Plasma cutting without utilities

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Howdy folks,I just introduced myself on the intro board, so I'll spare you some of the preliminary stuff.  We work on undeveloped forest land, so common utilities seem like a luxury when we're "on the mountain."  As we operate heavy equipment, pull trailers, skid logs, mill logs and perform various other forestry-related tasks while we're on the land, we naturally run into our share of welding- and/or cutting-related projects.As I mentioned in the intro section, I've always relied on others for these types of projects, but now I think it's high time that we learn to take care of some of these problems ourselves.At present, we plan to take an old refrigerated trailer we have, replace the rear doors and use it for extra storage space.  As I'd like to do the work on our own, once again, I'd like to have the ability to cut the old hinge welds, take the old doors off, cut off the old door "binders" off and install a pair of new hinged doors.  We've got a line on a MIG welder for fabricating the new doors, so the problem lies with the cutting aspects of the job.We've never owned any type of "heavy" metal cutting equipment, so we naturally started researching an oxygen/acetylene (O/A) torch setup.  As I was doing so, I started to read about plasma cutters and, specifically, how they're more diverse when it comes to cutting various types of metals (other than just mild steel).  As I understand it, most "affordable" plasma cutters require an external source of compressed air to operate.  Although we do have a pretty solid 12 kW+ generator on the property, we have nothing more to work with (at present).  In other words, if we run a compressor with our generator, we probably won't have enough source power for a plasma cutter to operate.  And before I discount the idea of investing in a plasma cutter, altogether, I wanted to run this by some folks in the know.  Are there decent plasma cutters available that have a sufficient air compressor built into them?We would like to have the ability to cut up to 1/2" mild steel, so that would also play into our power limitation as well. In short, it would seem that a full-sized compressor and a 1/2" plasma cutter are asking a bit much of our electrical source...but any productive thoughts in this regard will be much appreciated.Thanks very much for your time,RedOak
Reply:Are you telling me that you don't already have an air compressor, if only to service tires with? If so, all that is needed to use that air in a Plasma Cutter is a good filtration system. If not, maybe it's time to get a gas powered compressor. To answer your question, I don't know of any units which have built-in air and also have much capacity; they are more designed for cutting sheet metal only, I believe.
Reply:I'm sorry if wasn't clear enough on that point, OldIron2.  Yes, we have a compressor, but we have only one generator to run it.  The compressor requires quite a bit of juice to run, so the issue is running both the air compressor and a plasma cutter, simultaneously.Thanks for your thoughts on cutters with built-in air: it certainly reads as if we do have an issue here after all...
Reply:I have seen a few plasma cutters that have the air compressor built into them, but I don't know them off the top of my head.  What I do wonder though, is what the amp capacity of your generator is.  I've got little to no experience on this topic, but what I do know is that many air compressors consume a large kick of energy for a moment as they get up to speed, once they are there they use about half of whatever it is they may be rated at.  For an air compressor you probably need around 8 amps of extra power in 120v.  Outside of that thought is the idea of using some kind of lawn mower engine or something like it to turn the air compressor's motor as you weld.  Just a few thoughts that came to mind as I believe you are pretty limited in selection when it comes to plasma cutters with built in compressors, not to mention you probably aren't going to consume less power just because the compressor is inside of the plasma cutter.http://www.google.com/#q=plasma+cutt...9faa430ac3503fMiller 330 a/bp water cooledI believe in gun control, I hold my gun with two hands.  If you want to know why, click here.Buy American or bye America.
Reply:You can get compressed air in cylinders just like you would get oxygen for oxyacetylene. For a big job you could get a liquid oxygen tank, but it does not sound like you will need to go that route.
Reply:Originally Posted by weldingliferYou can get compressed air in cylinders just like you would get oxygen for oxyacetylene.
