SURFACEPRACTICEFORNEWUSERS
If you are a new cutting torch user, to avoid serious
injury or death, follow the safety information in this section regard-
ing surface practice for new users
i
a
o
w
s
Fumes from burning tape can cause respiratory injury. Always re-
move the tape insulation from underwater cutting rods before burn-
ing at the surface and keep your head away from the fume plume.
Cutting torches can cause burn injuries. Always wear adequate
protective clothing, welder's gloves, and face and eye protection
specifically designed for burning (use a #6 welding lens if using a
battery and a #10 with a welding machine).
1. Cutting with Broco Underwater Ultrathermic cutting rods requires prac-
tice. A diver with surface arc welding or cutting qualifications will get ex-
cellent results underwater in a short time.
2. Burning at least three or four rods on the surface before attempting to
cut underwater is essential to gaining maximum proficiency with the
Broco Underwater Ultrathermic cutting system.
3. Do not try to "maintain an arc." Instead practice metal to metal contact,
keeping the rod tip in the molten puddle, and adjusting travel speed to
ensure complete penetration.
TECHNIQUES
Note: Continuous power is recommended for cutting with the 1/4" diam-
eter Broco Underwater Ultrathermic cutting rod, otherwise it is difficult to
maintain ignition.
Cutting Steel
The 1/4" diameter Broco Underwater Ultrathermic cutting rod may be used
for cutting steel up to 1/2" in thickness for maximum cutting economy. The
1/4" rod leaves a narrow kerf and is preferable for fine cutting.
In bad visibility or for thicker steels, the 3/8" diameter cutting rod will give
better production. For materials 1/2" thick or thicker, the 3/8" rod is prefer-
able. For metal several inches thick, employ saw and wedge cutting (anal-
ogous to chopping wood) to achieve full penetration.
Broco, Inc.
10868 Bell Court
Rancho Cucamonga, CA 91730 USA
Ph: (909) 483-3222 (800) 845-7259 Fax: (909) 483-3233
e-mail Sales@Brocoinc.com
www.Brocoinc.com
www.strongweldingproducts.com
© Copyright 2007 by Broco, Inc., all rights reserved. Any reproduction
in whole or in part without the express written permission of Broco,
Inc. is expressly prohibited.
2. The Broco Underwater Ultrathermic cutting rod requires oxygen of at
least 99.5% purity to sustain ignition without power. Cutting with con-
tinuous power, a reduction in the purity of the oxygen by 1% can de-
crease cutting efficiency by 25%.
If the rods continuously extinguish underwater, or burn erratically, the
problem is probably poor quality oxygen.
Solution:
A. Obtain a source of oxygen from a different, unrelated supplier.
Note: Since a gas supplier will usually have all his oxygen coming from
one manufacturer, changing cylinders for one filled at the same place or
time will not solve oxygen purity problems, Using oxygen of other manufac-
ture will either solve or rule out an oxygen purity problem.
Power source problems:
1. If the rods consume too quickly, it is likely the welding power source is
delivering greater than 150 amps.
Solution:
A.Use an in-line or clamp type ammeter to verify current output. Adjust
as necessary.
Note:
The U.S. Navy Underwater Cutting and Welding Manual, NAVSEA
0929-LP-000-8010, gives estimates for the 3/8" Broco Ultrathermic cut-
ting rod at the high end of these ranges.
Cutting Cast Iron, Stainless Steel and Non-Ferrous Metals
The Broco Underwater Ultrathermic cutting rod will melt all of these ma-
terials. Make sure that the tip is firmly buried in the work. Saw and wedge
cutting may be necessary. Maximum cutting efficiency may be achieved
by burning a series of holes through the piece prior to cutting across it.
Cutting Thick Non-Ferrous Metals
Note: Increase oxygen delivery pressure to 110 psig over ambient pres-
sure for metal over 3" in thickness.
Create a puddle and dip the rod tip slightly below the surface of the
molten metal. From time to time push the cutting rod deeper into the
metal to wash it out and blow the slag away.
Cutting (Melting) Concrete and Rock
Note: Always use the 3/8" diameter Broco Underwater Ultrathermic cut-
ting rod when cutting concrete or rock.
Light the rod by striking the tip against a copper or steel plate attached
to the ground cable. Keep the oxygen lever depressed and raise the rod
from the plate to the workpiece. Call for the current to be switched off.
Press the rod tip into the material to create a molten pool. While melting
through the material, periodically move the rod in and out and around to
enlarge the hole to vent gases and to blow the molten material away.
Cutting Rope and Wood
Light the rod by striking the tip against a copper or steel plate attached
to the ground cable. Keep the oxygen lever depressed and raise the rod
from the plate to the workpiece. Call for the current to be switched off.
Apply firm pressure to the tip to keep the maximum heat in direct contact
with the material to be cut. In ship work, the rod may be angled or bent
up to 90 degrees to prevent damage to the hull, shaft or stern tube. On
wire rope the 1/4" diameter rod may be used for finer cut control. When
using the 1/4” rod, continuous metal to metal contact is necessary to
maintain rod ignition.
Using 3/8" Broco Underwater
Ultrathermic Cutting Rods With a Battery
Note: Use of a battery power source is not recommended for cutting at
depths below 60 fsw.
A vehicle or boat battery (12v or 24v DC) may replace a welding machine
as the ignition power source. The use of a safety knife switch is recom-
mended, although jumper cables may be used as the make/break con-
nection. To preserve battery life, the tender must disconnect the battery
immediately on the diver's command once the rod is ignited.
ROD DIA.
PLATE THICKNESS
RANGE OF CUT
PER ROD
1
/
4
”
1
/
4
” 20”–25”
1
/
4
”
1
/
2
” 10” – 15”
3
/
8
”
1
/
2
” 12” – 20”
3
/
8
” 1” 9” – 14”
3
/
8
” 1
1
/
2
” 8” – 12”
"Rule of Thumb" estimates:
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