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Old 27-02-2008, 09:15   #1
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Hts-2000 Aluminum Repair Brazing Rods

I have a small crack (1/4") in my mast where the hard vang attaches to the mast. I'm going to eliminate the tackle on the vang and a lot of the associated pressure as it's not needed and has been known to put too much stress on the boom and the mast (hense the small crack at the bottom of the attachment point). To get a rigger to repair this would require them to pluck the mast and attach a mechanical plate, which granted would be much stronger, but if I'm going to eliminate most of the pressure I'm wondering if I could use HTS-2000 as a repair. It seems like it would do the job just fine, but was wondering if anyone had actually used this product. Aluminum welding - Aluminum Repair - Aluminum Brazing - AluminumRepair.com

Galvanic action is neglible, repair strength should be stronger than the previous weld and it is more flexible so can withstand the pounding more. If no has experience with this, I'll do it anyway is it would save literally thousands and give a long term report after a year or so.
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Old 27-02-2008, 11:46   #2
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It totaly depends on how the crack formed in the first place. Was it shearing by weight being placed by the fitting, or is it a cyclical stress fracture. If the latter, you have a serious strength issue and I suggest a sleeve would need to be fitted.
As for welding, you need to ensure you have maximum penetration of the material. It does not want to be surface only, which is oftent he case with Brazing as Alloy is very quick at disappating heat and you can not get the depth of wled. So you will need to grind out the crack and fill properly.
I am not familiar with HTS, but I suggest you maybe best to MIG wled. This way you can achieve getting the heat required for good penertration and most importantly, you can use the Alloy wire of same material type as the mast, which I imagine would be Marine grade Alloy.
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Old 27-02-2008, 12:29   #3
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talk to me about the fitted sleeve option, I imagine I could get a metal shop to make it and then I would mechanically fasten it to the mast? As to the type of crack it's basically a welded on eye to which the hard vang attaches, at the lower right hand side it has a small 1/4" crack indicating that it had too much pressure on a particular tack. By removing the tackle from the vang and having it just function for support and not restraint and thereby relieving a lot of pressure.
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Old 27-02-2008, 21:43   #4
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Is the mast anodised or painted in anything that will be difficult to fix once welded??
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Old 28-02-2008, 07:42   #5
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I second the sleeve idea as a likely better solution. Without being able to see the mast wall from the inside, I sure would want to overdue the reinforcement in the event that the aluminum is fatigued beyond the visible crack.

Is the mast deck or keel stepped? If deck stepped, the crack is near the mast base. An external sleeve should prevent the crack from worsening due to dynamic mast loads against the static mast base. Or if keel stepped, you may consider an internal sleeve that extends below the partners. There’s a lot of loading on the mast (vang or not) where it passes through the deck.
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Old 28-02-2008, 08:09   #6
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I would have a professional with lots of experience with this kind of thing look at it. Too much is on the line for an amateur to do it on his own.
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Old 28-02-2008, 10:57   #7
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The professionals with lots of experience have said that it's a minor crack, localized and we could continue to sail with it but not overload the rig. If it's something minor, I'm really thinking that spending $2000 plucking the mast and having a sleeve put on is overkill when I'm removing most of the pressure by removing the blocks. There's some debate on whether a hard vang is needed at all. I've got to admit I'm a little jaded against the typical riggers as they seem to invariably suggest the most expensive solution possible.
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Old 28-02-2008, 11:47   #8
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The rigid vang is there only to support the boom when the sail is down and allows the freedom of not having a topping lift. A topping lift added will do the same job and result in the boom being supported out at the end which is better stress wise.
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Old 28-02-2008, 12:28   #9
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I have a topping lift as well, always on. The hard vang from what I thought was there to not just support the boom but to restrain the boom. The restraining part was known to crack booms so many are just using it as support, but if I have a topping lift then it's really pointless?

