EQUIPMENT COMPACTION CHARTS

 

UNDERWATER CUTTING

Courtesy of Broco

BROCO

BROCO CUTTING MANUAL

P.O. BOX 1758

POMONA, CA 91769

714 623 2544                                                                                                        

                Made by divers for divers:

1.- BROCO ROD 18” (45.72 CM)LONG INSULATED WRAPPED

                 
 

                                                                      

   SECCION 3/8 " DIAMETRO

                                                                   

                                                                                                                                                           

 2.-3/8” OUTSIDE DIAMETER WITH OXIGEN (O2) INSIDE (Will be lited as soon as it has oxigen flowing)

3.- SEVEN ALLOY INTERIOR  RODS  PROVIDE  10,000 +◦F(5538◦C) AT THE TIP.

4.-COPPER COATED FOR BETTTER CONDUCTIVITY AND CORROSION RESISTANCE.

1.-BROCO TORCH DESIGNED FOR MAXIMUM OXYGEN FLOW TO SUPPORT BROCO RODS AT ANY DEPTH.

2.-OFFSET HANDLE  DESIGN DECREASSES FOREARM FATIGUE.

3.-ACME-THREAD INSIDE COLLET NUT REQUIRES FEWER TURNS TO SECURE AND RELEASE THE BROCO ROD. THE NUT IS ALSO LESS VULNERABLE TO FOULING FROM GRIT OR SAND.

4.-REDUCED ELECTROLYSIS DERIVED FROM UTILIZATION O LIKE METALS.

5.-TWO-PIECE BODY PERMITS RAPID DISASSEMBLY AND FIELD SERVICE.

6.-INTERNATIONAL ORANGE CASING PROVIDES MAXIMUM RECOGNITION.

7.-VALVE HANDLE ELECTRICALLY UNCOUPLED.

 

 

 

 

 

1.-BROCO REGULATOR, HIGH OXYGEN FLOW: 4400 CU FT/HR, OVER 70 cfm.

2.-SAFETY SSTAGE REDUCES CYLINDER PRESSURE BY 90%.

3.-LARGE  SECOND STAGE  DIAPHRAGM  AFFORDS CLOSE ADJUSTMENT, ACCURATE AND CONSTANT DELIVERY AT UNIFORM PRESSURE.

4.-VENTED AND EQUIPPED WITH PRESSURE RELIEF VALVE BETWEEN STAGES.

5.-INLET FILTER TO KEEP OUT FOREIGN MATTER.

6.-UNDERWRITTER’S LABORATORY APPROVED.

 

                                

 OPERATING INSTRUCTIONS

EQUIPMENT REQUIRED

1.-The Broco torch, preferred since it is designed  for  divers comfort, maximum O₂ flow, ease of operation and maintenance.

2.-High-volum O₂ regulator, capable of handling over 70 c.f.m. The Broco High-Volume regulator meets these specifications. Many other good regulators do not.

3.- Single-pole throw or double-throw single pole safety switch  (400 ampere DC, unfused).

4.-C-type grounding  clamp (appropriate for underwater use).

5.-150 to200 Ampere DC Welding machine. 100% duty cycle or 12 volt car battery.

6.- ‘1/0 welding cables for torch and ground clamp.

7.-Oxigen cylinder(s).

8.-3/8” inside diameter O₂ supply hose, from regulator to torch.

9.-2-way diver-topside communication system.

RIGGING FOR CUTTING OPERATIONS

1.-Assemble O₂ supply or manifold, utilizing clean high-volume regulator, and clean 3/8” inside diameter supply hose. Make sure regulator, hose and torch are free from any grease, oil or particles.

2.-Set O₂ pressure to 90 psi over bottom or whichever is required due to depth or operation. Pressure must be increased with increased working depth. See Table #1-“Setting O₂ Delivery Pressure VS. Depth”.

3.-Purge regulator, hose and torch. Check for leaks with soapspuds.

4.-Tape O₂ hose to power cable at 2” intervals.

5.-Connect safety switch along the negative lead to the torch and whitineasy reach of the tender. The switch is activated only upon command from the diver.

6.-Set welding machine to straight polarity: negative to torch, positive to ground or “C” clamp. If there any question about the efficiency of the cutting, check to see that the leads are properly connected and that the welding machine is delivering the indicated  amperage  and correct polarity.

