Unless you get/have lots of experience stay away from aluminum. Welding it takes skill and experience not to mention specialized equipment.
That being said I'll suggest you stick with good old steel. As for sticking it together I'll also suggest you buy and get good with a nice little wire feed (MIG) welder. Brazing with an oxy/acetylene torch will work but being proficient at it takes practice and the right materials and again, equipment. The MIG welder can be mastered quickly with practice and will give you strong/safe welds. Before you start building bicycle frames I'd suggest you do some reading on basic metal working. There's more to it than simply cutting and welding things together. You'll probably get several opposing opinions on this; mine is just one.
Tom
GLO 2 Door!
So many red flags!
GLO kicking!
You'll learn what you want so much faster (and likely better) by having a mentor. It seems that you've a lot to learn to be capable of the creativity your talking about; by tapping anothers experience you'll likely avoid a lot of potentially dangerous "HardKnocks" schooling too! Look forward to seeing your work!
Tensile steel absorbs the motor vibration well and should be far easier to weld than aluminum or thin wall chromemoly steel. Some of the mainstream bicycle forums have a lot of info on frame building. The freakbike forum members do a lot of cutting and welding on tensile steel frames. Read before you cut.
Assuming you can get a welder to do it, the easiest way to make a good frame is to braze steel tubing. Steel tubing is easy to braze or weld, but welding thin-wall tubing tends to burn off some of the wall thickness opposite the welds, so brazing usually ends up being stronger.
Aluminum can be welded and brazed (with Durafix rod) but it is much more difficult than steel, because of the way that heat spreads out quickly in aluminum. Also some people have found that aluminum brazing rod does not hold well if it gets flexed at all.
Galvanized steel is never good for structural metal use for two reasons. First reason is that the zinc coating burning off while you are welding it is a health hazard, and second is that the chemical bath necessary to apply zinc coatings weakens the surface of the metal. So no good-quality steels are ever normally zinc-plated. Electrical conduit is steel, but it's a very low-grade soft steel.
In the US the main two metals to look for are 4130 cro-moly steel and 6061-T6 aluminum. Mild steel can also be used, but it is not quite as stiff and resilient as 4130 steel would be.
Anything else is either too weak (cast iron pipe) or a lot more expensive (stainless steel, titanium, ect). ....And aside from simply costing a small fortune, stainless steel and titanium are also very difficult to cut, drill and weld properly.
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Unless you get/have lots of experience stay away from aluminum. Welding it takes skill and experience not to mention specialized equipment.
Well, no.Oxt-,Acetylene weiding of aluminum is not a good idea...
This I will agree completely on.Flux Core Mig Welding without gas of any metal is not a good idea..
Here's another thing to consider if you do end up using steel as a material for your frames. I'm still on my first bike build using a regular V-triangle frame but I've been contemplating boing a custom frame build myself for my next project (funny that I'm already planning my second build before my first one is completeed, I dunno if any of you guys are like that too LOL) so I called a very reputable local bike shop that dabbles in this kind of stuff since I don't yet trust my welds. The bike shop owner also said that I might want to consider what frames I'm using since all steel frame tubing material is not the same and there might be some compaibility issues wih different steels when it comes to welding. Some frames use chro-moly tubing, other, cheaper frames use other grades of steel. I have an old Fuji MTB frame and the guy said that Fuju uses their own grade steel unique to them whereas my Raleigh frame uses more common chrome-moly tubing, etc. Dunno if this is all true or not, just relaying what I was told. Maybe someone else with more materials knowleedge can chime in on this and clear things up.
exactly old frames for practice and are geting hard to find like hens teeth ,, i make proto types a lot of times , out of pvc pipe , and dont glue them so as for referance and measurments.. i had to get an electronic tape measure so i could see lol cost $$$$ , im think when it comes to this bicycle work stuff its all metal and that to me is a ((great need to use a metric ruler ? ))