AFTER completing various sections of welding metal together, the next step is achieving a seamless finish.
Grinding Techniques advise that blending welds is the action of combining two metal pieces together through welding and the grinding down of the weld to produce no visible seam.
Before welding can commence, the workpiece needs to be cleaned to remove any rust or mill scale that has formed. For this application, the Superflex rough cleaning, or non-woven flap disc is ideal. Once the cleaning process is completed you can determine the type of weld that is required.
Two types of welds can be distinguished. MIG welding, also known as Gas Metal Arc Welding and TIG welding, known as Tungsten Inert Gas Welding. Where MIG welding is known to be a low cost yet highly productive method of welding, and mostly used on common metals like Carbon Steel and Alloys, TIG welding is a more precise form of welding and requires a bit more skill, as it results in a neater and smaller weld.
The choice of weld will be dependent on the required finish, which is determined by the original material of the workpiece. Carbon steel is almost always painted after welding, where Stainless steel usually requires a polished finish. If working on Carbon steel, not all welds need to be removed, as the seam will not always be visible. Stainless steel, like elevator panels, or handrails on the other hand requires a highly refined finish to disguise scratches.
When preparing to blend a weld, it is important to ensure that you are working with a clean, good weld, free from air bubbles or porosity. There should also be no undercut for example edges that doesn’t intrude or fold into the surface of the material.
The Superflex range consists of different product options when it comes to blending weld applications. Removing the weld can quickly be accomplished with our AS30R Professional grinding disc.
We recommend, a criss-cross motion to knock down the high spots when grinding, as you will remove stock quicker and easier without damaging the workpiece around the weld.
It is important to refrain from too much pressure when using a grinding disc, as you wouldn’t want to grind into the weld causing damage that could potentially weaken the weld leading to it needing to be redone. In some cases, a used grinding disc might offer the perfect solution, as it will be less aggressive on application. It is important to note that the final required blend will require further rework with a finer grit abrasive product after grinding.
If opting to use only one product, the Flap disc, is ideal to remove both the weld and produce the final blend.
As a third option to blend welds, Superflex Fibre Discs can be used. A P80 grit used at a really low grinding angle of about 45 degrees, will blend the weld perfectly. Once satisfied with the finish, you can use a finer grit fibre disc, either P120 or P150, to remove the scratch marks either . Take care not to use excessive pressure during this application.
The surface is now perfectly prepared for painting, however if a mirror finish is required, we suggest using a Superflex Non-woven Medium Flap disc followed by a Superflex Non-woven Fine Flap disc.
For further information contact +27 11 271 6400 Email: info@grindtech.com or visit: www.grindtech.com