7.-To check polarity, inmerse rod and grounding clamp in bucket of salt water, approximately @” apart. A stream of bubbles will rise from the tip of the cutting rod when the current is turned on. If they don’t reverse the polarity. NOTE: AC welding current is undesirable for underwater cutting because it has no constant polarity. Accordingly it increases electrical hazard to the diver and shortens the life of underwater equipment due to electrolysis.

8.-To check amperage use clamp-on gage.

9.-Establish that cables and connections are in perfect condition.

10.-All connections must be installed and made watertight by careful taping.

11.—Furnish diver with proper diving dress.

12.-Start welder, and set dial to 150 amperes maximum(at rod tip) Consult Table #2-“Setting Amperage for Cable Length and Size”.  Establish that safety switch is open (off).

13.-Attach eyeshield to diver’s faceplate:

#4 lens for muddy water

#6 lens for average conditions.

ONCE THE DIVER IN THE WATER:

1.-Secure ground clamp to work. If any part of work is above water, ground clamp may be secure there. In any case the diver must face the work as he performs. Serious shock hazard to the diver and electrolytic damage to the diver’s helmet and equipment can result if his body comes between the rod and the ground.

2.- Call for “current on” or “make it hot” and commence cutting operations.

3.-NEVER”TURN YOUR BACK” ON THE GROUND CONNECTION.

 

TABLE#1 SETTING O₂ DELIVERY PRESSURE FOR DEPTH:

                                                                                         PRESSURE GAUGE SETTING

DEPTH IN FT	DEPTH IN M	psi	Atmosphere
33	10	108	7.4
40	12	112	7.6
50	15	117	8.0
60	18	123	8.4
70	21	128	8.7
80	24	134	9.1
90	27	139	9.5
100	30	145	9.9
110	34	150	10.2
120	37	155	10.5
130	40	161	11.0
140	43	166	11.3
150	46	172	11.7
160	49	177	12.0
170	52	183	12.5
180	55	188	12.8
190	58	194	13.2
200	61	199	13.5
210	64	204	13.9
220	67	210	14.3
230	70	215	14.6
240	73	221	15.0
250	76	226	15.4
260	79	232	15.8
270	82	237	16.1
280	85	243	16.5
290	88	248	16.9
300	91	254	17.3
310	94	259	17.6
320	98	264	18.0
330	101	270	18.4
340	104	275	18.7
350	107	281	19.1

 

When depths exceed 350 ft. calculate your gauge pressure as follows:

For every 10’ of hose required, add (1) psi to the 90 psi necessary at the tip. This compensates for traditional line losses. Additionally, add 0.445 for every foot of working depth to compensate for increased hydro static pressure.

Table#2 SETTING AMPERAGE FOR CABLE LENGTH AND SIZE*:

LENGTH OF POWER CABLE	LENGTH OF POWER CABLE	#1/0	#2/0	#3/0
FEET	METERS
150	46	155	152	150
200	61	157	154	152
250	76	159	156	154
300	91	161	158	156
350	107	163	160	158
400	122	165	162	160
450	137	167	164	162
500	152	169	166	164

 

*The increases in amperage compensates for resistance losses.

For greater lead lengths, add 2 amperes per fifty feet to settings.Calculating Pressure and Amperage Settings:

EXAMPLE: A working dive to 560 ft.

Require: 150 amperes at the rod tip plus 90 psi over bottom.

Given: 650 ft of hose and #2/0 cable.

Pressure Calculations:

560ft x 0.445=………………………………………..249.2 psi   plus

650 ft. of hose x 1 psi=……………………65.0 psi

(For each 10 ft. of hose)

Base requirement………………………   90.0 psi

                                                              404.2 psi total

Set gauge at 404.2 psi to deliver 90 psi at the rod tip at 560’depth with 650 ft. of hose.

Amperege Calculations:

For 650 ‘ of #2/0 cable , start with 66 amperes for 500’ and add 6 amperes for 3 additional 50’ sections=172.0 amperes.

SAFETY PROCEDURES

Underwater cutting involves lethal electrical currents, combustion promoting oxygen, and cutting rod tip temperature in excess of 10,000 ◦F. Nevertheless, this procedure can be performed in safety providing good judgement is used, and the procedures in this manual are observed. Following some general precautions:

1.-No work of any kind may be permitted on the surface over the area in which the diver may be working. A radius equal of the depth at which the diver will be working must be kept clear.

2.-The diver’s dress and communications equipment must be in perfect work order.

