Aluminium Mast re-painting or ?

[Searles]

Have done many Ali masts ,generally re building painted sections ,first strip off all fittings drill out rivets also re move or drill out all bolts or broken fittings to a bare tube ,we then strip all remaining coatings using soy gel wash of with fresh water., normally clean section with kerosene and wet rub paper ,starting with 320 finishing with 500or 600 then polish with a high quality alu wax and polish to a mirror finish,re fit all necessary fittings with monel rivets with taf gel or sim ,lasts many years .a lot of work but the best result.happy new year

[wingssail]

Originally Posted by nfbr

When you say tef gel for parts
Did you remove every screw and rivet?
Spreaders? Reinforcing layers etc?

When we did it we removed every part that we could get off. There is some sections of internal re-enforcing held by screws which we left. Otherwise it all came off. not too hard anyhow since 18 years previous to that we did it before and used anti-seize then also.

[kryg]

Don't paint! I had rejigged my boat with Dyneema. I had pulled my mast out to have it inspected stripped of all paint with antifouling paint remover film left on overnight scraped the paint off and rebuild because of an accident. Furthermore, I had the mast burnished and then sprayed 3 coats of EverBright. Now instead of touch up or repainting the mast, all need to will do is clean it by wipe it down and re-coat it with EverBright with a sponge to keep it fresh. Once Every 3 or 4 years if it needs it, no more chalking or peeling paint. VHF Antennas - Wind inst-+ Mouse halyard line.jpg Views: 117 Size: 422.5 KB ID: 229499" style="margin: 2px" />

Originally Posted by nfbr

27yo white painted aluminium mast is losing paint / showing surface corrosion at most rivet / screw points.

I have to replace standing rigging anyway, so it's time for mast to come off and

a) leave raw aluminium?
b) Clear coat?
c) Passivate some other way?
d) Re-paint?

Whats the consensus? I figure the paint will just corrode under again, though maybe not take so long this time.

Thanks
Paul

[Jammer]

Originally Posted by searoom

PTI makes something called Aircraft Paint Remover.
Comes by the quart from Aircraft Spruce.
Be sure to wear protective gear and good mask.

It formerly was mainly methylene chloride. People are dying using methylene chloride to strip bathtubs and so it can no longer be sold as a stripper and everything has been reformulated so that it is more flammable, less effective, but less toxic. Caveat emptor

[dfelsent]

Originally Posted by CarlF

Only small masts are anodized these days. The EPA made the anodizers switch to smaller tanks to reduce air pollution 20 years ago

Umm. I’m not quite so certain. While I’m not sure there are any US based aluminum big rig suppliers these days there are several suppliers that provide large anodized aluminum masts. Selden for sure. Maxspar likely and others as well.

The mast market is global.

[CarlF]

Originally Posted by dfelsent

The mast market is global.

Good point. I was thinking of just the US market

But I can't remember the last time I saw a new big aluminum Selden mast at a boat show that wasn't painted.

A quick google search for "Selden anodized mast" only turned up dinghy and small keelboat masts.

But I agree that mast length anodizing tanks must still exist in some countries.

[Celestialsailor]

I have done 3 masts over the years. I took the advice of the Pro's. Paint stripper down to bare aluminum. Acid wash, warm water repeated rinse. Thoroughly dry. Two very light coats of Strontium Chromate Epoxy...then one tack coat of LPU paint, followed by two full coats of LPU...spray of course. Let dry for 4 days.

[mlydon]

I just did mine last year - looks fabulous....used interlux perfection, following their directions
Basically:

Take EVERYTHING off
Have 3-4 sawhorses along the length, and a means to flip the mast over (I had 2x4s stuck in the spreader brackets)
9” backing pad an an angle grinder, with 60 grit disks
Grind/sand off as much from one end as you can get in an hour - through all paint, bond coat, etc, down to shiny aluminium. Do a few feet, flip the mast over and do the other side, back, forth, back forth, ‘till the hour is up. do not wipe with anything - blow off with air, use a paint brush to ‘sweep’ dust away.
While your getting close to your hour, a helper is mixing up barrier coat (interlux 2000) thinned as directed
Coat the section you just ground - important to get this done within the hour.
While it’s drying, go do the other end, then call it a day
Next day, grind the next section inward, taking off a bit of what you coated the previous day, and repeat - an hours grinding, coat, do the other end, call it a day.
Keep doing this till you have one section left in the middle, and do that one.