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The rigid vang is there only to support the boom when the sail is down and allows the freedom of not having a topping lift. A topping lift added will do the same job and result in the boom being supported out at the end which is better stress wise.
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Old 28-02-2008, 12:32   #10
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Schoonerdog, I have a small dent and 'fissure' in the front cross-beam of my cat and am considering brazing with HTS 2000 and then either mechanically fastening (with aluminum rivets) or brazing on a shaped aluminum plate, rather than a full sleeve. Since there is no sign of (nor reason for) damage to the opposite side of the mast, it strikes me that this should be doable for you as well. My plate will be formed to fit precisely to the one (the damaged) half of the foil, and to have significant overlap in all directions.

As to welding the aluminum extrusion, aluminum can be (and frequently is) weakened by the extreme heat required and, depending upon the thickness of your spar, I would certainly be fearful that you are going to make matters worse rather than better. The advantage to using this product is that the relatively low heat required in brazing will not distort or weaken the aluminum that is being repaired.

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Old 28-02-2008, 13:40   #11
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The primary purpose of a vang is to oppose the upward force on the boom created by the sail. When the main is sheeted in, the mainsheet is oriented along the vertical load line and so does a good job of holding the boom from going up. The further the boom is off centerline, the mainsheet angle becomes less vertical; meaning the sheet pulls the boom back, but not down. This is where the vang is most effective. A rigid vang does have a secondary benefit, which is to support the weight of the boom. This helps when sailing in light air and in place of a boom topping lift.
For what it’s worth, I wouldn’t cruise without a working boom vang. It provides a significant amount of mainsail control when sailing downwind; translating into safety and performance. Especially when the breeze is up. If properly done, the boom should not cause boom or mast failure any more then another part of the rigging. If the vang cause a boom crack then the boom was likely not reinforced from the beginning. Imaging attaching a shroud to the deck without a chainplate.
I agree with schoonerdog in that riggers tend to follow a highest cost alternative approach. Whether or not you keep the vang is your choice, but eliminating the vang does NOT eliminate all the mast loading at the deck level. It may be the crack is insignificant, say like a hole ľ” hole in the mast from where a cleat was once mounted. However it seems that the vang is a pulling force; and if enough force was generated to cause a visible ľ” crack, what don’t you know about the integrity of the aluminum around the crack. If it is weakened, the mast pumping going into a head-sea would create an awful lot of stress at that area of the mast.
I’m not saying you can’t do this yourself. I just think you should inspect it really really well. Talk with a local machine shop; if someone there knows there stuff have them inspect it (at half the cost of a rigger?) and then figure out the solution. I’m doing this with my chainplates now. They looked fine until I took them off…
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Old 28-02-2008, 14:13   #12
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svTotem - I agree that boom-vangs are (hugely) important in a monohull, although they are much LESS important in a cruising cat with travellers that are often 15-20 feet (or more) wide! Many production cats don't have them for precisely this reason.
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Old 28-02-2008, 14:22   #13
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svTotem made a very good reply. My traveller isn't 20 ft wide, but it's mid boom and extends around 10 feet so often there really isn't that much mainsheet out, even in down wind runs. Also in down wind runs ideally I would fly a chute, which on a cat can be done without a pole. I'll talk with a rigger about the possibilities. Thanks to everyone for their input!
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Old 07-02-2009, 00:42   #14
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Quote:
Originally Posted by Southern Star View Post
Schoonerdog, I have a small dent and 'fissure' in the front cross-beam of my cat and am considering brazing with HTS 2000 and then either mechanically fastening (with aluminum rivets) or brazing on a shaped aluminum plate, rather than a full sleeve. Since there is no sign of (nor reason for) damage to the opposite side of the mast, it strikes me that this should be doable for you as well. My plate will be formed to fit precisely to the one (the damaged) half of the foil, and to have significant overlap in all directions.

As to welding the aluminum extrusion, aluminum can be (and frequently is) weakened by the extreme heat required and, depending upon the thickness of your spar, I would certainly be fearful that you are going to make matters worse rather than better. The advantage to using this product is that the relatively low heat required in brazing will not distort or weaken the aluminum that is being repaired.

Brad
I think your right aluminum plate may be weakened by extreme heat required..


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Old 07-02-2009, 20:01   #15
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if you are still thinking of doing this repair,drill small holes at each end of the crack,this will releave the stress,then v grind the crack and use the rod. i have used that prodoct at work and had good results.aluminum cracks like to run,repair soon.good luck
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