Cracked frame

[tmaybee]

I just recieved a 14" 856 from ebay that was to be built up as a nice light xc bike for my gf.     On closer inspection I found a crack in the spot that these frames are known for, the weld between the seat tube and the rear swingarm pivot.  

I am going to try to get some pics tonight.  I have also contacted the seller to see what he would like to do.  Now, if I keep the frame, does anyone have any ideas for a repair job or has anyone successfully repaired one of these frames?

Thanks for the help,
Trevor   [smiley=beer.gif]

[Sprucey]

Despite what people say aluminium can be welded to repair it - you just need to find someone who is skilled at it. I am lucky - I live in the centre of the marine/yachting/boating industry in the UK with several alumium mast makers and ally fabrictors locally.

Also, how big is the crack - is oit really likley to be catastrophic?

Sprucey

[shovelon]

Where do you live?

Here is the scoop. I own a metal fab shop in Los Angeles. I repair framesets quite frequently. I also was the contract weld shop for the now defunct Natural Dynamics bikes. My current line is machined weldments for defense electronics, and audio structures for Harmon electronics.

Most  of the bikes that I now repair are out of warranty GT I-drive bikes that break at the seat clamp or on the rear triangle.

The fix is as follows: remove the paint 1 inch from around the crack. Bevel the crack if it is thicker than 1 mm. Warm the area to about 200 degrees F, but not more than 250 degrees. Fill/weld the crack with 5356 rod or 5183, tig or heliarc only (same process), full penetration.
Let cool and paint if you wish. No need to strip the bike to bare frame. It can be done in less than 1 hour. '

This is the same routine we do for 6061 T6 frames as well as 7005 frame. The difference is that 7005 rehardens immediatly as opposed to 6061 that  needs artificial ageing to harden. But it will harden/age  on it's own over time.

I would be happy to do the repair no charge if you bring it to me.

Terry

[guy]

Terry
I was wondering if Fork Crowns can be welded
Since my cracked and don’t want to spend $80 for a new one
Z1 fork and it cracked at the bolts that clap onto the stanchion tubes
thanks

[shovelon]

Guy,

Fork crowns are a different animal. Typically a forging or a 7075 alloy machined item. Then carefully heat treated for strength. These I never touch because they were not designed to be welded during manufacture.

Sorry, Terry

[tmaybee]

Hi.  Thanks for the help everyone.

Terry - Thanks for the offer.  I really appreciate it!  I am located in Canada.  That info will be very helpfull if I ever need to have any repairs done, or I may ship everything to you.

I took my frame to an aluminum shop and they did a penetration test on the weld to check if it was still structurally sound.  The crack was only at the surface, so they polished it smooth and said everything should be fine.

Thanks again for the help! [smiley=beer.gif]

Trevor [smiley=beer.gif] [smiley=beer.gif]

[shovelon]

GREAT!!!!

Terry

[mcnisiv]

Anyone know someone in the Boston, MA area who could make such a repair?   I've got a 957 frame with a crack near the seatpost clamp.

Thanks,
Nisi

[sammydog]

I've just found a crack in my 955 at the same spot. Don't know how long it has been there for, but it runs in the weld and is currently about 2mm long.

Investigating how to get it fixed at the moment.

[efxguy]

This looks like a case of Nigel's Disease for sure! Check your frame, you may be in for a surprise.

Terry guided me on repairing my frame and it is a successful repair! I welded it my self as I own a pretty nice TIG machine.

My point is, don't lose hope, these cracked frames can easily be repaired and back on the road for a minimal cost.

Best wishes,

Michael
955 Pro-Flex
Chicago-ish, IL USA