout said..
We always sanded the masts if they were painted applied the primer then sprayed the mast, the thickness loss of aluminium on a mast is irrelevant.

Ok thanks, great, 100% agree that alum masts (whether new or being refurbished) are best carefully sanded back and etch primed then sprayed with 2 pack poly using the suitable products. But to say "thickness loss of aluminium on a mast is irrelevant" can't go unresponded to sorry. I assume you are talking about the minimal thickness loss resulting from sanding which would be in the 0.1-0.2mm range or less as per my prior post. But to state so broadly that thickness loss is irrelevant is not valid. Mast inertia (stiffness) results from diameter and wall thickness and the diameter is far more significant in the formula - but the thickness also is included in the formula obviously. The thickness at local stress concentration points also needs to be maintained otherwise bending or buckling failure will occur. If you have alum mast wall thickness corroded away to nothing under stainless spreader bands - due to breakdown of the Duralac barrier between them as per prior posts as per I have experienced and caught just in time - then your mast will fail. A prior post of an S80 mast suffered this fate.

I'd say best left as bare aluminium. It's not pretty but will outlast a coated mast. (Except anodised coating)
Etch primer with 2 pack will be pretty good, but with any coating, get a scratch or chip and some moisture will get under the paint and the corrosion will start as under the paint as protective oxide layer will not form.

Slapping on a few coats of good old Penetrol works.