Do spars deteriorate?

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I'm looking at getting a new top section for my mast but have been offered the top section from a very old laser that has hardly been used in the last 5 to 10 years. Does it lose any flexibility or change in any way with age?
 
Flexiblilty - no

You do want to check that it's straight.

You do want to check to see if it's already been end for ended. If it hasn't, that's a plus and probably the first thing you want to do if you decide to get it.

If it's already been end for ended, it's worth well less then 1/2 the cost of a new one
 
If the spar was put away wet, especially after a sea outing, I would be concerned about corrosion.
 
You do want to check to see if it's already been end for ended. If it hasn't, that's a plus and probably the first thing you want to do if you decide to get it.

What is the reason behind end for ending the top section? Also wouldn't you be left with a rivet hole where the stop fitting was. What is the recommended way to do this?

Ta Ian
 
I'm looking at getting a new top section for my mast but have been offered the top section from a very old laser that has hardly been used in the last 5 to 10 years. Does it lose any flexibility or change in any way with age?

From a metallurgical perspective, the mechanical properties of the spar will not change with age (unless stored at temperatures close of above the boiling point of water).

The main issue is with corrosion around the rivet holes, particular the rivet on the collar as this is a high stress location. If there is any corrosion it would be a good idea to end for end the section.
 
What is the reason behind end for ending the top section? Also wouldn't you be left with a rivet hole where the stop fitting was. What is the recommended way to do this?

Ta Ian

The most common cause of breakage is at the rivet hole on the collar (max load from bending, corrosion, putting the rivet towards the front, etc) So, not knowing the history, swapping the ends lets you "start over" with a section that has not been subject to those stresses.

Yes, you have a left over hole - but it's in a location near the top now that has very little stress, and you can simply cover it with tape
 
The aluminum is protected by a thin layer of aluminum oxide, for this reason the metal has good corrosion resistance.

You should check that the spar is straight, shows no signs of corrosion, cracks ect (corrosion and cracks=time for a new spar). If the top mast is bent you can bend it back by placing it in the lower mast section, resting it between the ground and a solid elevated base, then apply smooth downward pressure until the bend is out.

When you have to straigten the mast on a regular basis then its time for an end for end, or a new top mast section.
 
Had a look at the spar on the weekend, it is straight but the collar (is that what it is called?) that the bottom section comes up against moves a bit with some slop in the rivets. Each plastic bit has been put on with 2 rivets, I'm starting to think it might be better with just one. This spar comes at the price of a beer so I'll take it, just need to work out how to make sure it will be OK to use.
Regards.
 
The timing on this thread is funny as I just broke my top section tonight in a breeze of about 15-20kts. The snap was the classic break right at the rivet and collar and I can only assume was due to deterioration on my 1996 Laser and original spars. Now the question is whether to purchase a Laser top section or a practice upper spar from APS or intensity. Any thoughts or personal observations on practice spars?

Also, what is the general consenus on the placement rivet of the upper spar.....do u like it to face aft or forward when you are sailing? What is the best position to lessen the load on this weak spot?
 
You want the rivet facing aft.

As far as practice vs class legal. The upper is standard extrusion, so they should have similar characteristics.

(and you can turn your broken upper into a spare boom)
 
Even if the dimensions are the same, it doesn't mean that the alloy composition or the heat treatment that gives the mechanical properties are the same.
 
Agreed - That's why I said similar, not same. (but I have deflected one and it fell within the range of others that I have numbers on)
 
Deflection tests are related to the stiffness. But stiffness is dependent upon only the cross sectional area and the young’s modulus. The young’s modulus is within most aluminium alloys identical and not impacted by the heat treatment. Essentially as long as long as you remain within the alpha phase alloys (most commercial alloys) the number is the same.

Alloy composition and heat treatment impacts on a range of mechanical properties including yield strength (when the material deforms permanently), UTS (when it fails because of the load), brittleness, hardness etc.

Variations between top sections deflection will be identical if the wall thickness and diameter are identical. But chemical composition, heat treat will determine whether the spar permanently bends in 10 knots or 30 knots, whether the spar snaps in 20 knots or 50 knots. When people start measuring the vaiation of deflection, all they are really doing is measuring the wall thickness, this can also be done by measuring the weight.
 
So taking that one step further, what you are saying is that the chemical composition and heat treatment of a spar has no effect on racing performance.... ;)
 
If the spar snaps in a 15 knot breeze -- then you don't finish the race. I guess that would be considered performance.

It would seem to me that the original spars were *off the shelf* back in the 70s when they locked down the design for the Laser and the industry has moved on past to new alloys and processes today, so after following the long thread about the legacy sailcloth in the sail, I wonder if the builders are required to keep the same alloy and process alive for the legal spars and this would keep the cost of production up.
 
Aluminium heat treating consists in three phases: solutionizing, quenching and artificial ageing. Because it changes properties with time. Aluminium alloys do not allow to control hardness like the steel. If chemical composition is right, then laser spars are well made or not depending on heat treatment. The only way to control them is by hardness tester. Webster scale. Many times, even in world championships, sailors complain about stiffness and many times they bend. In our factory we always test one by one.
 
