The Hull Truth - Boating and Fishing Forum

Go Back   >
Search


Reply
 
Thread Tools Search this Thread
Old 08-02-2007, 07:59 AM   #1
Senior Member
Thread Starter
 
Join Date: May 2002
Location:
Posts: 924
Default Aluminum Tower Snapped...Can It Be Welded?

I have a T-Top made from aluminum. It is high quality, but it snapped right next to a weld. The aluminum pipe itself snapped, and part of the break followed the contour of the weld joint itself. Can this be welded. If so, what type of weld/preparation should I insist on?

Thanks
thunnus is offline   Reply With Quote
Old 08-02-2007, 08:29 AM   #2
Senior MemberCaptains Club Member
 
Join Date: Mar 2001
Location: Louisissippi Coast
Posts: 10,813
Default RE: Aluminum Tower Snapped...Can It Be Welded?

A couple of hose clamps and some duct tape should have you back in action.
Paul Barnard is offline   Reply With Quote
Old 08-02-2007, 08:57 AM   #3
Senior Member
 
Join Date: Feb 2007
Location: landlocked in New Mexico
Posts: 1,755
Default Re: Aluminum Tower Snapped...Can It Be Welded?

Ask around for recommendations for a good welder then have him make the repair. If he is good he won't need any
of us to tell him how to do it, and wouldn't appreciate it anyway. Pick the right person to do the work and leave
him alone.

jenkinsph is offline   Reply With Quote
Old 08-02-2007, 09:48 AM   #4
Senior MemberCaptains Club Member
 
Join Date: Feb 2002
Location: North East
Posts: 5,937
Default Re: Aluminum Tower Snapped...Can It Be Welded?

An expert should be able to get you back on the water and they will likely recommend a couple of support braces seeing how the tube cracked and not just a weld; this tells me the structure was not properly supported.
FireFly is offline   Reply With Quote
Old 08-02-2007, 12:52 PM   #5
Junior Member
 
Join Date: Jul 2007
Location:
Posts: 13
Default Re: Aluminum Tower Snapped...Can It Be Welded?

Quote:
jenkinsph - 8/2/2007 8:57 AM

Ask around for recommendations for a good welder then have him make the repair. If he is good he won't need any
of us to tell him how to do it, and wouldn't appreciate it anyway. Pick the right person to do the work and leave
him alone.

Total BS. Why? If there IS a welder that thinks he knows it all, walk away ,,,fast.
I've been welding AL for years and still do not admit to knowing everything. Nobody can.
I'm sure that he thought that the original builder was an "Expert." If he was, it shouldn't have snapped. A pic would be nice to give some more info. There are some engineers on here that could maybe do more than a guy that can weld aluminum.

I've said this a thousand times, "Just because some guy has a shop, doesn't mean he knows his business. He just knows more than his customers."

If it was the process, or material, someone here can help. And if it WAS made of pipe, it was the material. MOst towers are made of spec AL tubing.

If it DID follow the contour of the weld, just outside of the weld, then it overheated the material. So it was either not a good choice on the alloy/heat treat of the material or not an experienced welder to overheat the parent material.

And it most likely needs some bracing to spread or control the vibe or stress at that area. Not well done to begin with. But a good repair might be a lifesaver with a good look at the rest of the structure.


DG
dirtguy is offline   Reply With Quote
Old 08-02-2007, 12:59 PM   #6
Senior Member
Thread Starter
 
Join Date: May 2002
Location:
Posts: 924
Default Re: Aluminum Tower Snapped...Can It Be Welded?

I was hoping to find out what kind of weld I should require, MIG/TIG, what type od welding material should be used, should the whole pipe be replaced or can it simply be welded together, etc.

Thanks agsin
thunnus is offline   Reply With Quote
Old 08-02-2007, 01:01 PM   #7
Junior Member
 
Join Date: Jul 2007
Location:
Posts: 13
Default Re: Aluminum Tower Snapped...Can It Be Welded?

TIG by all means since the heat and purity, can be more tightly controlled by the welder.


A good pic would be a great addition. A wide shot to show the structure. And a couple of closer shots to show the near vicinity. Then finally a close up to show the affected weld and break.
DG
dirtguy is offline   Reply With Quote
Old 08-02-2007, 01:51 PM   #8
Senior Member
Thread Starter
 
Join Date: May 2002
Location:
Posts: 924
Default Re: Aluminum Tower Snapped...Can It Be Welded?

Unfortunately, the boat is 100 miles away. I didn't think to take a picture before I left it at the marina.

