is this for Real...Electrical Conduit for Frame building?

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shamrock395

New Member
Jul 25, 2010
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Milwaukee
OK... I admit I am a newbe here to the forum and I dont want to russel any feathers but i was thinking of building my own frame. The thing is, when I do a search for frame material I keep coming up with posts where people are using "Thin wall Electrical conduit" for there frames. Now I am no expert at frame building but I do alot of electrical work and I am concerned about the strength of thin wall and the welding penitration it is after all "galvivized" and thats not good for the lungs. So I guess my real question is , is there correct tubing to use to put these together? and/or what about using bike lugs for the connections?
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,837
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up north now
I am going to bump this one up. All I will add is that I used to build ultralights, and you'd be amazed at what people would build those things with....most lived to tell about it, but I doubted the longevity of some of the "designs" I saw flying.
 

sportscarpat

Bonneville Bomber the Salt Flat record breaker
Jun 25, 2009
1,839
471
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california
I wonder if people are refering to ERW or electrical resistance welded tube, and then just guessing the electrical reference means it is conduit. I would never use electrical conduit for a bicycle frame. Besides, all the zinc coating would make for difficult welding. From my experience ERW tubing is pretty good material and DOM is better still.
 
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GearNut

Active Member
Aug 19, 2009
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San Diego, Kaliforgnia
Do NOT use electrical conduit for making a frame! That stuff is too soft and will fail.
It was designed to hold and protect wires and be relatively easy to install, nothing else!
Mild steel tubing is stronger than that steel reinforced bubblegum that conduit is made out of.
Most suitable tubing is ERW. Mild steel or better yet Chromoly.
 

2door

Moderator
Staff member
Sep 15, 2008
16,302
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Littleton, Colorado
Conduit, (EMT) is okay for exhaust systems but DO NOT try to build a frame from it. I've seen guys build extended front forks from EMT...I would not ride that bike. Thin wall electrical conduit has some uses other than protecting and concealing wiring but bicycle frames are not one of them. Yes, it is easy to bend and make the shape you want but it does not have the strength to hold up to the stresses imposed on it as a bike frame; especially a motorized bike.
Mile steel will serve you well and if you're a qualified welder, Chrome Moly but leave the conduit to electricians.
Tom
 

Maxvision

New Member
Jun 13, 2009
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San Diego, CA
Check out a metal supply business, look for the 18 guage welded tubing. It's walls are 1/16th in. thick and comes in wide assortment of sizes.
 
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shamrock395

New Member
Jul 25, 2010
3
0
0
Milwaukee
It was EMT that people were using, and some interesting looking frames, some were real neat . But I am looking to build a drop loop and eather a doner bike will do or like GearNut said some ERW will do best.
Now about the frame lugs , I keep reading and seeing how people are just welding the frames together (thats how my Columbia is ,or more like brazed). I will be tig welding mine but I will have to say those frame lugs look nice, I just dont know where to get them or if it is even worth the hassle to find them. I trust my welds but -sun of a gun - if 1 fails when I am doing 20 of 25 MPH I will be in a world of pain.
 

donutguy

New Member
Feb 4, 2010
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PA
I have a friend that's an engineer and he builds bicycle choppers out of some sort of conduit. I have no idea what type he uses but to my knowledge-he's never had one fail. I think a lot of how a frame performs has to do with how it's designed.
 

motorbiker

New Member
Mar 22, 2008
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Tampa Bay Florida
It was EMT that people were using, and some interesting looking frames, some were real neat . But I am looking to build a drop loop and eather a doner bike will do or like GearNut said some ERW will do best.
Now about the frame lugs , I keep reading and seeing how people are just welding the frames together (thats how my Columbia is ,or more like brazed). I will be tig welding mine but I will have to say those frame lugs look nice, I just dont know where to get them or if it is even worth the hassle to find them. I trust my welds but -sun of a gun - if 1 fails when I am doing 20 of 25 MPH I will be in a world of pain.
It's all here. Henry James Investment Cast frame Components usflg
 

Earthman

New Member
Mar 24, 2009
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Pittsburgh, PA
The fumes from welding or brazing galvanized (zinc coated) material will cripple or kill you. So will using conduit for structural applications. Don't do it.