Welding stainless with flux core

admin

HI all, I'm a newbie here(and to welding) and this is my first post.  Please excuse my ignorance to much of this.I bought a lincoln MIG welder from home depot(or maybe lowes) about a year ago and have only been using it to weld mild steel with the provided mild steel flux core wire.  I'm learning a lot and have a ton to learn.At this point I'm only interested in using flux core, can't buy the tanks to do MIG currently.My question is:  I bought a 304 SS muffler and I believe the stock exhaust pipe on my truck is 409 SS, and I'm wondering if it's possible to weld this together with flux core.  I've been searching for a SS flux core wire but can't find any.  I was told by some friends who weld TIG to use 309 wire for dissimilar materials, but again can't find that in flux core wire.Is this possible and is what wire do I need?If it is NOT possible, my friend can TIG weld it, but I'd like to do it myself to learn and for practice.  He is new to welding as well but knows how to do this.  He just doesn't know much about flux core or MIG I guess.Also, I don't care how the welds look or anything(as I'm often told is a downside to flux core), as long as they hold and don't break/rust.
Reply:Im researching the same thing, what lincoln do you have?  From what ive gathered you need 308LSi for welding stainless but everything ive seen says you need to be using a tri mix gas as well.
Reply:i know that i have welded my SS tip on my truck and just used mild steel wire. it just wont be stainless any more. i assume that FC will work the same.Miller Pro 300 SS w/ cat Miller Bobcat 250Miller Diversion 165 Miller 211Miller Xtreme 375Miller 12vsMiller Dynasty 200 DX Miller Passport Plus w/ Spool GunMiller 30a spoolmaticLincoln AC225 Buzz Box VictorMathey Dearman - H&M
Reply:We run 309L flux cored wire in a dual shield process.  One of the biggest issues is cost.  We buy 45lb spools and they run upwards of $300 if I remember correctly.
Reply:If you dont care that its no longer stainless AND its just a slip fit joint and not a but joint you can probably get away with flux core.     Its not RIGHT and it wont be pretty but it should stick one to the other.Vantage 500's LN-25's, VI-400's, cobramatics, Miller migs, synch 350 LX, Powcon inverters, XMT's, 250 Ton Acurrpress 12' brake, 1/4" 10' Atlantic shear,Koikie plasma table W/ esab plasmas. marvel & hyd-mech saws, pirrana & metal muncher punches.
Reply:jblackwell, I don't know the exact model off hand, but it is a 120v lincoln MIG from either home depot or lowes.  I think it's like ~125 amp.  It was about $300-$400.  It's pretty nice for the price and for my use at my skill level(or lack there of  ) IMO.  I've found the same as you I think, flux core wire for SS that says to also use gas.  If that's the case then why use flux core wire....?grindel, thanks, I have found on google that I could do this, but I want it to all be stainless.  If I can't do it myself I can have my friend TIG it.76gmc1500, sorry for my ignorance and lack of knowledge, but do you mean that you run flux core wire with additional shielding gas?So basically it is not possible to weld SS with flux core wire without additional sheilding gas and keep it stainless?  That's what it seems like.  Doesn't make sense to me but that's why I came here for advice...
Reply:Time to tig it... or find someone that has a bottle to loan youMiller Pro 300 SS w/ cat Miller Bobcat 250Miller Diversion 165 Miller 211Miller Xtreme 375Miller 12vsMiller Dynasty 200 DX Miller Passport Plus w/ Spool GunMiller 30a spoolmaticLincoln AC225 Buzz Box VictorMathey Dearman - H&M
Reply:Ok well that kind of sucks, I'm a little shocked that there's no way to weld SS with just flux core.  But then again I don't know much about this.I guess I'll mock it up and tack it together, then bring it to my friend and have it TIG welded.  Thanks for the help everyone.  I really like this welder, it's extremely easy to use and quick, and being 120v I can plug it in pretty much anywhere.
Reply:depending on the model you should be able to run gas and you will love welding with gas.
Reply:Oh yeah sorry it is a MIG welder and can run gas.  I just am not currently set up for it, and at this time don't want to get into it because I have a lot of things on my plate.
Reply:Hello snrusnak, ESAB makes a self-shielded wire that goes by the trade name "Core-Bright",  there are a number of alloys that would work for your application. The down-side to all of this is that the diameters available appear to be limited. As I have been able to determine, their smallest diameter is .045, too large for use in your 110 machine. You may still wish to check with your local welding supplier(s) to see if they know of any small diameter self-shielded stainless wires (.030 or .035), if either of these diameters are available they might work for your 110V machine. The other downside to this for you could certainly be wire cost, as others have eluded to. Self-shielded wires are already expensive when compared to other wire types, SS wire of a self-shielded type can be really expensive, so brace yourself and don't rule out having your friend Tig this up for you. Good luck and best regards, Allanaevald
Reply:Thanks for the info!
Reply:The 409 will rust anyhow, I would just weld it with what you have already.
