Help with material selection

[Kushagra.Asopa]

Hi guys, I'm building a 1kw stand-up scooter.I have sourced the parts for it. I have designed a simple frame to put it all together in. But I'm having a hard time deciding which material to use for the frame. I considered chromoly 4130, since it's the most common steel material used in bicycles. I understand that it requires heat treatment both before and after welding, I imagine a lot can go wrong with that. I'm wondering if there is a beginner friendly material that someone with basic arc welding and gas welding skills can use to build a sturdy enough frame.
Can anyone point me in the right direction?

 

[amberwolf]

Aluminum would require heat treatment, different for different alloys.

I'm not aware that cromoly would require it (though it certainly *can* be heat-treated for different hardnesses/etc); it is commonly brazed, or arc-welded, without issue, AFAIK.

I've used various mixed scrap steels including old bike frames made from cromoly (including 4130) to build my heavy-cargo bikes and trikes from without issue from the welding, using a crappy harbor freight flux-core welder.

The design of the frame itself, to put the loads in the right places and design the joints correctly to handle those loads, is more of a challenge than assembling it.

 

[Kushagra.Asopa]

Thanks for the tip. That gives me some perspective. Guess I've been overthinking on material selection. I'll try to get my hands on some chromoly and get started

 

[Overclocker]

i built this w/ mild steel :lol:

you could definitely build a lighter frame w/ chromoly using thinner wall tubing which is more difficult to weld, may need TIG w/ less readily available filler rods

mild steel is easy to weld w/ MIG using off-the-shelf wires (er70s6). mild steel w/ 1.2mm wall is reasonably lightweight and easy to weld w/ 0.6mm wire (0.023")