help with plasma cutting. can't cut $h1t

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hi guys,   I recently got talked into buying a plasma cutter after a friend kept raving about his.   I have tried using one in the past and it didn't seem to cut worth squat.   I can cut just about anything with a oxy acetylene torch up to a couple inches thick with no problems at all..   one of the reasons I was hesitant to get a plasma,   however recently I have wanted to do some more exotic cutting, light gauge, aluminum etc...   The machine I bought off craigslist is an ESAB 875.   supposed to cut up to 7/8ths and sever 1 1/4 inch.      i recenty tried cutting some 1/2 and 1/4 plate and again it didn't seem to work very well.   lots of slag on the bottom side, had trouble cutting all the way through etc...   so I am open to any help on how to cut better with it.   amperage setting,  air PSI for cutting  travel angle and speed etc...   should I error on the side of too much air/amps or be on the low side and work up??? thanks
Reply:WOW! you like to start at the top of the ladder. That is one expensive machine.Are you using on a three phase grid or just normal household 220 volts? What is the breaker amperage feeding the outlet you are using and what gauge wire is feeding it?Do you have the factory manual on how to set up and use?
Reply:Did you get the manual with it? It will have the rundown on air pressure, amps cut speeds etc..Matt
Reply:a pic is worth a 1000 words
Reply:heh its on a 50 amp circuit and its feeding of 6 gauge or 8 gauge cable depending which cord I use...  its on household single phase 220downloaded the manual from their website.... sorry no pic of it, its the older square shape not the newer "aerodynamic" looking onePaid $500 for it...  tips were worn but happened to be the same one my friend has so he gave me one of each new piece for torch as his had all the accessory pack with itTiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:Have you had your friend cut with it yet to rule out any issue with the unit itself? 50 amps should mean you are not coming up short on the powersource.
Reply:The cutting chart for a 40amp setting on 1/4" should let you travel up to 36 IPM. I'd set the air per the manual turn the torch a bit towards the cut and go.Too much power or too slow with the torch can give you more dross (slag). Too little power or too fast with the torch it won't cut through.Maybe just a little practice with a strange new handle in your hand is all that's needed.Matt
Reply:Another tip- the air has to be DRY.  If you don't have an air dryer, the moisture could be affecting it.  You're clamping the work/"ground" cable to your workpiece, not the welding table, right?  Are you traveling too quickly, perhaps?   Alternatively, (and hopefully not the case) you bought a problem that someone wanted to unload!Lincoln AC225 & MigPak 140, Lincoln Magnum SpoolGun, Miller Spectrum 375-X Plasma, Syncrowave 200 TIG, Millermatic 252 MIG, Miller Digital Elite, General 7x12" horiz/vert bandsaw, 3' box/pan brake, 20 ton press, milling machine, 12x28 lathe, etc.
Reply:Follow the specs exactly as the manual says. Use genuine Esab consumables with the part numbers listed in the manual. Make sure any orings on the torch are in place and in good shape. Make sure the torch retaining cap is in good shape. Ensure you have clean, dry air, and it is at exactly the same pressure the manual recommends.....and this should be adjusted dynamically (with air flowing).This is an inverter plasma system.....and in 99.9% of the complaints regarding poor cuts the power supply is not at fault...inverters usually work correctly or don't work at all!I have cut with this Esab system, and while it is not a Hypertherm (had to put that in there!) it does cut reasonably well when operated as designed.Jim Colt
Reply:thanks for the pointers...   I do have a very good air dryer on compressor as i use it for HVLP painting sometimes.   I do not believe that there is anything wrong with the machine, it does cut just didn't seem to be clean and pretty like its supposed to.   I did not use the values from the table so Ill print out the manual and give that a try.   my other thought was I was cutting with the workpiece only about 6 inches off the ground so maybe that was an issue too.   consumables are also OEM ESAB that my friend gave me,  I will check the o rings etc in the torch.    I see it has a seat which i did not remove,  so Ill give that a check also and try again today....Definitely gonna need some more practice..Last edited by soutthpaw; 05-12-2010 at 08:56 AM.Tiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:Actually....if you can cut well with an oxy-fuel torch, you will be a wizard with a properly operating plasma! Plasma is an easy process to grasp....unless something is not working as designed. Keep us posted on what you find.Jim
Reply:Will do, Found the chart in manual..   I had the air pressure too hi at 90,   this unit requires 65-75psi regardless of thickness.    will have to practice my IPM torch speed handling,  think my standoff was not enough so will try again  3/16 to 1/4" is recommendedTiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:Did more cutting with the Plasma today,   I was trying to blow holes through a double wall medium duty truck frame. (about 7/16" combined)..   I found that sometimes I was able to penetrate both pieces at once and other times it just seemed to gouge the second piece.    Any suggestions here.   Are they designed to cut multiple pieces together?  I was thinking that maybe if there was an air gap between the two pieces that could cause the problem I had..   Also noticed the air was coming out at an angle,  not a perfectly straight spray or whatever the technical term for it is....   Changed nozzle and was better for a short time till i fouled it up with some splatter   gotta order me some more consumables for sure...cutting some thinner 3/16 and 1/8th single wall stuff I did a bit better this time...    The chart in the manual has reference to Speed vs thickness and standoff but nowhere does it give recommended amperage for various speeds and thickness.. so I just had it at 50 I think...   