Reply:Well from what I understand the 409 forms a thin layer of rust but this actually protects the rest of the pipe.  It won't continue to rust further and this is what makes it great for exhaust pipe(it won't continue to corrode and appearance doesn't matter for most applications).
Reply:Your 110v machine could handle it IF you can find the SS flux core wire in the correct wire size and IF you can find it in a small spool (so you dont have $250 of wire left over).  Or you could get a small spool of SS solid wire and a bottle of argon mix gas...$$$.  Or your friend can TIG it for you (I'm guessing) at the cost of a case of beer, with correct filler.  Not considering skills or equipment or if it will rust, but how much do you want to spend welding a muffler on?  And you can probably help drink the beer!Good luck!
Reply:I understand all of this about cost and time vs what it's worth.  But if it was possible to find that proper wire to use for flux core with my machine, I'd buy it as I will have other SS welding projects in the future.  If not, then I'll have to get gas(and most likely will at some point anyway).Looks like for this job though, if I can't easily find that wire I'll just break down and buy that case of beer
Reply:Originally Posted by snrusnak76gmc1500, sorry for my ignorance and lack of knowledge, but do you mean that you run flux core wire with additional shielding gas?
Reply:your flux core will weld it. it wont be stainless anymore, but if thats all you have weld it together clean the flux off ( it doesnt like moisture) and paint it with galvinizing paint or something similar. it will hold just fine.Millermatic 250Lincoln 180TLincoln SP-135Miller Thunderbolt AC/DCThermal Arc 161SAirco 300 Heliwelder
Reply:You should consider the upgrade to gas, even for mild steel.   You will be amazed with bead appearance.TA Arcmaster 300CM3XMT 304S22P12 suitcase feederX-Treme 12VSOptima pulserTA161SMaxstar 150STLHypertherm PM45OP setupStihl 020AVP, 039, 066 Magnum
Reply:Thanks all.  I found out there's a welding supply store(praxair) right next door to my office so going to see how much it would be to set up for shielding gas.  If I don't do it right away I will eventually.Does it matter what gas I use for mild steel vs SS?
Reply:Yes.  Very much so.  Mild steel in short circuit transfer is most commonly Ar 75% with CO2 25% (AKA C25).  You can use 100% CO2, it's cheaper, but most say you get more splatter.  100% CO2 does make for a hotter weld with better penetration though.  On your 110v MIG, it might be best for you.  There are other mixes of COand Argon that people prefer.  SS in MIG is welded with other gases.  Some are proprietary blends.  Mostly Argon, with a mix of Helium, CO2, Oxygen, and or Nitrogen in varying amounts.  I tig SS, one only needs 100% Argon for that.Last edited by Drf255; 07-19-2012 at 05:36 AM.TA Arcmaster 300CM3XMT 304S22P12 suitcase feederX-Treme 12VSOptima pulserTA161SMaxstar 150STLHypertherm PM45OP setupStihl 020AVP, 039, 066 Magnum
Reply:Ok, so I could probably get away with a CO2 tank and an Argon tank to weld both mild and SS with my welder?  CO2 for mild, and mostly Argon mixed with CO2 for SS?Thanks for the info.
Reply:Maybe I read that wrong.  Yes to needing two tanks. Tank #1 - CO2 or argon/CO2 for mild steel MIGTank #2 - Helium/Argon/CO2 mix for stainless steel MIGStraight Argon is for SS TIGYou will not get good results if you try to mix a tank of CO2 and a tank of Argon to make your own stainless steel "gas mix".  To mix your own and do it repeatably and accurately you need more gases than that and alot of $$ in equipment.For home/hobby or small shop use, just buy/rent the tank with the gas premixed in the bottle.  If your going to need alot of unique blends and can justify the cost then look into a mixer.
Reply:Ok I didn't realize you buy them premixed.  I thought you would have two tanks and mix them.  I'll take it to praxair and see what they recommend, maybe I can get two tanks, one for mild steel and one for SS.
Reply:About a year ago, I came across a company that claims to have a self-shielding flux core wire that does not require any gas.  If I recall, it cost somewhere around 70-80 bucks for a 2 lb spool.  I can't remember the name of the place, or the name of the wire because after seeing the price, I dismissed it as a viable option.  I figured if the project was small enough that buying $40/lb wire was cheaper than a tank of argon, you could probably find someone to do it the right way for that kind of money.You didn't build that.'85 Miller AEAD-200LEyou need to decide if you want your stainless to remain stainless. if it doesnt matter then use what you have or buy some er-70s6 and a bottle of c25 and go to town. it will weld them both. if your going to weld stainless to mild just use what you have, because mild isnt going to have the properties of stainless anyway. if its stainless to stainless and you dont want any paint on it go the route mentioned.Millermatic 250Lincoln 180TLincoln SP-135Miller Thunderbolt AC/DCThermal Arc 161SAirco 300 Heliwelder
Reply:Here's another question lol...I did some research on exhaust pipe and 3" SS pipe is very expensive, especially for mandrel bends.  I'm considering getting aluminized pipe(I'm not in a corrosive environment).  Can we still use the TIG to weld it with the ss wire?