3.-The cable connections should be fully insulated and watertight.

4.-The diving station and the immediate area around it must be free of combustible or explosive materials.

5.-The diver and supervisor should take every precaution to assure that the structures being cut are gas-free and oil free. And the diver should make certain that the oxygen and combustion by-products are not captured in a pocket overhead where they can ignite  and explode.

6.-Tend the diver closely. Keep air lines, torch O₂ and power supply out of work area.

7.-Since BROCO 3/8”  cutting rods will sustain ignition without electrical supply while oxygen is flowing, diver may tell topside to “make it cold” or turn “current off” once the rod is lit.Broco ¼” rods require electrical supply during the cut. In any case, current must be off while changing rods, and except when actually cutting. (Rod should be removed from torch before torch is lowered into or raised from the water).

8.- Torch maintenance:  rinse torch in fresh water and dry it after each day’s operation. Check flash arrestor and monel screen after each day’s operation for electrolysis or clogging. The screen must be replaced if clogged with dirt or slag,  or if burned out.(frequent clogging or screen burn-out indicates  either inadequate O₂ supply pressure or burning the rod past the minimum 3” remainder). NOTE; It is not safe to operate the torch without the fresh arrestor.

 

STARTING TO CUT:

1.-Loosen the Broco Collet nut. Side the Broco Ultrathermic Rod into the collet opening unit it bottoms out on the washer. Lock the rod in place on the washer by tightening the collet nut.  The heavy, coarse acme threads of the collet nut permit fast and positive rod emplacement.

A variety of collets are available for the Broco torch. A 3/8” collet is standard, but 5/16”, ¼”,3/16”,5/32” and 1/8” are available to adapt the torch to other cutting or welding rods.

IMPORTANT NOTE: Use the appropriate washer with the proper collet. An oversize washer will cause the rod to bottom on the flash arrestor, creating  electrolysis and possibly arcing. An undersize washer will restrict the flow of oxygen to the larger bore rods, causing them to work inefficiently.

2.- Before starting the cut, test for O₂ flow by squeezing the lever. A six-inch stream of oxygen should issue from the rod. Release the lever.

3.-Call for “current on”. The tender will close the safety switch.

4.- Draw the tip of the cutting rod across the work to strike the arc.

5.-Once the arc is established, squeeze O₂ lever full on, and at the same time, drag the cutting rod along the line to be cut. The angle of the rod to the work should be between 30 and 90 degrees depending on the metal thickness.

6.-Maintain pressure to keep the rod against the work while holding the rod with your free hand  like a pool cue, approximately 4” from tip for a more stable cut. Keep the tip of the rod in the puddle at all times. Move slowly at first, maintaining full penetration of cut. S you increase cutting speed, back spray and increased cutting noise will indicate lack of penetration.(Do NOT try to hold or maintain an arc. Just keep the rod against the work while cutting at all times.)

7.-When the rod has burned to whithin 3” of the torch collet nut, call for “current off”. When tender has confirmed “current off” , loosen collet  nut  a half of turn and blow cutting rod  stub from torch by squeezing O₂ lever. Insert a new cutting rod  in the collet and repeat the starting procedure. NOTE: There is no economy in using the last 3” of rod . You can damage the interior of the torch.

8.-Broco Ultra-Thermic rods will continue to burn with power off,  as long as the O₂ is still flowing tough  the rod.

9.-When using Broco Rods with other torches, make sure that both the Broco collet and the washer are employed.  The smaller washers in other torches restrict O₂ flow, and will reduce the effectiveness of the Broco rods.

10.-When cutting or melting nonconductive materials such as concrete, rock, coral, mastic, rope or marine growth, a striker plate is necessary to strike an arc. This metal plate is connected to the ground cable and placed next to the material to be cut.

When the rod is lit, maintain the O₂ flow and bring the rod to the target material. If the rod ignition is lost, relight the rod from striker plate by repeating the ignition procedure. Each subsequent rod must be lit from the striker plate in the same manner.

 

TECHNIQUES

1.-CUTTING STEEL

The Broco ¼” rod may be used for steel up to 1/2” in thickness for maximum cutting economy. The ¼” rod leaves a narrow kerf and is preferable for fine cutting. However, in bad visibility or for heavier steels, the 3/8” rod will give higher production. For materials1/2” thick and over. The Broco 3/8” rod is preferable. For materials several inches thick, saw and wedge cutting (analogous to chopping a tree with an axe) may be necessary to make entry space for cutting process.

