To braze or not to braze - that is the question
 

I need advice about brazing a damaged frame.

I picked up a bike today that has nothing but potential. I offered $10 Canadian for it and paid $20. ($20 Canadian is about $15 American so you can see I am not risking a big investment).

I bought it knowing full well that the front seat tube was cracked right above where it goes into the front bottom bracket. Not cracked as much as SPLIT. The split is about .75 of an inch long and parallel to the tube. The bike was left out over a winter and water accumulated in the frame at the lowest point and froze, splitting the tube. See picture.

If I get ONE ride out of this bike I got my moneys worth, but if I can actually fix it, that os BONUS. It has Rino BBs and seat posts, Campagnolo pedals, dropouts and brakes, Gardin stem and starling bars, Miche cranks and Batta headset so I know I can get good stuff off it if the frame fails.

Zo..... Is brazing up a frame tube a yes or no proposition ??

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Never seen a crack or a split with square ends and parallel sides.

The one thing I can virtually guaranty is that the tube is not cracked. That's some kind of intentionally manufactured slot that was cut or punched into the tube before brazing.

I can't tell you the purpose, or anything else about it, except that it's a manufactured slot. Feel free to braze, to fill it if you wish, or simply clean it up and close it with body filler if you prefer a cold repair. To use filler properly and do a permanent job, use the end of a rat-tail file to put some relief along the edges of the slot. Then remove the BB, press in body filler, and reach in with a finger or stick to pack it back over the sides on the inside. That combined with what is spread into the filed relief will act like a spread rivet head and keep the filler home.

The process is similar with braze, file some relief on the outer edges so when you dress the braze smooth you'll still have some strength keeping it home.

BTW - a skilled welder, used to working with thin material can do the repair very cleanly with less overall heat, and less paint burnt off.

Strip It. blast off all the paint to expose all the metal bare to see if its just surface rust. my guess (new Pictures) Lower cost Seamed Tube, weld Opened Up

maybe add gussets to stiffen up your BB seat tube area. if flexing was what caused the paint to flake Off..

double up with tubing with a patch , sweat braze on more tubing..

Or photoshopped.

The actual crack is behind the chain ring.

I could not get a good picture of the crack because the chainring interfered with the flash....

Here are a couple of close-us between the web of the chainring. You can see the tube swelled where it froze...


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Oh, I see. It was on the opposite side of the tube in the first photo and we supposed to use our X-ray vision to check it out. Or maybe peer through the tall window.

Anyway, b razing may or may not work depending on how badly the area is rust compromised. In any case you have little to lose besides your time.

first pic looks like a tube busted by ice, as OP states. last pic looks like, well, IDK what. not a split anyway.

Really, according to your original post it does not need any repair.

It looks like the seat tube filled with water and it froze. Oh, you're in Ontario? Isn't that like San Diego where NOTHING freezes?

It is NOT a stress crack.

I'd get a partner and try it out on the road and see what it feels like.

You could strip it down and TIG weld it if you wish. It wouldn't be too hard to do. It looks like the tube has expanded a bit from the water damage, but it is probably still sound.

I agree that the non-drive side crack is a manufactured feature, likely a drain hole as FB mentions, which apparently didn't work as intended given the freeze damage to the tube. The drive side crack and bulging looks like a result of that freezing. I'd clean off the rust, stop-drill the ends of the crack, paint it with something and ride it. I'd want to pull the BB and have a look inside the frame sooner rather than later, though.

Use tube blocks and reduce the bulge, then have it tig welded. Strip the frame, powder coat and it will be like new.

There isn't any non drive side crack.

Tube blocks..... what exactly are these ??

Thanks for chiming in with all the suggestions, guys. I thought I might get a bunch of "SCRAP IT" replies but now it looks like I may have got myself a bargoon Benotto.
It was originally priced at $200 on the local Buy 'n' Sell but for $20 (Canadian)

I took a gamble on it hoping it might be repairable or a source of good parts.

Bink

Clean rust, unbulge, tig weld, rattle can. It's in a spot where I wouldn't bother doing the whole frame. Removing the bulge might be a little tricky because the metal has expanded which means it's thinned. If I could see it in person, I might be inclined to, after thoroughly cleaning, bringing the edges of the crack close enough together to weld and leave it at that.

I agree with the suggestion to clean up the site, squeeze the bulge back as round as possible (with blocks) and then I'd braze on a sleeve over the crack. I'd split a tube that will otherwise slide over the ST and sandwich both parts of the sleeve around the bottom of the ST. I'd have this sleeve contact the BB shell so it will be brazed onto the shell also. I'd shape the upper end of the sleeve to be aestheticly nice to look at (like a lug shore line). I'd then do a complete alignment check/correction on the frame and apply anti rust stuff to the insides.

BTW there is the framebuilder's forum here. Not sure how many members pay attention to this mechanics forum. Andy.

The degree of rust on the frame suggests that nothing short of a tube replacement will produce a lasting repair -- chainstays are one of the easier tube replacements, but I wouldn't be surprised if the seat tube were on the verge of rusting through completely as well. That's a much more complicated repair; difficult enough on a single bike and more so on a tandem.

Unless you have a lot of time on your hands and can do the work yourself, it's not going to be a cost-effective repair. Ride the bike as is; maybe you'll get a few rides of even a whole season out of it. Then strip the frame and scrap it.

I love a challenge and I have nothing but time - as I am retired - and I do have the required equipment to weld, silver solder or braze. Before I retired I spent a few decades working as a maintenance mechanic at a company where much of the exotic machinery required parts made of unobtanium so there was often a bit of one-off machining and fabricating involved.

