Hole in steel frame
 

Hi all. I've managed to put a hole in one of the chainstays of my raleigh stowaway, right near to the bottom bracket. I was hack-sawing off the mount for the kick-stand so I could more easily shorten the width of the bb shell, and unfortunately the movement of the mount as I sawed tore it off, bringing off part of the frame with it where they were brazed together. The hole is 6mm x 7mm. I took some pics to upload but I'm not allowed to post images.
I still have the piece, so it could be salvaged and replaced on the frame. Any advice? Is this a right-off, too risky to ride now?
Cheers for your help.

You could introduce yourself & greet other new members in the "Introductions" forum and find a few other threads to contribute to, getting up to 10 posts

Contact me via PM so I can get your photos and then I'll post them up for you.

From what you state, the damage sounds bad and should be fixed.

It's steel, steel can be welded or brazed. Or if you want to preserve the factory paintwork from getting charred by heat there's epoxies like JB Weld... amazing stuff YMMV.

Thanks for the suggestions - as it's a £40ish second hand frame, I'm disinclined to pay someone to weld or braze it (unless I could find someone who could do it very cheaply). JB Weld sounds like an intriguing suggestion, I wonder if it's capable of retaining the structural integrity of the frame though...

Excepting a massive amount of patch and bonding area any bonded repair is really more of a "keep the water out" result then a "it will be as strong as before" one. But until we see photos we can't have much opinion to current structural integrity. Andy

Agree with Andrew Stewart, JB Weld will fill the hole but do nothing for structural integrity. You should be aware that absent a
backer of some sort behind the hole the JB Weld will require 3-5x as much volume behind the opening as in the opening. JB Weld
is functionally an epoxy like semi-solid with fillers that hardens into a solid and can be plastically shaped. If the opening is into the
bottom bracket area you will have to deal with the glop that ends up there and keep it out of any threads.

Thanks Andy and sch. Nessism is going to upload the pictures for me, so hopefully that will give a bit more clarity on the issue.

https://predatorcycling.com/products/carbon-repair-kit

https://www.rhinocarbonfiber.com/pro...te-repair-kit/

https://www.ebay.com/itm/Real-Carbon...-/391695466513

...another vote here against epoxy of any kind by itself without some other additional structural support.

If you can remove the paint and rough the exterior surface for an inch or two past the hole on both sides, those CF repair kits with a CF sleeve would probably work (linked above). Otherwise, sleeving and brazing the sleeve in place with some sort of steel tubing of the proper diameter, or some thin sheet steel. You still need to clean down to bare metal to get a decent braze attachment.

At the price youi mention for the frame, and with that kick stand plate as original equipment, I'd be inclined to toss the frame unless it has some sentimental value. I have repaired stuff like that out of sentiment.

Here are the photos. I'd fashion a steel patch and braze it in place.https://cimg3.ibsrv.net/gimg/bikefor...4f1e7591cd.pnghttps://cimg4.ibsrv.net/gimg/bikefor...fbb8f4f457.png

Steel and epoxy are just about as strong as each other in many respects. Epoxy bonds very strongly to many different things. But Steel and epoxy do not have the same torsional and bending characteristics when exposed to stress. So I absolutely would not use any type epoxy/jb weld.

Find a welder that does brazing and let them patch it. If you have a bike builder nearby, they probably could replace the whole chainstay, though depending on how bad you cut into it, it's probably not necessary.

I have the ability and equipment to repair that, but given the value of the frame, I would just leave it alone and ride it. If it cracks in the future, I would repair it at that point. Just think of it as an oversized vent hole.

Yes. Just ride it and watch for cracks or deformation. I'd put a piece of tape over the hole to reduce ingress of wet muck.

Nice shoes!

There are no measures of strength of which I am aware for which epoxy is as strong as steel. Any steel in a bike will have tensile strength of 40ksi or more, epoxy is about 3.5ksi, max. Put some carbon fiber in the mix, and sure, it's strong, but not pure epoxy.

Epoxy will seal the holes, temporarily I think. Not sure that filling the holes with brazing material will do much better.

I'm guessing that, with a kickstand, the bike was not chrome manganese (e.g. 531) and it looks like its been welded. The kickstand was certainly a weld job. So the steel is a weldable type. Maybe tig weld small plugs (to minimize heat) to fill the holes? Not sure where the view becomes not worth the climb. Maybe fill the holes with epoxy and hope for the best?

