How to repair aluminium mast.

Seems as if nobody has the heart to tell you but the mast is totally knackered. There is signs of electrolytic action going on, there are stress cracks, there is elongation of some of the tang slots.

Whilst you can Argon Arc TIG weld aluminium, the mast section is very thin and would terd to burn even with very large back purge of Argon. The welding process also tends to soften the parent metal.

If it were to be repaired, I would not even set a Flag on it far less several hundred feet of sail.

Sorry to be so negative.
 
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Well I would suggest a completely different answer. All the damage is at the bottom of the mast. Here all the loads are in compression there are no signs of actual compression failure.
You need to remove all the attachments and clean up the mast to good metal. You then need to measure and decide if corrosion has indeed caused loss of a significant amount of metal. Remember that it is the circumferential area of the mast that matters. Mast can and often do have holes in them which are just a small part of the circle.
The cracking can be repaired with doublers of ali rivetted over the area. Use lots of Duralac. I would not suggest welding as this changes heat treatment of the mast. True it does not matter so much at the bottom and top. But doublers can be just as good.
A radical option might be to cut off the offending bottom metre or so and sleeve in a new piece of mast or just shorten the mast, stays and sails.
Much depends on your budget and sailing aspirations and obsessiveness about perfection. It obviously has not failed so far so is not so bad but then you might feel you can't be really confident of it in a blow. good luck olewill
 
If you can find a mast bit of the same section and a sleeve to fit internally - sounds a long shot but check places like the barge at Bursledon - it would be simple to cut off the knackered bit and rivet on a new one, this time with Duralac anti-corrosion paste.

However, people have varying ideas of ' too expensive ' - the acid test is, imagine clawing off a lee shore on a black night in a F6+ with a young family on board, would you be happy ?
 
The mast in indeed knackered. It's not entirely compression at the bottom of the mast, far from it. The boom supplies considerable point load at the gooseneck and as a consequence masts are usually sleeved in this area.

Riveting plates to the outside of the mast does absolutely nothing to redistribute the stresses. It also reduces the strength of the mast in that section.

The mast is cracking because the alloy has degraded. It has no saving graces at all.
 
the guys are right. There is evidence of serious corrosion in multiple places on the pics, so it is likely that there will be more corrosion on e.g. spreader bases, shroud and stay tangs, other sheave outlets, mast cap, in places not shown.

I am as keen as anyone to save a piece of useful kit, so if you scrap the whole mast, you might be able to save a section as a leg, or even two.


The risks of repair failure and other corrosion points are too great.
 
If you look at pic 4, it looks a bit like the bark of a tree has been removed by a grizzly bear. To my eye, it actually gives the impression that the mast has already been sleeved and the outer shell has corroded away. I wonder if the yacht has been sunk for a couple of years to above the gooseneck giving rise to galloping electrolytic action.

I just don’t like be so negative but it is in a pretty poor shape. HOWEVER

If the mast is ok above the damaged area shown and as an alternative to an internal aluminium tube insert, I wonder if a Douglas Fir or other suitable mast timber insert could be driven up to above the damaged area giving support such that the gooseneck etc could be fixed to the insert. Would have to loose the luxury of internal sheave but it may just work.

You would need to seal the end grain of the wood against water ingress to stop it swelling. The insert could be made from planks glued together rather than solid which would be easier to plane to shape.

Best of luck "Djubaca", let us know how you get on.
 
Hi again.

Thank you for answers. I dismount the mast and the situation around the step was horrible.
The mast have 2 piece of about 6m each. The bottom will be retired according to huge damages.

So, i am looking for the mast with height about 12,7 m ( 11,1 ).
Easiest way to supply is to find the mast somewhere in UK or Europe.

Thank you again and i wish succes.

P.S. sorry for my bad english
 
Djubaca said:
Hi again.

Thank you for answers. I dismount the mast and the situation around the step was horrible.
The mast have 2 piece of about 6m each. The bottom will be retired according to huge damages.

So, i am looking for the mast with height about 12,7 m ( 11,1 ).
Easiest way to supply is to find the mast somewhere in UK or Europe.

Thank you again and i wish succes.

P.S. sorry for my bad english
Click to expand...

As some of the other guys have said you really need to check the 'whole' mast to see if its recoverable. If it is just the bottom section that has deteriorated it is possible to sleeve it and add another section without any loss of the masts integrity, but only if your problems are localised. To do that though you will need to find an identical section of mast. Is there a makers name plate on your mast? Many mast/extrusion manufacturers have gone out of business over the years, so you really do need to know exactly what extrusion your mast was made of. I had a similar problem on a 1980 Beneteau First 35 I owned several years ago. The mast section was made by Isomat who had gone out of business but managed to get an identical section from http://www.sailspar.co.uk/ in Plymouth UK.

Failing that you could try Z Spars to see if they can help you with a section or whole extrusion. Here's the links to their spar sections and prices...

http://www.zsparsuk.com/sec02.htm

http://www.zsparsuk.com/web prices 2012.pdf

Good luck...
 
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The top half of mast is in good condition and it is usable if i find the same section for the bottom half. For 2 months i didnt find here in Bulgaria.
Section mast is like this :
mast section.jpg
dimensions : ~ 155mm / 115mm
As you see on the pictures mast is painted so i dont know what is its maker. People around me talking about Proctor but i didnt find the same profile in http://www.proctormasts.com/

I prefer whole mast in used and usable conditions. There is some in ebay but delivery from USa will be very expensiv.

Thank you
 
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To try and identify the section used... what is the make of the boat and year? As 'Seajet' says, contact http://www.sailspar.co.uk/ it was them that supplied me with my mast section that I needed.

As I said in my earlier post, so many mast manufacturers no longer exist, but some have been taken over by other companies along with their extrusion profiles. If you can't identify the section by a name-plate, the next best bet is to start with the boat and its year. It might take a bit of research but I'm sure you'll get an answer in the end.
 
When I bought my 13m mast from ZSpars it came in two sections which made shipping quite afordable.Why don't you try contacting them? Their prices are not bad.
 
30boat said:
When I bought my 13m mast from ZSpars it came in two sections which made shipping quite afordable.Why don't you try contacting them? Their prices are not bad.
Click to expand...

30boat... I've heard several times over the years that the maximum length of mast extrusion supplied in one piece is 40'. Not quite sure if its true or not, but your purchase from Z Spars seems to bare this out....
 
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