I may just have been unfortunate but I broke a top section and my local chandler only had a replica parts in stock so I bought one so I could sail the next weekend. It was a disaster, the boat would not point and I could not keep up with the sailors I usually race with. When I checked, the spar was very soft and it's weight was 10% to 15% less than a selection of class legal spars I weighed in the dinghy park. Bought a class legal spar and my old boat speed came back. I'm sure there are good replica spars out there but you do have to be cautious. I just buy from Laser now and keep a spare in the garage.
 
Aluminium heat treating consists in three phases: solutionizing, quenching and artificial ageing. Because it changes properties with time. Aluminium alloys do not allow to control hardness like the steel. If chemical composition is right, then laser spars are well made or not depending on heat treatment. The only way to control them is by hardness tester. Webster scale. Many times, even in world championships, sailors complain about stiffness and many times they bend. In our factory we always test one by one.
As explained above, stiffness, how much your mast flexes is a factor or Young's modulus, diameter and wall thickness. Young's modulus is fixed for all alpha phase aluminium alloys irrespective of the heat treatment or hardness and chemical composition (alpha phase alloys only). The yield point, ultimate tensile strength, where the mast permanently bends or breaks is something controlled by the heat treat and chemical composition and that can be indicated by the hardness, although it only an indicator, it can be wildly inaccurate, the only true test for YS and UTS is tensile testing.

AlanD former Metallurgical Engineer.

Btw the depending on the alloy natural aging does occur and not all aluminium alloys will age, this is very much controlled by the chemical composition.
 
Glad to talk with a colleague. I am also engineer and GGM laser sailor. I own a commercial heat treatment and manufacture laser and opti practice spars.
You are right. Because the laser spars are made with 6061 alloy, with a well done T6 you get a hardness greater than 16HW and you can be sure of getting a very good quality.
 
Can you clearly metal stamp the spars with the Intensity Logo. As a former international measurer, it's almost impossible to identify "practice" equipment from the authentic equipment and this played a major component of me stopping being a class official.
 
Since JOTAG is a trademark in the USA from the beggining of this year, we identify our products with a sticker. They are sold by Intensity Sails and West Marine.
They were approved for the class just a month before Primex in Chile closed. After that, we were not interested in trying it again.
We do an inhouse heat treatment of spars in Argentina. We keep a little piece of each spars and stamp a hidden mark to identify each one in case of a claim.
It is not an aeasy matter practice spars as you know. For example, I do not know another manufacturer who makes the right size of radial lower masts ( 2 mm wt and reinforce inside ). Sellers usually have a full rig one adapted. Then when people use the wrong radial lower mast, the upper mast suffer a lot, because it must bend more than normal. And you can see wrinkles in the joint. Then people tend to claim for the upper. It is wrong.
 
A sticker isn't good enough as it's easily removed. None of the copy sails go out of their way to make themselves identifiable, even to the point of using blue corners and a red product label, just authentic radial sails. You try measuring a couple of hundred boats in 2 days and it's easy to miss something.

The replica manufacturers and suppliers are claiming they are helping the class, they could help a whole lot more by making their gear clearly distinguishable from the authentic equipment.
 
I don't know why someone would like to remove our sticker. If the authentic spars are well done, practice spars can be the same, not better. We want to asure the quality only for our customers with lower costs.
 
Stickers fall off with age. People also want to use their cheaper illegal equipment for racing their boats and so if removing the sticker makes it look the same as a legal spare which has lost its sticker.
 
We do not manufacture illegal spares. Only ones to practice, unauthorized to race official championships. Official spars should be metal stamp. It happens that often the " legal spars as you say" often are not well done.
 
They were approved for the class just a month before Primex in Chile closed. After that, we were not interested in trying it again.
Now this is interesting. So Jotag spars actually fit in the class tolerances? That would make them a very special case. When did Primex close, and why? Are the spar manufacturers tied to a specific builder, that is, couldn't other builders sell your spars as legal (as they were apparently already approved by ILCA)?
 
We manufacture training spars and dollies and our sales policy is train with ours and race with authorized ones. This makes it cheaper for young sailors to start sailing and for professionals and recreational ones.
I do not know if Primex closed by bankruptcy or by the change of the class policy.
 
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@AlanD I'd just like to point out that numerous Laser Class official items are marked with stickers only. In my experience, most of the time a sticker and stamp are present, but I have seen new Lasers with spars only marked with stickers. Not trying to spark a fire here, but I think all Laser sailors would benefit from having stamps on all gear that represents their respective manufacturer.
 
I fully agree with all equipment being permanently stamped by the manufacturer. The main difficulty with the legal gear being stamped is that it hasn't been stamped for the last 45 years, so anything presented which isn't stamped can't necessarily be identified as being legal.
 
Understandable dilemma, but I don't think the addition of a stamp to gear would be difficult, expensive, or politically controversial. This is only improving transparency of the class, however, this is just IM(unqualified)HO.
 

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