Reply:Heavy equipment repair in remote areas screams engine drive arc welder and oxy acetylene torch. MIG welding and plasma cutting are indeed a luxury, and more suited to (but not limited to) fast paced shop / production work. What did the contractors have that did your work previously?That being said a gas compressor would work fine.JasonXMT 350 MPA Dynasty 280DXSuitcase 8RC / OptimaSpoolmatic 30AThermco Ar / C02 mixerAssorted O/A gear
Reply:Sorry, I edited my post to add more details, but lost the changes. Don't have time to repost, but I'll mention one thought. Depending on your situation, you may want to look at rigging up a utility trailer (or pickup if practical) with an engine drive (usually has a 5-10kw generator built in), O/A torch, and handtools to bring right up to crippled equipment in difficult to access areas. That's what several folks in similar businesses do that I know of.JasonXMT 350 MPA Dynasty 280DXSuitcase 8RC / OptimaSpoolmatic 30AThermco Ar / C02 mixerAssorted O/A gear
Reply:[QUOTE=DSW;432672]As far as O/A vs plasma, for heavy equipment work, I'd pick O/A over plasma if I could have only one. The ability to cut well past 2-3", the ability to heat metal to loosen stuck pins, nuts and bend steel is better than the ability of plasma to cut stainless and alum. Oxy propane would also be a good route to go, especially for heating and the large fuel demands big cutting tips and rosebuds require. If I had to cut the doors off our trailer with out looking at it, and I did have to cut alum rather than steel, I'd probably grab the grinder with slitting disks, or the 14" gas cutoff saw with abrasive disks rather than try and drag out a big genset, my hypertherm 1000 plasma and the air cyl's./QUOTE]I agree with DSW. Unless you're cutting ALOT of other metals, go with oxy propane. I mainly use my plasma for cutting long straight lines, where it is fast and easy to use a straight edge guide. I don't cut alot of materials other than steel, so it hardly gets used. And from what you described, to me it seems like the majority of work will be steel. But if you're hooked on a plasma, get a gas drive air compressor. My Hypertherm Powermax600 is pretty air hungry. I also agree with BCRD, forget the mig, get an engine driven stick welder. Mig needs gas. Most work on heavy equipment is going to require a good size mig welder. If you're stuck on mig, go with a suitcase wire feeder and a 15' torch. That way you can get right up to the work area."Where's Stick man????????" - 7A749"SHHHHHH!! I sent him over to snag that MIC-4 while tbone wasn't looking!" - duaneb55"I have bought a few of Tbone's things unlike Stick-Man who helps himself" - TozziWelding"Stick-man"
Reply:You could cheat with your 12kw generator depending on how large the tank is on your air compressor.  If it's 60 or 80 gallons you can probably turn on the air compressor, let it pump up, then turn it off and start cutting with the plasma.  Keep an eye on the pressure gauge and turn the air compressor back on when needed.  With my 80 gallon tank at 175psi I'm not sure how long I can cut continuously, but I can do layout, cutting, etc for a good 30 minutes.  I've had several times where I forgot to turn on the breaker for the compressor.  I've been happily working along for a while when the plasma will no longer throw an arc.  I get a few worried minutes thinking I've broken the plasma before I discover it has detected low air pressure and refuses to turn on.When I cut anything I usually reach for the plasma, BUT if you don't have a O/A setup I would buy that first (and probably two sets of tanks since it sound like a trip to the welding supply may be lengthy).  A plasma only cuts, O/A does lots of things.Dynasty200DX w/coolmate1MM210MM VintageESAB miniarc161ltsLincoln AC225Victor O/A, Smith AW1ACutmaster 81IR 2475N7.5FPRage3Jancy USA1019" SBAEAD-200LE
Reply:As said, there are a couple of ways to go.An engine-drive welder with generator capabilities would be high on the list.Oxy-fuel has uses.If you have a need for 'remote' air, such as airing up equipment tires in the field, then you pretty much have or should have some sort of 'decent' air compressor already.  Either a pretty big electric to run off of a pretty big gen set (stand-alone gen or the engine-drive welder with generator) or an engine-drive air compressor.  I don't think the little 'hot-dog' or  'wheelbarrrow' type engine drive air compressors would cut it for a plasma cutter air source, especially not for a plasma that can easily cut 1/2 inch thick material.  Those 'little' air compressors don't have enough engine or air tank capacity to really run a plasma cutter.  That sort of air demand is in the realm of the ubiquitous 30 gallon 13hp (or so) gasoline engine air compressor.An engine drive welder to run SMAW, an engine drive air compressor, a Hypertherm PM45 or maybe the new PM 65 (needs a pretty big generator for full output power though) plasma for cutting and gouging, an oxy-fuel set-up for heating and cutting, some carbon-air parts for cutting and gouging, and a 'suitcase' wire feeder running FCAW as well as GMAW and you are set for almost anything.    The best laid schemes ... Gang oft agley ...
