# 7005 Frame - Crack Welding Repair



## swensonator (May 8, 2010)

I have been browsing the internet for a few days since I cracked my 7005 frame at a gusset weld, which then propagated down through ~1/2 the downtube all within a week or so, this frame is known to crack at this location.















The bike is great, I want to keep it, I ride it hard.

I am connected with some master AL TIG welders who work on auto racing parts and mountain bike frames. They have both told me that they can weld my 7005 frame no problem and it will be just as strong, it is an advantage of 7005.

The plan is as follows:

1) Remove paint and prep weld area appropriately

2) Weld crack + area around crack, will be a multipass weld most likely

3) Artifical aging of frame for 6 hours at 200 deg F, then 4 hours at 320 deg F

4) Spray paint over weld

I appreciate any and all comments from the frame building community, if anyone has had success stories with welding 7005, please let me know! Also, any failure stories with 7005 are much appreciated as well!


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## briderdt (Dec 14, 2012)

There's an area of the crack under the current weld that won't be repaired. Likely that crack will just continue to propogate -- through or around the weld repair.


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## swensonator (May 8, 2010)

briderdt said:


> There's an area of the crack under the current weld that won't be repaired. Likely that crack will just continue to propogate -- through or around the weld repair.


What if that weld was ground down and then gusset to tube was rewelded? Or the gusset removed, the frame welded, and then the gusset replaced.

Also - what makes you say that there is an area of the crack under the current weld? It seems like crack has gone along the edge of the weld and then down into the tube itself.


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## life behind bars (May 24, 2014)

Try it, you'll only be out the repair costs. That said, I think you'll only delay the inevitable next failure.


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## swensonator (May 8, 2010)

Why is that? That seems to be the general consensus amongst people, but I don't see why. Is it because aluminum is designed for so many stress cycles? And if I have a crack somewhere that is fixed another stressed area will just crack as well?

This frame fails in this area relatively commonly, so my thought is that melting (welding) that area will relieve all the stresses and form a stronger area that before with new multi pass welds on it.


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## life behind bars (May 24, 2014)

swensonator said:


> This frame fails in this area relatively commonly, so my thought is that melting (welding) that area will relieve all the stresses and form a stronger area that before with new multi pass welds on it.


Using that logic the original weld would have eliminated all the stress, no? The leverage of an extended seat post is creating the cracks in the HAZ of the gusset weld.


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## swensonator (May 8, 2010)

With that logic yes, all of the stresses that I am inducing through riding, any micro-fractures will be melted and reformed as a solid again, right?


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## life behind bars (May 24, 2014)

And rinse and repeat.


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## swensonator (May 8, 2010)

life behind bars said:


> And rinse and repeat.


As in I'll just end up in the same place as I am now? Just down the line, and not necessarily soon? That is just the nature of dealing with aluminum?


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## Cham24 (Mar 17, 2021)

swensonator said:


> I have been browsing the internet for a few days since I cracked my 7005 frame at a gusset weld, which then propagated down through ~1/2 the downtube all within a week or so, this frame is known to crack at this location.
> 
> View attachment 1218735
> View attachment 1218736
> ...


Hey man did you ever figure out what was the most ideal direction for yourself and if so, did it prove successful? I funny enough too have a Banshee frame, a 2016 Spitfire which failed in pretty much the exact same spot in the same way. I guess this is why I'm very curious because I noticed the crack just this past day. Hopefully you see this, let me know what's up!


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## swensonator (May 8, 2010)

Cham24 said:


> Hey man did you ever figure out what was the most ideal direction for yourself and if so, did it prove successful? I funny enough too have a Banshee frame, a 2016 Spitfire which failed in pretty much the exact same spot in the same way. I guess this is why I'm very curious because I noticed the crack just this past day. Hopefully you see this, let me know what's up!


Oh man, I just sold it to someone who wanted to repair it  I think you need to weld it with heat treatable filler material and then heat treat the sucker.


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## Cham24 (Mar 17, 2021)

Wow I'd say that's incredible timing haha. I've done some research and some sources seem to support that naturally aging would suffice for 7005 and that artificial aging is not a necessity like it is for 6061 post-fab. I'm hoping this might make sense otherwise, finding a professional to artificially age a full frame would require more than a reasonable compensation (my guess is close to the cost of a comparable frame). Why did you never attempt the process you outlined in your first post, was it because you found out its cost?


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## swensonator (May 8, 2010)

Cham24 said:


> Wow I'd say that's incredible timing haha. I've done some research and some sources seem to support that naturally aging would suffice for 7005 and that artificial aging is not a necessity like it is for 6061 post-fab. I'm hoping this might make sense otherwise, finding a professional to artificially age a full frame would require more than a reasonable compensation (my guess is close to the cost of a comparable frame). Why did you never attempt the process you outlined in your first post, was it because you found out its cost?


Because I got a homie discount on a new Santa Cruz Bronson frame through a friend who works their, couldn't pass it up.


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## Cham24 (Mar 17, 2021)

Haha I don't think there's any questioning that choice. I'm curious how you were able to find someone to buy your old frame, Pinkbike? Also any chance those discounts are shareable haha?


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## swensonator (May 8, 2010)

I sold it on pinkbike for $100. And the frame was a scratched one from Asia so they couldn't sell it so definitely got the hookup.


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