Repair weld of toptube on 94' L Titanium Fat

[bonsaii]

Hi-ho-Silver!!

Extention of the thread in the For sale section: http://www.fatcogs.com/forum/showthr...2693#post12693

Scott, thank you so much for your help in all these Fat matters! You're the best, man! Mabye I should bring my Titanium Fat collection to you and get some shape-up!! (My wife has a cousin in Boston.)

I work for an engineering company that has a production company (machining, welding, assembly and testing) which makes all our special tailormade solutions for the Norwegian oil- and gas industry. I have done much mechanical completion, FAT (Factory Acceptance Test) and other testing on our equipment with the people there. They are highly skilled welders, and one of them is a certified titanium welder. They have a "clean" welding unit for Titanium- and other complicated alloys, inlcuding Duplex, Super Duplex and (other) acid resistant metal. There's alot of special equipment for clamping and pre-tension of various parts during welding. But no bicycle frame jig, I'm afraid...

The carbon steel welding area looks and feels like an invironment from a science fiction film.. Dusty and dirty as hell!! You know what I mean..

I actually printed your procedure from this thread and will let him read it. He's well aware of the procedures for welding Ti, but have'nt done grade 9 for some time. There will be purging with argon, clamp-on copper jackets on both side of the welding area and pre-tension on the the tube. And he's offcourse intructed to say "no" the second he feels insecure.

Do you know the wt of that area of the toptube??

Like I wrote earlier today; I'm amazed by the beautiful tubing in this Titanium Fat model. I also have a sleeve-construction type (first edition, ehh?) and they sertainly have their charm, the both! It must have been expencive to make all those tubes on the late, ay? Lots of hours in there?

I'll keep you posted! You will know when the operation will take place!

Thanks so far, Scott, for the important inputs! And for the kindness to "lend" me your name and creds!

bst rgds,
arne

Originally Posted by I-ROBOT

Hey Bonsaii

Originally Posted by I-ROBOT

If you can find a shop in your corner of the world that seems capable of doing the repair, let me know who they are and I will ask them to submit their repair procedure to me for review before they do the job.

Purging the inside of the frame with argon is an absolute MUST!!!!!!!!!! If they are not willing to purge the inside of the frame then DO NOT let them do the welding!!

Please feel free to use my name and credentials if you talk to anyone about repairing the frame. I have a college degree in welding engineering and I am an American Welding Society Certified Welding Inspector (CWI).

Send me a PM if you have any questions.

Good Luck - wish I could fix it for you
Scott Bengtson

[I-ROBOT]

Hey Arne

It sounds like you have the right equipment and tools to make the repair. I really like the idea of using the copper, too.

Just make sure the area to be welded is as clean as you can get it.

I would guess that the thickness of the top tube in that area would be somewhere in the range of 0.025" and 0.030" (probably why it was torn like that)

If you keep the heat input down, I don't think you will get enough distortion to throw off the alignment. The copper will help that quite a bit. A frame jig is not an absolute necessity.

Does the shop have some kind of surface plate for doing inspections? You could put the frame on that and take some measurements and then measure again after the weld repair is complete and the frame is cooled back to room temperature.

If your welder is certified for TI welding, grade 9 will not be any different to weld than other typical grades.

Remember: CLEAN CLEAN CLEAN!!!!!

My welding professor used to say "Cleanliness is next to Godliness... and weld prep falls somewhere in between."

Good luck and keep me posted

Scott

[jesse]

i'm way late on this conversation, but if anyone is looking for a ti repair job, steve potts does some amazing work. only downside is he's incredibly busy these days, but he does seem to sneak a lot of repair work in between fabricating new frames and forks. he uses an ultrasonic cleaner to clean tubes before welding them, if that gives you an idea of how clean you need to keep things...


i'm going to play around with welding titanium on the next month or so. if i'm lucky i'll make an ashtray.

[bonsaii]

Thanks for the input, Jesse.

I'm going to use a welder I have worked with before, here on the iceberg. He knows his trade. I have a wt=0.9mm tube for him to practice first, as he don't burn these thin wall every day.

I'll come back with info when the time comes. Having a period of approx one month work at this engineering workshop closer to spring.

-bns

[bonsaii]

Hia.

At last I got the time to deliver the frame to mr. welder. Boring, I didn't get the time to be there while the work was performed. Lots to do, so there hasn't been time to prep further. The finger grease around the weld came there after the two tigged dots.

I belive the repair is a success! And the frame is still straight as a all the arrows!

-bns

[Stingercut]

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