Cutting Mixed Metals

woodlandfarms · Jun 26, 2015

OK, again everyone thank you for all the help in regards to welding mixed metals. Keep those thoughts and answers coming.

Now I am looking at the things I need to cut up. I have a band saw, scroll saw, chop saw, circular saw, 4" and 7" grinders, Oxy Acet and a Plasma Cutter, and niblers.

I am going to need to cut copper plate into shapes (may need to cut aluminum plate as well). Can this / should this be done with my Plasma or......

Gary Fowler · Jun 26, 2015

Anything that conducts electricity can be cut with a plasma torch. Other than a saw, that is about all that will cut aluminum and copper except maybe a super high pressure water jet. Most if not all of those also use an injected abrasive to assist in the cutting. I doubt even Shield Arc has one of those.

Big Barn · Jun 26, 2015

Gary Fowler said:
Anything that conducts electricity can be cut with a plasma torch. Other than a saw, that is about all that will cut aluminum and copper except maybe a super high pressure water jet. Most if not all of those also use an injected abrasive to assist in the cutting. I doubt even Shield Arc has one of those.

He's prob working on acquiring one as we speak ....

Terry

Shield Arc · Jun 26, 2015

When I was building my shop crane. The head of the engineering department for the construction company I worked for ran all the numbers for me. I told him I was going to buy a CNC plasma table. He suggested I look into CNC water jets. Come to find out three of the biggest water jet manufactures in the world are right here in the Puget Sound area. The cheapest 2' x 2' CNC water jet table was $70,000.00.

An that was not a very powerful one at that. Its amazing the amount of 3-phase power you have to have to run the pumps for the bigger water jets!:shocked:

woodlandfarms · Jun 26, 2015

So I spend part of my time in LA and the local craigslist has some crazy stuff.. No, I will not be buying a water cutter, but boy do I want one. And a CNC Machine, and a plasma table, and a and a.....

The truth is I really wanted an aluminum spool gun cause I was sure I was going to be working on aluminum shortly. it has been sitting in its case for over a year and a half.

Thanks guys. The wife wants dercorative "Leaves" on this project and I really wanted just a template and to cut them out with the plasma.

Oh, and as far as I know no 3 phase in my hood. Totally kills some crazy good deals on big metal working machines.

dstig1 · Jun 27, 2015

Around here they just will not pull a 3-phase drop to a residential address, no way no how. You get a flat NO and they have heard all the whining a million times, and won't bend. It doesn't matter if there is a 3 phase line running down your road, a 3 phase transformer on your property and a spare set of connections with nowhere to go, they just won't do it. Now keep in mind: Farm does not equal Residential, so yes you can have some fun if you have a farm, but it will still cost a lot. That is a different story of course...

MinnesotaDaveChalmers · Jun 27, 2015

Don't let those awesome deals go by you - one of our local woodworkers bought a 3 phase converter so he could get the good stuff - works great

My table saw is a 3 phase and I bought a $90 phase converter for it - cheap since I only bought it to run one item.

muddstopper · Jun 27, 2015

MinnesotaDaveChalmers said:
Don't let those awesome deals go by you - one of our local woodworkers bought a 3 phase converter so he could get the good stuff - works great

My table saw is a 3 phase and I bought a $90 phase converter for it - cheap since I only bought it to run one item.

be careful with those $90 phase converters. I assume since it was $90 is was a static phase converter and not a rotary phase converter. The static phase converter will only allow a 3 phase motor to run at 2/3 of its hp rating and is not designed to be used with really old motors, (1965 and older motors). You can burn up some really hard to find motors using a static box if your not careful. Rotary phase converters are fairly simple and cheap to build. Just find a 220/230 motor of a equal size to the 3phase motors you wish to power, buy a few $25 capacitors, you need start and run capacitors, a little wire and an enclosure to put the electronics in, and you can run a entire 3phase machine shop off one rotary phase converter. My machinist friend runs 3 lathes and 2 milling machines and a surface grinder at the same time off his rotary converter. I think his rotary motor is something like a 10hp, maybe even bigger.

He has a 1947 Brown and Sharpe mill I am thinking of buying for my shop. This mill has 3-3phase motors on it and a rotary would be the only and cheapest way to convert the machine to run off my 220v.

