Dealing with rust holes
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Dealing with rust holes
Hi there, I'm after some help with rust holes in a steel road bike frame. The frame is an unknown make but light weight. I had it sandblasted and it came back with tiny holes in the downtube.
I've read other material about how to deal with rust holes in tubes, but want to know more. I'm hoping answers provided could make this a useful sticky for dealing with this issue. I'd like clarification on my existing knowledge and assumptions about stripping steel frames and repairing rust holes. Having a clear approach to dealing with stripping and repairing for refinishing would be of great help to everyone who wants to restore bicycles. Your input is much appreciated!
Sandblasting or other media blasting, or chemical stripping? I made a conscious decision to have the frame sandblasted as opposed to the use of chemicals or other blasting media. The sandblaster I used explained he has experience with all types of frames and that it's the best way a) to make new primer stick and b) actually identify any issues with the frame (such as rust holes) that would be hidden by other/weaker stripping methods. This is contrary to comments that sandblasting as an abrasive stripping process is too harsh on thin steel.
Whether the tube should be repaired or replaced? I recently had another frame that had a cracked top tube that was obviously a candidate for replacement. But what about rust holes? What size or number of holes determines whether it needs to be replaced? Other threads I have read generally indicate it's ok to patch the hole, but does this maintain the strength of the tube? As far as repair options, I'm familiar with welding processes, and the sandblaster suggested drilling the holes and silver or bronze welding them, and I have also seen this approach mentioned in the forums. What about fibres and resins like fibreglass or carbon fibre repair? Can a thin sheet of fibre be applied over the holes or somehow inserted into the tube as a backing and epoxied? Can this approach maintain a strong tube? What can be done at home as opposed to seeking professional repairs?
Thanks
Andrew
I've read other material about how to deal with rust holes in tubes, but want to know more. I'm hoping answers provided could make this a useful sticky for dealing with this issue. I'd like clarification on my existing knowledge and assumptions about stripping steel frames and repairing rust holes. Having a clear approach to dealing with stripping and repairing for refinishing would be of great help to everyone who wants to restore bicycles. Your input is much appreciated!
Sandblasting or other media blasting, or chemical stripping? I made a conscious decision to have the frame sandblasted as opposed to the use of chemicals or other blasting media. The sandblaster I used explained he has experience with all types of frames and that it's the best way a) to make new primer stick and b) actually identify any issues with the frame (such as rust holes) that would be hidden by other/weaker stripping methods. This is contrary to comments that sandblasting as an abrasive stripping process is too harsh on thin steel.
Whether the tube should be repaired or replaced? I recently had another frame that had a cracked top tube that was obviously a candidate for replacement. But what about rust holes? What size or number of holes determines whether it needs to be replaced? Other threads I have read generally indicate it's ok to patch the hole, but does this maintain the strength of the tube? As far as repair options, I'm familiar with welding processes, and the sandblaster suggested drilling the holes and silver or bronze welding them, and I have also seen this approach mentioned in the forums. What about fibres and resins like fibreglass or carbon fibre repair? Can a thin sheet of fibre be applied over the holes or somehow inserted into the tube as a backing and epoxied? Can this approach maintain a strong tube? What can be done at home as opposed to seeking professional repairs?
Thanks
Andrew
Last edited by swin1; 09-29-15 at 12:10 AM.
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I would not ride that frame. I have no idea how you would repair a rust hole other than to replace the tube. I can't see riding a bike with any rust holes. Sandblasting can make holes in a tube, but I've never managed to do it myself.
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I agree with Eric. The concern isn't the holes themselves, there are vent holes and such that have no issues. But it's the condition of the tube which has now resulted in some holes. The tube's integrity is now comprised, no telling how little steel (as opposed to rust) wall remains.
I did a tube replacement a while ago which was similar. Frame had received some additional braze ons then sent off to the painter who used a soak tank for paint removal. They contacted me because of tiny rust holes on the TT underside. Frame came back to me and the rider decided to have me replace the tube. Here's a link to a Flicker album showing some of the steps. https://www.flickr.com/photos/731955...57644238503485
The shot that I didn't get well enough to publish is that of looking down the length of the cut away TT and seeing a path of rust about 3/8" wide running along what had been the bottom of the tube. When water would get inside the tube (both the HT and ST had small vent holes) it would slosh along the tube's length but sit on the bottom only. A very interesting finding. I dod check the rest of the frame, paying attention to the chain stays as they are the next tubes that are nearly horizontal. They were relatively rust free so we went ahead with the TT replacement. Andy.