Reply:Depending on what your cutting needs are, you might be well served by a 14" gas cutoff saw.They're pretty limited to straight cuts (plasma is great for fabricating shapes), but will cut through just about anything (with the right wheel).
Reply:An engine drive welder to run SMAW, an engine drive air compressor, a Hypertherm PM45 or maybe the new PM 65 (needs a pretty big generator for full output power though) plasma for cutting and gouging, an oxy-fuel set-up for heating and cutting, some carbon-air parts for cutting and gouging, and a 'suitcase' wire feeder running FCAW as well as GMAW and you are set for almost anything.
Reply:RedOak,You do know about search engines like Google, right?  Or you could just go to say, a welding manufacturer like Lincoln or Miller and look up all sorts of info there.  Like different kinds of welding, and some of the different machines, and so on.www.lincolnelectric.comwww.millerwelds.comwww.esabna.com  (especially look through the info/education sections there, good stuff)SMAW : Shielded Metal Arc Welding, aka 'stick' weldingFCAW : FluxCore Arc Welding, a wire-feed welding process which is similar to stick welding.  Comes in two 'flavors', FCAW-S (self-shielding, the wire has the flux core inside and that shields the weld from the air) or FCAW-G (there is a flux core inside the wire but it has been formulated to also use an external shielding gas).GMAW : Gas Metal Arc Welding, aka 'MIG' welding.  A wiere-feed welding process that uses an external shielding gas to protect the molten weld from the air.  The best laid schemes ... Gang oft agley ...
Reply:Have you ever had the Google redirect virus?  It's named for the original effect, but it eventually hits all search engines.  It's an extremely nasty PC virus, and we're currently trying to eradicate it without having to go "off the air" (so to speak) for an extended period of time.  Thanks for helping us out, regardless, MoonRise.
Reply:Originally Posted by RedOakHave you ever had the Google redirect virus?  It's named for the original effect, but it eventually hits all search engines.  It's an extremely nasty PC virus, and we're currently trying to eradicate it without having to go "off the air" (so to speak) for an extended period of time.  Thanks for helping us out, regardless, MoonRise.
Reply:FYI, I think his reference to the redirect virus does not mean he does not want to get it from going to google etc.  He already has a virus on his computer and one of the "cute" things it does is when the user opens the internet and attempts to go to a search engine such as google the virus redirects them somewhere else.  Usually to some sort of scam webpage where they sell "virus removal tools" to get rid of the problem.  So he literally is unable to do a search for anything.  Thus preventing people from searching on how to remove the virus etc.RedOak: As for your virus problem, I would suggest malwarebyte's free anti malware utility.  It works great and depending on what virus you have it should most likely help you solve the problem.http://download.cnet.com/Malwarebyte...-10804572.htmlLike previous posters have mentioned it sounds to me like you would be best served with a O/A torch setup and a gas or diesel powered welder.  The benefits of getting a gas or diesel powered welder for your application may surprise you quite a bit if you are not familiar with them.  The first and most obvious benefit is that it will free up your existing generator for whatever you may need it for (compressor etc).The other advantages are:Welders are notoriously hard on standard generators and can really use up their lifetime very quickly.With a gas or diesel powered welder you now actually have 2 generators if you ever require additional power.  They also have a 220v outlet usually, as well as a couple 110 outlets so you can run grinders, lights etc on site.  A good engine driven welder will allow you to do stick welding, as well as flux core or mig welding (if you get the suitcase feeder) so you now have many different processes at your disposal.  You may need these different processes depending on whats broken, and what the weather is like.  If its a real windy day you would probably want to do a repair with stick or flux core welding.  If its thick material you probably want to use stick, and if its something thinner, it may be easier to use flux core or mig.Depending on where you are its usually pretty easy to find a good deal on a lightly used engine driven welder (Craigs List), sometimes already on a trailer for several thousand dollars less than a new unit.  On my local craigs list i see Miller trailblazer's and Lincoln Rangers pretty frequently.Last edited by ggarner; 10-26-2010 at 01:08 PM.
