Whether it involves fabricating the massive external structure of a ship or installing important components inside, there are many critical welds in shipbuilding applications. Proper weld
preparation, cleaning and post-weld finishing play key roles in creating high-quality results. This is important to meet the stringent weld standards and tight timelines of shipbuilding.
Knowing how to select the right abrasive product for cutting and grinding operations – and following some common best practices – can help produce optimal results.
There are many handheld tool and product options for shipbuilding applications. However, it’s important to determine the best solution for the job to improve productivity, extend product life and increase cost savings. Pneumatic, cordless and electric right-angle grinders and die grinders are common choices for weld prep, cleaning and finishing.
Cutting and grinding work is frequently completed in confined and hard-to-reach spaces inside the ship because this is where the final assembly of many components and parts takes place. As a result, proper tool and product selection is especially crucial – it helps operators best reach the work, optimize efficiency and avoid wasting time.
Many key factors – from any space limitations where the work is being done to how far the operator must carry tools and equipment to the point of work – help in product selection.
First, it’s important to consider the base material when choosing cutting and grinding products. When working with aluminum, for example, be sure
to choose products specifically designed for that material. Using products designed for carbon steel can result in cross-contamination and loading. Abrasive products specifically designed for aluminum or stainless steel should not be used again if they have inadvertently been used on carbon steel.
The conditions and work environment are also important factors in choosing the right product. If it’s time consuming for the operator to get to the point of work – and if a confined space limits how many tools and abrasives they can carry – consider an alternative. A long-lasting product like a ceramic disc is a good option because it requires less frequent changeover. This helps save time and improve efficiency. In situations where the operator is trying to prolong battery life on cordless tools, a very thin cutting or grinding product is a good option. Consider a 1-mm-thick wheel to reduce strain on the tool.
Another factor to consider is the finish requirements of the part being fabricated. For example, parts for a commercial fishing vessel will have much different final requirements and specifications than parts for a military ship. Different abrasive products will result in different finishes and final look of the base material, so it’s important to understand these requirements.
Abrasives for shipbuilding
There are many abrasive product options for the weld preparation and cleaning jobs required in shipbuilding. Here are some of the most common types of products and the jobs they are
best suited for.
- Coated abrasives: Products in this category, which include flap discs and resin fiber discs, are often used for oxidation removal, blending, and grinding and finishing welds. For example, resin fiber discs can be used to remove excess material and get to bare metal. Benefits of coated abrasives include a fast cut rate and the ability to grind and finish in one step, which eliminates the need to switch out consumables.
- Bonded abrasives: Cutting discs and grinding wheels fall into this category. Grinding wheels are good for removing thicker mill scale during weld prep or for grinding down completed welds. Operators use cutting discs for many types of cutting jobs when preparing parts, plunge cutting and sizing workpieces.
- Power wire brushes: Available in many different configurations, such as end brushes, cup brushes and wheel brushes, power wire brushes are frequently used to remove the discoloring that forms on aluminum during welding. They can also be used to remove spatter between weld passes. Smaller sizes and styles of wire brushes are helpful for cleaning in corners or harder-to-reach spaces. Wire brushes provide efficient cleaning action and can deliver great productivity gains compared to some other products used for similar jobs, such as needle scalers.
Tips to success
Choosing the right abrasive product for the job is the first step toward optimized results. It’s also important to follow some common best practices for safe and effective use of those products. Here are three tips for getting the most from abrasive products.
First, stay focused on safety. No matter how challenging the environment or demanding the timeline, safety should never be an afterthought in cutting, grinding and finishing. Always use the tool guard and wear proper safety gear. Never run any consumable over the maximum rated rpm, and follow other recommended techniques for safe product usage. Knowing the proper angle, speed and pressure for safe and effective use of each type of abrasive reduces hazards to the operator. It also can help prolong product life and save time.
Next, match the product to the work. Abrasive products are not one size fits all, so the same accessory should not be used for every job. It may seem like a pain to carry more than one abrasive product – especially when the work is far from the power source or in a hard-to-reach space. But making sure each task has the best abrasive for that job can help ensure success and improve efficiency and operator safety.
Last, understand tool limitations. When using pneumatic tools for the job, be aware that the farther an operator stretches an airline from the compressor, the more the pressure will drop. This drop can result in pressure being too low to efficiently run the tool or abrasive.
To avoid this issue, try not to use extremely long air hoses or power cables for handheld electric or pneumatic tools. If this situation cannot be avoided, use a cutting disc or grinding wheel with a softer bond. These abrasives help optimize performance when a tool is underpowered. Be aware of the available pounds per square inch (psi) where the work will be performed in order to choose the right tools and abrasive products.
Metal preparation, cutting, grinding and finishing are critical steps in creating high-quality welds in shipbuilding applications. The shipbuilding environment is often challenging and the timelines demanding. Choosing the right abrasive product for the work lays the necessary foundation for optimizing performance and results. Careful consideration of product selection and key best practices can also help save money, improve efficiency and reduce safety risks to operators.