Alternatives to Sand-Blasting Mast ?

[Weyalan]

I am planning to re-paint the mast in the not too distant future.

The mast is about 60' long, aluminium. It is currently painted (black), using what I would guess is a 2-pack paint.

The usual way to get the paint of would be, I guess, to get it sand blasted, but around here, that is a very expensive exercise.

Are their any viable alternatives to sand blasting? If I thought that I could hand sand it in less than a week, I would give that a go, but I have no idea whether it is viable or not.... any thoughts?

[AnchorageGuy]

I would not sand blast the spars since that could do more damage than help. Take a took at how we did ours at

Voyages of Sea Trek: Refurbishing The Spars

and maybe you will get some ideas.

[Weyalan]

Thanks Chuck. Lots of good advice there. From reading the link, it sounds like you didn't necessarily sand the old paint all the way back to bare metal. So, if you just sand enough to give the old paint a good "key", is that enough, where the old paint is in good condition? I'm assuming you took it back to bare metal where the paint was bubbling or damaged?

[AnchorageGuy]

That is pretty much correct. The key is to get the old oxidation sanded off and use the correct primers, etc for the bare spots and the over paint.

[Weyalan]

I was planning on etch-primer, then 2-pack high-build primer, then 2-pack enamel... but I'm sothing of a novice here.

[hooked on water]

Hi Weyelan

Talk to Jotun in derwent park, just the stuff for the job, and will give you the advice you need . Paint tech corner of derwent park and sunderland st.
hope to see you around some time
I am about to paint my mast for the first time, and am just using jotun system with hardtop ultra as final coats. and the etch primers they have suggested (name evades me - old age)

Just PM me if you wish to chat further about local things

Greg

[Weyalan]

Greg,

Thanks for the advice. I'll have a word with the guys at Jotun. I work close to Derwent Park Road, so I can easily enough drop by. Up until now, I have been using Wattyl, because I have a mate that works in their shop on Main Road, and he gives me "mates rates", but if the Jotun product is significantly better, it is probably owrth the dollars.

The thing that is really making my head ache at the moment is whether or not to sand-blast. If I don't sand blast I can pull the stick out at BYC with their mast crane ($0), put the mast in their shed ($0), strip the mast out, and sand it back myself ($0), do the etch prime and primer myself, then just pay a professional to spray the top coat. On the other hand, if I sand blast, it pretty much has to be done at the Clean Lift at Goodwood, which will be $70 per day or so, plus crane hire ($400), plus $300 per hour for the sand blasting, etc... you can guess which option is looking more attractive right now!

Anyway, it is friday afternoon, it is almost beer o'clock... this can wait for another day!

Whats your boat called, and where do you keep it?

Cheers,

Patrick

[hooked on water]

I have used the jotun range through paint tech for many years on boats, and their service adn price is good
it should not be too hard to sand the oxide off, you can also use cleaners as a prep that will eat the oxide. alot easier than sanding, only do a final sand and degrease after

Paint tech also are good for all the equipment
I have an airless sprayer too for painting the mast if you need
not hard to do

cheers
Greg

[hooked on water]

By the way patrick, have not got a name for my boat yet
it is at Kleen Marine in goodwood being fitted out
hope to have it in the water for christmas
It only just arrived here - hull and deck only at this stage
first days work is tomorrow, levelling it, and cleaning it ready for base coats.
I am epoxy coating the whole boat basically, and using Jotun products right through.
should catch up some time
I will be keeping mine at the motor yacht club when it is in the water
yours is bellerive I gather then

[viking69]

just wondering, those of you that have painted masts how long does the paint last on them for. i do imaging like most painting it is all in the prep work to get a good lasting job?

[Wotname]

Weylan,

I hand sanded a 35 ft mast about 20 years back, took about 2 days if I remember rightly (after stripping off the fittings etc). Might take me longer now .

I would consider paint strippers also; ones suitable for Al. Talk to the local aircraft painters - if there is any around - if not, I can ask the local aircraft painters - I know they have a few different types they use depending on the existing paint type.

For what it is worth, the local mast guys at Taskers did not reccomend painting my current mast is anything but PERFECT conditions (ie temperature, humidity and drying time). Commerical pressures (time and customer expectations) means that they often do paint them in less than ideal conditions but the paint life is ALWAYS shortened.

Their view was WAIT or leave it unpainted (and as they have been painting masts for years and were not selling me anything - rather the opposite - I listened and took note).

I am thinking that winter must approaching Tassie by now.

[Alan Wheeler]

You are correct. The prep work on Aly is essential.
If you did go with Sandblasting, it will be the easiest method of getting back to clean Aly fast. Different mediums can be used. Walnut shell, Glass etc. There are even different grades and types of sand. The Sandblasting company should be able to give you the best advice of which method to use. If they are not sure, don't use them. The don't have the experiance you require.
If the Aly is corroded, that lose paint and corrosion has to be removed. A Brass wire buff on a grinder will do that very fast and efficiently. If the paint is sound, then a good sand to create a key is all you need. If you expose Aluminium with any of the above methods, you need to obtain a good clean Aly surface by sanding, then wipe with thinners to ensure no oil is on the surface, especially if it has been blasted. I suggest you look for a Paint system. Altex, Epiglass/International, whom ever you choose. The mast will need to be very clean. Wash with a pre-painting detergent or a pre-painting cleaning solvent. The companies will have a system that includes that. Altex has a three step system. P40=detergent, 121 etch primer and top coated with their elite polyurathane.
Ask for a read the information on the product and be well aware of its hazards and how to use it. A two pack Polyurathane or Epoxy paint system will give you a very long lasting, hard wearing coating. The mast is in a high wear catagory due to sheets and sails rubbing against it.

[GordMay]

Prior to painting, bare metal surfaces should be abraded to about* a 2-3 mil profile and properly cleaned to remove salt, oils and other contaminates.
* consult specific paint manufacturer

See also “Painting VP Outdrive”
http://www.cruisersforum.com/forums/...ive-14234.html

Fine blasting media:
Utilized for new construction, light paint and rust removal and special maintenance applications requiring reduced profiles. Requires a minimum suggested nozzle size of 3/16” and under standard blasting conditions will achieve a 2-4 Mil profile.

Extra fine blasting media:
Applicable for light blasting requiring a clean surface and minimum anchor profile including Brush-Off Blast or high-pressure water blast systems. Requires a minimum suggested nozzle size of 1/8” and under standard blasting conditions will achieve a 1.5-3 Mil profile.

[Robertcateran]

Avoid brass brushes as it can lead to electrolysis. Find some stainless ones. I learnt that in building an alloy tri.
You can go the whole hog and get it anodised if you want protection. I can't really see much advantage in painting aluminium, except for antifouling. It concentrates the corrosion where it is scratched off
Robert

[Wotname]

Again, the local Tasker's guys suggested the ONLY reason to paint an Al mast was cosmetic and then you still had to put up with the downsides (and expense) of painting.