Reply:I've got a 7kw portable generator and a miller 625 plasma. I've run the plasma off the genset just as a matter of exercising the genset two or three times a year. For most small cuts everything is A okay but start into 3/8th" or 1/2" material and the genset is hacking up hairballs. It hangs in there and does it just fine but I wouldn't want to run for extended periods that way. That brings me to think that a 12kw just might be able to squeek by with running a small compressor and a plasma at the same time for light duty."The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:Yes, GGarner has it right.  We're currently suffering with a variant of the infamous Google Redirect Virus that effects any search engine.  In fact, we're getting intermittent redirects and jumps even when we type a URL directly into the URL address field -- very nasty bug.GGarner: Your words on engine-driven welders are well taken.  I've seen some Miller units on the back of work trucks, and I've often wondered exactly how they operate them.     Sandy: I'm happy to read that it's within the realm of possibility to do some plasma cutting using only one generator.  By the way, are the spec's on your cutter the maximum thickness, literally, or are they based on what you can cut in a single pass?  Please forgive my inexperience, but can you cut material that's thicker than the specified thickness by making more than one pass?  I also like your signature.Have a good one
Reply:Originally Posted by RedOakSandy: I'm happy to read that it's within the realm of possibility to do some plasma cutting using only one generator.  By the way, are the spec's on your cutter the maximum thickness, literally, or are they based on what you can cut in a single pass?  Please forgive my inexperience, but can you cut material that's thicker than the specified thickness by making more than one pass?  I also like your signature.Have a good one
Reply:Plasma can cut more metals but Oxy/A is so much more versatile when it comes to steel.  You can use it for cutting steel, washing welds out, beveling, gouging, welding, brazing, solderig, heating, bending.  The only real weakness of O/A is when working with materials less than 1/8th inch.  Even the most basic torch can cut steel from 1/8th to 6 inches with just a tip change.  The thickest steel I have had the misfortune of cutting was 3", the thickest  I have had to pierce was 2 inch.Every shop needs these things in this order.  A vice, a grinder, an O/A setup, a welder, and the rest.Last edited by 76GMC1500; 10-27-2010 at 12:59 AM.
Reply:Handheld plasma cutters?Try   http://hypertherm.com/en/Products/Ha...lasma/Systems/As I mentioned above, the PM45 can cut 1/2 inch just fine.http://hypertherm.com/en/Products/Ha...ax45.jsp#specsAnd it can run at full power off of an 8Kw generator/engine-drive.The bigger PM65 is more powerful and need more power to run it.Read the specs for yourself.  As to cutting thick metal with a plasma or O-A in multiple passes, not really.  You have to use the 'correct' tool for the thickness of the metal that you are cutting.  It's not like cutting with a circular saw where you can make a pass at partial depth through the material and then set the blade and go back and make another deeper pass and repeat until you are either through the material or can't set the saw blade any deeper.    The best laid schemes ... Gang oft agley ...
Reply:Stick with O/A in the field!! As said above plasma does have benefits but in the field the O/A is easier to work with and doesn't require a compressor or generator.Co-Own CNC shop:Miller :1251 plasma cutter, MaxStar 700 TIG/Stick, & XMT 456 Multiprocess Welder.&  2 Hypertherm HPR260's Plasma CutterSorry I had a bad stroke but now I am back.