“Rule of Thumb” estimates:

ROD DIAMETER	PLATE THICKNESS	RANGE OF CUT PER ROD
¼”	¼”	20-25”
	½”	10-15”
3/8”	½”	12-20”
	1”	9-14”
	1-1/2”	8-12”

 

NOTE: THE U.S. NAVY UNDERWATER CUTTING AND WELDING MANUAL, NAVSEA 0929-LP-000-8010, GIVES ESTIMATES FOR 3/8” BROCO ROD AT THE HIGH END OF THESE RANGES.

 

 

2.-CUTTING CAST IRON, STAINLESS STEEL AND NON FERREOUS METALS

The Broco Rod will melt all of these materials with its 10,000◦ F tip eat. Make sure that the tip is firmly buried in the work. Saw and wedge cutting( see above) may be necessary. Alternatively, maximum cutting efficiency may be achieved by burning a series of holes trough the piece prior to cutting across it.

 

3.-CUTTING THICK NON-FERROUS METALS

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 pool trough. The speed of the cut will  depend on the type and grade of metal and the technique developed by the burner. Increase O₂ pressure to 110 psi at the tip for metal over 3” in thickness.

4.-CUTTING CONCRETE AND ROCK WITH 3/8” ROD

Light the rod tip on a stricker plate and press the rod tip into the material to create a molten pool. As you melt trough the material, periodically move the rod in and out to allow the O₂ to blow the molten material away.

5.-CUTTING ROPE AND WOOD

Apply firm pressure to the tip to keep the heat in direct contact with the material to be cut. In ship work, you may choose to angle the cut and /or  bend the rod up to 90◦ to prevent damage to the hull, shaft or stern tube. On wire rope you may choose to use ¼” rod for the finer cut control. However, it is  difficult to maintain ignition with the ¼” rod without continuous rod-to-metal contact.

6.-USING 3/8” BROCO ROD WITHOUT A WELDING MACHINE

A vehicle or boat battery may replace a welding machine as ignition source. While we recommend use of a knife switch wherever possible, jumper cables can be used in a pinch as the make/break connection. In this mode, the tender should disconnect the battery on the diver’s  command as soon as the rod is lit. This will guarantee maximum battery life. Obviously, the battery used to ignite the Broco rod should not be  relied on later to re-start the boat engine. Check alternator circuitry before attempting to light a Broco rod from a running charging motor.

7.-USING 3/8” ROD WITHOUT ELECTRICAL IGNITION

To free a shackle or burn off a nut in very shallow water, the rod may be lit on the surface and taken below to do this work. Accordingly, if an oxygen supply is available, the rod can easily be lit with a gas torch or with some care with a cigarette and wooden plank. For the second method, place the cigarette on a plank and use a very low flow of O₂ from the rod to flame the wood. Press the tip of the rod into the charred wood to create a hot pocket, slowly increasing the O₂ flow and heating the rod tip to incandescence. The rod will then ignite. The Latter technique takes a delicate touch on the O₂ supply to keep the oxygen from cooling the tip and blowing the flame away from it.

8.-SURFACE PRACTICE

Cutting with Broco rod requires minimal skill and experience. In a recent test at the Professional Diving School of New York, dicer-trainees using Broco rod outcut their instructors when the latter used the leading big-bore tubular steel rod. A diver with surface arc welding or cutting qualifications will get excellent results underwater in a very short time. However, burning three or four rods on the surface before going underwater is the quickest route to maximum proficiency with the rod. Do not try “maintain an arc”, instead maintain metal-to-metal contact by keeping the rod in the puddle. Surface cutting requirements: For surface  cutting, use a welder’s helmet and  the proper lens. Good body protection (either welding leathers or other heavy clothing) is essential.

MAINTENANCE

MAINTAINING THE TORCH:

1.-After each use , remove collet nut and washer, parts #104 and #105, remove parts #106 and #123, and with medium screwdriver, un screw and remove flash arrestor and monel screen, parts #107 and #108 inspect all parts  for corrosion damage or foreign matter. Clean or replace as necessary.

2.- Dip head of torch in fresh water to clean exterior and flush interior (the hose need not be disconnected for this procedure).

MAINTAINING THE REGULATOR

1.-Before each use , prior to connecting the 3/8” oxygen hose, flush with oxygen from high pressure supply to blow out any foreign matter.