Reply:Your going to have one hell of a time doing it.  Your going to have to make sure you get every speck of the aluminizing off of the pipe in the weld zone.Vantage 500's LN-25's, VI-400's, cobramatics, Miller migs, synch 350 LX, Powcon inverters, XMT's, 250 Ton Acurrpress 12' brake, 1/4" 10' Atlantic shear,Koikie plasma table W/ esab plasmas. marvel & hyd-mech saws, pirrana & metal muncher punches.
Reply:Originally Posted by DualieYour going to have one hell of a time doing it.  Your going to have to make sure you get every speck of the aluminizing off of the pipe in the weld zone.
Reply:Hello snrusnak, if you opt to weld it with wire, specifically GMAW(solid wire) or self-shielded FCAW it is very weldable. If you choose to weld it with the TIG/GTAW process you will need to remove the aluminizing back from the end of the aluminized pipe inside and out for a distance of at least a 1/4". The TIG/GTAW process won't be tolerant of the aluminized coating. If you opt not to do any removal of the coating you will not see a very clean puddle while welding and you may also end up with varying amounts of porosity and experience tungsten contamination even if you don't dab the tungsten or hit it with the filler. Best regards, Allanaevald
Reply:Originally Posted by anickodeAbout a year ago, I came across a company that claims to have a self-shielding flux core wire that does not require any gas.  If I recall, it cost somewhere around 70-80 bucks for a 2 lb spool.  I can't remember the name of the place, or the name of the wire because after seeing the price, I dismissed it as a viable option.  I figured if the project was small enough that buying $40/lb wire was cheaper than a tank of argon, you could probably find someone to do it the right way for that kind of money.
Reply:Originally Posted by snrusnakWell from what I understand the 409 forms a thin layer of rust but this actually protects the rest of the pipe.  It won't continue to rust further and this is what makes it great for exhaust pipe(it won't continue to corrode and appearance doesn't matter for most applications).
Reply:Ok thanks for the responses.  I'm pretty sure I'll go with the aluminized steel since it's much cheaper and I'm not in a corrosive environment.  There's a good chance I'll be doing headers down the road and reroute the exhaust anyway.  Would it be best to use that SS wire linked above or should I use the regular steel wire that came with my machine?  I'll do flux core for sure as it should be easiest/cheapest for me with my setup.
Reply:Ok all so I figured out everything I need to do my exhaust with aluminized steel(less than half the cost of what it would have been in SS) and am ready to place an order for all the pipe, bends, etc.  The only thing I really need to know is should I use the regular gasless wire that came with my machine or should I use a SS gasless wire like this:http://www.ebay.com/itm/035-308L-FCO...#ht_1034wt_699I'd think SS wire would be better(for rust prevention) but it says in the description "This wire can be used to weld all stainless alloys up to 308 without gas" and I think the stock exhaust pipe is 409 SS.  So what will happen if I do this?Thanks for all the help.....I'm almost there for this project lol.
Reply:Alright lol.Well I think I'm going to order the ss flux core wire and give it a shot, if it fails I'll use the regular wire.  Not sure if anyone cares but I will post pics when it's all done.  Might be a month or so as I need to order and receive all the parts then find a free weekend.  I'll post pics as long as no one makes fun of my welding "skills" lol.  As long as it holds and doesn't leak I'll be satisfied.  I'm sure the more projects I work on the better I'll get.I also have an exhaust project for my buell, but need a baffle out of the stock truck muffler, so shortly after this project is done I'll move on to the bike and will post pics of that as well.  That's all mild steel.
Reply:You want to use 309L wire, not 308 for welding on mild steel.  Using 308 wire will make brittle welds.
Reply:Originally Posted by 76GMC1500You want to use 309L wire, not 308 for welding on mild steel.  Using 308 wire will make brittle welds.
Reply:Yeah sorry I know I've changed direction now, not going to do SS pipe since it's crazy expensive.  My y pipe and muffler are still SS though.  I was just going to use the flux core wire that came with my machine for everything (aluminized to SS and aluminized to aluminized).  Then spray all the weld joints with some high heat rattle can paint.I bought a cheap chop saw from HF for this project and the saw seems to be decent actually, it cut through some 2" steel pipe I had with ease(way better than how I was cutting metal before...).  I practiced a little welding and I'm not good so need some more practice before doing my exhaust.  I can eventually get a decent weld but it takes 5 or 6 tries before I get the settings right.I did order all the pipe for my exhaust though, so once it gets here and I get enough practice to make decent welds I'll be doing it.
Reply:I just realized I never followed up with a response here.  I took some pictures of the exhaust the other day.  It turned out good, I did ok welding but had some trouble so my buddy pretty much came in and finished all the welding for me.  I would have been able to finish it all myself but it would have taken a lot longer and not been as good.  I still need to practice a lot.  Anyway, here's the exhaust, I reused as much oem SS pipe as I could, and the new pipe is aluminized.  I painted all welds with high heat black spray paint to help with corrosion resistance.  Also reused all stock hangers, so it's a nice clean install.