I'm pretty sure it's not practical, but what are replacement boom arms worth? A new boom would be around $350 and repair would require replacement of both arms.
Don't do it! Buy a new boom. Looks like a 10 year old + Chinook that I've just replaced which broke in the same place.
I had similar issue about 6 weeks ago and posted a question on how to fix.
Do you know what "anneal" means?
I didn't. But thanks to Markaustralia and Google I do now 
Essentially, an alloy requires exact heating and cooling conditions in order to maintain original properties. If welding is involved the surrounding aluminium will become soft.
Less than 24 hours later and its back together and if the wind comes up this afternoon I'll be using it with confidence that its in better shape now than it was 24 hours ago, yep I need to replace it but that's at least a week away before I can get to town again.
For those that are interested I can put up a pictorial of the steps I went through,
removal and shortening both arms
straightening ends to reinsert into head
bending arms without point loading
gluing and re-assembly
I guess I just cant help myself, once I start pondering fixing something/anything, if I think its worth the effort I will.
Select to expand quotepirrad said..
Less than 24 hours later and its back together and if the wind comes up this afternoon I'll be using it with confidence that its in better shape now than it was 24 hours ago, yep I need to replace it but that's at least a week away before I can get to town again.
For those that are interested I can put up a pictorial of the steps I went through,
removal and shortening both arms
straightening ends to reinsert into head
bending arms without point loading
gluing and re-assembly
I guess I just cant help myself, once I start pondering fixing something/anything, if I think its worth the effort I will.
While I would agree with others to say that a new boom is in order, I am definitely interested in your repair... it isn't always possible to get new gear, particularly if one is located say at Gnaraloo or some other remote location.
Did the same thing to a boom many years ago as the closest windsurf shop was at least 300km away and wanted to get back on the water asap! Also never liked buying unfamiliar makes of booms, or anything else gear related without seeing them up close.
Regular problem with older booms where arms are fixed into head with screws or rivets. Corrosion takes its toll when salt water gets in around holes or anywhere the alloy has been cut or drilled. Makes sense to get a new boom with front end moulded around continuous tubing.
Not sure this gained much but removed screw, blue tacked holes and soaked in vinegar.
Cut both ends back square and stripped off grip
W
Went to scrap yard and got piece tube 30mm id, forced arm in and bent ends back straight to insert into head.
Used above piece of tube on end of arm and bent some more curve into arm
Pre assembled arms to square up with head and tailpiece, drilled, disassembled, glued and reassembled
Good morning, Pirrad,
Whilst you seem to have solved your problem, for other Chinook owners, Chinook are one of the few companies that sell spare parts for their booms, including arms. You might care to contact Stuart Bell Sails (the importer) at johntrev@nw.com.au, to see if they have parts for your boom, or can get them.
Hope this helps.
