Marine buisness practice

Cultural issues


As we discussed in class. New Zealand is a multicultural country with people with different accents. Some accents are very strong and is very difficult to understand. It becomes very difficult to run a buisness if people dont know what you are saying. There should be a good level of english. You should talk clearly and slowly for people to understand you if you have a strong accent. Customers will be more confident and comfortable doing buisness with you when this is achived.

Charge out rates


As we discussed in class, it is very important to know how you are going to charge your customers. Calculation this you should know how you are going to charge them by the hour. Depending on your skill, market value for doing the particular job etc. You should also look at ur overheads and calculate how much income you need to run your business smoothly. Some people have a less hourly rate but charge for longer hours to match their overheads, Customers could also try different places and get quotations get a cheaper place to do their jobs. therefore your charge out rate should be reasonable according to the market value to do the job.Calculate how much money you need to make to cover your expenses. Expenses include materials, wages, advertising and anything else that will take away from your profit base.Look at what your competitors are charging for similar services. You should look into how long they have been in the business and how well they are rated throughout the community.Determine whether or not your charge-out rate will be based on an hour or daily rate. 


Warranties and Guaranties


Warranties


In business and legal transactions, a warranty is an assurance by seller to the customer that specific facts or conditions are true or will happen; the customer is permitted to rely on that assurance and seek some type of remedy if it is not true or followed. The seller will have to fix or replace the product if the product is not doing what it was told to do and is covered by the warranty period.


Guaranties



A guarantee is a promise by a person (the guarantor) to settle a debt or fulfil the promise of someone else.   The person to whom the promise is made is called the creditor or lender and the person on whose behalf of the promise is  made is called the principal debtor or borrower.

Guarantees often state that the obligation  of the guarantor is  equivalent to the borrower’s obligations.  In such a case the lender may call on the guarantor to pay the debt in full without requiring payment from the borrower, without exhausting all of their remedies against the borrower, or without exercising any rights under any securities given by the borrower. In these circumstances when the guarantor  repays the guaranteed debt in full, the guarantor may be able to seek reimbursement from the borrower by taking over the lender’s debt and receiving a transfer of  any security given to the lender by the borrower.  If the borrower is insolvent or the security transferred is inadequate, then the guarantor may be unsuccessful in recovering the debt from the borrower. Because a guarantee exposes a guarantor to potential liability for another person’s debt without any direct benefit, a potential guarantor  should carefully consider whether or not to give a guarantee.  In practice, the guarantor’s decision to give a guarantee is often determined by factors other than an assessment of the likelihood of the guarantee being called up.  For example, a creditor’s loan offer may be conditional
on a guarantee being given.

Quotations


A quote is a written agreement, given to a customer before the required work is done. Once a company has given a customer a written quote; it becomes a legal document, in which the given price for the job is not allowed to change. This includes things like labour, materials and parts..Giving a Quote for something you should always be sure of the cost and hours spent on the job.




Estimates


Estimates should be a general or fair idea of what the cost would be. It is calculated but an estimate for the part price and how long it will take to perform the job. It is just an opinion to the customer on how much the cost would be. 




Courtesy Services


Business courtesy plays a very important role in running a business you should be always polite and kind when taking to customers. You should be approachable.The customer should always feel comfortable talking to you. Phones should be answered prepositionally and polity in a good manner. Also the tone of you voice should be controlled when talking to someone. All this contributes to a healthy business.




References


http://www.davidstonelawyer.co.nz/legalbrochures/guarantees.pdf
www.wikipedia.org
http://www.consumer.org.nz/?gclid=CO6dyMjO0KwCFYSFpAodfG6CqQ

cooling and corrosion

Explain the terms conduction, convection and radiation.

Conduction is the transfer of heat by touch from one solid object to another. Convection is the transfer of heat  by movement through liquid and gases. Radiation is transfer of heat from an object travelling through a space until absorbed by another object.

Direct Cooling?

Direct cooling is a water cooling system. The water is drawn into the water jackets to cool the engine. The water absorbs the heat from an engine and cools it. The picture above also has a radiator which cools off the coolant. Marine engines just pull in water and pump it back out.

Indirect Cooling?

The picture above is a heat exchanger. This type uses coolant to cool the engine. The coolant is circulated through the engine and the heat exchanger. The heat exchanger takes the heat off the coolant. Raw water is drawn into the heat exchanger jackets to cool off the heat exchanger and then pumped out the exhaust.  The cool raw water absorbs the heat from the heat exchanger and the heat exchanger abosrbs the heat from the engine.

