Painting a 20 metre mast.

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mack3737

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I would like to repaint my mast, it is in the boatshed but the roof leaks and I cannot control the temperature of the shed (huge shed and no doors).
I am proposing to build a tent over the mast to keep dust off and buy a 10" fan, 3KW fan heater and flexible hose to blow warm air up the interior of the mast.
Hopefully this will raise the surface temperature of the mast to around 15 deg.C to ensure that the International Perfection will cure.
The average temperature in this part of Scotland is around 6 deg.C and from previous experience of doing repairs it takes ages for the paint to harden and has a matt finish (instead of gloss) when I have painted in winter before.
Do you think this could work?
 
My concern would be that the fan won't generate enough pressure to drive the air through the flexible tube and down the length of the mast. In the worst case this would reduce the airflow over the heating element and the fan will cut out, or possibly overheat.

Tube heaters under the mast at regular intervals might be a better and safer bet, especially if you can close the ends off the tent.
 
Camelia said:
It might be quicker to ask your local garage paint shop to do the job.
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with a 65ft mast ?



IE points out the lack of umph in a normal fan heater. Perhaps try a suction cleaner hose at the top of the mast, gaffa taped round the halyard sheaves ?
 
sarabande said:
with a 65ft mast ?



IE points out the lack of umph in a normal fan heater. Perhaps try a suction cleaner hose at the top of the mast, gaffa taped round the halyard sheaves ?
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That must help but surely at best you will have one end hot and the other cold, the aluminium will quickly transfer the heat to the surrounding air. Just stop and think of another scheme until we have a warm spring day.
 
Just to add to my previous post, I'm getting a 22m mast painted this winter, when I worked out the cost and time to lifting the boat, de-rigging the mast and then the time it would take to strip the mast of all the fitting, sand and clean it, paint it, then refit the mast, re-step and then launch and re-tune the rig. Not to mention finding somewhere big enough to get the mast under cover in and establishing a reasonable temperature for painting. I decided it was a big job and I was more than likely to make a mess of it, for a relatively small saving in cash terms. So the mast is in Silvers Marine to have the job done professionally. For sure it'll cost more, but I figured the risk of failure, i.e. making a mess of the paint job was too high!
 
I did this with a friend here, same size. The first thing to do was remove all the fittings, spreader etc and then sand it down. That took some time. We had the opposite problem, the paint set off too quickly, so we painted first thing in the morning when it was cooler. The matt finish that you mention might be due to high humidity. I would be inclined to make the tent as small, snug, as possible which should allow you to raise the temperature in the tent evenly and if you use some form of electric heat you might get the humidity down (I'd seal the floor, polythene sheet) to stop damp.

The idea of waiting till a decent spring day has considerable merit

edit The previous post and mine crossed, but moving a a 20m mast is not easy and it might not be anywhere near anyone who can paint it professionally. close edit.
 
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mack3737 said:
I would like to repaint my mast, it is in the boatshed but the roof leaks and I cannot control the temperature of the shed (huge shed and no doors).
I am proposing to build a tent over the mast to keep dust off and buy a 10" fan, 3KW fan heater and flexible hose to blow warm air up the interior of the mast.
Hopefully this will raise the surface temperature of the mast to around 15 deg.C to ensure that the International Perfection will cure.
The average temperature in this part of Scotland is around 6 deg.C and from previous experience of doing repairs it takes ages for the paint to harden and has a matt finish (instead of gloss) when I have painted in winter before.
Do you think this could work?
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You seem to be attracting a lot of negativity here. I would say, try the set-up as you suggest, and see how it goes. It's not going to cost a bomb. All you're needing to do is raise the temperature a wee bit, and make the surface bone dry. I'm not sure how you avoid quite a temperature gradient along the mast.
 
I painted my 43 ft ally mast in similar conditions managed to hire the services of a professional auto sprayer and he used a workshop space heater I think it was paraffin and electric fan the mast was heated gradually and considering the barn was the size of an aircraft hanger it only heated the general area. The final finish was similar to a new car and over ten years later apart from small impact damage it remains intact with no peeling . I used Epifanes aluminium system for smooth surface ally there is no rubbing down to key or acid etch instead one coat of AQ Washprimer ( a resin one part clear liquid) again no rubbing down , after that 2 Part epoxy zinc phospate primer then 2 pack polyurathane undercoat and topcoat . Apart from washing the mast initially with solvent there was no sanding done and the primer was so thick it covered all small imperfections. To strip the mast of all rivets and fittings was a massive task and transporting home and back was not easy total cost at that time including rebuild was circa £600. It is a bit of a gamble especially in the winter but my mast is tapered for the top 8 ft with aerofoil cross trees and is in one piece not the usual heavy section joined with multiple rivets so I am hanging onto it if poss .
 
Spyro said:
Serious question. Why would you paint an aluminium mast in the first place?
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Mainly cosmetic same reason one paints a grp hull but I had removed a boltrope track section that left rivet holes up the mast and generally it had lost the gold anodising in a patches and also I like the look of a white painted mast .
 
parbuckle said:
Mainly cosmetic same reason one paints a grp hull but I had removed a boltrope track section that left rivet holes up the mast and generally it had lost the gold anodising in a patches and also I like the look of a white painted mast .
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I suggest you don't consider anything other than Awlgrip. Probably the most expensive, although you won't need a lot, and two-pack is more problematic than single. The results will definitely be worth it. We watched Boatyard Palma doing superyacht masts and superstructure with it, utterly brilliant finish.
 
Just a thought on heating that as said you may end up rstricting the air flow of a fan heater in trying to funnel the air down the mast. A vacuum cleaner on the other hand provides a more powerful concentrated blast of exhaust air which is somehwat heated by the motor. So more successful at getting air through the mast. Just leave the suction inlet near the fan heater which will primarily be used to warm the air outside the mast. It all sounds 'orrible to me.
I have seen aircraft painted with beautiful 2 pack gloss where the metal underneath has still corroded causing a horrible mess. Perhaps bad priming/treatment.
I just paint my mast with enamel oil type gloss. It does not look brilliant but is easy to touch up when it gets scratched and so always looks tidy at least. good luck olewill
 
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vyv_cox said:
I suggest you don't consider anything other than Awlgrip. Probably the most expensive, although you won't need a lot, and two-pack is more problematic than single. The results will definitely be worth it. We watched Boatyard Palma doing superyacht masts and superstructure with it, utterly brilliant finish.
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FWIW: Alexseal is apparently taking significant market share from Awlgrip in the superyot sector as it claimed to retain it's gloss longer than the newer 'reduced VOCs' Awlgrip.
 
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