MAINTAINING THE RODS

1.- If rods are taken into salt water, rinse with fresh water before storing.

 

TROUBLESHOOTING

The Broco rod is different from the conventional tubular steel rod. A single rod will cut two to three times as far as conventional rods and do so at a higher rate of speed. Alternatively, cutting at a fixed distance normally takes under half the time and half the rods of conventional systems.

However, conventional oxygen and amperage requirements do NOT apply to the most effective use of Broco rods. Broco rods require higher oxygen flow and lower amperage than conventional rods, and most operational problems stern from operators accustomed to conventional techniques.

 

O₂ SUPPLY PROBLEMS

Broco cutting relies on good and unobstructed oxygen flow for maximum effectiveness. With inadequate oxygen flow, the rod can burn without affecting the work. Since the cutting effect is largely derived from the volume of oxygen reaching the work at the high tip temperatures provided by the rod, anything restricting oxygen flow decreases efficiency.

Symptoms: Rod burns down in more than 60 seconds of continuous use, cuts less than 12” in ½” thick steel plate. When O₂ jet from end of rod is less than 6” underwater, look for oxygen-delivery related problems.

PROBABLE CAUSES:

1.-Wrong torch. Volume of O₂ to rod tip too low. Cutting torch designed for 5/16” rods. (Old Arc Air, Craftsweld).

2.-Regulator incapable of delivering over 70 c.f.m.

3.-Dirt or obstruction in the torch, such as damaged flash arrestor, clogged or burnt monel screen, damaged O₂ flow valve.

4.-Use of ¼” or 5/16” O₂hose, clogging or obstruction of 3/8” hose. NOTE: in all these cases , the pressure at the regulator appear normal.

 

 

FIND AND  SOLVING THE PROBLEM:

a.-Shut off power torch.

b.-Remove rod from the torch and blow trough cutting rod to  check the passage.

c.-Checck supply pressureat regulator for depletion rod O₂ supply. Checkdelivery pressure, nominally 90 psi of the tip while O₂ is flowing.

d.-Remove O₂ line from torch handle and flow O₂ trough the hose. If the flow  rate is weak, the problem may be  either  in the hose or the regulator. Check each independently, and clean and/or replace. If the flow rate is strong at the end of the hose, then:

e.- Check torch collet washer to stablish that it  is in place, that is the proper one for the rod used, and that is not obstructing the collet. (Note : washers for non-Broco 5/16” r smaller  diameter cutting rods will obstruct flow significantly).

f.- Remove flash arrestor and screen from torch and inspect. Replace if necessary. Blow O₂ trough the torch and valve to ensure clear passage.

This should complete the checkout of O₂ supply. Recheck syntoms to establish that the problem has been solved.

 

EXCESSIVE CURRENT SUPLY PROBLEMS.

Broco rods require no more than 150 amperes at the tip at any time. Excessive amperage will cause the Broco rod to burn quickly.

Old hands experienced in conventional underwater cutting, will frequently endeavor to “help” the diver by increasing amperage to levels normal tubular steel rods-300 to 400 amperes, particularly for thicker metals. This can create severe operational problems with the Broco system, One hundred and fifty amperes (150) at the tip is the absolute maximum.

SYMPTOMS: Poor cutting efficiency, insulation bursting of the rod, rapid electrolytic damage  to underwater equipment.

POSSIBLE CAUSES: Welding machine set too high an amperage, elding machine delivering too high an amperage even trogh setting appears correct (this is not uncommon), polarity wrong (cables  can be  crossed or welding machine  can be incorrectly wired or marked).

FINDING AND SOLVING THE PROBLEM: Use the polarity test in section C #6 and #7 (Rigging for Cutting Operations). Check indicated amperage. If apparently O.K. , reduce  by 25% and check results.

 

 

INADEQUATE CURRENT SUPPLY

The problem provides a familiar set of symptoms to the experienced operator.

SYMPTOMS: Slow cutting, difficulty in stricking arc, cutting rod  sticks or welds itself to the work.

POSSIBLE CAUSES: Bad cable connections (they must be insulated and watertight), ground clamp making poor contact with work, welding machine delivering too low a current.

SOLVING THE PROBLEM: Check indicated amperage on welding machine. Then check ground clamp and clean ground if possible. If problem persists, redo all cable connections. Finally, increase amperage settings at welding machine.