Perforated Stainless Steel Welding Question

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Hello.  I am new to this forum and have a question regarding welding perforated 16 gauge stainless steel.I have a Lincoln 3200HD MIG welder.  I am using 308L Stainless Wire (.030), and am using Helium Argon C02 gas.  The perforated stainless has perforations that are 3/16" in diameter, and I am trying to join to 16 gauge stainless non perf sheet.  Stainless is type 304 for both the perf and sheet.Here is the problem I am running into:  Bead is a mess, and the metal edges of the perf holes tend to go bye bye.  Suggestions for voltage?  Wire feed rate?  Any other help with suggestions on welding this crazy stuff would be appreciated.Thanks,Len
Reply:Get a piece of copper to use as a backing.  It will help with the burn thru.  The type of material you are dealing with is one of the toughest to weld for someone with not alot of experience in my opinion.I'm a Lover, Fighter, Wild horse Rider, and a pretty good welding man......
Reply:Originally Posted by Hammack_WeldingGet a piece of copper to use as a backing.  It will help with the burn thru.  The type of material you are dealing with is one of the toughest to weld for someone with not alot of experience in my opinion.
Reply:Are you trying to run continuous beads on the material?How are you trying to join the pieces? Lap joint, butt joint, etc?When I weld perf. metal with MIG I always find that "spot" welding it works best.If you are doing a lap joint and can overlap the pieces enough, the 3/16" perf. holes are pefect for spot welding the pieces together.Len, give us a little more info and pics, if you can, so that we can help you out.- Paulhttp://all-a-cart.comWelding Cart Kits and accessories
Reply:Why Helium...you don't need/want the extra heat. I'd opt for C25 if that's an option.I've never GMAW perf with less than .045 but it's easiest to roll up onto the perf so you don't burn the edge down as you say you're doing. You also want to stay in "short-arc", 16GA is going to disappear quick if any hotter. I don't know your machine or it's characteristics so can't recommend settings.Anything worth doing is worth doing RIGHT
Reply:Book says use a helium mix for more energy in the weld, you don't need more energy in that thin 16 ga sheet!That and the tri-mix runs about 6 volts more than the arc with 98-2 mix!  I don't know if the HD3200 can push that much voltage.Try 98-2 Ar-O2.  If you use a high CO2 gas (more than about the 2.5% in the tri-mix gas) with stainless, you may end up with rusted weld beads because of the gas used (carbon pick-up from the CO2 makes the steel not-stainless)!  So C25 would typically NOT be a good choice for MIG on stainless.Your manual (Table B.1 or Table 1, depending on how new/old your machine and manual are) suggests 98-2 Ar-O2 and settings A-3 for welding 16 ga stainless.You did turn the gas on and have the MIG nozzle (the copper one, not the black FCAW nozzle) installed before trying to MIG that stainless, right?  No gas when MIGing = bad welds.  And the polarity for MIG on stainless is DC + (the usual MIG polarity, make the torch and wire the + and the work clamp is - ).  Wrong polarity = bad welds.
Reply:Ditto!My Babies: HF Drill pressHF Pipe Bender3   4.5" Black and Decker angle grindersLincoln Electric PROMIG 175that´s it!
Reply:Originally Posted by ZTFabAre you trying to run continuous beads on the material?How are you trying to join the pieces? Lap joint, butt joint, etc?When I weld perf. metal with MIG I always find that "spot" welding it works best.If you are doing a lap joint and can overlap the pieces enough, the 3/16" perf. holes are pefect for spot welding the pieces together.Len, give us a little more info and pics, if you can, so that we can help you out.- Paul
Reply:Originally Posted by MoonRiseBook says use a helium mix for more energy in the weld, you don't need more energy in that thin 16 ga sheet!That and the tri-mix runs about 6 volts more than the arc with 98-2 mix!  I don't know if the HD3200 can push that much voltage.Try 98-2 Ar-O2.  If you use a high CO2 gas (more than about the 2.5% in the tri-mix gas) with stainless, you may end up with rusted weld beads because of the gas used (carbon pick-up from the CO2 makes the steel not-stainless)!  So C25 would typically NOT be a good choice for MIG on stainless.Your manual (Table B.1 or Table 1, depending on how new/old your machine and manual are) suggests 98-2 Ar-O2 and settings A-3 for welding 16 ga stainless.You did turn the gas on and have the MIG nozzle (the copper one, not the black FCAW nozzle) installed before trying to MIG that stainless, right?  No gas when MIGing = bad welds.  And the polarity for MIG on stainless is DC + (the usual MIG polarity, make the torch and wire the + and the work clamp is - ).  Wrong polarity = bad welds.
Reply:Was just checking for the obvious regarding the gas being on and using the right nozzle and polarity.You did clean and degrease the metal before welding?  And a quick wire brushing with a dedicated stainless steel wire brush (powered or handheld)?  (if you use a carbon steel wire brush on stainless, you can transfer carbon steel into the stainless and then you end up with crud and rust afterward.)The tri-mix needs a bit more voltage than the recommended 98-2 Ar-O2, so the A-3 settings for 98-2 will probably be to low on the volts when running the helium-blend tri-mix.  Turn the volts up and the wire speed down slow until you get spatter (volts too high).  Then go back one setting on the volts.Then adjust the wire speed to get the amps/heat you need to properly melt/weld the edges.  It will be a little tricky because the volts setting changes the amps output even if the wire speed is left alone on that machine (and others in that class of machine, it's not just the HD3200).Oh, and did you have a GOOD work clamp (ground) connection to the work?  A little crud or oil film under the workclamp can really interfere with good welding.  Been there, done that.  Wire brush and a quick blast from a can of brake cleaner fixed it.  Make sure the solvent is all gone before welding, and don't spray or apply solvent to the hot metal where you were welding (or attempting to weld).And you were trying to weld the edges of the perfs to the solid sheet underneath, right?  Not just trying to 'blast' it all together?Pics might help to give more suggestions on how to do it or what to try.
Reply:Remember start your bead on the non perf sheet and then push to the expanded.  You'll see the expanded melt into the puddle, and also remember to leave your nozzle over the work for a few seconds while the pool solidifies.  This type of extended spot welding is the best way, IMO, to Mig expanded sheet.  Also when you are dealing with stainless steel (300 series) you will want to either purge the back side of the weld with argon to prevent sugaring or use Solarflux Type B.  Then again you are just making a roasting drum so weld porosity and microbial growth niches aren't going to be a concern for spoilage...so disregard what I just said about purge or flux.  PS- Straight Argon shielding gas for stainless is your friend.  Using Argon/CO2 mixes when trying to GMAW stainless produces a rough finish weld and you will here and see cracking as soon as the weldment begins to cool.  Good luck and be sure to get a good ground to the sheet before you start or else you will make a stub weld mess MoonRise was all over that one:-)!
Reply:Thanks for all your recommendations.  I ended up turning up the volts to C (from A setting), and turning down the wire feed to 2 (from 3).  I am starting the weld in the perforated hole (lap welding perf and 16 gauge solid sheet stainless).  Worked excellent.Len
Reply:Glad it worked out.  Now where are the pics?
Reply:Originally Posted by MoonRise Glad it worked out.  Now where are the pics?