Repair Your Car’s Plastic Bumper with the Best Plastic Welder and These Caveats

If you have a car with dashboard cracks, a broken plastic bumper, or one of any number of other hard-to-find car components that are made of some type of plastic, then this recent Project Farm YouTube channel episode is a must-watch for the DIY mechanic that will open a world of possibilities of what you can (and should not) do toward repairing or restoring a car.

From Metal to Plastic

In an earlier article we learned that one of the banes of modern cars is the reliance of automotive manufacturers resorting to using plastic car parts to save money and lighten the weight of their automobiles.

Unfortunately, plastic parts can lead to engine damage as pointed out in some Toyota Tacoma models with this plastic part fatal flaw.

While I am not fond of jerry-rigging repairs, sometimes whether it’s because you can’t find the replacement part you need, the expense is too much, or you are on the road and in need of a quick fix, using a superglue-type of adhesive to take care of a broken plastic part---at least temporarily---is acceptable at times.

When Bumpers and Bodies Were Real and Steel

Back in the day when cars were made of steel, a dented bumper and body meant a trip to an autobody specialist and at least a few days of repair while the dent was hammered out, the body puttied, the bare metal primed (or chromed), and then finally painted with hopefully an identical and matching paint job.

Today, it’s a different story. Many bumpers are covers made of plastic and the problem is resolved by a shop tossing the old bumper and re-installing a new one. It’s not cheap and can cost over $1000, but it is effective and quick. In some cases, the shop may decide to “pop” the dent out hoping the paint isn’t too damaged, but then again this can still cost you a few to several hundred dollars.

Fortunately, in some cases, that bumper can be DIY repaired by following this Consumer Reports “Used Car DIY Fix for a Dented Bumper” article posted earlier.

But what if that damaged bumper is more of a crack or larger fracture and you want the least expensive option when it comes to a DIY repair aside from resorting to some mechanic-recommended automotive superglue?

Plastic Welders Review

Be aware, that there are expensive specialty plastic welding tools used by experienced welders that are typically the better option for automotive repairs involving plastic parts. However, they are beyond the scope of this article, which is more about affordable DIY plastic welding options for car repairs you can do at home in your garage or workshop.

One of the first things you need to understand is that automotive plastics designed to withstand high temperatures and chemical corrosion are not the same type of plastics used in other items that you normally repair around the house.

Some of the more common plastics you will find in cars include:

Polypropylene---a thermoplastic polymer that is easily manufactured into almost any shape. It is both chemical and heat resistant to a high degree (see what I did there) and is applicable toward high impact forces such as those experienced in car bumpers. It is also a good inexpensive plastic for vehicle carpet fibers.

Polyvinyl Chloride (PVC)—a malleable flame-retardant plastic that is often used in dashboards and automotive body parts.

Polycarbonate---is another impact resistant plastic used in not just bumpers but headlights as well. Another feature of this plastic is that it is lightweight and very resistant to 4-season weather conditions.

Acrylonitrile Butadiene Styrene (ABS)---is similar to PVC in that the final product offers a sleek finish and is typically used in steering wheel covers and dashboards. It also has the property of absorbing and redistributing the energy during an impact, offering the driver and passengers some protection during an accident.

In other words, not all crack fixatives or adhesives will work on all plastics, nor are all repair methods a solve-all solution.

To get a feel for why these differences are significant, watch the video posted below and note how some of the plastic “welders” do better than others depending not only on the application technique, but also in the type of plastic being tested.

Caveats to Plastic Repairs

While the video is informative, its limitation is that it is mostly a functional strength test plastic patch repair demonstration more than an actual plastic repair that is aesthetic and something to be proud of you may want done to your car. Still, if you have never done plastic repair on anything, it is a good starting point toward learning the proper way to approach a repair and whether you really want to resort to any of the affordable DIY tools reviewed.

That said, the other value of the video are the comments posted by viewers who have done plastic repairs, including some reputedly experienced within the industry who offer additional advice and tips on what it takes to make a plastic repair better. Such as:

• Heating the wire mesh into the plastic BEFORE adding the melted plastic/adhesive.
• Knowing what plastic type you are working with and why this matters.
• Applying a bevel or other channel-type to the joining edges of the plastic.
• Why heat is your best friend, but you have to treat it with respect…and practice.
• Plastic scrap sources around the house you can use to practice on before committing to a repair.
• Pretreatment of difficult plastics with chemicals, or heat, or abrasives to insure good plastic bonding.
• Instances in which plastic repair should not be done.
• If you want high-quality results, expect to have to buy pricier plastic welders.
• Techniques that come from experience.
• And more…

Number 1 Caveat Warning---Be sure to always, always, always wear a respirator when using any chemicals on plastic, especially when heat is being applied. It does not take much exposure to toxic vapors to ruin your health forever when working with plastics.

Final Caveat---While it might be tempting to just jump in and buy one of the reviewed products, the best approach is to do your research first. Pick a plastic project you want done, determine the plastic type, and then look for video demonstrations about the type of repair you want and how it was done. In addition, be sure to follow the comments because there is always someone out there with some added advice and tips to do it better. Once you have the info you need, then it’s time to get the tool(s) and start practicing on scrap plastics of the correct type before doing the actual repair. You will be glad you took the time to do it this way---guaranteed.

Bonus Video on How Plastic Bumper Repair is Done with Better Plastic Welding Tools

For additional articles related to car repairs, here are a few for your consideration:

• If Your Car Is Damaged in a Storm, Do This Not That When It Comes to Floods
• Easy Toyota RAV4 DIY Fix That Can Save You Hundreds of Dollars
• Clean the Inside of Your Car with a Leaf Blower Is a Bad Idea

Timothy Boyer is a Torque News automotive reporter based in Cincinnati. Experienced with early car restorations, he regularly restores older vehicles with engine modifications for improved performance. Follow Tim on Twitter at @TimBoyerWrites for daily news and topics related to new and used cars and trucks.

COMING UP NEXT: Top Ten Weirdest Cars from Ford and Why You Should Grab One Today

Image Source: Unsplash