Repairing Urethane Bumper Covers with an Airless Plastic Welder


Looking at the back of this bumper cover,
we find the symbol “PUR.” Find the symbol on the label inside the plastic welder. For PUR, we need to use R01 rod. To keep the damage aligned while performing
the repair, use aluminum body tape. Aluminum body tape is stiff and can
withstand the heat from the repair process. Because thermoset urethane will not melt,
you will need to grind a v-groove along the crack line. Use a rotary tool with a teardrop shaped cutting
bit and grind about halfway through the plastic. Round off any sharp edges. This will help eliminate any stress risers
that may compromise the integrity of the repair. Set the temperature of the plastic
welder to match the selected rod. While holding the welder’s tip off of the surface,
melt the rod into the v-groove. Don’t overheat the base material. Simply melt the rod onto the surface. The repair on thermoset urethane is not a
true fusion weld, but more like a brazing process. The urethane rod should maintain its clear
appearance when melting without excessive smoke, discoloration, or bubbling. Allow the repair to cool before you begin
working on the opposite side. Peel off the tape that was
used to keep the crack aligned. As you did on the opposite side, v-groove
along the crack line with a rotary tool. Grind the area surrounding the
crack line to expose more plastic and round off any sharp edges
to eliminate stress risers. Apply melted rod into the crack and exposed plastic
the same way that you did on the opposite side. To reduce the chance of the repair failing, continue applying melted rod all the way around the edge. Even though the repair is not a true fusion
weld, it is still a very strong repair.

8 Comments

  1. Em` u September 27, 2018 at 7:14 am

    I have a cracked bumper and now i will try your version. Thanks you

  2. lutfi thepoet November 14, 2018 at 3:40 pm

    How to repair broken lock bumper?

  3. --cLAsic-- November 25, 2018 at 5:48 am

    24.3k views and only two people said thanks . i will be number 3 . Thank you .

  4. Sportysport December 7, 2018 at 12:54 am

    I guess using zip ties is out of the question.

  5. Polyvance. February 26, 2019 at 7:49 pm

    Visit this video page on our website to see the full list of products used and other helpful tips: https://www.polyvance.com/video/polyurethane-repair/repairing-urethane-bumper-covers-with-an-airless-plastic-welder

  6. RANDOM STUFF May 26, 2019 at 4:30 am

    Will be doing a neon srt4 with this process, thank you!

  7. JM_User July 7, 2019 at 1:11 am

    Do you remember the dremel bit name or number? Thanks

  8. karnal August 11, 2019 at 12:32 am

    Hi. I have repaired a PURIM bumper with the machine and with your instructions. I have several concerns:

    Does polyurethane welding maintain its properties over the years or will it come off in the future?

    Does polyurethane welding need some kind of internal reinforcement to help with the passage of time?

    thank you

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