Thermal Dynamics DRAG-GUN 38, Instruction Manual

Page: 23 / 60

Manual 0-2729 17 SECTION 4: OPERATION
D. Dross
When dross is present on carbon steel, it is commonly
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 distance. "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 bottom edge of the plate. It
can vary from a light to heavy bead, but does not ad-
here 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 some-
times useful to reduce the cutting speed to produce
"slow speed dross". Any resultant cleanup can be ac-
complished by scraping, not grinding.
4.08 Hand Torch Operation
A. Cutting with a Hand Torch
1. The torch can be comfortably held in one hand or
steadied with two hands. Choose the technique
that feels most comfortable and allows good con-
trol and movement. Position the index finger or
thumb to press the control switch on the torch
handle.
2. For edge starts, hold the torch perpendicular to the
workpiece with the front of the tip on the edge of
the workpiece at the point where the cut is to start.
For piercing, angle the torch slightly to direct sparks
away from the torch until the pierce is complete.
3. For drag cuts keep the torch in contact with the
workpiece. For standoff cutting, hold the torch 1/16
-1/8 in (2-3 mm) from the work.
4. With the torch in starting position, press and hold
the control switch. After an initial gas purge, the
pilot arc will come on and remain on until the cut-
ting arc starts.
5. Once on, the main arc remains on as long as the
control switch is held down, unless the torch is
withdrawn from the work or torch motion is too
slow. If the cutting arc is interrupted, the pilot arc
comes back on automatically.
6. To shut off the torch simply release the control switch.
When the switch is released a 15 second post-flow
will occur. If the torch switch is closed during the
post-flow, the cutting arc will restart immediately
when the torch is brought within range of the
workpiece.
B. Piercing with a Hand Torch
1. When piercing with a hand torch, angle the torch
slightly so that blowback particles blow away from
the torch tip (and operator) rather than directly back
into it.
2. Complete the pierce off the cutting line and then
continue the cut onto the line. Hold the torch per-
pendicular to the workpiece after the pierce is com-
plete.
3. Clean spatter and scale from the shield cup and the
tip as soon as possible. Spraying the shield cup
(shield cup only - no other parts) in anti-spatter
compound will minimize the amount of scale
which adheres to it.
4.09 Recommended Cutting
Speeds
Cutting speed depends on material, thickness, and the
operator’s ability to accurately follow the desired cut line.
The following factors may have an impact on system per-
formance:
• Torch parts wear
• Air quality
• Operator experience
• Torch standoff height
• Proper work cable connection
• Alloy content of material
NOTE
This information represents realistic expectations
using recommended practices and well maintained
systems. Actual speeds may vary from those shown
in the charts depending on the alloy content of the
selected material.
For complete cutting speed chart data refer to Appendix
III.