quote:Originally posted by Geeto67
uh....who told you stainless doesn't rust? you can go tell that to the ducati sport classic guys with warranty claims whose stainless spokes rusted, or ikea when their stainless shelves rusted.
Like Rosko said, most any stainless can be made to rust and the easiest way for 300 food grade series to rust is for it to be contaminated (which can happen many ways...ie lay black metal on or against it, scrub with steel wool, acids, blast cabinets that have blasted ferrous/black metals... etc) by black steels. This is why the ducati guys food grade stainless spokes rust.
Food grade is easily bent and formed, however, 303 doesn't weld well at all and it is very likely the sink is 303. This is why, if you are observant, you may have noticed 303 stainless commercial food stuff silver soldered. 304L welds very well and although I don't find it difficult to weld, it's much more difficult to weld than black steel and easier than Ti. The beads don't lie, any gray in the bead means you cooked the chromium out of it and it's NFG.
any sink you get for $40 new is not going to be the rust proof kind of stainless, it is merely going to be rust resistant and even at that resistant as compared to bare metal.
you are confusing food grade with 400 series and even it is much more rust resistant than black steels once it's been properly heat treated. I have some 2205 Super duplex here if you'd like to see if you can make some serious stainless rust, Interesting stuff and has strength and elastic properties much like Chrome Moly. Too many variables out there to be making such hard and fast dogmatic statements which end up being quite misleading.
quote:Originally posted by trepanned23
Good idea, now I'm thinking about it. It really shouldn't matter that much if the cheap 304 stainless isn't as good as 316, the corrosive potential of the hydrocarbons going inside the finished product will be minimal compared to say acid or water. One thing everyone should remember about stainless is that what makes stainless stainless is a very thin layer of chromium oxide on the surface ONLY. Sanding, wire brushing ( especially if the wire brush isn't stainless) will strip off or foul this thin layer of chromium oxide thereby rendering everything you liked about stainless in the first place, useless. Still though, hydrocarbons are not particularly corrosive to metal - so OK. Still will work. If you're really serious about welding stainless and want to do a proper job, solution anneal after welding. Just find a shop with an oven that goes to say 1175F - I think, check it out. You need to solution anneal to bring the chromium oxide back into solution especially in the weld areas or the beads won't be quite "sticky" enough.