Thin frame tube hole repair

[gabareba]

There is a seat tube. 0,55mm wall thick in the middle. There was a dent, I filled. After this I try to file and finish, but I used too much sandpaper, so I made a little hole, next to the filled hole. The hole is in the middle of the seat tube and it's about 2-3x1mm. Can I filled it somehow? Any advice?

[Will Neide]

You sanded/filed a hole straight through the metal?

[gabareba]

yes, it was my fault...

[mjbabcock]

yes, it was my fault...

It will be fine. Think about drilling for Di2. Put electrical tape over it and forget about it.

[Will Neide]

It will be fine. Think about drilling for Di2. Put electrical tape over it and forget about it.

There is a difference b/w drilling a hole through a tube with proper thickness, and sanding a hole through a tube. The tubing surrounding the hole is going to be wicked thin.

My first thoughts on a proper fix are, in this order:

1) Consult Rody's (Groovy) blog. He has lots of good info there on fixes and what not.

2) Replace the tube.
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3) Backyard engineering, to which I'll leave to the imagination.

[gabareba]

It's a seat tube. I never changed seat tube and I don't want to change if possible any other solution. @Jason I want to paint after finish, so electrical tape isn't the best , I think.

[gabareba]

Will, if I fill the hole, the wall will be thicker again, isn't it? I mean I want a bigger place to fill to cover the whole hole with silver or bronze.

[Rody]

Gabareba,

First off, you need to get your full name in your signature line as dictated by the rules of the forum before this thread gets nuked.

As for the hole, there are multiple methods for filling such an error, each will be dependent on the current condition of the tube, and the method you used already to try to repair the dent.

Here is a restoration post from a number of years ago where I filled a LOT of holes in a tube as the customer wanted to keep the frame as original as possible. These rust holes were drilled out to new metal, filled with a TIG torch to create a small positive deposit superior of the tube circumference, then sanded down to base level.

Groovy Cycleworks 330-988-0537: Doctor, to the Emergency Room...ASAP!

If it is a small hole, it is possible to fill it with silver using good heat control.

If it is a large area and is beyond your ability to fill confidently, it will require internal support, which is a whole different process.

Post up a pic of your issue and we'll help steer you in the right direction.

rody

[gabareba]

Here's the picture. It's little bit larger than I told before. There is no rust inside, it's a plenty young frame, one year old with a Reynolds 631 seat tube. Thanks for your help!

Gabor

sth.JPG

[Will Neide]

That's not as bad as I had envisioned.

[afwalker]

Wait, 1.3 cm is not 2-3mm. Silver won't fill that, maybe brass or nickel silver but probably tig would work well for that crater. Sanding error? It's a good sized defect. Fill it up and sand it down and it will work out well.
cheers
andy

[Rody]

Thanks for posting a picture.

Here's what I'd do to save the frame if a tube replacement is not possible. As this is in the "middle" of the tube and should not interfere with seat post insertion, you will need to create an internal sleeve to re-enforce the area.

Measure 2.00" up from the tear and mark the tube. Draw a line around the circumference.

Repeat the process below the tear.

You should now have a 4.00" section of seat tube with the tear in the middle.

Measure the diameter of your seat tube. Cut a section of the same diameter x .045 straight gauge material 4.00" long. Cut the tube in half length wise, allowing it to spring open.

Remove a .250" strip of material lengthwise so that the tube can be compressed to a smaller outer diameter than the inner diameter of the seat tube. You have now created an internal shim/sleeve that will be inserted into the seat tube and slid down over the torn area when ready.

Using your reference lines on the seat tube, measure down and up toward the tear .500" and drill four small bullet holes at 12:00, 3:00, 6:00, 9:00 o'clock around the tube at each end. These will be feeder holes for you to draw silver into and through the seat tube and sleeve. Use a de-burring tool to clean the inner edge of each hole.

Meticulously clean everything and prepare it for brazing.

Orient your sleeve so that the compression slot is opposite your tear and press it down into the seat tube until it covers the defect and is positioned at your reference lines. You should now see the shim through the bullet holes and tear.

With good heat coverage and control, warm the entire area and feed silver from the top bullet holes,pulling the material down until you see it through the bottom bullet holes all the way around the tube.

You can then focus your heat on the defect and bullet holes to fill and build those areas.

GENTLY file down to the tube surface.

You should now have a repaired area that will be durable.

Good luck.

[Mark Kelly]

Great work, Rody.

[gabareba]

Thanks Rody for the great explanation. I think, I understand everything. Just ask. As I mentioned above, I never change seat tube. But maybe I should try. Which is the easier method? To change or repair? I found an article, but I don't know how can I remove the old seat tube without strip the frame. Can you check it? Any other method to replace? Or enough to cut the seat tube 1-2" above the bottom bracket, and braze with an inner tube/sleeve?

Thanks all for your help!

MEECH Custom Bicycles: Seat Tube Replacement

[progetto]

If your not sure if you can replace the seat tube, don't try. Rody,s sleeve solution will be enough for you to deal with by the sound of thing's.

[emanuel]

seattube is the bitchiest tube to replace.

[gabareba]

one thing is not ok for me. as I mentioned, there was a dent what I filled. So if I want to slide an inner sleeve to the seat tube, then 1. I can't put to the correct place or 2. if I can, maybe it won't be fit to the seat tube inner surface. am I right?

[Rody]

Gabor,

Easier=repair

Customer/Warranty Issue=replace

You will want to repair the area on a personal frame with your current level of skill.

Please do not use the mentioned article as an example of how to replace a seat tube, no more needs to be said.

cheers,

rody

Post script...

I see you posted just after me.

If there is an inward deflection in the area of the hole, then no, an inner sleeve will not work.

Your next option is to cut the seat tube above the hole and dent, make a second cut as close to the bottom bracket as possible and remove that section of tube.

Carefully remove any remaining seat tube down to the base of the bottom bracket and down tube.

Fabricate a new section of tubing to fit the Bottom bracket and snug to the remaining tube.

Use an internal shim to as noted previously to bridge the space between both halves and to provide alignment.

Braze/weld in place as noted after tacking the seat tube to the bottom bracket.

Repaint the frame, cause it's gonna be toasty.

r

[Eric Estlund]

Repairs can be tricky. If this is for you it's ok to jump into something over your head as a learning experience. Sometimes learning experiences teach you what not to do- be sure to listen to your internal metric and know when you are having fun and learning, and when it's time to walk away from a project that isn't going to right the ship or be safe.