Plasma cutter shields, stand-off dist., gouging

[Flat-out]

I'm going to be trying my new 625 this weekend and noticed that there wasn't much guidance in the manual on what affect the different shields (the last piece on the torch) have on performance.

It is clear that the drag shield is for dragging, but does it work any differently than the "deflector shield" when using the standoff roller or the circle cutting guide? Also, does the gouging shield work differently when used w/ the standoff roller?

If I have the standoff, is there any reason I would want to drag cut?

I seem to remember that the cutting capacity is higher w/ standoff, is that right?

Any other guidance on how technique/capacity varies between SS, MS, Al and Cu?

By looking at the cutting speed chart, it seems that I should go just a hair slower than the speed at which it does not break through to get the cleanest cut. Is this correct?

One last thing, anyone tried to build up the tips when worn with TIG so that they last a bit longer?

[Blondie_486]

Flat out,

I plas cut everyday and use the drag method. It works fine for freehand cutting and following patterns and straightedges. I haven't found any difference in cutting capacity whether dragging or standoff so I don't think the stand off will gain you any capacity. I find especially when cutting thin stock if you drag the torch as fast as it can cut through the material the amount of dross on the bottom side of the cut is reduced thereby reducing the amount of clean up time. I cut 20 guage all the time and don't even have to clean the bottom side. I also drag cut stainless and aluminum although aluminum tends to melt and leave deposits in the cutting path making the torch a little more difficult to drag in some cases. As far as TIG welding the components to extend life I don't think that will work so well. If you cut properly a tip and shield will last quite a long time. I usually get close to a month out of a tip and I use it quite a bit. As for the gouging shield it's used for gouging out welds whether for disassembly of a weldment or to gouge out a bad spot in the weld much the same as carbon arc gouging or as most call it air arcing. A little practice with your plas cutter and you'll wonder how you got along without it.

Good luck
Blondie_486

[HAWK]

Flat-out,

Blondie_486 is right as usual. I too always use the drag tip. Basically it is a standard tip with the "stand off" built in to provide easier tracing of patterns, etc. I have never used the circle cutting guides, but bet they specify the standard tip because you will have an 1/8" standoff when using these attachments-at least I think so-have never used Miller's attachments. As for gouging with a plasma: I don't like it. I have 2 Arc-Air gouge torches and use 3/16" and 1/4" carbon rods to remove old or bad welds. Gouging has been done with carbon arc and air for years. I doubt the plasma and a specialized tip will change the industry standard anytime soon.

[Blondie_486]

Hawk,

I guess we're just a couple of old timers as I too prefer the carbon arc method of gouging and still use it much to the boss's dismay. We had one welder that used the plas arc for gouging but he's no longer with us so now the plas arc is used for cutting only and I have the air arc torch for gouging.

Blondie_486

[Flat-out]

Guys,

Thanks for the good input and welcome to Blondie_486.

Here is what is says for the stand-off roller:

"Helps maintain recommended standoff distance to maximize cutting performance and improve tip life."

What do you say about that?

It would be nice to get Andy or a Miller guy to check the board once in a while.

I also remeber that the website used to list different cutting capacities for whether it was a drag cut or stand-off cut. Now that info has disappeared. Does anyone else remember that or have a print out from a while back?

So how long do tip, electrodes and shields last then?

Have you done anything that makes them last longer?

What equipment do you need to CAC?

Hope to try out the 625 today.

[Blondie_486]

Flat Out,

To do carbon arc cutting or gouging you'll need an air compressor prefrably at least 5hp and a 60 gallon tank and a dc machine although I have done carbon arc gouging with an ac machine. Dc works a little better though. You'll also need a carbon arc electrode holder (torch) Mine is an older Airco that I've had around for years I looked in the Miller catalog and didn't see a carbon arc torch but check with your welding supplier I'm sure if they don't have one they can get one.

Blondie_486

[HAWK]

Flat-out,

Try this link for a pdf catalog on Arc Air gouging torches. The K2000 Angle Arc does a great job up to 1/4" carbon rod. If you go to the K3000 or K3 (straight-not angled), you need to run at least 16CFM at 90 PSI. This really pushes the best single stage gasoline compressors on pontoon tanks. Unless you are running 325 AMPS+ the 1/4" carbon is all your machine will stand anyway. If more gouging is required, make a second pass. If you've never done it, let a local machine shop show you. It's a blast (pun intended). All in all it is the best metal removal method out there and works on all conductive metals. I've been in a jam and cut aluminum plate nearly as good as a plasma. I know that sounds crazy, but experience will teach you many a trick when all you've got it just that: You can groove plate for the perfect butt weld with a steady handy and the right CAC set up. I believe they even show this in the link. You may have to copy and paste this url if it won't send you direct.

ENJOY!!!

http://www.thermadyne.com/ta/literature/pdfs/section/64_2103_ARCGOUGING.pdf

[Flat-out]

HAK and Blondie_486,

Thanks for the info on CAC.

Right now I'm more interested in my new toy!

