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DRJDVM's '69
05-06-2006, 01:15 PM
I'm very new to the welding and plasma cutting world so I'm looking for some tips and suggestions on using these type of tools correctly.

I just got a Thermal Dynamics Cutmaster 38 plasma cutter and all I can say is..... me likey very much :) ...... its a wicked tool !!! I cant wipe the grin off my face while I'm cutting through stuff like butter...

Anyway......

My first question...... is there a general guideline on the machine setting for certain thickness cuts etc in order to get the best clean cut ?? Alot of my stuff is going to be sheetmetal (floor pans, patch panels etc etc), so I want to get a good clean cut without blowing it to pieces.

Second question... do you guys use a standoff ??? I want the wand about 1/4 inch off the surface when I'm cutting right ??? I'm just having a hard time keeping a straight line and a separation from the surface..

I'd love to hear any tips you veterans have learned over the years for using this tool the best way...

colt zantop
05-06-2006, 01:42 PM
I can cut a straight line if I have my arm rested on something...thats what I found to be easiest. I hold my wrist with my other hand and run my forearm along something like tubing etc...

tbair
05-06-2006, 05:28 PM
I use a 2x4 as a guide on a flat piece of metal.

ProdigyCustoms
05-06-2006, 06:00 PM
I like to use one of those aluminum yard sticks for a guide. We also do a lot of 1/4" plywood, and masonite for patterns. I hate stand off tips. We always use drag tips. A few years back we took on a big project and bought 3 Thermo Dynamics, Pac 50s and love them. You bought a good one.

DRJDVM's '69
05-06-2006, 06:21 PM
So whats exactly is a drag tip vs the standard tip that come on the gun ??

The standoff looks kind of awkward and I see it getting in the way unless the piece is very flat and you have alot of room around to position the gun.

What about my question about settings for different thickness ??

ProdigyCustoms
05-06-2006, 06:47 PM
As for settings, Ours are set on kill all the time. never really seen a need to trun one down, just move faster, lol!

The drag tip is exactly what it sounds like. Ours uses a tip about 3/8" around and about 1/2" sticks out of the end of the retainer cup, so no big standoff noozle. With a drag tip, you simplly drag it along the surface. Much easier to control in my opinion.

On ours, the torch and tip are different for drag VS standoff

Matt@RFR
05-06-2006, 09:15 PM
Go here (http://www.millerwelds.com/products/plasma/spectrum_625/accessories.php), then look at the Plasma Standoff Roller Guide and the Plasma Circle-Cutting Guide.

Even with a drag tip, tip life is much better when you use a gap instead of dragging the tip. Also, never pierce with the tip on the material.

As far as settings go, Frank is right on. I've cut 18ga with a 120 amp plas at full tilt. Quite the experience.

The tip to reducing or eliminating dross on the far side of the cut is to have your travel speed as fast as you can go and still get a good straight cut.

pav8427
05-07-2006, 06:37 AM
we fab stuff at the shop and on the job site all the time and regularly cut 1/2-3/4 inch stock. the units we have at the shop will cut up to 1 inch, but when cutting that, the slower the cut can be made the better. drill a start hole if you plan on cutting thick stock. take a straight edge and make a trial cut, then measure from your straight edge to your cut. use this dimension when ever you need to layout something and compensate w/scribe marks. use this offset on the piece you want to save otherwise you have to take into account the width of the kerf. if cutting thick stock, start out with a new tip. this will keep your cut straight. the higher the amperage is set the wider the kerf will be. the drag tip works great on sheet metal up to atleast 1/4 inch. also when cutting ours cut better if you point down and towards the direction you are dragging the tip, especially on thick stock.

ProdigyCustoms
05-07-2006, 09:56 AM
also when cutting ours cut better if you point down and towards the direction you are dragging the tip, especially on thick stock.

Ahh, good advice. Ours has a gun that angles the tip at 20 degrees or so if the gun is held level, but we do get a nicer cut standing the tip straight up.

Camaro Zach
05-07-2006, 10:46 AM
For guides i have an assortment of bar stock straight edges. Its 1"x3/16" mild steel and in 6",1',2',3',4',6',8' lengths so you can cut just about anything

wendell
05-08-2006, 05:54 AM
I've had a 40A thermal dynamics and love it. I use 5/16 masonite for paterns and it gives me a perfect 1/16 stand off. I use a TON of masonaite and have even set up a second band saw and sanding station for it. Masonite is the best because it has no grain and cuts easy.

I almost never use my plasma free hand.