I did a tube replacement a while ago which was similar. Frame had received some additional braze ons then sent off to the painter who used a soak tank for paint removal. They contacted me because of tiny rust holes on the TT underside. Frame came back to me and the rider decided to have me replace the tube. Here's a link to a Flicker album showing some of the steps. https://www.flickr.com/photos/731955...57644238503485
The shot that I didn't get well enough to publish is that of looking down the length of the cut away TT and seeing a path of rust about 3/8" wide running along what had been the bottom of the tube. When water would get inside the tube (both the HT and ST had small vent holes) it would slosh along the tube's length but sit on the bottom only. A very interesting finding. I dod check the rest of the frame, paying attention to the chain stays as they are the next tubes that are nearly horizontal. They were relatively rust free so we went ahead with the TT replacement. Andy.
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Thanks for the replies. I've taken some time to respond as I've put this project on the back burner. I did not mention that before blasting I used a lot of caustic soda to melt a stuck seatpost, and that the frame spent about 12 hours with caustic soda sitting in the downtube and chainstays as the bottom bracket holes were plugged. I figured the rust has been caused over time but maybe not?
My first thought was that given the number of holes the tube is considerably weakened. The sandblaster mentioned that the holes found are essentially the extent of the problem and that bronze filling them will do the job. Thanks in particular for those pictures of tube replacement Andrew. I'm almost tempted to just cut the tube out in pieces to see the effect the rust has had on the inside.
My first thought was that given the number of holes the tube is considerably weakened. The sandblaster mentioned that the holes found are essentially the extent of the problem and that bronze filling them will do the job. Thanks in particular for those pictures of tube replacement Andrew. I'm almost tempted to just cut the tube out in pieces to see the effect the rust has had on the inside.
Last edited by swin1; 10-17-15 at 04:21 AM.
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I would strongly consider replacing the tube. Remember that the hole you see is like the tip of the ice burg. Most of the damage is unseen. Andy.
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I would strongly consider retiring the entire frame. If the top tube is rusted through then there is almost certainly rust in some of the other tubes. Unless the frame has significant sentimental value it's hard to imagine it being worth the cost of the rebuild and repaint.
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I would strongly consider retiring the entire frame. If the top tube is rusted through then there is almost certainly rust in some of the other tubes. Unless the frame has significant sentimental value it's hard to imagine it being worth the cost of the rebuild and repaint.
#8
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probably has rusted through from the inside to make that number of holes
Or since Its the down tube .. wheel spray kicked up stones that chipped the paint and those spots rusted through, is another possibility.
Or since Its the down tube .. wheel spray kicked up stones that chipped the paint and those spots rusted through, is another possibility.
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My mistake in thinking the tube in question is the TT. Andy.
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It's the DT, the other tubes seem fine. It's pretty light weight - 1.85kg, and the fork is only .65kg, so in terms of building a light weight vintage bike it's desirable to fix up. It's exactly the right size for me as well - 58cm c-c both TT and ST.
I'll be painting it myself so really only need to spend money on having the DT replaced.
If I wanted to cut it out myself to see the damage, would a frame builder have a problem with this? Andy I see from your pics you did some cutting close to the lug and the ground the remains back to the edge of the lug?
I'll be painting it myself so really only need to spend money on having the DT replaced.
If I wanted to cut it out myself to see the damage, would a frame builder have a problem with this? Andy I see from your pics you did some cutting close to the lug and the ground the remains back to the edge of the lug?
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ask the framebuilder to send you the rusted tube. Don't do it yourself unless you are fixing it yourself
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Agree completely wit Eric. the frame needs to maintain it's geometry so a documentation can be done (a jig set up with the frame in it) before any tube is cut out. You need to have a frank and full discussion with who ever you have repair this frame. When does he/she communicate with you and when can they just continue with the process.
Yes cut the tube (a TT) close the to lug's edge then ground out the "back wall" of the ST and HT. This allowed a full depth grinding out of the TT layer within the lugs. In theory one can look for the color change as the material is ground away and the filler layer is revealed. I wasn't able to see this and ground away more then needed. Once at this point the rest was relatively easy. the frame can be sprung apart and a replacement tube installed then brazed in. I left the tube a tad too long and ground down the slight protrusions in the ST and HT. There are more details but this is the short version. Andy
Yes cut the tube (a TT) close the to lug's edge then ground out the "back wall" of the ST and HT. This allowed a full depth grinding out of the TT layer within the lugs. In theory one can look for the color change as the material is ground away and the filler layer is revealed. I wasn't able to see this and ground away more then needed. Once at this point the rest was relatively easy. the frame can be sprung apart and a replacement tube installed then brazed in. I left the tube a tad too long and ground down the slight protrusions in the ST and HT. There are more details but this is the short version. Andy
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So DMC707- Is your post like when you call a friend and decide in the middle of their answering that you really don't want to talk to them, so you change your voice and say "sorry wrong number" before you hang up? Andy.