Structurally the hole is not likely to be a problem in ordinary riding. Now jumping off curbs or
higher.... I would just ride it. If something HAD to be done just for the sake of doing it,
maybe a piece of tape over the hole, replaced as needed or something like this: https://www.amazon.com/Super-Glue-Re...SIN=B000LGV0XE

Thanks Nessism for uploading these pictures and thanks for all the suggestions. I guess I'm going to patch it up to prevent corrosion and keep an eye on it for cracking until I can get my hands on another frame, which I'll endeavour not to wreck this time. Lesson learned I suppose...

If you have the resources to cheaply braze a patch over it then go for that option. If not, I would see if the edges of the big hole can at least be smoothed out with a drill bit slightly larger than the hole... the jagged edges are more likely to be a problem than anything else.

Also, the location of those holes is such that they may actually help prevent corrosion - they will function as drain holes to let accumulated moisture fall out. Perhaps spray some sort of oil in there and roll it around inside to coat the surfaces to help prevent or slow corrosion.
But in reality, that old frame does not have thin tube walls so corrosion would have to advance a long way to cause any structural problems.

If by patching it up, you gob a bunch of epoxy/jb weld up into the hole, then you will be potentially blocking the path for moisture to get out of the weep holes. As well if your patch covers the tube outside, you might be hiding the first evidence of any future cracking from sight.

If you are not going to get it brazed, then just smooth the jagged parts of metal with a file or something. Spray some clear on it and be done. Then at least you can watch for cracking.

Another vote here for simply smoothing off the edges and riding it. I do not believe it will be a problem in practice.

Squirt in boiled linseed oil as a rust cover so it wont get worse.. slosh it around for more complete coverage...

leave the hole in the BB shell for condensation draining....

I just noticed that the frame design has holes designed in. So water can get out. You don't need to seal all the holes.

The hole I believe that the OP is referring to is the big one at lower right. Given the existing drain holes, the only reason to put something in to replace the divot you made is for structural purposes. So I'd do as suggested above: file the edges very smooth, getting down to 220 grit sandpaper (aluminum oxide works ok). The idea is to remove any notches or pits in the hole edge. These notches and pits can concentrat stress in which case you end up with a crack propagating from the hole. Then paint the edges and the hole.

If you choose to patch the hole, here's my not-so-humble opinion. Again, epoxy is worthless in reducing stresses that would affect the metal. Same thing for filling in with brazing material.. Recall that brazing is a process that does NOT involve melting the native metal of the joint. You are applying a lower melting point alloy to the steel, where the steel doesn't melt. If there were things as strong as steel that melted at brazing temperatures, we'd use them. So the brazing material will not have the same strength as steel. Again, I view this as pretty useless.

There are three options left, as I see it. First, if you insist on brazing, would be to fabricate a steel patch to go over the hole. A piece of steel about the same thickness as the wall of the stay. Bent to conform to the stay surface. Then strip the paint from around the hole, clean it up very diligently, and silver solder the patch on. The material over the hole is then steel, and the joint is very strong silver-solder with enough area to hold it together. Pretty much a "lug for the hole". BTW, silver soldering is really silver brazing because silver solders all melt above 450°C. This operation will be costly, and would require brazing expertise at the frame-builder level.

Two welding option remain. The first is to use welding rod to fill in the hole. This would involve melting a lot of metal and hence putting a lot of heat into the frame, and I don't like it. The other option would be to make a small metal disk that fits the hole, and very carefully (TIG) weld the coupon into place. Since the coupon is the bulk of the joint, you put less heat energy into the thing. This requires a good TIG welder. Again, expensive.

If this were a vintage Cro-Mo frame of great value I'd probably either file, smooth, and paint, leaving the hole or, if I bothered to fix the thing, I'd do the coupon thing.

What I would not do is waste my time with epoxy. If my resolve did weaken enough to opt for a cosmetic/water seal fix, I'd still file the hole smooth so that there were no stress concentrators.

really curious.....why would you be doing that?

Thanks so much to everyone for all these considered and useful replies. Should have clarified that the other holes are indeed meant to be there, although it's a shame the one I created is so close to a drainage hole, as I'm sure that makes it more vulnerable than it would otherwise be. As I can get a replacement frame by waiting around until one comes up for about £40 on ebay, none of the expensive brazing options seem worthwhile. I'll certainly follow this advice regarding smoothing off the rough edges - had no idea they could cause cracks in themselves!

The raleigh twenty has a crazily long bb shell (around 76mm off the top of my head). If you want to replace the cottered cranks with square taper, there are a number of complicated options, the most simple (and cheapest) one being to take some of the width off with a hack saw and fit a 68mm threadless bb.
I should have provided an image of the entire bike, to see what kind of heavily-modified beast we are dealing with.