Strangely enough, the water that came out of the Benotto frame was clear, not brown as I expected, and the external rust , although it looked severe in the pictures, wiped off with really fine 000 grade steel wool and Combat. The bike is actually coming together... starting to look more like a decent bike. Of course the forecast for tomorrow is snow.

One outstanding issue now is that the rear RINO seat post is pretty solidly frozen and is resistant to movement. The last time I had one of these it was in a neglected Bianchi and I had to cut it off above the seat tube to expose the hollow core and then CAREFULLY chew it twice with a hand-held hacksaw blade. (see last two pictures)

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Good to hear.

I think the flutes on my Campagnolo Seat Post extended down a bit further... I was able to twist it a bit this summer, then used WD-40 to really break it loose.

Here was a note earlier about Seat Posts and Kroil, altough you may have to be more creative to get inside the tube.

It should be a nice ride when you're done, and if the sun ever returns to your neck of the woods.

Clifford: I see they have it in quarts and shorts, as well as in aerosol cans. I would LOVE to have nab ounce or two of KROIL, but naturally, it is only available in the USA - and comes with a $30 shipping fee (!) except for a company in Calgary that might have some.

If only there was an American with a pint can of Kroil that would put an ounce or so into a tiny bottle and send it my way....... in exchange for a few PayPal $$......

Bink

I can imagine part of the problem with the US Trade Deficit when inbound postage is much cheaper than outbound postage. It is often cheaper to ship something from China to the USA than it is to shop something across the city.

Perhaps this one?
Vintage Kano Kroil OIL TIN CAN 8 OZ Half Pint Nashville Tennessee | eBay

It appears as if "Priority" is the same price in the USA as First Class for small packages, but internationally, there is a HUGE difference between the two. That looks a bit battered, but maybe the oil is ok.

Is there really a difference between new oil and old oil? What about different brands?

I don't have any Kroil, so I can't sayif there is a big difference between it, Liquid Wrench, or WD40, all of which are available in bulk.

I am definitely shopping for a case of Kroil the next time I am in the States. I'll bring them back to Canada, keep one for myself & put the rest of them on eBay.ca !!

The Sellers on eBay can ship me ten bicycle bells that cost 99 cents each from China to Eastern Canada for FREE -- but if one of them is broken I can ship it from Canada to China for a little over $11.00.

That eBay listing you mentioned is for 4 ounces $26.53.
I do not know how it appears in the USA but up here that ad says the opening bid is $15.10 and shipping is $11.43.American
There has got to be a better way.

The farmers at work used to scorn Liquid Wrench, WD-40 and penetrating oils of all sorts because kerosene was 30 cents a quart and did the same thing. Kerosene is the lube of choice for tapping in aluminum...

Binky

I looked up WD40, Liquid Wrench & Kroil on the web.
There was an often repeated study. Apparently only ONE, where KROIL was #2 by quite a wide margin.
#1 , however, was a 50/50 mix of Automatic Transmission Fluid & Acetone.
Diesel or Kerosene are also referenced, without test data, but you could certainly add some to your cocktail.

OT - Penetrating Oil
Home and Auto WD40 vs PBblaster vs Liquidwrench [Archive] - ChiefsPlanet

Anyway, if you can figure out how to get access to your tube, it might be worth it to try your own homebrew mix. And, for pennies a quart, you could just add PLENTY to cover the bottom of the seat post.

As far as shipping, I occasionally buy items on E-Bay from Canada, and don't think there is that much of a shipping penalty. I think the penalty is primarily shipping from the USA to elsewhere (not just to Canada, but to everywhere). Stuff coming in from China is dirt cheap.

I wonder if the shipping is even more expensive than say the cost of shipping across the USA plus the cost to ship across Canada.

I could imagine a new business... shipping to a border town, loading a truck, hauling stuff across the border, and reshipping.

I found the data just a few seconds ago:
It is FASCINATING. Hold the Kroil. I have ATF and Acetone.

Penetrating Oils Compared

Machinist's Workshop magazine actually tested penetrants for break
out torque on rusted nuts. Significant results! They arranged a subjective
test of all the popular penetrants with the control being the torque
required to remove the nut from a "scientifically rusted" environment.

Penetrating oil .......... Average load
None ..................... 516 pounds
WD-40 .................... 238 pounds
PB Blaster ............... 214 pounds
Liquid Wrench ............ 127 pounds
Kano Kroil ............... 106 pounds
ATF-Acetone mix............ 53 pounds

The Automatic Transmission fluid (ATF)-Acetone mix was a "home brew" mix
of 50 - 50 automatic
transmission fluid and acetone.

Note the "home brew" was better than any commercial product in this

one particular test. A local machinist group mixed up a batch and all now
use it with equally good results. Note also that "Liquid Wrench" is about
as good as "Kroil" for about 20% of the price.

Bink

Well as an industrial mechanic myself, I have always been a big fan of Kroil. I've got cans everywhere, but now I can't help but be intrigued by the ATF-Acetone mix. My only question there is: Does acetone = nail polish remover, or is there a more pure source of acetone? What kind of shop would one acquire this pure acetone at (automotive, industrial supply, plumbing, etc)?

Keeping off topic, it's cheaper to ship from New York to Los Angeles than it is to ship from Buffalo to Toronto. What's worse is that a Honda Civic built in Alliston Ontario is cheaper in Seattle, both in sticker price and less "freight" than it is less than an hour down the road in Toronto.

I'm not an engineer, but can't see where the junction of the seat tube to bottom bracket would see that much stress, but maybe on a tandem there could be more?