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Arc Fabrication Titanium Framed Ducati

Started by Travman, August 27, 2009, 03:58:03 PM

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Speeddog

#120
July 15, 2010, 12:25:44 PM
Quote from: jwoconnor on July 15, 2010, 12:17:28 PM
+1
Doesn't look like there was much penetration.

Look closely at the 2 pics.
By my eye, there's a sleeve/liner inside the Ti tube for holding the bearings.
The Ti tube is broken at the edge of the weld.
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MonsterMan1036

#121
July 15, 2010, 08:11:57 PM
Looks like the Ti on the head tube was just for cosmetics and there wasn't any penetration into the dissimilar metal (as stated above). That weld just pulled away. :o
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Monsterlover

#122
July 16, 2010, 02:45:15 AM
The head tube was Ti with an aluminum liner pressed in for the bearings.

The weld broke right at the HAZ, a problem often seen on some stainless and apparently Ti as well. I notice it seems to happen more on brittle materials.
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Preisker

#123
July 16, 2010, 07:58:14 PM
OK, I'm not an engineer, we'll get that out of the way, right away.   But looking at that frame, in the first post, and in the crashed post, are some of those angles and joints kind of odd looking?   And from what I can see, there are a few not too pretty welds.    But as I said, I'm not an engineer, nor am I an accomplished welder.  The guy that built that bike certainly has a lot of go for it.  Ambition if you will.   Good luck.

ducpainter

#124
July 17, 2010, 03:08:01 AM
Quote from: Preisker on July 16, 2010, 07:58:14 PM
OK, I'm not an engineer, we'll get that out of the way, right away.   But looking at that frame, in the first post, and in the crashed post, are some of those angles and joints kind of odd looking?   And from what I can see, there are a few not too pretty welds.    But as I said, I'm not an engineer, nor am I an accomplished welder.  The guy that built that bike certainly has a lot of go for it.  Ambition if you will.   Good luck.
You're right about the angles...Doug's design was very different from what you usually see.

If you see the welds in person they look great.

I'm not going to comment on the fact they broke in a crash.

I know that the bike worked perfectly during normal use.

It wasn't designed to crash.
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Howie

#125
July 17, 2010, 04:53:36 PM
Doug repaired my step son's fancy high line titanium bicycle frame that cracked.  The bike came back with perfect welding and alignment was also right on the money.

DRKWNG

#126
July 17, 2010, 05:41:39 PM
What brand frame was it?  Only asking because I'm surprised a high-end frame went belly up to begin with... 

Howie

#127
July 17, 2010, 06:00:48 PM
Quote from: DRKWNG on July 17, 2010, 05:41:39 PM
What brand frame was it?  Only asking because I'm surprised a high-end frame went belly up to begin with... 

I don't remember.  One of the chainstays cracked in half.  I'll try to remember to ask. 

Ducatl

#128
July 17, 2010, 09:51:46 PM
Just to clarify I wasn't implying anything about the quality of the craftsmans or his work, it's surely a stunning and beautiful bike.

I've never welded titanium nor do I know much about it but I was under the impression that discoloration of the metal around the weld might be an indication that welds were contaminated. Perhaps somebody with titanium experience can actually chime in.

Or

Maybe it just broke because the frame was exposed to some ridiculously large force it was never designed for, like crashing, I could also believe that ;D
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