air at 75 psi as suggested in manual... Anyone have amperage suggestions for me?  The machine shows Drag for 30 amps and below.  how thick can I cut with dragging?  with dragging is the tip directly on the work piece and perpindicular to the work or do you angle it  (haven't tried drag yet)Any changes for out of position Plasma cutting like overhead???thanks againTiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:some plasma systems may have trouble on multilayer materials if there is even a slight air gap between the two. The option is to go much slower.The Esab 875 consumables are not shielded.....if you drag cut at powr levels above 30 amps....or even contact the plate once...expect the nozzle to be damaged and the arc to exit the torch at varying angles. The unit will eat up consumables compared to a Hypertherm shielded process which allows drag cutting at full power. You got a good deal on this machine, you may have to live with its drawbacks!Jim
Reply:Ditto Jim's advice.Laminated things can be troublesome for plasma and O/A, heavy oxides and dirt collect in vehicle frames and don't play nice with the cut. Turn it up max and angle the torch towards the travel a bit, you may have to wiggle and maybe circle the torch some to keep the cut going. It's much like O/A in that when slag comes back at the torch bad things happen...Matt
Reply:Originally Posted by jimcoltsome plasma systems may have trouble on multilayer materials if there is even a slight air gap between the two. The option is to go much slower.The Esab 875 consumables are not shielded.....if you drag cut at powr levels above 30 amps....or even contact the plate once...expect the nozzle to be damaged and the arc to exit the torch at varying angles. The unit will eat up consumables compared to a Hypertherm shielded process which allows drag cutting at full power. You got a good deal on this machine, you may have to live with its drawbacks!Jim
Reply:I'm not actually a salesman....rather I have been involved with the development and improvement of plasma cutting systems for Hypertherm for 32 years. In this process I get very familiar with the workings of most brands and models of plasma cutters from 12 amps to 1000 amps. There are major differences in technology betwen brands and models....and yes, there are a few areas that non-Hypertherm units have the upper hand. To your point....I probably won't bring those topics up!Best regards.....and good luck getting used to your new plasma. You got a great price.Jim
Reply:Yeah the price was a steal so could not pass it up..how do gouging nozzles differ from reg nozzles?  are they just a diffused airflow so not to penetrate the work...  Are there any different thing things to do for cutting aluminum or is it the same process as steel?What would be a current and older model equivalent Hypertherm model to keep my eyes out for???   I hit the equipment auctions on a regular basis so I do see various units for sale...   Bought my TIG at auction..Tiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:On my machine (thermal dynamics) the only difference I can tell between cut and gouge tips is the size of the hole.  I take my old worn cutting tips, sand the tip flat, drill a new oversized hole and use them for gouging.  Seems to work fine.  The reworked tips cut fine also if you don't mind a sloppy cut.Dynasty200DX w/coolmate1MM210MM VintageESAB miniarc161ltsLincoln AC225Victor O/A, Smith AW1ACutmaster 81IR 2475N7.5FPRage3Jancy USA1019" SBAEAD-200LE
Reply:Originally Posted by AndyAOn my machine (thermal dynamics) the only difference I can tell between cut and gouge tips is the size of the hole.  I take my old worn cutting tips, sand the tip flat, drill a new oversized hole and use them for gouging.  Seems to work fine.  The reworked tips cut fine also if you don't mind a sloppy cut.
Reply:I had the same trouble.I was using 100 feet of eight wire for power.I cut ninty feet off and it worked way bettertractor,loader.dozer,backhoe,and all the tools to keep em movin
Reply:yep I am on a 100 foot extention But I could easily make a short one of about 15ft to go from electrical panel to garage.     Ill can also move machine over to electrical panel to try it out...  I'll post up if it makes any differenceTiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:Well nothing like a holiday weekend to force me to give the plasma another shot.   I have been doing a couple projects which i reverted to using the OA torch to cut after my initial attempts that I tried in the start of this thread... Of course I ran out of Acetylene yesterday and everything is closed for the holiday..   The good news is all my consumables that I ordered via eBay arrived last week.   so I changed the seat as I got 3 of them with the tool for $6 delivered.  not sure what the seat actually does or how you know if it needs changing but as I got the new parts (factory sealed packaging too)  I went ahead and changed them.   also I changed the tip and electrode which were both a bit different than the  one I had in there.   the new electrode looks more like a mig electrode in shape and the tip had 4 little raised points on it unlike the beveled version I was using.    Anyway I turned the machine down to 40 amps, the max rated for dragging on this machine and gave the drag approach a shot... did not try dragging last time...  WOW, whatever combination of things I did sure made a difference.   was shortening a flatbed from 12 to 9 feet cutting channel and 12ish gauge steel... worked like a champ.       Maybe I had a 30 amp tip or something before or maybe it needed a new seat..    At least I know its not a machine problem.......Got a truck to cut up for a friend this week and take to scrap metal plant so I decided I will go ahead and get some practice with the Plasma cutting up the truck ....QUESTION,HOW DO I TELL if the amperage is too low or too high for the metal thickness I am cutting???Tiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:Originally Posted by soutthpawQUESTION,HOW DO I TELL if the amperage is too low or too high for the metal thickness I am cutting???