What is the purpose of the thermostat?

The thermostat controls the temperature of the engine. The valve opens when the engine has reached its maximum operating temperature. The cool coolant then circulates through the water jackets cooling the engine. The valve is then closed again when there is cool coolant in the jackets.


Pressure cap?

The pressure cap is on top of the radiator at the fill port. The pressure cap increases the boiling point of the coolant. The cap is a pressure release valve.When the fluid in the cooling system heats up, it expands, causing the pressure to build up. The cap is the only place where this pressure can escape, so the setting of the spring on the cap determines the maximum pressure in the cooling system. When the valve open excess coolant returns to the resavoir. When the radiator cools back down a vacuum is created sucking the excess coolant back into the radiator.


Why are engines fitted with a core plug and what is the purpose?

.
There are holes in engine block that were required to cast the engine upon manufacture. Plugs were installed at the end of this process. These plugs are designed to POP out if the engine freezes due to lack of antifreeze. They can save the engine from requiring total replacement if this condition happens.






 How does the centrifugal circulating water pump work?

The centrifugal pump uses a rotating impeller to increase the pressure of the fluid. Centrifugal pumps are commonly used to move liquids through piping. The fluid enters the pump impeller along or near to the rotating axis and is accelerated by the impeller, flowing radially outward into a diffuser or volute chamber (casing), from where it exits into the downstream piping.




Why is it important to lubricate the impeller when fitted from new?

When the impellor is fitted  it is dry and there is no lubrication , all impellors rely on being wet as a way of lubrication, so a little silicone or grease is to be used so that the impeller can turn easily in the housing before it is meets water.




When fitting a impellor what should you check before refitting the housing and why?
It is important to check the gaskets are good and in place Also to check for cracks.. Because there is a lot of force in the water when the impeller is working. The pressure can cause it to fail.




What is the purpose of a oil cooler and how does it work?

The oil cooler works like the radiator. Instead of the coolant, it circulates the engine oil which takes the heat of the oil and helps keep the engine cool.




Why do we have Inhibitors and Antifreeze?

Antifreeze are used in radiator  to help raise the boiling point, and  lower the freezing point of the coolant. The inhibitors are used to stop rust and sludge build up in the  system.




How do you test antifreeze?





What is Cavitation Corrosion?

Cavitation corrosion occurs when steam pockets or bubbles eat away into the metals. This form of corrosion will eat out the volutes and impellers of centrifugal pumps with ultrapure water as the fluid. It will eat valve seats. It will contribute to other forms of erosion corrosion, such as found in elbows and tees. Cavitation should be designed out by reducing hydrodynamic pressure gradients and designing to avoid pressure drops below the vapor pressure of the liquid and air ingress. The use of resilient coatings and cathodic protection can also be considered as supplementary control methods.




What is galvanic corrosion?

Galvanic corrosion is an electrochemical process in which one metal corrodes preferentially to another when both metals are in electrical contact and immersed in an electrolyte. The same galvanic reaction is exploited in primary batteries to generate a voltage.




Describe the terms:


Stray Corrosion ?
Stray current corrosion refers to corrosion damage resulting from current flow other than in the intended circuit.


Corrosion Fatigue?
Corrosion fatigue is damage in a corrosive environment. It is the mechanical degradation of a material under the joint action of corrosion and cyclic loading.


Stress Corrosion?
By cracking under a sudden unexpected failure of normal ductile metals in a corrosive environment. This happens when the temperatures of metals are high.


Crevice Corrosion?
Crevice corrosion is a corrosion occurring in spaces to which the access of the working fluid from the environment is limited. These spaces are generally called crevices. Examples of crevices are gaps and contact areas between parts, under gaskets or seals, inside cracks and seams, spaces filled with deposits and under sludge piles. Common with stainless steels.


What is electrolysis?
 is a method of using a direct electric current  to drive an otherwise non-spontaneous chemical reaction. Electrolysis is commercially highly important as a stage in the separation of elements from naturally occurring sources such as  using an electrolytic cell.


What are sacrificial anodes made off?

  
Sacrificial anodes are made off zinc, and are very common in the marine industry, to help protect components in the salty environment.



