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Old 08-26-12, 05:59 PM   #1
Starscream
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EMERGENCY Frame Repair (worst I've ever SEEN!)

I have a Giant Lite LA Free Electric Bicycle.

So where my down tube meets the bottom bracket (well what's actually the top of my engine), has snapped. Not cracked. SNAPPED. OFF. Right now I'm just dealing with getting all the plastic guards off the engine/frame, and taking the crank arm off. Afterwards, I have JB Weld epoxy putty. I don't know what the best way to use it is, or if it's the best thing to use at all. Any tips?

Also, when I actually get it permanently welded, will I have to take the whole engine off? I need help!!
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Old 08-26-12, 06:04 PM   #2
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frame warranty would be the first step.
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Old 08-26-12, 06:09 PM   #3
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Use JB weld if you would like to wake up in a hospital in the near future.

If the frame is alloy, it's not safe to weld either.
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Old 08-26-12, 06:21 PM   #4
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frame warranty would be the first step.
+1 sounds like a lost cause bring to the dealer where it was purchased. See where to go from there.

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Old 08-26-12, 06:24 PM   #5
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Replace that frame, don't repair it.
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Old 08-26-12, 06:55 PM   #6
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JB Weld, is really not a "WELD" It's an Epoxy, and a disaster waiting to happen if you use it on a frame. JBW is great for some things, but I would never trust it on something like a frame.
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Old 08-27-12, 08:25 AM   #7
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Giant Bicycle, Inc. ("Giant") warrants the frame and rigid fork of each new Giant brand bicycle and Giant brand frameset to be free from defects in material and workmanship for as long as the original purchaser owns the bicycle. ALL WARRANTIES ARE VOID IF THE BICYCLE IS MODIFIED FROM ITS ORIGINAL CONDITION OR THE BICYCLE IS USED FOR OTHER THAN NORMAL ACTIVITIES, INCLUDING, BUT NOT LIMITED TO, FAILING TO FOLLOW THE OWNER'S MANUAL OR USING THE BICYCLE FOR COMMERCIAL ACTIVITIES OR IN COMPETITIVE EVENTS, INCLUDING BUT NOT LIMITED TO BICYCLE RACING, BICYCLE MOTOCROSS RACING, STUNT RIDING, RAMP JUMPING OR SIMILAR ACTIVITIES, AND TRAINING FOR SUCH ACTIVITIES OR EVENTS.

http://www.giant-bicycles.com/en-us/page/175/#question2
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Old 08-27-12, 08:43 AM   #8
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I don't understand why people insist on using JB Weld to fix cracks on frames like it's really going to hold?

JB Weld big no vote from me.
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Old 08-27-12, 09:01 AM   #9
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Another no on JB Weld. Very bad idea.

See if the frame is under warranty and get a replacement.
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Old 08-27-12, 09:05 AM   #10
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JB weld is nothing but epoxy filled with aluminum powder. Despite some of the claims made for the product, it's just glue/filler and in no way a replacement for metal.
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Old 08-27-12, 11:00 AM   #11
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JB weld is nothing but epoxy filled with aluminum powder. Despite some of the claims made for the product, it's just glue/filler and in no way a replacement for metal.
It does make a very good bedding agent for rifles though.
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Old 08-27-12, 11:17 AM   #12
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I cannot really see any place on a bicycle where you can safely use JB Weld on, as mot items on the bike are stressed/structural.
On the other hand, JB Weld works best for just filling holes like on cracked or holed motorcycle side engine cases that usually is a reault of a dropped or crashed motorcycle. Basically just to keep the oil in the engine in such cases, but nothing really structural. Even then, most regard such fixes are temporary and the part should really be replaced asap as I suspect that the heat cycles an engine goes through would eventually loosen up any JB Weld patches.

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Old 08-27-12, 06:17 PM   #13
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Use JB weld if you would like to wake up in a hospital in the near future.

If the frame is alloy, it's not safe to weld either.
So is it generally agreed that I can't get it welded either? I've already spoken to multiple welders and it doesn't sound like it's going to be a problem. So I'm not sure if you have room to be so sure of yourself, are you a welder? I think a welder with a cert only needs to know exactly what the alloy is to weld it.

