Tweco 82 PlazMaster - Manual (Page 35)

PLAZMASTER 82
Manual 0-5096 4T-3 OPERATION
Edge Starting
For edge starts, hold the torch perpendicular to the
workpiece with the front of the tip near (not touch-
ing) the edge of the workpiece at the point where
the cut is to start. When starting at the edge of the
plate, do not pause at the edge and force the arc to
"reach" for the edge of the metal. Establish the cut-
ting arc as quickly as possible.
Direction of Cut
In the torches, the plasma gas stream swirls as it
leaves the torch to maintain a smooth column of
gas. This swirl effect results in one side of a cut be-
ing more square than the other. Viewed along the
direction of travel, the right side of the cut is more
square than the left.
Right Side
Cut Angle
Left Side
Cut Angle
A-00512
Side Characteristics Of Cut
To make a square - edged cut along an inside
diameter of a circle, the torch should move coun-
terclockwise around the circle. To keep the square
edge along an outside diameter cut, the torch should
travel in a clockwise direction.
Dross
When dross is present on carbon steel, it is com-
monly referred to as either “high speed, slow speed,
or top dross”. Dross present on top of the plate is
normally caused by too great a torch to plate dis-
tance. "Top dross" is normally very easy to remove
and can often be wiped off with a welding glove.
"Slow speed dross" is normally present on the bot-
tom edge of the plate. It can vary from a light to
heavy bead, but does not adhere tightly to the cut
edge, and can be easily scraped off. "High speed
dross" usually forms a narrow bead along the bottom
of the cut edge and is very difficult to remove. When
cutting a troublesome steel, it is sometimes useful
to reduce the cutting speed to produce "slow speed
dross". Any resultant cleanup can be accomplished
by scraping, not grinding.
4T.04 Hand Torch Operation
Standoff Cutting With Hand Torch
NOTE
For best performance and parts life, always
use the correct parts for the type of operation.
1. The torch can be comfortably held in one
hand or steadied with two hands. Position
the hand to press the Trigger on the torch
handle. With the hand torch, the hand may
be positioned close to the torch head for
maximum control or near the back end for
maximum heat protection. Choose the
holding technique that feels most comfort-
able and allows good control and move-
ment.
NOTE
The tip should never come in contact with the
workpiece except during drag cutting opera-
tions.
2. Depending on the cutting operation, do one
of the following:
a. For edge starts, hold the torch perpen-
dicular to the workpiece with the front
of the tip on the edge of the workpiece
at the point where the cut is to start.
b. For standoff cutting, hold the torch 1/8
- 3/8 in (3-9 mm) from the workpiece as
shown below.
A-00024_AB
Shield Cup
Torch
Standoff Distance
1/8" - 3/8" (3 - 9mm)
Standoff Distance