References 

http://en.wikipedia.org/wiki/Conduction_(heat)

http://coolingtower-design.com/2011/01/15/engine-cooling-system-2/

http://www.zitrec.com/Applications_indirect_cooling_systems.htm

http://auto.howstuffworks.com/question248.htm

http://auto.howstuffworks.com/cooling-system7.htm

http://en.wikipedia.org/wiki/Core_plug

http://www.aquaskier.com/articles/impeller_replacement.htm

http://en.wikipedia.org/wiki/Oil_cooling

http://corrosion-doctors.org/Forms-cavitation/cavitation.htm

http://en.wikipedia.org/wiki/Corrosion_fatigue

Automotive Gearbox

What type of gears are used for forward and reverse in a manual gearbox? Give an explanantion for your choice.

The above pic is a straight cut or spur gear which is used for reverse gear in automotive gearboxes. The reverse driven gear, idler and driving gear is all strait cut. This is used because the gears are easily engaged.

The above pic is a helical cut gear which is used for forward gear in the automotive gearbox. There is more contact space therefore the gears are more stronger, quieter and smoother than the straight cut gear.


What is the purpose of a bualk (synchro) ring?

The Baulk ring ensures the gear changes are smooth and quiet by preventing the gears to be engaged until both components coming into contact are at the same speed. The baulk ring speeds up or slows down a gear before engagement.


What is the purpose of a synchromesh unit? Explain the operation of a synchromesh unit.

The syncromesh unit has a hub, a sleeve , bearings and the baulk ring. When a gear is selected, the shift fork pushes or pulls on the sleeve. As it moves, the small teeth engage the teeth on the synchro ring, which causes the synchro ring to rotate at the same rate as the synchrmesh assembly, which are splined to each other as well as the output shaft.  As the sleeve continues to move toward the gear, the inside of the synchro ring is pressed up against the conical shaped part of the gear.  This causes the gear to match speed with the synchrmesh, and once the speeds are matched, the synchronizer sleeve continues to slide toward the gear, engaging the teeth on the side of the gear.


What type of bearings do we find in gearboxes?

We find a lot of different types of bearing in gearboxes. We have needle roller bearings inside the input shaft. We also have caged needle roller and main shaft bearings which are bigger. The bearings differ due to load capcity, size and type for the application.


Give an explanation of a gear ratio.

A gear ratio of a gear box is the ratio of the speed of the input shaft to the speed of the output shaft. The gear ratio comes form the teeth on the gears. The driver gear drives the driven gear. If both the teeth of the driver and driven gear are the same the ratio is equal to 1:1. Different gear ratios allow the final drive to achieve different speeds and torques.


References

http://wiki.answers.com/Q/What_is_a_baulk_ring

http://moodle.student.cnwl.ac.uk/moodledata_shared/cdx%20etextbook/dswmedia/trans/clutchMan/gearLayOp/baulkring.html

http://members.cox.net/elans4/Transmission.htm

http://en.wikipedia.org/wiki/Gear_ratio

Marine GearBox

Explain what a duo propeller system is and how it works and operates?

The duo propeller system uses 2 propellers instead of one.The propellers are fully submerged. The propellers are counter rotating. One propeller spins clockwise, while the other rotates counterclockwise. This reduces wasted energy and results in better efficiency through the water.




Explain the different type of gear selection systems (in outboard gearcases and stern drivers and Inboard marine gearboxes)

The stern leg system uses a tapered cone dog clutch system to select forward and reverse gear. the cone is pushed against the tapered surfaces to select gear. As the gear selector is moved the cone moves closer to the taper and then the two components are locked up together to engage the selected gear. The outboard gear case system on  uses a dog clutch system which moves up and down the output shaft to select forward and reverse gear. I found the video below on YouTube which shows how the clutch dog moves up and down to select gears.




What type of gears are used in outboards and stern legs?

Outboards and stern Legs use helical cut gears which are in constant mesh. Helical gears are cut at an angle to the face of the gear. Manufacturers choose this type of gear because it is much  quieter, stronger and smother. They can carry heavy load because of the greater surface contact with the teeth. As in outboards the gears are meshed at 90 degrees, these gears are able to be mounted on perpendicular shafts adjusting the rotating angles by 90 degrees. The teeth on helical cut gears are also stronger.


Why would a V drive be used instead of a standard shaft system ?

The V-drive system is a propulsion system for boats that consists of two drive shafts, a gearbox, and a propeller. Using V drive the engine can be mounted in the rear of the boat. In this system, the output shaft of the engine faces forward, and the shaft carries the drive to a V drive gearbox, which turns the drive through an acute angle and thus back toward the stern. V drives system can allow the boats to have flatter bottoms and are more roomy than standard shaft systems. The boat also have higher top speeds as most of the weight is at the rear if the boat.