Once the barrier coat is done, a couple coats of high build epoxy primer, sanding to smooth and level. These you can wipe the dust off with solvent.

Finally, a few coats of linear urethane ( I used perfection), and stand back an admire your handiwork ( and put all the hardware back on with tefgel as previously mentioned.

Doing my 70’ mast took 3 days to barrier, 2 days to epoxy prime, 3 days to topcoat, and a couple of days to put everything back on. Certainly not easy, but it WAS cheap, the mast was down anyway, and I had good friends to be my assistants. All painting was done with 4” rollers - looks as good or better than a spray job.

Matt

[David B]

Originally Posted by nfbr

27yo white painted aluminium mast is losing paint / showing surface corrosion at most rivet / screw points.

I have to replace standing rigging anyway, so it's time for mast to come off and

a) leave raw aluminium?
b) Clear coat?
c) Passivate some other way?
d) Re-paint?

Whats the consensus? I figure the paint will just corrode under again, though maybe not take so long this time.

Thanks
Paul

It will look great re-painted, and with modern coatings and isolation/sealing products like TefGel, in theory, you should be able to get at least as good service life out of it second time around. If it was me, I would re-do it.

Are you planning on still having that boat in 10 years, 15 years, 20 years ....?

[Celestialsailor]

Originally Posted by mlydon

While your getting close to your hour, a helper is mixing up barrier coat (interlux 2000) thinned as directed

Why would you use Interlux 2000? It is a Microplate barrier coat specially formulated as a preventative for water absorption on fiberglass hulls. Strontium Chromate epoxy was specially formulated for aluminum aircraft as it chemically bonds to aluminum and linear polyurethane bonds very well the SCE.

[CdS2 Roland]

Hello,
Today it is perhaps a third way to consider : wrapping. I would that way.
Happy new year.

[nfbr]

When everyone says, take everything off
Does that include Spreaders, double skins etc?
My mast has a double skin riveted or screwed over about 50% of it’s length that attaches the arms for the diamonds.

Could be complex to remove.

[Rucksta]

Originally Posted by Celestialsailor

Why would you use Interlux 2000? It is a Microplate barrier coat specially formulated as a preventative for water absorption on fiberglass hulls. Strontium Chromate epoxy was specially formulated for aluminum aircraft as it chemically bonds to aluminum and linear polyurethane bonds very well the SCE.

Interlux sticks well enough to well prepared Aluminium and is hard enough to resist halyard wear.

Without spray application Strontium Chromate is difficult to get coverage without lumps even with two coats.

If all you have is a roller or yard rules make spraying too hard, Barrier Coat is a good alternative.

[Benz]

Another vote for bare. I painted mine with zinc chromate and Petit Easypoxy which held up well for ten years except where the gaff saddle (since replaced by jaws) wore away the paint.
Faced with a chalky finish that needed a re-do, I just sanded the whole thing with 80-grit and left it bare. No more worrying about the paint; no more little bubbles around fittings; easy to clean. Since it's down for the winter, I'll sand it with 150 grit: by the time I die I'll have got it to 400 or so.
The stainless fittings with Tef-gel that I put in originally are still in perfect condition: you cannot afford not to Tef-gel.

[FAST FRED]

A very simple solution is to simply polish the mast .An extruded mast is not really smooth but with a good polishing gear (as used on aircraft) you can create a mirror shine that lasts a long time as its smooth.

A bright mast is great for locating your boat in a pack of anchored boats , as it stands out well.

Here is my suggestion,


https://www.google.com/search?q=Airc...68302988758180