Also, I was really very clear on where the break is. If it snaps, I'm not going to fly off my bike. I didn't "wake up in a hospital" after it snapped initially.

I think my point is, when you're replying to someone on the internet who needs a little help, you shouldn't be so rude and treat them like and idiot. Do you help to feel superior? How about helping for the sake of helping. Thank you.
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Old 08-27-12, 06:28 PM   #14
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Also, I would like to say that I'm using the JB Weld PUTTY not the glue. It is STEEL REINFORCED not just "glue and filler". Has anyone used anything other than "JB Weld" glue? This putty is used to repair American vehicles. I've seen it used to reinforce frames many times. I've seen epoxy resins used to BUILD BICYCLE FRAMES. People who build bamboo frames use epoxy putties and resins. Even companies such as Stalk bicycles use an epoxy system to build their bamboo frames.

This is an aluminum frame, so I understand that it isn't the safest method. This is for a strictly temporary fix, until I either replace the frame or have it welded. The break is not in a very dangerous spot as far as my safety goes, just the safety of the cords that run into my engine.
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Old 08-27-12, 07:18 PM   #15
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Originally Posted by Starscream View Post
So is it generally agreed that I can't get it welded either? I've already spoken to multiple welders and it doesn't sound like it's going to be a problem. So I'm not sure if you have room to be so sure of yourself, are you a welder? I think a welder with a cert only needs to know exactly what the alloy is to weld it.

Also, I was really very clear on where the break is. If it snaps, I'm not going to fly off my bike. I didn't "wake up in a hospital" after it snapped initially.

I think my point is, when you're replying to someone on the internet who needs a little help, you shouldn't be so rude and treat them like and idiot. Do you help to feel superior? How about helping for the sake of helping. Thank you.
??? I saw no sign of rudeness in any of the responses. I have no idea why you would interpret the helpful responses above in such a manner.
The advice was sound. Why the aversion to trying a warranty claim?
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Old 08-27-12, 07:41 PM   #16
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Also, I would like to say that I'm using the JB Weld PUTTY not the glue. It is STEEL REINFORCED not just "glue and filler".
JBW Putty is no stronger than the other JBW. The putty just holds it's form better while setting up. STEEL REINFORCED means it has steel filler. There is no way it is going to harden into STEEL. And I'm not trying to be rude either, but I feel you are wasting your time and money if you think this will hold. Maybe a day, maybe a week, but the right bump, and you are going to have to clean it all off before a welder will even touch it.

I agree with others, try the warranty route first.

You asked and, you received a lot of opinions. You as the owner must weigh all this info and make a calculated decision. No one here thinks you are an idiot for asking. But if everyone tells you you shouldn't, and you do it anyway...
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Old 08-27-12, 08:33 PM   #17
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You probably won't listen to this either, but here are some actual figures:

Tensile strength of typical Aluminium alloy (6061 T6): 310 MPa.
Tensile strength of same alloy after welding (no PWHT): 120 MPa
Adhesion strength of JB Weld: 12 MPa


The frame is toast.
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Old 08-27-12, 08:39 PM   #18
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All I can say is you asked you got some great answers, if you are going to do as you like than go ahead use your method and I say good luck.
I know quite a few like you who ask question and advice and still do as they want and regret it later.
So keep safe thats all I can say to this thread.
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Old 08-27-12, 09:36 PM   #19
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Actually, yes, I do have welding experience. My father ran an automotive and machinery restoration business and I've welded, silver soldered and brazed parts for valuable antique vehicles as well as having done custom automotive body and fame work. I also made custom knives, both art and working pieces, and have a decent understanding of metallurgy. I have used JB weld numerous times for a variety of purposes and as I stated, the JB Weld putty or paste is nothing more than epoxy with a metalic filler. Epoxy can and has been used to build bicycle frames, carbon fiber bikes are entirely fiber reinforced resin. That is a far cry from sticking two pieces of structural aluminum together with epoxy putty.

The people here are trying to help you. If you don't think we know what we are talking about, feel free to take your question to the framebuilder's forum and ask it there.

