Welding

General Tips

• If it’s not held, it will deform
• If it is held, but has gaps, it will deform (i.e, a tube joint should be precise)
• If welds are asymmetric, it will deform
• Fillet welds deform more than flat welds
• Your jig is the “upper limit” of accuracy
• The ONLY way to ensure it does not deform, is to gusset. An aid is well-ordered tacking (4 points)

4130 steel gets brittle when welded. To fix, Heat treat (either with an oxy-acetelyne torch, or a proper oven treatment). A potential way to avoid this is to weld with referrer=https://www.google.com/ ER70 S6 (weaker, but produces more mallable welds). Unless sufficiently proven, it would not be advised to design a frame with a <3 FOS, without heat treatment. The usage of a single cylinder also without soft mounting may be enough to crack a non heat treated (or even heat treated?) frame.

Aluminum is more difficult generally, since the oxidation layer has a higher melting point than the layers underneath. So, a tendency to blow holes is the result. Not all aluminum alloys are weldable, and the ones that are will be very brittle unless heat treated properly in an oven.

TIG

NOOOOOOOO YOU CAN'T JUST USE ONE HAND TO WELD

Highly versatile. Control of heat and feed independently (one in each hand) - allowing for fine tuning of the weld to the material at hand. Can work for aluminum and steel. A good welder will be able to weld ~.06in aluminum, and .028 steel.

The drawback is that it requires more skill, and more active work - making the welding slower and higher effort. While a begginer can learn to tack within less than 1h, to become capable of performing hours of structural welds takes more effort.

MIG

haha, welding gun go brrrrrrr

Same science principle of TIG, but now the heat and the feed are combined into one torch, with a wire spool instead of "filler rods" also serving as the electrode to close the circuit. Advantage? easy to learn, and if you weld alot of the same tube thicknesses, its "set and forget". Fast and easy, while also allowing one hand use which makes reaching into difficult spots in the frame much easier. Disadvantage? harder to do thin and small stuff - .035in steel is roughly the limit. Welds are less pretty and slightly heavier. How much heavier? I've weighed a baja frame tacked and fully welded, and on a 72lb frame, the welds were 2.5lb. I dont have any numbers for TIG, but i'd be surprised if the difference is more than 1lb. The time saved however is substantial - that frame took ~5h of shop time (not welding time) to finish weld - from tacked frame tubes+tabs, to ready to paint. The formula frames i've worked on took multiple full days, by multiple welders.

Stick

Does anyone in FSAE use this?