 Compare a jet unit with a surface drive unit and give reasons why you would choose one system over the other.

The jet system draws water from under the boat into a pump inside the boat, then expels it through a nozzle at the stern at high pressure which makes the boat to move. Whereas the surface drive uses propellers half in and half out of the water to propel the boat.


Surface drive is more cheaper to less fuel consumption than jet drive systems. Also the jet drive system sprays a lot of water out and get the deck messy. Jet drives are pretty inefficient at low speeds. Advantage of jet system is it has no exposed propeller therefore it can run around in shallow waters. But i was thinking you would not want to run them in shallow waters anyway as it would suck up sand into the pump and cooling system and cause damage. Also the jets can suck things up into the jet pump example plastic bags and ropes and etc and cause major problems.Therefore i choose the surface drive system over the jet system because of the above reasons and its simply surface drive systems are more efficient and cheaper to maintain than the jet system.


References

http://www.ehow.com/how-does_5336911_volvo-outdrive-duoprop-works.html

http://books.google.co.nz/books?id=cwEAAAAAMBAJ&pg=PA106&lpg=PA106&dq=tapered+cone+clutch+in+stern+leg&source=bl&ots=Szbu1jXwcC&sig=VhpaHGkYGfTy9Dx9rY5L-2s6aKQ&hl=en&ei=BPqQTt-HKaeYiAeaxrToDQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CCYQ6AEwAA#v=onepage&q&f=false

http://www.perfprotech.com/store/articles/sterndrives.aspx

http://www.sterndrive.info/outboardmotor/heavy_duty_gears.html

http://www.tadiesels.com/borg_warner-vdrive.html

http://www.searay.com/boat_graphics/electronic_brochure/company22491/TST_9.pdf

http://www.utoronto.ca/ski/water/faq/btdrivetrain.html

http://en.wikipedia.org/wiki/Jetboat

Gearbox Questions

1- Explain the difference types of gear selection systems found

• In outboard gear cases ans stern drive
• Inboards marine gearboxes

2 - what type of gears are used in outboard and stern legs.

• give an explanation of why manufactures chooses this type of gear

3 - Explain what a duo propeller system is and how it works and operates.

4 - What would a V drive be used instead of a standard shaft drive system,

5 - Compare a jet unit with a surface drive unit and give reasons why you would choose one system over the other.

Health and Safety (WELDING)

The gas welding plant consists of the 2 gas cylinders, oxygen and acetylene. The hoses, flashback arrrestors, gauges and the welding tip and torch. The video is a introduction about gas welding.









Safety Protection

When doing gas welding you must always wear safety equipment. As mentioned in the first part of health and safety you must wear proper steel toe safety boots and overalls to suit the job. You must wear 100% cotton overalls as it does not catch on fire from sparks and molten metals flying around. A welding leather apron can also be worn for more protection.


Eye safety is a must when doing gas welding. You must always wear the right type of gas welding goggles when doing gas welding. The goggles will protect your eyes from flying sparks and bursting molten metals. Also protects your eyes from the fumes that come out of the burning metals. I know people who did not use their googles properly and now suffering from very poor eye sight.

Leather gloves can also be worn for more protection to the hands. But I dont like wearing gloves as i dont get a proper fell of torch. For me welding without gloves is more better. But i am very carefull of not to touch hot metals and burning myself. I have burnt myself once when i picked up the filler rod from the hot side. Then i treated it by puting my finger under cold running water for about 10 minutes and it was just fine. So i tink it is a good practice to wear gloves to prevent yourself from burns.


Oxygen Cylinder

The oxygen cylinder is black in colour and the valve outlets are right hand threads.Oxygen cylinder is a solid drawn cylinder out of mild steel or alloy steel. Mild steel cylinder is charged to a pressure of  2000psi and alloy steel cylinders to  2500psi.Because of the possibility of the oxygen pressure becoming high enough to rupture the steel cylinder in case the temperature rises, an oxygen cylinder is equipped with a safety nut that allows the oxygen to drain slowly in the event the temperature increases the gas pressure beyond the safety load of the cylinder.An oxygen cylinder has an inside diameter of 21.6 cm, wall thickness 0.650 mm  and length  127.5 cm. In order to protect cylinder valve from getting damaged, a removable steel cap is screwed on the cylinder at all times When the cylinder is not in use.


