Bumper Repair with Hot Air Plastic Welder

Bumper Repair with Hot Air Plastic Welder

This video will demonstrate how to weld plastic
using a hot air welder and standard welding rods. As with all plastic repairs, you will need
to clean the repair area with plastic cleaner. Put on a heavy wet coat and wipe the area
with a clean paper towel. Wipe in one direction to avoid
re-contaminating the surface. Use a DA sander with 80 grit sandpaper to
remove any coatings that are on the plastic. Remove the paint and any primer that may be
beneath the paint until you’ve exposed bare plastic. Remove paint on both sides of the
crack and along the crack line. After removing all the paint and exposed the bare plastic, blow the dust away with compressed air. Turn the bumper over and clean
the plastic with plastic cleaner. If there is any paint on the surface, you
will need to remove the paint with a DA sander. Align the damage and apply aluminum body tape. Aluminum body tape is very stiff and can withstand
the heat from the welding process. Use a body spreader on the tape to squeeze
out the air and maximize the adhesion of the tape. Leave an edge of the tape unstuck to ease removal. Apply tape along the entire crack and especially at the edge, as this is the most difficult part to keep aligned. Use a rotary tool with a teardrop shaped bit. Be sure to round off any sharp edges. From the back of this bumper, we find the symbol TPO. Look up the symbol in The Book of Plastic Repair that was included with your welder or on the Internet at polyvance.com. We will be using a TPO rod for this repair. Set the temperature of your welder to approximately
eight hundred thirty degrees Fahrenheit and wait for the welder to
achieve operating temperature. Heat the tip of the rod and the base material
with the welder until the rod melts together with the base material. Apply downward pressure on the rod as it is melting. The downward pressure will give the rod better
penetration into the base material. Continue melting the rod along the crack line
until the crack is completely filled. Allow time for the plastic to cool, then peel
the tape from the opposite side. Use a rotary tool with a teardrop shaped bit
to grind a v-groove along the crack line. Be sure to round off any sharp edges. Heat the tip of the rod and the base material
with the welder until the rod melts together with the base material. Apply downward pressure on the rod as it is melting. The downward pressure will give better rod
penetration into the base material. Continue melting the rod along the crack line
until the crack is completely filled. Use a rotary tool with a teardrop shaped cutting
bit to grind away excess plastic. Grind the plastic until it is slightly below
the level of the surrounding plastic. Use a DA sander and 80 grit sandpaper and
sand away the high spots and to abrade the surface. Abrading the surface will help the
epoxy filler bond better. Since this plastic is TPO, apply adhesion
promoter to any exposed plastic, so that the filler will have a better bond. Parts A and B must be mixed in equal
proportions to cure properly. Adding more Part A will not make it cure quicker. Use a body spreader to mix the two components. Continue mixing until there are no streaks
and you have a uniform color. Be careful not to mix air into the filler
as this will create pinholes in the epoxy. Apply the filler to the repair area and allow
time for the epoxy to cure fully. Even though the epoxy is sandable in about
20 minutes, it is not fully cured. Maximum adhesion is not achieved
until the epoxy is fully cured. Cure time can be reduced with the application of heat. Sand and contour the filler to match the profile
of the surrounding plastic and finish sanding with 180 grit sandpaper. Sand the area where primer will be
applied with 320 grit sandpaper. The tight spots may need to be sanded by hand. Blow the dust away with compressed
air or use a tack cloth. Paint will not stick well to TPO unless an
adhesion promoter is applied. Spray a light coat of adhesion promoter on
any exposed plastic and allow time for it to dry. Spray primer on any areas that will be top coated.

About the Author: Michael Flood


  1. I think it's important to note that while advertised as a tool for body work, this has plenty of other applications, considering how much stuff is made out of plastic.

