Rust Scale removal by chipping, hammering, scaling and painting constitute the major portion of hull maintenance and requires labour and costs. It is important to do chipping properly not to allow rust again in the place where chipping was carried out once.
It is better not to remove rust than chipping halfway through
What is Chipping?
The removal of weld spatter, rust, or old paint from ironwork using a hammer and cold chisel is called chipping.
Chipping Tools
Air Hammer
Air Disc Sander
Air Chisel (Jet needle chisel type)
Chipping hammer
Scraper
Wire Brush
Precautions before chipping
- Has the Pre-meeting or Toolbox meeting carried out?
- Is proper Personal Protective Equipment worn by the seaman?
- Are the instruments, tools, and hoses being used not damaged?
- Do the tools function properly?
- Is the surface washed with fresh water and then sufficiently dried?
- Salt, in particular, contributes to the peeling of paintwork. Once the flaking of paint stats, it is troublesome to restore the situation. It is ideal to wash with fresh water pressurized to 50-100 kg/cm2 if such a facility is furnished onboard.
- Are proper scaffoldings and lighting provided?
Precautions during chipping
- Consideration should be given so that the same person may not use the same instrument for a long time, e.g. one should take different postures by shifting in sequence from one type of job to another e.g. use of an air hammer, sweeping of the place where chipping was carried out and the use of an air sander.
- A sufficient distance from other workers should always be maintained, and no work should be done in the direction where rust particles may fly.
- Never forget lubricating air-driven tools. It advertises itself by heating immediately when it runs short of oil.
- The paper for the disk sander should be replaced after disconnecting the universal coupling as a safety precaution.
- Small rust scale should be removed by using a disc sander or cupped wire brush. The surface must not be damaged by using an air hammer unnecessarily.
Precautions after chipping
- The adjoining area which was sanded with a disc sander should be cleaned thoroughly of iron powder which will adhere to it and turn it to rust red with the lapse of time.
- The steel section damaged by chipping tends to rust very easily, compatible painting should be applied with sufficient coats and thickness.
- Lubricate the working parts by supplying a few drops of oil to pneumatic tools.
*Places where small rust has begun to form because of a thin coat (insufficient thickness), should be re-coated rather than scaling to a film thickness of at least 350 microns.
On Tanker ships, the process of chipping as mentioned in company’s SMS may require a Cold Work and/or a Hot Work Permit.
Personal Protective Equipment
Excellent personal protective equipment is available abundantly but still, there are many cases of mishaps, surveys have revealed that many injuries are attributable to not using the protectors.
Chipping Goggles
Especially for chipping tasks, it is very important to protect your eyes. In working under the scorching sun, the lens of goggles tends to get blurred due to sweat. Even “anti-dim’ processing is not helpful in this matter. The accident often occurs that iron rust sticks an eye of the worker who wears sunglasses instead of goggles to prevent blurring due to sweat. Flying of iron chips in using a disc sander is very dangerous. They may not directly attack the user but may come in the eye of another worker even when he is wearing goggles. A person in charge must give advice about the procedure of the work, checking the condition of the entire workplace.
It is important to make it a rule to ‘correctly wear complete protectors’
• Prepare an eye wash with 1% to 2% boric acid solution so that the workers can wash their eyes at any time.
• When the foreign matter comes into seaman’s eye, do not rub the eye but wash it. Rubbing the eye does not remove the foreign matter at all.
• If the injury is slight, blink your eye in water and use eye ointment.
Dust mask
General gauze mask is used for a hygienic purpose and not for dust Prevention. To work in a highly dusty place, you shall wear a dust mask. Fine particles of 0.1 to 5 micron in size are dangerous to human lungs. 10 micron or larger particle hardly come in our lung and therefore is not so problematic. Gauze mask is sufficient when air hammer or air chisel (multi-needle) type is used.
Earplugs
There are two types of earplugs for noise prevention while working:
- to cut low and high frequencies of noise
- to cut only high-frequency noise while allowing the low frequency to pass through
For deck department jobs, chipping work needs earplugs. Various earplugs are available which differ in material and shape. Use one which fits your cars. Especially when air hammer is used to emit high noise, wearing both earplug and earmuff is highly effective with it.
Vibration-Proofing Gloves
When a device which strongly vibrates is being used, such as air hammer, wearing vibration-proofing gloves is very effective. However, most important thing is that you do not use such device for a long time.
Keep things in order
Keeping workplaces and tool stores in order is important not only for increasing work efficiency but also for preventing accidents. Arrangements shall be done by responsible personnel but keeping in order is very important and shall be done by all workers.
- Put tools in specified places so that they can easily be taken out.
- Protectors and detectors shall be stored so that they can rapidly be used on an emergency.
- Unnecessary facilities shall be removed, unnecessary goods be early disposed of.
what is the extent of hearing damage that could have been done when using the needle chipping guns with out any protection for ears or or the dust from doing this in the Navy it the late 60’s
is it safe to use sunglasses while chipping
No. You may see some bosun or AB getting too sweaty and take off their goggles for sunglasses/common glasses but don’t follow them. Even with a very tight goggles, I got rust in my eyes when I first did the sanderling and so did my fellow OS. Getting dust in your eyes is very uncomfortable and dangerous too. If you are used to working you will see, there are times when you work under 45 celcius degree with old T-shirt wrapped all your face and good goggles won’t cause you so much more trouble.
where in perth can I buy a scraper?