You should never use bottled oxygen as compressed air. Never put oil or grease on oxygen guages, regulators or screw threads as pure oxygen reacts with the oil and can cause an explosion or spontaneous combustion. Keep this bottle very secure. If it drops and breaks the tap it becomes a live rocket due to the pressure. The video show how it dangerous the oxygen bottle can be.











Acetylene Cylinders

A acetylene cylinder is maroon in color and and all valves a screwed left handed. It can be easily recognised as the nuts have a cut or grove on them to show they are left hand threaded. This is also a solid draw steel cylinder with a pressure of  225psi. This is very low pressure compared to the oxygen cylinder.


The acetylene cylinder is filled with a porous type material that acts like a sponge. The sponge is filled with acetone. When the acetylene is compressed into the cylinder it is dissolved in the acetone. Never use the cylinder lying down orelse if there is a liquid draw into the hoses there can be explosions. Safe working pressure in the lines are up to 15psi. The video shows an acetylene factory explosion,







Safety With The Cylinders


Cylinders must be prevented from sharp impact with one another or with the ground.  Acetylene cylinders must always be kept upright.  A cap must be fitted on the cylinder while it is not in use.  Cylinders should not be exposed to welding flame, direct sun­ light, water, etc.  Cylinders should be well fastened at their places so that they do not fall.It should be stored in a well protected, well ventilated, dry location, well away from highly combustible materials such as oil or excelsior. One should not smoke at the place where gas cylinders have been stored. Cylinders containing acetylene and oxygen should be stored separately or quite far apart from each other.

• Do not use a cylinder as an electrical ground connection.
• Do not fasten cylinders to a work table or to structures where they could become part of an electrical circuit.
• Do not strike an arc on a cylinder.
• Do not use a flame or boiling water to thaw a frozen valve. Valves or cylinders may contain fusible plugs which can melt at temperatures below the boiling point of water.

• Mark or label them as "Empty cylinder" and store empty cylinders away from full cylinders.
• Return empties to the supplier.
• Remove regulators when not in use and store these away from grease and oil. Put protective caps on the fittings when in storage.
• Keep cylinders and fittings from becoming contaminated with oil, grease or dust.
• Do not use a cylinder that is not identified or if the label is not legible. The colours of industrial gas cylinders are not standardized.
• Remove the regulator and replace the valve protection cap before moving a cylinder.Move cylinders with appropriate trolleys. Use proper lifting cradles.Do not lift a cylinder by the valve cap..Do not drag, slide, or drop cylinders. If an acetylene tank has accidentally been left on its side, set it upright for at least one hour before it is used.Do not try to refill a cylinder or mix gases in a cylinder.

Pressure Guages

The pressure regulator has 2 gauges. One is the contents pressure and the other one is the working pressure you want to choose by turning the knob. Oxygen and acetylene use different gauges. Oxygen is right hand thread and acetylene is left hand thread. Therse are precision instruments and should be used very carefully. It should not be dropped.


Use the correct pressure regulator for a gas. For example, never use acetylene pressure regulator with any other gas. A pressure regulator shall be used, only, at pressures for which it is intended. Handle pressure regulators carefully. Cylinder valves should be opened slowly to avoid straining the mechanism of pressure regulators. Do not move the cylinder by holding the pressure regulator. For repairs, calibrations or adjustments purposes the pressure regulators should be sent to the supplier. Do cracking to take dust and dirt out of the valves and threads before connecting pressure regulator to the gas cylinder.
 Connections on regulators shall be inspected before use to detect faulty seats which may cause leakage of gas when the regulators are attached to the cylinder valves. Never use oil, grease or lubricant of any kind on regulator connections. Video Shows regulator safety and how it burn out when safety precautions are not taken.











Welding Hoses

These hoses are made of reinforced rubber and are color coded. Oxygen are normally black, green or blue. Acetylene hoses are maroon or red.  And also the fitting acetylene is left hand thread nd oxygen is right so you don't mixup when connecting up the hoses.


Hoses should always be checked for cracks burns and other damages. Never repair the hoses. It is a gud exercise to always change the hoses if damages. Always protect hose from being trampled on or run over. Avoid tangle and kinks. Never leave the hose so that it can be tripped over.Protect the hose from flying sparks, hot slag, hot workpiece and open flame. If dirt goes into hose, blow through (with oxygen, not acetylene) before coupling to torch or regulator. Store hose on a reel (an automobile wheel will do) when not in use. Never allow the hose to come into contact with oil or grease; they deteriorate the rubber and constitute a hazard with oxygen.