  2. View this video on our website for more information about the products used for this repair and for some helpful tips! https://www.polyvance.com/video/nitrogen-hot-air-welding/bumper-repair-with-hot-air-plastic-welder

  3. Is this repair even worth it? Surely this costs more than a deductible? I just put my trailer hitch through my neighbors bumper, white car parked in the street during a blizzard…

  4. I like how he calls a heat gun a welder……. Clearly doesn't know anything about fabrication or any aspect of engineering…. 😂

  5. Its kinda cool I guess!! Definitely not worth the time if doing repairs at a shop! Bumper covers can be ordered to the door painted for about 350.00

  6. Flathead hot soldering iron from the back 2 mil deep and every 2mm apart continuously strait down the crack so it will look like stitch, nice and slow so the plastics all melts and bonds back together… lay mesh like chicken wire over the crack and melt with soldering iron into the bumper for reinforcing or lolly sticks and glass fiber…use soldering iron to butter away the fine hair line crack on the front sand the now minor repair, probably won’t even need filler and paint the whole bumper… much easier

  7. For the price of tools and materials you could just buy a new bumper and paint it. You already have to sand and paint it anyways.

  8. Great video brother! It's really incredible what you are able to do with plastic welders and a DA! It came out looking amazing! We just did a super similar video on a fiberglass bumper this week! Thanks for sharing your experience and keep em coming!

  9. This is awsome and all but with all the different chemicals we have today this job can be done in minutes with the right glue.

  10. One question why you didnt put aluminium onli from outside and put pis of plastic onli from behaind you vil save mony for paint

  11. I never figured it out,
    Why would car companies make ruber or plastic bumpers???
    Was metal ones not working?

  12. I blow torched a teaspoon until it was red hot,then touched the crack lightly until the crack melted together, started from the top then moved it to the bottom until the crack was gone and it bonded together,but it was for no reason because I used fiberglass afterwords and found that once you apply it on the bumper it's never comming apart unless you hit it again…. fiberglass is strong stuff ,,and probably all you need if applied right,,just clean the rip ,or cuts in the bumper then apply the fiberglass from the inside and out, then just sand it,,,,

  13. The video is great good job thank you interesting stuff. The gentleman that's doing the welding has a wedding ring on he should have his Jewelry off doing any kind of this work in the shop I know a couple people who have lost fingers due to having wedding bands and other Rings bracelets Etc I've had really bad situations so if you like your fingers I suggest you remove your wedding band. Best regards Chris

  14. I only watched untill you started grinding the plastic which you just cleaned in 1 direction to stop contamination……why clean an area with solvents and then grind it away right after the cleaning???? Am i missing a step here?

  15. I would say that bumper needs a buff and polish also before they even start thinking about grinding on it.

  16. Curious to know the cost differential between this and just replacing the bumper. This is a nice, professional job but it seems very labor intensive.

  17. so cool, you found way to fix $50-100 worth bumper using only $300+ worth of tools and supplies, and it only takes about a day of my time, worth mere $100. so cool

  18. 플라스틱 제작소
    경기도 남양주시 경강로 124번길 21 (이패동)
    모든 플라스틱용접 합니다.

  19. When i heat up my work piece that has a crack. It warps and recedes back making the gap larger.
    Any ideas.
    Its polypropylene

  20. Naaa!…i'll just use gorilla glue for now! Just too much work! And later buy the whole bumper! I'll leave that to the profesionals!

  21. It seems too costy to repair the bumper with so many different tools. I even need a wedding ring to make it work properly.

  22. Awesome video and thanks for making it . For anyone who is saying they will just buy a new bumper off eBay than do it. Guys in Alaska and Hawaii are limited and have high shipping prices .

  23. Ok so my polyvance plastic repair class instructor did it wrong,lol. He didn’t sand off the paint and he didn’t use the filler or adhesion promoter . Oopsy.🤭

    He did do a good job on the rest of it though.

  24. Namaste aur bataiye welding machine ko purchase karne ke liye Kaise Hum purchase kar sakte hain iska Koi contact number koi address location

  25. Perfect video, not all cars have Bumper replacement, there are cars with parts discontinued and the only way is fixing the broken plastic part, so this video is perfect for those that have cars with discontinued parts…

  26. Load of shit . Use super glue and bicarbonate soda. Itsetslije rockhard resin and sandable and shapes easy and can be painted

  27. A dude from Indonesia had a better solution for this, simplest, cheapest, out of the box and creative idea (whatever you named it) 🤓. Using some pieces of Instan noodle and super glue. Check this out 👉🏽.. https://youtu.be/2x29WoUdvq4

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