Thx
thunnus is offline   Reply With Quote
Old 08-02-2007, 04:56 PM   #9
Senior MemberCaptains Club Member
 
Join Date: Jun 2006
Location: Atlanta / Tarpon Springs
Posts: 240
Default RE: Aluminum Tower Snapped...Can It Be Welded?

The reason it fractured next to the weld is because the welding drastically decreased the strength of the material at that point. Welding really degrades the temper on all structural aluminum.

To realize how much welding affects aluminum, here are some allowable stresses for 6063 alloy at T5 and T6 tempers.

6063-T5
Tension- 11500psi or 8000psi within 1” of a weld. (30.4% Reduction)
Compression- 8500psi or 6500psi within 1” of a weld. (23.5% Reduction)
6063-T6
Tension- 18000psi or 8000psi within 1” of a weld. (55.6% Reduction)
Compression- 13500psi or 6500psi within 1” of a weld. (51.9% Reduction)

These are allowables for the indicated materials from the Aluminum Design manual by The Aluminum Association and apply when the slenderness of the member is below the slenderness limit. They are also global values. There are also many other checks that have to be made so don’t go designing based on the above values. (end of disclaimer)

Notice that the temper doesn’t affect the allowable stress for the material within 1” of a weld. This means that, on a welded structure, if the actual stress away from the weld does not exceed the allowable for a T5 temper, using a T6 temper would be money poorly spent.

Many times you’ll see a condition where the fabricator increases the diameter of the tubing in the weld area. The increase is to provide more material, and the resulting increase in the section properties, close to the weld. Even the best welding still degrades the temper of the metal adjacent to both sides of the weld. The result is an area of brittle material that’s subject to fatigue cracks.

Just making a guess based on your description above, it sounds like the crack can be repaired, but the other joints may need attention also. I’d be wary of a guy that says he can just weld the crack without reinforcing the joint and, if gussets are to be used, make sure the fabricator can design and install them as to resist punching of the tube wall.

Trey1096 is offline   Reply With Quote
Old 08-02-2007, 06:19 PM   #10
Senior Member
Thread Starter
 
Join Date: May 2002
Location:
Posts: 924
Default Re: Aluminum Tower Snapped...Can It Be Welded?

Wow. That's some info!
thunnus is offline   Reply With Quote
Old 08-02-2007, 07:14 PM   #11
Junior Member
 
Join Date: Jul 2007
Location:
Posts: 13
Default Re: Aluminum Tower Snapped...Can It Be Welded?

Wouldn't you want more flexibility than even T5 allows? At that point, more ductility would mean to go to a lower temper, not higher.

Unless it stiffened structurally to the point of moving the natrural freq out of the operating range. Stiffness raise the frequency and mass usually lowers it. So thicker and stiffer keeps it in the same spot. But it would need more amplitude to accomplish a failure, or move it to the attachment object.

The welding aftertreatment would be more important than initial temper since quenching would yield a softening of the adjacent material. How much would take some experince. Remember that aluminum softens when quenched: exactly the opposite of steel. So, it would lower the ultimate tensile, but the flexibility would increase.
Need more material data on those excerpts.

Great discussion!


DG
dirtguy is offline   Reply With Quote
Old 08-02-2007, 08:44 PM   #12
Senior MemberCaptains Club MemberPLEDGER
 
Join Date: Mar 2005
Location: Whitesboro, texas
Posts: 8,047
Default Re: Aluminum Tower Snapped...Can It Be Welded?

Call the T-top manufacture and ask for a recomendation to repair the top. Ya never know they might fix it for you.
If not , find a good shop.

Don't forget to remove any wiring in the tube's.

FYI ,I have been welding for 26 years and I hate it when someone try's to tell me how to do my job.
And yes, every rod or filler material I use is like learning to weld again cuz no 2 burn the same.

welder is offline   Reply With Quote
Old 08-03-2007, 01:22 AM   #13
Senior Member
 
Join Date: Feb 2007
Location: landlocked in New Mexico
Posts: 1,755
Default Re: Aluminum Tower Snapped...Can It Be Welded?

welder, Exactly why I posted my reply above,, better to find a welder with good references and have him to do
the repair than to pisz him off before he starts the work.

I ditto calling the manufacturer to see if they will fix it, they should be very interested in knowing why it failed.


dirtguy You need to work on your reading and comprehension skills, I never said "ask the welder if he is good
or if he considers himself an expert ". Why would you have a problem with getting recomendations from others
in this posters locale? Recomendations are what builds a good business, a wise man should know this.


Steve
jenkinsph is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are Off

Forum Jump


All times are GMT -7. The time now is 08:09 AM.


©2009 TheHullTruth.com

Powered by vBulletin® Version 3.9.3.0
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.