Welding Torch and Tips

The welding torch is where the 2 gases are mixed to get the working gas. There are 2 control valves one for the oxygen gas which is black or blue and the other one for acetylene which is red or maroon in colour. These valves are there to control how much of each gas you want to make your working flame.  The mixing chamber 
has the threading fitting in which the tips are fitted.


The tip and all fittings should be tight so that there is no gas leaks. Always leave the torch on the holder and turn it off when not in use.

Welding tips are made of pure copper and shaped inside to give an ideal welding flame. There are diggerent sizes of tips for different applications and heats. For general gas welding we used a 8mm tip and to make the flame a bit hotter we went for a 10mm. The tip cleaner is used to clean the tip when it gets noisy or the flame seems to be a bit out.


Gas torches and tips should be stored in clean boxes to avoid gas holes from becoming burred and choked with dirt. Never use a gas torch as a lever or hammer. A spanner and not a plier should be employed for changing tips. Screw tips only tight enough for a gastight Joint. All blow pipes and other apparatus shall be periodically dismantled and cleaned internally, preferably by the supplier. Gas holes must be clean, smooth and of correct size.During working, if the tip becomes overheated it may be cooled by plunging the torch into water; close the acetylene valve but leave a little oxygen flowing. Never hang a torch with its hose on regulators or cylinder valves. The video shows how to set up your plant properly.







Flashback Arrestors

A flashback arrestor is a device in the welding plant that prevents the flame burning back to the gas cylinders and causing explosions ad fires. This is a safety device and all welding plants should have it fitted. The arrestors are fitted to the regulators and are able to be reseted after a flash back occurs.


Flashbacks are caused by:

• wrong gas sequence during start up
• insufficient purging of gases before use
• blocked,worn,undersized or overheated tips
• hoses run over a vehicle during welding
• incorrect gas pressures
• blocked or kinked hoses
• flame held too close to working surfaces
• inappropriate use of the welding equipment

Flashbacks happen very quickly so before you could turn the system off the flashback arrestor shuts the gases from flowing ans saves you and your system from damage. It is a must to be in every welding plant and is part of the health and safety rule for gas welding. The Videos below show a good understanding about flashbacks and how the flashback arrestors work.

Welding Flames

Neutral Flame


A neutral flame is used for most weldings. It has roughly equal amounts of oxygen and acetylene. It can be recognized by a light blue inner flame cone with a darker blue outer flame. The neutral flame takes its name from the fact that it produces very little or no chemical reaction in the molten metal. In fact, the neutral flame actually acts as a gas shield to protect the weld pool from chemical reactions with the atmosphere. This flame is used to weld Mild steel, stainless steel, copper and aluminum. 


Carburising Flame


The carburising flame has excess acetylene and are used for specific processes. This can be done by reducing the oxygen. It contains three distinct levels of color: a very light blue cone at the nozzle, surrounded by an envelope or feather of darker blue; both of those are surrounded by an outer envelope of even darker blue.It is used for welding high-carbon steel and other metals that do not readily absorb carbon.  It is also used for hard facing materials as stellilte and silver bronze. If used for normal welding it will leave a lot of caron on the weld resulting in a poor weld.


Oxidising Flame


Oxidising flame has excess oxygen.The flame is shorter and bluer than both the neutral and carburizing flames, and the inner cone is more pointed. The excess oxygen from this flame will combine with the metal and form oxides, which are brittle and weaken the weld and the metal. Because of its oxidizing properties it is seldom used to weld steel, but is sometimes used for copper-based and zinc-based metals, as well as cast iron and manganese. A slightly oxidizing flame is used in braze-welding and bronze-surfacing while a more strongly oxidizing flame is used in fusion welding certain brasses and bronzes.


The video shows different flames types.






References



http://en.wikipedia.org/wiki/Oxy-fuel_welding_and_cutting
http://www.welding-technology-machines.info/gas-welding-processes-and-equipments/oxygen-gas-cylinder.htm
http://www.airproducts.com/nr/rdonlyres/9d325c49-7c62-41e5-aa0b-8411db4d84f8/0/safetygram13.pdf
http://www.ccohs.ca/oshanswers/safety_haz/welding/storage.html
http://www.hse.gov.uk/pubns/indg297.pdf
http://www.commerce.wa.gov.au/worksafe/PDF/Guidance_notes/WSguidnote_flashback.pdf
http://www.weldreality.com/gasdata.ht

http://en.wikipedia.org/wiki/Oxy-fuel_welding_and_cutting#Types_of_flame