Choosing the right frame material

[cojaro]

I know robert's bike was made of 3/4" pipe, but i don't have access to a pipe bender, so tubing is my only way.

My question is, would 1/2" (or 3/4") alum. tubing work, or would it not be strong enough? And if alum. tubing is too weak, is copper tubing any stronger?

[frank]

I think i can bend copper with my hands... and i dont know if alminum can be welded

[cojaro]

I think i can bend copper with my hands... and i dont know if alminum can be welded
Alum. can't be welded? I'm pretty sure most metals can be welded.

And yeah, copper and alum tubing is more malleable than steel pipe, but it didn't seem to be so much so that a copper/alum frame would warp.

[mikeandike]

Copper dosnt weld and aluminun deos for sure

[imported_robertdjung]

I know robert's bike was made of 3/4" pipe, but i don't have access to a pipe bender, so tubing is my only way.
You mean Alum tubing is the only way (so that you can bend it?)

If you can't find a bender ($70 at harbor freight) then I'd just use square and have a frame that doesn't have any bends. All sharp angles.

To weld aluminum you'll need a mig welder with special gas, and aluminum wire. For that cost, you can buy a bender. OR, find a place that will bend tubing for you cheap.

[cojaro]

I know robert's bike was made of 3/4" pipe, but i don't have access to a pipe bender, so tubing is my only way.
You mean Alum tubing is the only way (so that you can bend it?)

If you can't find a bender ($70 at harbor freight) then I'd just use square and have a frame that doesn't have any bends. All sharp angles.

To weld aluminum you'll need a mig welder with special gas, and aluminum wire. For that cost, you can buy a bender. OR, find a place that will bend tubing for you cheap.
What about steel conduit? I noticed that to bend those, one only needs the cheap $30-70 manual benders. That seems to be the route as of now

[jrjulien1]

i think that aluminum is not a good idea because of the chalanges in welding it {and its expensive} because even if you did get the frame bent up you would still need to weld other things to the frame and as for steel conduit im not sure what that it unless its the correguated stuff which if thats the cast its BUTT UGLY and i wouldnt go that way in my oppinion the cheepest way to go even if it dosent look as clean as round tubing is to do square steel tube and sharp angles and if you wanted to dress it up a little just turn the backbone of the frame and the downtube on edge to make it look a little cooler

ps. copper is NOT very strong and i do not suggest using it to make your frame out of as it would probably break as soon as you sat on it if not then certainly soon after

just my oppinion

[imported_robertdjung]

I would either buy the HF bender for $70 and use pipe, or I'd just not use bends.

[jrjulien1]

i agree with robert its just better to use whats allready been tried and tested rather than trying to use things that wernt ment to be put under this kind of strain

[imported_robertdjung]

I've heard that you can use rigid conduit --- but I wouldn't. 30 MPH + metal failure = pain.

[cojaro]

I've heard that you can use rigid conduit --- but I wouldn't. 30 MPH + metal failure = pain.
So I guess I'll go with steel pipe, bending it with the cheap non-hydraulic pipe bender that I can find at Home Depot (the manual kind). I'm going to be using 1/2" pipe since my bike is somewhat smaller, to accomodate my smaller person (5'3").

[jrjulien1]

that sounds like a good idea i bet the thing will be very light so you wont have to use a massive engine to go fast

[seney2]

HF pipe bender may kink or flatten the pipe... if it does you can cork one end with wood or rubber and fill it with sand. Take a angle grinder or other tool and hold it against the side of the pipe.... this will vibrate the sand tight in the pipe... cork the other end and then bend it....

DO NOT ADD HEAT TO A SAND FILLED PIPE! Sand holds moisture..... moisture + heat = steam which = pressure which = BOOOOM

[jrjulien1]

thanks or the tip on not heating the tube it sounds like the kind of thing i would do and not realize its dangerous