Crack in aluminum mast : options?

[SloopJonB]

Originally Posted by hellosailor

sam-
"Please correct me if i am wrong for believing this."
AFAIK you're correct to worry. Which is why you would need a competent welder, not just an alleged welder, some bozo with a welding rig. And the reason you should consider having a collar (plate) lapped up over it, for a belt-and-suspenders approach.
Rivets can be applied properly or improperly--just like welds. Supposedly it was rivet failures that unbuttoned on the Titanic and let the ocean in.

I've found that locating a competent welder is pretty well as simple as looking at some of their welds. If they're pretty, the welder is good. This is particularly true with TIG welding. If the weld looks like a row of dimes overlapped by about 60%, the weld is good.

Of course, only X-Raying will TRULY tell the story but the appearance is usually enough - were not talking nuclear reactors here.

[jimjazzdad]

Originally Posted by JedNeck

I am a certified welder here in WA and I agree with svHyLyte completely. Have a pro TIG weld it as he described. Heat control is huge with any kind of welding, especially aluminum. Drilling the holes and full-pen welding the cracks is key. The plate should be added as well IMO. It sounds like this area of the stick gets worked pretty hard.

This completely correct. Find a certified welder and have him/her appraise the damage and suggest the repair. Follow the expert recommendations. Otherwise, get a new spar.

[svHyLyte]

Originally Posted by samgary

Hello and thank you to everyone for the insight.

I apologize for not making it clear, I always use the running backs because of how much the mast pumps.
The sheave-box is about 12 inches above the running back tangs.

As svHyLyte noted, i do not have forward or aft lowers, and i do have a baby stay. The line in the picture is only a place holder for the wire to rope halyard which was being replaced.



My one concern with welding the mast would be the loss strength in the process. By no means am i an expert but I have read about issues with the aluminum warping and weakening as a result of welding.

Please correct me if i am wrong for believing this.

What about drilling holes at the aft most points of the cracks to stop the propagation of the cracks then riveting a plate on as opposed to welding?

Thanks again for all the feed back!

A weldment laid by a competent, preferably certified, welder will not compromise the strength of the tube but, in fact, restore it. A mechanical fastener will not suffice for the prospective tensile loads the spar will be subjected to. (I appreciate that you may be/are looking for a less costly option for this repair but this in one time when the lowest bidder is not/"ain't" an acceptable option). Again. The proper repair should not be that costly--relatively speaking (particularly relative to loosing the whole darned rig!).

N'any case, Your yacht/Your call. Good luck.

FWIW...

[SloopJonB]

Originally Posted by svHyLyte

A weldment laid by a competent, preferably certified, welder will not compromise the strength of the tube but, in fact, restore it. A mechanical fastener will not suffice for the prospective tensile loads the spar will be subjected to. (I appreciate that you may be/are looking for a less costly option for this repair but this in one time when the lowest bidder is not/"ain't" an acceptable option). Again. The proper repair should not be that costly--relatively speaking (particularly relative to loosing the whole darned rig!). N'any case, Your yacht/Your call. Good luck. FWIW...

Hylyte is absotively correct. A properly welded joint is indistinguishable from the parent metal. I once had a double rail stern pulpit that had been bashed against a tree by a "Boat mover". I took it to the best S/S shop around here (Irion) who had in fact built it for me. The bends & kinks were right in the corner radius of the tubes. I assumed they would have to cut the rails off and replace them but instead they merely cut out the damaged sections and welded in new curved pieces. Once they were polished you couldn't detect where they had been joined - and I KNEW where. They were perfect.

From what I understand, aluminium is easier to weld than S/S as well. Both these metals have the rep of being exceptionally difficult to weld well but that goes back to the days of stick welding. MIG & TIG welders have made welding them much easier - although they still require skill, just not a "magic touch" like the G.O.D.'s.