There are many welders who work with aluminum, both of my stepsons are experienced welders, one of whom worked for an aluminum truck box manufacturer as a lead welder and the other works at a company that contracts to produce military equipment. Both are qualified in variety of specialty welding applications, including aluminum. Can an aluminum frame be repaired, sure, but you would not only have to get the joint welded, you would also have to stress relieve the frame to prevent brittleness that could lead to later cracking. As mentioned, you probably have a warranty claim for a new frame that will also be under warranty. That goes out the window the second anyone else tries to weld or glue the frame back together.

Do what you like. Good luck to you.
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Old 08-27-12, 09:43 PM   #20
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Originally Posted by Starscream View Post
Also, I would like to say that I'm using the JB Weld PUTTY not the glue. It is STEEL REINFORCED not just "glue and filler". Has anyone used anything other than "JB Weld" glue? This putty is used to repair American vehicles. I've seen it used to reinforce frames many times. I've seen epoxy resins used to BUILD BICYCLE FRAMES. People who build bamboo frames use epoxy putties and resins. Even companies such as Stalk bicycles use an epoxy system to build their bamboo frames.

This is an aluminum frame, so I understand that it isn't the safest method. This is for a strictly temporary fix, until I either replace the frame or have it welded. The break is not in a very dangerous spot as far as my safety goes, just the safety of the cords that run into my engine.
Good luck with your bicycle. Instead of discussing the merits of welding with us, why don't you call GIANT and let us know the result, so something useful can come out this thread.
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Old 08-27-12, 10:13 PM   #21
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So is it generally agreed that I can't get it welded either? I've already spoken to multiple welders and it doesn't sound like it's going to be a problem. So I'm not sure if you have room to be so sure of yourself, are you a welder? I think a welder with a cert only needs to know exactly what the alloy is to weld it.

Also, I was really very clear on where the break is. If it snaps, I'm not going to fly off my bike. I didn't "wake up in a hospital" after it snapped initially.

I think my point is, when you're replying to someone on the internet who needs a little help, you shouldn't be so rude and treat them like and idiot. Do you help to feel superior? How about helping for the sake of helping. Thank you.
All alloy frames are heat treated. This is what makes them strong. This is done by putting the entire frame, before painting, in an oven for several hours at high temperatures.

Welding will destroy the heat treatment and significantly compromise the structural integrity of the frame.
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Old 08-28-12, 04:37 AM   #22
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This:
Quote:
Originally Posted by Mark Kelly View Post
Tensile strength of typical Aluminium alloy (6061 T6): 310 MPa.
Tensile strength of same alloy after welding (no PWHT): 120 MPa
Adhesion strength of JB Weld: 12 MPa

The frame is toast.
And LOL
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Old 09-13-12, 10:14 PM   #23
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FIRSTLY, I was pretty sure I stated the warranty is already void. The bicycle is discontinued. So you can stop with this "Contact Giant and let us know the result so we can laugh at you."
I already know. This isn't the issue, I wasn't asking about information on the manufacturer.

The words strictly temporary mean absolutely nothing, do they?
I used two tubes of the highest quality steel reinforced putty I could find.
I STRICTLY TEMPORARILY reinforced the break using one tube, layering a few steel mesh patches over it, then using the other tube over the patches. I added a few touches to reinforce it, all of which you holier than thou bicycle enthusiasts would probably make fun of.
I've ridden it for almost 2 weeks every day for at least 2 miles, with some caution but not extreme caution.
It's just now starting to crack.

Epoxy putty is not all the same, and entirely depends on how it's used.
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Old 09-13-12, 10:16 PM   #24
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The words strictly temporary mean absolutely nothing, do they?
Not when you become a stain on the pavement. Be smart about this.
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Old 09-13-12, 10:22 PM   #25
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So your clever repair lasted for about 30 miles of gentle riding. Hardly sounds like a repair, not even an emergency one. Sounds like you fixed your frame about as well as a roll of duct tape would have done.

When folks here tried to help you, they were probably assuming you wanted an actual repair, not a duct tape level of kludge.
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