How big is the leap to stainless?

[tomplum]

I've done so little with stainless steel really. I stumbled across a bit of stainless steel. Everything from channel steel, angle ,solid bar, tube, brackets, strut- and the list goes on. Lots of pipe and a pile of fittings too. Heavy and light. So far besides regular carbon steel repairs- I build things. Functional and not. So I look at this as a learning opportunity. I cut my steel either with a cold saw, plasma mainly. I have mostly standard bits. Can either mig or stick, though I have DC TIG which I am horrible at. What is the logical next step here from a hobbyist POV?

 

[Jason280]

I would get a bottle of tri-mix shielding gas, some stainless wire (309, 308, 316), and weld with the MIG. Just be aware stainless is some tough stuff, and can be hell on blades and drill bits.

 

[3Ts]

If you weld stainless (or anything that makes fumes) there is an issue with the chrome. Same issue as with zinc fumes from galvanized metal. Look up metal fume fever.

 

[yomax4]

Depending on what you are expecting the welds to look like you can use regular 75/25 argon co2 but just know your welds will be blackish and discolored. I have a machine that has programs for 98/2 argon/co2 which I use mostly and that gives a great looking weld. You can jump up to a tri mix argon/helium/co2 for best color match but prepared for the sticker shock with any gas mixed with helium these days. Stick welding stainless is also a viable option if you're a stick welder. The stainless rods run very nice. As long as you ended up with some stainless you can perfect your DC Tig skills. Good Luck.

 

[Tinhack]

From a machining standpoint, SS is a nightmare. It will work harden if you look at it twice. If you're drilling or milling, the tooling needs to be sharp and RPM about half of that for mild steel. Don't hesitate or dilly-dally on feed or it turns to diamond and eats your tooling. It's in the same machining class as Titanium and Tool Steels.

Other than that, it looks really nice.

 

[LittleBill21]

i was all about to get trimix for my first attempt with welding, the gas guy shockingly said, unless you want it to look pretty, just use regular 75/25, it will just look black. and thus i welded stainless with regular gas with 0 issue and no real change in the process, was pretty shocked to say the least, and the gas guy lost out on a sale. props to him though

 

[dstig1]

SS is not the same issue as galvanized/zinc. The hexavalent Chrome that comes off SS is considered to be hazardous (but more of a long term issue). If you are doing a ton of it, then a respirator is wise but probably not needed for a little hobby putzing around in the shop on it as long as you maintain some decent ventilation. Zinc will give you metal fume fever which is supposedly horrible for about 24 hrs and then clears (never had it myself, never will) but no long term issues from it.

TIG on SS is kinda fun, IMO. And regular steel too. It is tough to get right on thin stuff as it is too easy to overheat and it does warp a lot more than steel does but I like it. Since you have DC TIG capability, I would do that and open up your world. TIG is sooo much nicer to run than MIG or stick, but yes it is somewhat harder with all the things going on at once that you need to control. Just need 100% argon to do it, plus the right fillers. 308 is the common one for welding 304 SS which is most common (note that 303 is considered "unweldable" due to sulfur content which makes it machine better). 316 filler is used on 316 SS. 309 and 312 are "magic" fillers that can be used to join SS to mild steel and is also useful for unknown steels.

 

[tomplum]

Interesting. I have lots of practice drops. I know that some is marked 316, it has been outside for several years. At least the lengths. Do you worry about cross contamination from discs, brushes like you would aluminum? What is the best way to cut or drill stainless? I cringe at buying an Evolution blade because I'll probably destroy it. I due have a tank of Argon, so that's a plus...

 

[dstig1]

It depends on how picky you want to be or how critical your application is. If you cross contaminate SS with regular steel grinders, etc, you will probably end up with rust specks on the surface from the mild steel bits that contaminate the surface (assuming it sees any exposure that leads to rust). If it is critical, you can passivate or electropolish the stainless after welding/fab to eliminate any free iron at the surface and encourage chromium oxide growth which is what protects SS from corrosion.

I believe you can weld 316 with 308 filler, but it won't have the better corrosion resistant properties of the 316 over 304 near the weld joints. Don't quote me on that...but if you wanted to do it for practice it "should" work...

Cutting/drilling will work with conventional tools like HSS or carbide but yes it is much harder to machine than steel as noted by others above. It helps to have better tooling (cobalt drill instead of HSS for example). I have noticed tapping 1/4-20 holes that after even one hole in 1/4" 304 it feels like the tap has dulled significantly. After a few holes I would get a new one to avoid the risk of breaking one and ruining the work. And those were good quality taps. Plus I also used slightly bigger drill bits to get 50-55% thread depth vs the standard 75% thread. Trying to tap the 75% sized hole was near impossible by hand.

 

[Smokeydog]

I buy drops of SS and nuts and bolts from the scrapyard. Mix with structural projects for handles, special projects and such. Weld with mig carbon steel wire. Prefer to weld SS nuts instead of tapping. Cleaner than trying to remove antirust coatings.