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flag dump
Posted: May 7, 2016 at 18:36 Quote
cemi wrote:
Some paint and first proper ride... This is fun to ride! 66deg/75deg/0mm/410mm/630mm(465mm)/100mm...

looks great, congrats!
flag Compositepro
Posted: May 8, 2016 at 0:12 Quote
madm3chanic wrote:
downtube bellypan of the new ebike all finished and welded up

bellypan/downtube of the 12kw ebike all welded up Smile god damn i cant wait to try this thing out...

i did double fillets on the joints between the downtube ant the bellypan square tube, in case anyone is wondering why they look knda beefy. not entirely sure if it was necessary but what the hell, it looks nice.

It looks cool ...which is awesome
flag brigand
Posted: May 8, 2016 at 12:12 Quote
Does any of you guys have experience with annealing the alu frames, mine cracked so need to weld it and anneal it, the only guy that can do it here puts the frame in the oven but the paint remains so i'm guessing the temperatures he uses are not as high as it should be. Thinking about making my own oven for the job.
flag l-plates
Posted: May 8, 2016 at 15:29 Quote
What grade of Alu is it?

The HT for 70005 is quite different from 6061, it is likely one of the two but knowing which alloy it is is critical. It will be somewhere around 350degC

For what it's worth it is possible to change the properties of aluminum below paint melting temperatures, High temp powder coating and stove enameling use a bake/cure temperature (~210degC) that is actually capable of over aging copper based aluminum alloys.
flag TheUnknownMTBR
Posted: May 8, 2016 at 21:38 Quote
backpurging it like I suggested on your photo will make a big difference in strength, it's completely unnecessary to anneal the entire frame for such a small repair
flag l-plates
Posted: May 9, 2016 at 1:07 Quote
It's also 6061 so you may get away without doing any HT at all as it is only one weld. If you go in with a 4043 filler wire you should get away without HT, had it done before and it normally holds up for bike repair purposes, 6061 will naturally age up to about a T4 condition over about 2 weeks.

Looks like that crack has come through from the back of the tube up through the weld?
flag brigand
Posted: May 9, 2016 at 2:02 Quote
This is the picture:

photo

It is T6 - 6061.

Thanx guys for help, going to talk to the welder, still trying to get his phone number. Smile
flag l-plates
Posted: May 9, 2016 at 7:58 Quote
The big question is why it broke?
What frame is it?
How did it crack/how did you notice it?
flag nitzsche
Posted: May 9, 2016 at 10:44 Quote
brigand wrote:
This is the picture:

photo

It is T6 - 6061.

Thanx guys for help, going to talk to the welder, still trying to get his phone number. Smile

Easton has a chart-guide for post welding tratments for 7005 and 6061, google it, its really usefull and clear !
flag dump
Posted: May 9, 2016 at 11:15 Quote
This thread is pretty handy, in particular this message:
http://forums.mtbr.com/cannondale/powder-coat-voids-frame-warranty-428082-post4628637.html#post4628637

and:
Unsecure image, only https images allowed: http://fcdn.mtbr.com/attachments/cannondale/373532d1215029132-powder-coat-voids-frame-warranty-6061-aging-curves.jpg
fwiw, I couldn't find the Easton chart mentioned above.
flag brigand
Posted: May 9, 2016 at 11:33 Quote
l-plates wrote:
The big question is why it broke?
What frame is it?
How did it crack/how did you notice it?

It's a Nukeproof Mega AM 2013/14, the frame made clicking noises since new: bushings or main pivot were slightly smaller IMO (the main pivot slid out of frame without effort). Regreasing would help for some time, seat post was the culprit few times. I was checking the welds on the TT-ST brace regularly. Decided to check the pivots and found the frame cracked all around the weld. Contacted NP, they told me to talk to the place where i got it - they've said NP wont give me warranty. It all happened 10 days after the 2 year warranty period passed.
flag latheboy
O+
Posted: May 9, 2016 at 15:25 Quote
brigand wrote:
l-plates wrote:
The big question is why it broke?
What frame is it?
How did it crack/how did you notice it?

It's a Nukeproof Mega AM 2013/14, the frame made clicking noises since new: bushings or main pivot were slightly smaller IMO (the main pivot slid out of frame without effort). Regreasing would help for some time, seat post was the culprit few times. I was checking the welds on the TT-ST brace regularly. Decided to check the pivots and found the frame cracked all around the weld. Contacted NP, they told me to talk to the place where i got it - they've said NP wont give me warranty. It all happened 10 days after the 2 year warranty period passed.

That crack has been around for a while and would have happened within the warranty period.

I would email the NP rep with photos and if you hear nothing, post pictures to there FB asking why no one is returning your mail.
Try that first before getting it welded, they might fix it for you for free, they SHOULD fix that for you.
flag BungedUP
O+
Posted: May 9, 2016 at 23:35 Quote
The failure of that joint to me indicates that the weld itself was at fault, and not stresses caused by the design. Often, in the later case, the failure is near the toe of the weld puddle, but the weld itself remains sound (the tube breaks at the natural stress riser near the joint). This is interesting to me, as failure of the weld centerline is uncommon, as far as what I've seen. Something went wrong right from the beginning; I would guess that the joint was welded while the frame was under a lot of stress - perhaps due to expansion of the tubing while welding in a different area. That joint appears to me as if it were destabilized while the weld was being made.
flag brigand
Posted: May 10, 2016 at 4:30 Quote
The seat tube is straight gauge, the BB box is probably 3x thicker.

I did contact NP and they referred me to the dealer where i got the frame - he said NP declined warranty. Later i emailed NP to ask to buy a new front triangle and they've answered they don't have any larges or XL in stock. Also the dealer doesn't sell NP anymore. The crack happened inside the warranty period for sure, just being the end of winter i decided to re grease all the pivots and noticed it then, the frame made clicking noises since new but that was usually dealt with grease on pivots and seat post.

 


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