How to Repair Broken Straight Flange Slot Tabs on Bumper Cover

This instruction will show you guide on how to repair slot tabs on bumpers. “Slot Tabs” are those rectangular slots on the edge that snap into the brackets on fenders and quarter panels. These can break easily when you are removing the bumper. However, they are hard to repair using two-part adhesives since they present so little surface to stick to.

There are many sizes and shapes of slot tabs, but two common styles are like this, one where the flange is straight


And one where the flange follows the contours of the slot


Here we will show you how to repair slot tabs where the flange is straight.

For the other shape slot tabs repairing , please refer to below article:

How to Repair Broken Slot Tabs with the Flange Follows the contours of Slot



First cut out the bar going across even if it’s only broken in one place


Cut down a piece of narrow ribbon to match the width of the bar


Using a die grinder or dremel tool taper the bumper down on either side of the slot at least three-quarters of an inch, the plastic should be very thin at the edge of the slot


Use aluminum tape or a paint paddle covered in aluminum tape to support the melted.

Use the tape-coated stick and clamp it to the flange


Starting on one side, begin the welding process by pre-heating the bumper and the rod for a few seconds. When you touch the rod down and it sticks, you’re ready to weld.

Focus the heat a little more on the rod than on the bumper, since the bumper is so thin here.

The rod should fold down naturally as it gets to the right temperature.


When you get to the gap, continue to weld directly across, just as if you were welding onto the bumper. The aluminum tape underneath will support the plastic.

Pick it up on the other side by again, pre-melting the bumper and continue welding until you reach the end.If the plastic is a little low in the middle, you can immediately come back and do a second pass.

Notice we’ll just weld across the gap and that we are focusing nearly all of the heat onto the rod, since the plastic we just laid down is already nearly melted.

While the plastic is hot, use the hand seamer tool to flatten the weld. Press gently for a few seconds.


This will help to mold it to the same thickness as the flange, and also help to cool the weld so you can handle it right away.

Use a razor knife to trim the edge, or use the hot airless welder to shape the slot and smooth it ou. It is very important to get the dimensions of the slot and flange thickness the same.


A one-sided repair should be plenty strong to hold the bumper in place, however, if you want to get the ultimate strength, repeat the same process on the bottom. V-groove into the bumper on either side of the slot and also across the bottom of the bar you just welded on.


Use a round rod to lock into the welding rod on the other side, pre-melt the bumper and the end of the rod. Touch the rod down and keep the heat focused at the point where the rod meets the bumper.


When you finish the weld, smooth it out with the airless welding tip.


Note be careful when you’re welding very thin plastics, the base material may lose its structure if it gets too hot. If that happens, just back off, let it cool a bit and then come back later.



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