Surface World December 2018 Surface World Magazine December 2018 - Page 34

MASKING – TAPES, CAPS & PLUGS Masking Weld Nuts Weld nuts require additional care when painting and there are products available to help you quickly and accurately mask weld nuts. Weld nuts are common in many industries and are used where the main body of a part doesn’t have the thickness to support a threaded bolt. They are often used on frames and fabrications that need painting or surface finishing for corrosion resistance. As weld nuts are used where the assembly of parts is required, it is important that the threaded portion of the weld nut does not get coated with the rest of the part. There are numerous plugs available to mask threaded holes, but now there is a range of masking plugs available specifically designed for masking weld nuts. The weld nut plug (WNP) is inserted into the weld nut and pulled through from the back of the nut. A thin flange on the front of the plug collapses as the plug is pulled through the nut. This flange then springs back once it is through the threaded portion of the nut. There is a further thicker flanged area on the plug, which acts as a stop to ensure the plug cannot be pulled through the nut. This stop and collapsing flange arrangement ensures the plug is in the correct position for the finishing process. The weld nut plug features a chamfered end, to show which end of the plug should be inserted first. This chamfered end also makes it easier to install the plug. The other end of the plug is a T-shape, which speeds up the removal of the masks after the finishing process. For weld nuts that do not have a through hole behind them, there is the blind weld nut plug (BWNP). This plug pushes into the weld nut and masks the threaded portion of the weld nut. There is a thin flange on the front of the plug that collapses as the plug is inserted and springs back once the flange is through the threaded portion of the nut. This flange then helps retain the plug in the nut through the finishing process. the size of the weld nut they fit. If you need to mask weld nuts, a good masking supplier such as Caplugs or any of their distribution partners such as Greentree can provide samples of these weld nut masks for you to evaluate. John D. Gill John D. Gill is an Engineer with experience in masking and product protection throughout the UK, Europe and USA. He can be reached at www.johndgill.com and via Twitter @masking101 Weld nut plugs pull through weld nuts and mask the threaded portion of the weld nut. Both of these styles of plugs come in a range of sizes to suit metric weld nuts. The different sizes are colour coded to identify Blind weld nut plugs are ideal to mask weld nuts where there is no hole behind the weld nut. 32 DECEMBER 2018 read online: www.surfaceworld.com