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> new (I think) bumper top fix
gereed75
post Aug 7 2014, 06:46 PM
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My front bumper top pad is pretty much a loss so thought I would try an idea for a fix that was floating around in my head. I have used this stuff on my boat and thought it had possibilities. It is super sticky adhesive, comes in black, and available at home depot maybe. If not I got this from Grainger.


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gereed75
post Aug 7 2014, 06:49 PM
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Here is the typical bumper pad "D Chunk" failure. I cleaned it up better than this with a SS brush and some acetone down to bare metal and "clean" rubber.


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gereed75
post Aug 7 2014, 06:59 PM
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I gooped on a healthy glob of the 5200, making sure I filed the cavity. I am not a "put on thin layers" kinda guy. It does have a tendency to sag, so I unbolted the bumper and set it on a bench oriented in such a way That gravity held it in place.

I don't have any pictures of the smoothing process because this stuff sticks to everything and I did not want to get my cell phone. It does wipe off when wet using lacquer thinner.

I used a soft flexible squeegee cut from a plastic binder cover. It will stick to that or any other squeegee I tried, so you must use a very very slow pulling action like spreading icing on a cake ---slow slow slow movement so it slowly spreads. If you go fast, you will just pull it out of the puddle.

I was able to get it fairly into the desired shape and let it dry. I came back a day later and the skin was dry but the inside was still soft. I was afraid that it had skin cured and would never dry inside. I waited a week. After that it was completely cured through!!! There was virtually no shrinkage.

This is what it looked like after about 5 minutes of sanding with 100 grit paper.

It sands slowly. You almost have to "worry" it off, but it does sand. The durometer feels almost exactly like the original and there is no adhesion break at the joint.

So far so good.


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gereed75
post Aug 7 2014, 07:10 PM
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Here it is after maybe 15 minutes more sanding with 200 grit. It does not wear out the paper!!

You can see how much I removed by the debris under the bumper.

Looking pretty good!


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gereed75
post Aug 7 2014, 07:12 PM
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I was able to go back and smooth some of the voids/low spots with a thin layer almost like red spot putty.


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gereed75
post Aug 7 2014, 07:21 PM
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The thin top fill layer dried in a day and had perfect adhesion to the under coat. Some more sanding with 200 grit along the entire pad to blend it. Again there was no evidence of bond failure anywhere, not even in a small tear that was on the bumper.

I also patched a small chunked out spot on the sharp upper corner of the pad. Worked like a champ!

Looks pretty good. There is a slight difference in the original surface texture that grabs the light at certain angles and I can see the fix because I know it is there. You would not notice it unless you looked very critically up close. Again the hardness is nearly identical to the original.

There is no doubt in my mind that this would work to "set" a new anchor stud into the bumper top on the bottom attach side. This stuff has super adhesion and I know it would hold a new stud in place inserted into a rusted out cavity. Nice!!! (IMG:style_emoticons/default/piratenanner.gif)


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76-914
post Aug 7 2014, 07:26 PM
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Cool. I hope this works and that it ISN'T like spot putty. That red spot putty (IMG:style_emoticons/default/stromberg.gif) will come back and bite you in the ass. Nice approach. Do you think one could insert a hold down stud (like OEM) in this material with success?
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gereed75
post Aug 7 2014, 07:28 PM
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Another "done" pix. Not sure how it will wear but this stuff is unaffected by years of exposure on boats. Wonder how it will look after application of some of the popular rubber preservatives like Armorall??



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saigon71
post Aug 7 2014, 07:39 PM
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Looks good! (IMG:style_emoticons/default/beerchug.gif)



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Porschef
post Aug 7 2014, 08:10 PM
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5200 takes a week to cure fully, no problem there. It is incredibly tenacious once set, and wood will tear/separate before the joint when cured. Awesome stuff, plan on using the tube completely within a few days otherwise it's toast. As any urethane, it cures in the presence of moisture, and just loves sticking to your hands for a few days. Ain't gonna get near the wife like that. Use gloves.

I also used sandpaper on my front bumper top as it had something on it that wouldn't respond to any thinner or solvent. Started with 150 and worked my way up to 320. I'd go to 400. Followed that up with 3M 303.

Nice ingenuity. (IMG:style_emoticons/default/beer.gif)
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gereed75
post Aug 7 2014, 08:24 PM
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QUOTE(Porschef @ Aug 7 2014, 10:10 PM) *

5200 takes a week to cure fully, no problem there. It is incredibly tenacious once set, and wood will tear/separate before the joint when cured. Awesome stuff, plan on using the tube completely within a few days otherwise it's toast. As any urethane, it cures in the presence of moisture, and just loves sticking to your hands for a few days. Ain't gonna get near the wife like that. Use gloves.

I also used sandpaper on my front bumper top as it had something on it that wouldn't respond to any thinner or solvent. Started with 150 and worked my way up to 320. I'd go to 400. Followed that up with 3M 303.

Nice ingenuity. (IMG:style_emoticons/default/beer.gif)

Nice tip on the 303. Thanks
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euro911
post Aug 7 2014, 08:25 PM
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Awesome. There's a little chunk out of my rear bumper rubber, about the size and location as the one you repaired.

Thanks for sharing (IMG:style_emoticons/default/aktion035.gif)
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Krieger
post Aug 7 2014, 08:26 PM
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That looks great. If you had a mold you could make yourself an entirely new bumper top...
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Krieger
post Aug 7 2014, 08:26 PM
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That looks great. If you had a mold you could make yourself an entirely new bumper top...
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