In this video we will show you how to repair one of the "slot tabs" that are very common on bumpers. These are the rectangular slots on the edge that snap into the brackets on fenders and quarter panels. Often, these can break when
you're removing the bumper. They are hard to repair using two-part adhesives
since they present so little surface area 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. We will repair both using different techniques. First, cut out the bar going across,
even if it's only broken in one place. The repair will be stronger if you cut the bar out. For straight flanges, you can use a piece
of narrow ribbon that you have cut down 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 welding rod as you make your pass over the gap. Here, we'll 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. This will help to mold it to the
same thickness as the flange. Press gently for a few seconds. This tool will help to cool the weld so you
can handle it right away. Remove the backing support. It is very important to get the dimensions
of the slot and the flange thickness the same. You can use a razor knife to trim the edge, and you can use the hot airless welder
to shape the slot and smooth it out. Look at the backside of the flange where you should
still be able to see the original dimensions of the slot. 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. This time we'll use the 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. We'll focus a little more heat on the rod instead
of the bumper, since the bumper is so thin here. Go right across the bottom of the bar
you welded from the other side. This will help lock the repair
into the bumper even more strongly. When you finish the weld, smooth
it out with the airless welding tip. Just a side 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. Now we'll repair a slot tab where the flange
follows the curvature of the slot. Here, we'll use the round rod since it can
make curves a lot easier than the ribbon can. V-groove into the plastic deeply with a sharp
carbide burr like our part number 6125. We'll want to make a deep v-groove right to
the edge of the slot. This is what gives us strength across the gap. Because we're not disrupting the original structure
of the rod, it maintains its original strength. Continue the v-groove on both sides of the slot. Remove the burrs and also remove the paint from the edges of the flange, so that the welding rod will stick to it. Support the melted welding rod by using our
6485 aluminum body tape on the back side. You can use a couple of layers of tape to
make the foundation stiffer. Using the round polypropylene rod,
pre-heat the bumper and the end of the rod. We will direct more heat onto the rod,
since the bumper is so thin here. Note that the angle of the torch
to the bumper is almost flat. Apply a steady downward pressure on the rod and it will fold down naturally as it reaches the right temperature. Weld right across the gap on the aluminum
tape, just as if you were welding to the bumper. Pick it up on the other side and continue
to weld all the way to the end. Reheat the rod until it turns translucent,
then lightly squeeze with the hand seamer to get the repair to the same thickness as the flange. Peel off the aluminum tape and then
use the hot welder tip, a razor knife, and a rotary tool as required to
reshape the slot and the flange. DA the plastic to get it to the final shape. Test the strength by pulling on the tab. A one-sided repair will have plenty of strength for this. The tab is not meant to be bent on its application. If desired, you can further strengthen the repair
by welding on the backside as we did previously. Make a second pass over the middle
of the slot if necessary to fill it out. You can smooth the plastic and shape the slot
with the airless welder tip. A final strength test, and you're ready to go.