Do you have any responses to my plasma questions above?

I ran the 625 yesterday on MS, SS and Al. What a sweet tool. Glad that the kerf is so small. Seems like it could be a great art tool. Cut my daughter's name and a heart out for her - she's a sucker for that stuff.

I cut a circle w/ the circle cutter. Very nice first try! Doing freehand cutting is a a little tricky since every wobble shows up, but against a guide (I cut a 4'x8' sheet of 1/16 MS w/ a piece of wood clamped to it) it is fantastic.

I cut some thick (1/2") Al, which was pretty rough and it through a bunch of splatter back at my new Optrel.

Should get my contractor's kit today.

[HAWK]

Flat-out,

Use the plain tip for standoff cutting with the striaght line roller and the circle cutting attachments. Adjust about 1/8" or a little less stand off. These kits are great, but are complimented by a steady hand and patience with practice. I think tip life may be a little longer with a standoff if you can hold it steady or use the roller guides-not that much longer. I still prefer to drag with the drag tip!!! It is just the freehand art that improves your skills and eventually your project outcome. Dragging is way easier to trace patterns! I think your cutting capacity will be the same with drag or standoff because the drag tip adds the stand off for you. Other metals than mild steel will slow your travel times and lessen your cutting capacity somewhat. You can get the same capacity on other metals if you will slow your travel speed way down. It is hard on your tip, but it will get the job done. Would I tig a tip rather than buy? ....no way! Tips are inexpensive and time is valuable. I rarely tig a bandsaw blade unless the stores are closed and I have to have it. Back to speed and thickness: Experiment. Everbody's technique is different. I try to make the torch a dead 90 degrees to the work piece or maybe a slightforward tilt to get the best cut and capacity. do clean your tip often when cuttin aluminum. It is harder on tips than any other metal except maybe copper.
ENJOY THE NEW TOY!!!

[Trailermaniac]

To the new operator...try this neat trick...I use copper pipe fittings (had to use about .oio shim) or other round stock to fit over plasma gun insulator...build in suitable stand off to suit...

(now the trick part)...Measure offset (or build in a convenient offset) of the center of the cutting orfice to the outside of the slip-on copper fitting (mine is 1/2 inch)...

Calulate: 2 X offset + diameter of desired hole to be cut in material (example 2 X !/2 inch offset + 1 inch hole dia. = 2 inches)...

Use electrical knock-out punches or suitable cutting tools to make smooth holes in (preferably non ferrous) sheetmetal (or non conductive material ..ie. plastic, bakelite, fiberglass plywood, etc) that are easy to cut to make templates...(not ferros material may cause the plasma arc to drift...consider even when using straight edges)

Use spacers (I use nuts and bolts or stick on silicone feet for electronic boxes) to raise the templates about 1/8 inch off material to be cut...

Lay up holes on material to be cut with centerlines for holes

Center template over layup lines...and hold in place...

Start plasma cut inside confines of the template and trace cut...if you mess up and cut too far away from the edge of the template just make another pass...I was making 1 inch holes in 1/4 inch MS in under 10 seconds...try that with your "mag drill"...You can also make templates which incorporate other inside or outside features (just remember to compensate for the offset) and edge flanges to make line up and / or set up quicker on repetative work...consider using bar stock of the proper width instead of plate...costs a little more but might be offset by labor or time (time is money)...

note: Mark all your templates with purpose / actual dimensions of cut piece and what size (hole diameter) and save your templates for future use (Library?) ...TM

[HAWK]

Trailermaniac,

Very nice template set up! Thanks for sharing that trick.

[fun4now]

Flat-out

the plasma cutter is an artsy tool if ever there was 1

it will take some practice but you will soon enough be able to make any thing your or youre dauter's heart desiers.
i made a tigger for my neice. from a collering book (pic.1)
and a POW*MIA for my truck (pic.2)
with my plasma cutter they are great tool's and even greater toy's.

[Wheels]

Fun

You have a real talent with the plasma cutter, nice work! My biggest problem is marking the metal so I can see to cut on the line. Could I ask you what you use to mark?

Mike

[fun4now]

Wheels

i start with standerd carbin paper to get the pattern on the steel then i go over that with an ingraver. it takes a lil extra time but youre lines stay even if you rub it as you try to cut.
tryed lots of things but for the more elaberate desines the engraver works the best. i got mine at sears for like $19.00 I THINK BUT YOU CAN GET THEM AT WALMART FOR AS LIL AS $10.00 sorry hit the cap loock LOL i hate that thing .

thanks for the compements and i hope i was of some help to get ya cuttin the cool stuff they realy are great toys

[Wheels]

Thanks Fun

I think I need to make a trip to the eye doctor since I can`t follow a soap stone line on a piece of metal. I`m finding it more and more difficult to focus on my welding lately also. Just wondering if I should have a garage sale soon to get rid of al the tools I can`t see well enough to use.

Sorry for the gloomy outlook, but it has been (one of those days).

Thanks again Mike