I've got lots of emails and PMs with similar questions, so I'll reply in public so that everyone can read about it
If you have anymore questions, please feel free to ask.
About where I get the 304 and 420, a knifemaker friend of mine got it for me on a company that sells to factories. They sell thin stainless steel sheets for different uses, and since the thickness was appropiate for my use, I got some 2x1 meters sheets and got them cutted in strips to use.
I have no idea where to get that stuff in the US or Canada, but if I were to look for it, I wouldn't look for typical knife steel companies but to companies that cater to factories. For what is worth, I buy the carbon steel sheets I use on my regular damascus (1010 and 1070) in a place that makes huge metallic zip ties to tie tree trunks while in transport.
If you can not get 420, any other stainless steel with a regular knife steel carbon content and lower Chromium content than 304 will do. I use these two as they're a perfect combination of the steels I can get my hands on, but that doesn't mean this is the only stainless combo that will get this contrast.
I'm sorry to report that you will need a hydraulic press if you want to get full welded pieces and consistent results. Hand hammering will get you too much waste, as only some small parts will weld, I tried it several times before making my press and it's a real PITA and a dissapointment.
The burning of WD-40 soaked paper is to remove the oxigen so I can get the stainless steels to weld. I don't know how much (if any) carbon this adds to the stainless steel, but since I'm just welding it at that part, I don't care about it. As later on I forge to make it thinner and longuer and the direct flame already causes oxidation, I take care of the entire problem by grinding off that extra thickness I leave because of this.
No real plans yet to make an induction oven, I'm still in a generic research / knowledge gathering stage.
The acid I use for etching is indeed the same ferric chloride you can get at Radio Shack or similar. It's the one that's used to eat up circuit boards. What's important is that it's not overly used and "fresh" (not stale) as any of those circumstances will make for a bad etching. The end piece ends up looking washed up.
I never got anyone to complain about rash reaction to the nickel in the stainless steels, and since 304 and 420 are used in the medical field, I'd assume this probability is low. Might cause some rash in people with over sensitive skin, but so far I haven't got any problems with it (I've made several pendants for family members and friends and they all are happy with them)
The blacker parts will slightly fade a bit with continuous use such has pendants and the like, but a notorius difference will always remain there. It's a combination of factors (differende in surfaces, actual etching, light incidende, etc) that makes them look good even after a long time. And if you ever want to restore it to original condition, all you have to do is put it on acid for 30-60 seconds.
Ariel