Mysfyt · Jun 27, 2015

Also check out VFD's (Variable Frequency Drives). Single phase in, three phase out and all sorts of parameters you can play with, for example, having your motor come up to speed over a timed period. I have them on all sorts of 3ph machines in my man cave. You just have to derate them when using them for phase converting. Rule of thumb is to double the size of the vfd for the rated motor hp-buy a 2hp vfd to run a 1hp motor. They don't cost too much until you get into larger sizes. I actually run a 20hp motor for my big lathe using one. Have it start over a ten second period so it doesn't dim the lights. Check out driveswarehouse.com.

Rock knocker · Jun 27, 2015

dstig1 said:
Around here they just will not pull a 3-phase drop to a residential address, no way no how. You get a flat NO and they have heard all the whining a million times, and won't bend. It doesn't matter if there is a 3 phase line running down your road, a 3 phase transformer on your property and a spare set of connections with nowhere to go, they just won't do it. Now keep in mind: Farm does not equal Residential, so yes you can have some fun if you have a farm, but it will still cost a lot. That is a different story of course...

I think the NEC prohibits any power in a residence greater than 120 pole to ground. So it would be legal to supply a house with 208/120 3phase, but nothing else.

Legality aside, it also becomes the choice of the POCO.

dstig1 · Jun 28, 2015

Didn't say it was illegal, just that the power company won't do it... Not sure about your reference either, but it could be true, I just don't know.

Rock knocker · Jun 28, 2015

It's an ICC interpretation

E3702.1 Branch-circuit voltage limitations.
The voltage ratings of branch circuits that supply luminaires or receptacles for cord-and-plug-connected loads of up to 1,400 volt-amperes or of less than 1/4 horsepower (0.186 kW) shall be limited to a maximum rating of 120 volts, nominal, between conductors.

Branch circuits that supply cord-and-plug-connected or permanently connected utilization equipment and appliances rated at over 1,440 volt-amperes or 1/4 horsepower (0.186 kW) and greater shall be rated at 120 volts or 240 volts, nominal.

dstig1 · Jun 29, 2015

Hmmm. i wouldn't read that the way you said it earlier "limited to 120 to ground" This says between conductors, thus allowing 240V. Now you aren't going to get 460V 3ph this way, for sure, but I can only imagine someone seriously needing that at home... You certainly could get 208 3 ph by the way i read that restriction. And how does ICC apply to electric code? That is almost always based on NEC, IME...

Rock knocker · Jun 29, 2015

If the ICC "outlaws" an electrical application, then you can't put it into the house.

dstig1 · Jun 30, 2015

Well I suppose that depends on if your state adopts ICC or some other code... Or if they adopt it and modify it (seen that thing done here already...)

Rock knocker · Jun 30, 2015

dstig1 said:
Well I suppose that depends on if your state adopts ICC or some other code... Or if they adopt it and modify it (seen that thing done here already...)

Well you could weasel out of any code reference by saying it was dependent on if the AHJ adopted that particular code (in whole or part, without modification to the part in question). This includes the NEC.

Both residential codes in general use in the USA require general utility outlets and lighting circuits to be 120v, and other circuits cannot exceed 240v. A 120/208 three phase system is completely OK in a residence, it just becomes unlikely that the POCO will pull the service. But 277/480 service is disallowed in SFR's.

dstig1 · Jul 1, 2015

I don't consider it weaseling at all as being in Wisc, they do not fully adopt all the codes. No i am not current on it, but I recall noting it a couple years back when I was going for my permit. And furthermore they add their own stuff that is not in the national codes... Found that out the hard way in one instance. You work with whatever jurisdiction you are in. I'm quite sure you are right, but there may be exceptions around the country.

woodlandfarms · Jul 1, 2015

So here is a question about phasing. If you can get 208 3 phase will that run a lot of these 3 phase tools? I know the big boys are 460 but.....

Rock knocker · Jul 1, 2015

dstig1 said:
I don't consider it weaseling at all as being in Wisc, they do not fully adopt all the codes. No i am not current on it, but I recall noting it a couple years back when I was going for my permit. And furthermore they add their own stuff that is not in the national codes... Found that out the hard way in one instance. You work with whatever jurisdiction you are in. I'm quite sure you are right, but there may be exceptions around the country.

It is probably because of adopted codes, such as the ICC. But as you say, you wouldn't know because you're not current on code adoptions in your state.

dstig1 said:
Didn't say it was illegal, just that the power company won't do it... Not sure about your reference either, but it could be true, I just don't know.