How to Repair "Spiderweb Cracks" on Polyurethane Bumpers

Although Urethane bumpers are quite rare on late-model vehicles, the need may arise for one to be repaired from time to time. This bumper belonged to a 1992 Chevrolet Camaro, and, as you can see, it has developed what we call “spiderweb cracks”. These cracks are the result of dirt and grime settling inside cracked paint and eating away at the plastic over time. Let’s take a look at how to repair these cracks using products in Polyvance’s plastic repair line.
Chapters:
Intro: 0:00
Overview: 0:11
Sanding: 0:39
Grinding the shallow cracks: 1:06
V-grooving the deep cracks: 1:22
Weld with polyurethane welding rod: 1:35
Grind the weld: 2:01
Apply filler: 2:22
Sand the filler: 2:38
Prime, sand, repeat: 3:06
Final look: 3:26
Look below for links to some of the products from the video.
View this video on our website for more information and product suggestions for this repair: www.polyvance.com/video/therm...
5700HT Mini-Weld Model 7 Airless Plastic Welder: www.polyvance.com/Airless-Wel...
2000-T Flex Filler 2 Tube Kit: www.polyvance.com/Flex-Filler...
Waterborne Primers: www.polyvance.com/Waterborne-...
⚠️ Important ⚠️
- Always wear proper safety gear while working!
- The length of this video is in no way representative of the actual time required to perform a complete repair and therefore should not be used for estimating purposes.
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-Plastic welding rod: www.polyvance.com/Welding-Rod...

[@ikaros21]

Just what I need for my 1997 Pontiac trans Am. I will be doing this right after we go back to normal!

[@antonio_ws6]

Same here must be a major fbody problem lol

[@Reckless_In_Texas]

Yup, 2000 trans am with the same problem buuuuuut....My entire bumper is filled with them

[@polyvance]

Visit this video page on our website to see the full list of products used and other helpful tips: www.polyvance.com/video/thermoset-polyurethane-pur-repair/how-to-repair-spiderweb-cracks-on-polyurethane-bumpers

[@stevennewell5842]

Love the detail in the project No doubt that’s what separates a bad and a high quality finish !!!

[@mikejenkins18]

it does work awesome thanks for the great video

[@majesticpaint161]

thanks for the video I need this on a old 80s import I'm restoring.

[@danstein822]

cool very cool

[@RX7FDfreak]

Needed this for a 93 Rx-7

[@miles11we]

"36 grit" oh shit boys we goin hard

[@MrKiet76]

Now I know wht they charge so much to do my car! Very time consuming! I respect those that takes their time tho

[@JOEGGGJOE]

Great video. Just hope your not doing that whole bumper. Might be there for days, ha.

[@polyvance]

Haha, this bumper was definitely in pretty rough shape!

[@Andrii_Korobkov]

Hello . I'm in the Ukraine and did not have the opportunity to buy your rods, but you have a lot of experience in the repair of bumpers . I want to ask you for advice. Rods I buy in Poland they are high quality . When welding rod between the bumper and the bumper appears white coating and seam does not hold . This happens very often with PP- EPDM. I welding with air at a temperature of 570 - 700 F You are faced with such a problem ? What can be done ? I would be very grateful to you for the answer .

[@polyvance]

Thank you for watching! If you'd like, you can email [e-mail] for a more thorough answer to your question.

[@InvincibleMegaBeast]

Was wondering if it costs more to have a shop do this and repaint the bumper or just buy a brand new bumper or aftermarket bumper?

[@scottb7600]

It would be more expensive to buy a new bumper or have a shop do this for you. Another problem is, usually by the time the bumpers are old enough to spider crack, they are no longer available new unless you are lucky enough to own a car that is collectible and was made in high enough numbers for an aftermarket company to make replacements.

[@InvincibleMegaBeast]

Seems to be true. Thing is I have a 2015 vehicle and the front bumper on the wheel side had like 4-5 (about 3-5 inches long) crack paint and under the same side there are some crack paint there too. Looks like web crack paint and looks like a beast with sharp claws that scratch it. Think the previous owner used a ramp to get the car up and probably damage it. I don't want to get a new bumper, might have to get it repaint but maybe they might want to paint the whole bumper which will cost more.

[@scottb7600]

In 100% agreement with Kissalude. Cost of new plays a roll in the decision of making any repair. Generally cars with urethane bumpers tend to be higher end or older (pre-1990's) cars. Higher end cars tend to have expensive bumpers and older cars, don't generally have new replacements available.

[@brian8095]

Where the hell does someone buy "36" grit sandpaper?

[@polyvance]

Auto body supply stores should have it. A quick search also shows Lowes, Home Depot, Harbor Freight, and Amazon.

[@Cujucuyo]

Brian, how is Google still a foreign concept to you?!

[@miles11we]

Lol I remember the first time seeing (I think it was) 10 grit, fuckin big ass gravel glued to a fiber disk

[@DanoAuto1]

Seems like allot of labor and material cost when you can get a bumper cover in most cases under 500$ in mint condition with no possible material failures. Urethane plastic is tricky.

[@polyvance]

That may be the case if it is an aftermarket part. But with aftermarket parts, you have the risk of running into fitment issues. Then you would have to spend time and money having that fixed. Some people still don't think urethane is repairable. Urethane bumpers are more expensive than other bumpers.

[@scottb7600]

The trickiness comes because inexperienced or uninformed repair persons tend to overheat the base material and it decomposes. The resulting residue has virtually no adhesive properties. This mistake is easy to avoid and when repaired properly the strength is comparable to a new part. Why spend $500 to $3000 on a new bumper, when a repaired one is plenty strong, is much cheaper and doesn't have fitment issues? Not only that, but many urethane bumpers are no longer available, so you must repair them.

[@DanoAuto1]

I have repaired plenty with good results. It would have to be a crappy low rent shop to be able to fix something like that any less than 300$ time and materials. So instead of having possible failure cause NOTHING is guaranteed with this kind of repair. You can say what you want I have 5000 restorations under my belt with tons of plastic work. And 3k for a new pumper cover for what a newer super car that would not have those cracks from weathering anyway? It must be super rare or for a car no one desires so it was not remade.

[@DanoAuto1]

Say what you want I have lived it. I have fixed plenty with good results I would still rather spend more and get new. If you buy some Chinese parts like an idiot yea they will not fit but if you look and get a better product fitment is nothing a heat gun can not fix.

[@dsmchick935]

God that looks so hard so what about repairing fiberglass spider web cracks? It should be easier right just use fiberglass to repair it instead of plastic welding material

[@scottb7600]

You are correct.

[@mustangboss1246]

Lol I just grind out cracks then use filler to fill and flush lol

[@STARGAUD]

Cool, you can do it right or you can do it again.

[@reallifebartsimpson8829]

@@STARGAUD it works just fine as long as your not getting into any wrecks. Which at that point repairs would be needed anyway.

[@STARGAUD]

@@reallifebartsimpson8829 yeah probably easier. I’m about to attempt the weld. Filler is probably easier for those cracks.

[@Franc39A6DD]

Can we use a hot air gun with your PUR rods ?

[@scottb7600]

No. The problem is you would end up heating the substrate up to the point where it decomposes and would cause the bond to be very poor to nonexistent.

[@Franc39A6DD]

Scott B oh :-( Price of the kit airless for France 250€... It's way too much for me.