Interesting post as to quenching, and HF welders.
This is a mount for a header so no need to heat treat mild steel as that is what you are probably using.
A 90A wire welder is good for sheet metal to about 14 guage.
Go up to a 120-130A (prefer 130A) for anything in the real world as you can usuallpy adjust it for anywhere from the 90 to the 13A level. Hate to say it but most of the major USA mfg import from China now.. so what you see at HF is in a different package from your favorite US mfg.
Toss any welding rod or spools from HF or any other discounter including Walmart, HD, Lowes and Sears. They are crap and who knows how long they sat in the salty air comming over from ???
Go to a real welding supply store and admit you do not know a thing about welding (Play the dummy) but show them what you want to do. They are more then happy to sell you the correct wire and tell you how to use and store it (dry, dry, dry place)
If you have a wire feed, stick welder or gas you keep your rods, wire in a air tight container and buy quality rods to start with, diff rods for diff projects and that is not just the material but the size of the rod and coating. Tips are replaceable and wear out and need cleaned so get used to maintance of the equipment.
Wire feed is the easiest to use, stick earns its keep for heavy industrial use and if your into repairing machinery and a lot of cast iron the only way to go, gas is very easy to learn and difficult to master but worth the time to learn, If you ever soldered a water pipe you can gas weld (ok, somewhat).
I built a Whitman Tailwind (homebuilt aircraft) over 30 years ago and it was all gas welding as NO other welding was allowed on a homebuilt aircraft back then, the welding was the most difficult I ever did but now I can weld just about anything anywhere in any position with gas (yes you will learn about heatsinks and heat treatment in the process).
For most of the welding we would be doing on a bike go with a 130A MIG/TIG and quality wire and practice, besides with the right wire and a gas tank you can weld aluminum with the same outfit, much more easily and at a lower cost then with stick or gas.